HK1240070B - Powered ambulance cot with an automated cot control system - Google Patents

Description

Electric ambulance bed rest with automatic bed rest control system

Technical Field

The present invention relates generally to emergency patient transports and, more particularly, to an electric ambulance bed with an automatic bed control system.

Background Art

A variety of emergency patient transports are in use today. These emergency patient transports can be designed to transport and load bariatric patients into ambulances. For example, the bed manufactured by Ferno-Washington, Inc. of Wilmington, Ohio, USA, is a patient transport that is embodied as a manually actuated bed that can provide stability and support for a load of approximately 700 pounds (approximately 317.5 kg). The bed includes a patient support portion attached to a wheeled landing gear. The wheeled landing gear includes an X-frame geometry that can be transformed between nine optional positions. A recognized advantage of this bed design is that the X-frame can provide minimal flexure and a low center of gravity in all optional positions. Another recognized advantage of this bed design is that the optional positions can provide better leverage for manually lifting and loading bariatric patients.

Another example of an emergency patient transport designed for bariatric patients is the POWERFlexx+ electric recliner manufactured by Ferno-Washington, Inc. The POWERFlexx+ electric recliner includes a battery-powered actuator that can provide sufficient power to lift a load of approximately 700 pounds (approximately 317.5 kg). One recognized advantage of this recliner design is that the recliner can lift a bariatric patient from a low position to a higher position, i.e., the operator may need to lift the patient less frequently.

Another type of emergency patient transport is a multi-purpose roll-in emergency bed, which has a patient support stretcher that is removably attached to a wheeled landing gear or transport. When the patient support stretcher is removed from the transport for separate use, it can be moved horizontally around on a set of included wheels. A recognized advantage of this bed design is that the stretcher can be rolled separately into an emergency transport such as a van, truck, modular ambulance, airplane, or helicopter, where space and reduced weight are additional advantages. Another advantage of this bed design is that the separate stretcher can be more easily carried on uneven terrain and out of locations where the patient cannot be transported using a complete bed. Examples of these beds can be found in U.S. Patents No. 4,037,871, No. 4,921,295, and International Publication No. WO01701611.

While the aforementioned emergency patient transports are generally adequate for their intended use, they are not satisfactory in all respects. For example, the loading process of the aforementioned emergency patient transports into an ambulance requires at least one operator to support the bed's load during a portion of the loading process.

Summary of the Invention

The embodiments described herein relate to an electric ambulance cot with an automatic cot control system that provides improved versatility for a multi-use roll-in emergency cot design by providing improved management of cot weight, improved weight, and/or easier loading at any cot height while being rolled into various types of emergency transport vehicles such as ambulances, trucks, vans, aircraft, and helicopters.

These and other features provided by embodiments of the present invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of specific embodiments of the present invention may be best understood when taken in conjunction with the following drawings, in which like reference numerals designate like structures, and in which:

1 is a perspective view depicting a roll-in, self-actuating electric ambulance cot according to one or more embodiments described herein;

FIG2 is a top view depicting a roll-in, self-actuating electric ambulance cot according to one or more embodiments described herein and showing section line A-A;

3 is a side view depicting a roll-in, self-actuating electric ambulance cot according to one or more embodiments described herein;

4A-4C are side views depicting a raising and/or lowering sequence of a roll-in, self-actuating electric ambulance cot according to one or more embodiments described herein;

5A-5E are side views depicting a loading and/or unloading sequence of a roll-in, self-actuating electric ambulance cot according to one or more embodiments described herein;

FIG6 schematically depicts an actuator system for a roll-in, self-actuating electric ambulance cot according to one or more embodiments described herein;

6A-6D schematically depict a hydraulic circuit according to one or more embodiments described herein for use with a roll-in, self-actuating electric ambulance cot according to one or more embodiments described herein;

FIG7 schematically depicts a roll-in, self-actuating electric ambulance cot with an electric power system according to one or more embodiments described herein;

FIG8 schematically depicts a portion of a rear end of a roll-in, self-actuating electric ambulance cot according to one or more embodiments described herein, which has been cut away for ease of illustration;

FIG9 schematically depicts a rotating wheel assembly for use with a roll-in self-actuating electric ambulance bed according to one or more embodiments described herein;

FIG10 schematically depicts a rotating wheel assembly for use with a roll-in self-actuating electric ambulance bed according to one or more embodiments described herein;

FIG11 schematically depicts an upward escalator function for use with a roll-in self-actuating electric ambulance bed according to one or more embodiments described herein;

FIG12 schematically depicts a down-stairs escalator function for use with a roll-in self-actuating electric ambulance bed according to one or more embodiments described herein;

FIG13 schematically depicts a method for performing an escalator function for use with a roll-in, self-actuating electric ambulance bed according to one or more embodiments described herein;

FIG14A schematically depicts a perspective view of a roll-in, self-actuating, electric ambulance cot in a seated stowage or chair position according to one or more embodiments described herein;

14B schematically depicts a side view of a roll-in, self-actuating, electric ambulance cot in a seated stowage or chair position according to one or more embodiments described herein;

FIG15 schematically depicts a bed control system for use with a roll-in, self-actuating electric ambulance bed according to one or more embodiments described herein;

16 is a diagram illustrating communication messages sent by a motor controller of the bed control system of FIG. 15 according to one or more embodiments described herein;

17 is a diagram illustrating communication messages sent by the battery controller of the bed control system of FIG. 15 according to one or more embodiments described herein;

18 is a diagram illustrating communication messages sent by a graphical user interface controller of the bed control system of FIG. 15 according to one or more embodiments described herein;

FIG19 schematically depicts a motor controller of the bed control system of FIG15 according to one or more embodiments described herein;

FIG20 is a flowchart illustrating conditions automatically checked and operations automatically performed by the bed rest control system of FIG15 according to one or more embodiments described herein;

21 is a diagram illustrating input code signal correlation and motor state selection performed by the motor controller of the bed control system of FIG. 19 according to one or more embodiments described herein;

FIG22 schematically depicts a cross-sectional view taken along section line A-A in FIG3 of a pivot plate of a roll-in, self-actuating electric ambulance cot in a first position according to one or more embodiments described herein;

FIG23 schematically depicts a cross-sectional view of the pivot plate of the roll-in, self-actuating electric ambulance cot in a second position, taken along section line A-A in FIG3 , according to one or more embodiments described herein; and

24A-24D are drawings of graphical user interfaces, each showing an image representing a different selected operating mode of a roll-in, self-actuating electric ambulance cot.

The embodiments illustrated in the drawings are illustrative in nature and are not intended to limit the embodiments described herein. Furthermore, consideration of the detailed description will provide a more complete appreciation and understanding of the various features of the drawings and embodiments.

DETAILED DESCRIPTION

Referring to FIG. 1 , a roll-in, self-actuating, electric ambulance cot 10 is shown for transporting and loading a patient into an emergency transport. The cot 10 includes a support frame 12 having a front end 17 and a rear end 19. As used herein, the front end 17 is synonymous with the term "loading end," i.e., the end of the cot 10 that is first loaded onto a loading surface. Conversely, the rear end 19, as used herein, is the end of the cot 10 that is last loaded onto a loading surface and is synonymous with the term "control end," which is the end that provides multiple operator controls, as discussed herein. It should also be noted that when a patient is loaded on the cot 10, the patient's head can be oriented closest to the front end 17, and the patient's feet can be oriented closest to the rear end 19. Thus, the phrase "head end" can be used interchangeably with the phrase "front end," and the phrase "foot end" can be used interchangeably with the phrase "rear end." Furthermore, it should be noted that the phrases "front end" and "rear end" are interchangeable. Therefore, although these phrases are used consistently throughout for clarity, the embodiments described herein may be used interchangeably without departing from the scope of the invention. Generally speaking, as used herein, the term "patient" refers to any living or formerly living thing, such as, for example, a human, an animal, a cadaver, etc.

2 , front end 17 and/or rear end 19 can be retractable. In one embodiment, front end 17 can be extended and/or retracted (generally represented by arrow 217 in FIG. 2 ). In another embodiment, rear end 19 can be extended and/or retracted (generally represented by arrow 219 in FIG. 2 ). Thus, the overall length between front end 17 and rear end 19 can be increased and/or decreased to accommodate various patient sizes.

1 and 2 , the support frame 12 can include a pair of substantially parallel side members 15 extending between a front end 17 and a rear end 19. Various configurations of the side members 15 are contemplated. In one embodiment, the side members 15 can be a pair of spaced-apart metal rails. In another embodiment, the side members 15 include undercut portions 115 that can engage with accessory clamps (not depicted). These accessory clamps can be used to removably couple patient care accessories, such as IV poles, to the undercut portions 115. The undercut portions 115 can be provided along the entire length of the side members to allow accessories to be removably clamped to many different locations on the couch 10.

Referring again to FIG. 1 , the bed 10 also includes a pair of retractable and extendable loading-end legs 20 coupled to the support frame 12, and a pair of retractable and extendable control-end legs 40 coupled to the support frame 12. The bed 10 can comprise any rigid material, such as, for example, a metal structure or a composite structure. Specifically, the support frame 12, the loading-end legs 20, the control-end legs 40, or a combination thereof can comprise a carbon fiber and resin structure. As described in more detail herein, the bed 10 can be raised to a variety of heights by extending the loading-end legs 20 and/or the control-end legs 40, or lowered to a variety of heights by retracting the loading-end legs 20 and/or the control-end legs 40. It should be noted that terms such as "raised," "lowered," "above," "below," and "height" are used herein to refer to distance relationships between objects measured along a line parallel to gravity using a reference object (e.g., a surface supporting the bed).

In certain embodiments, the loading-end legs 20 and the control-end legs 40 can each be coupled to the side members 15. As shown in Figures 4A through 5E, the loading-end legs 20 and the control-end legs 40 can cross each other when the cot is viewed from the side (specifically, at the respective locations where the loading-end legs 20 and the control-end legs 40 are coupled to the support frame 12 (e.g., the side members 15 (Figures 1-3))). As shown in the embodiment of Figure 1, the control-end legs 40 can be positioned inboard of the loading-end legs 20, i.e., the loading-end legs 20 can be spaced farther apart from each other than the control-end legs 40, such that each control-end leg 40 is positioned between the loading-end legs 20. Furthermore, the loading-end legs 20 and the control-end legs 40 can include front wheels 26 and rear wheels 46 that enable the cot 10 to roll.

In one embodiment, the front wheels 26 and the rear wheels 46 can be swivel caster wheels or swivel locked wheels. When the couch 10 is raised and/or lowered, the front wheels 26 and the rear wheels 46 can be synchronized to ensure that the planes of the side members 15 of the couch 10 and the planes of the wheels 26, 46 are substantially parallel.

1-3 and 6 , the couch 10 may also include a couch actuation system 34 that includes a front actuator 16 configured to move the load-end legs 20 and a rear actuator 18 configured to move the control-end legs 40. The couch actuation system 34 may include a single unit (e.g., a centralized motor and pump) configured to control both the front actuator 16 and the rear actuator 18. For example, the couch actuation system 34 may include a housing having a single motor that is capable of driving the front actuator 16, the rear actuator 18, or both, using valves, control logic, and the like. Alternatively, as depicted in FIG1 , the couch actuation system 34 may include separate units configured to control the front actuator 16 and the rear actuator 18, respectively. In this embodiment, the front actuator 16 and the rear actuator 18 may each include separate housings having individual motors to drive each element in the front actuator 16 and the rear actuator 18 .

The front actuator 16 is coupled to the support frame 12 and configured to actuate the load-end legs 20 and raise and/or lower the front end 17 of the bed 10. Furthermore, the rear actuator 18 is coupled to the support frame 12 and configured to actuate the control-end legs 40 and raise and/or lower the rear end 19 of the bed 10. The bed 10 can be powered by any suitable power source. For example, the bed 10 can include a battery capable of supplying a voltage, such as approximately 24V nominal or approximately 32V nominal, for its power supply.

The front actuator 16 and the rear actuator 18 are operable to actuate the loading-end legs 20 and the control-end legs 40 simultaneously or independently. As shown in Figures 4A to 5E, simultaneous and/or independent actuation allows the sleeper 10 to be set to various heights. The actuators described herein may be capable of providing approximately 350 pounds (approximately 158.8 kg) of power and approximately 500 pounds (approximately 226.8 kg) of static force. Furthermore, the front actuator 16 and the rear actuator 18 may be operated by a centralized motor system or multiple independent motor systems.

In one embodiment schematically depicted in Figures 1 to 3 and 6, the front actuator 16 and the rear actuator 18 comprise hydraulic actuators for actuating the bed 10. In one embodiment, the front actuator 16 and the rear actuator 18 are dual piggy back hydraulic actuators, that is, the front actuator 16 and the rear actuator 18 each form a master-slave hydraulic circuit. The master-slave hydraulic circuit includes four hydraulic cylinders having four extension rods that are piggybacked (i.e., mechanically coupled) to each other in pairs. Thus, the dual piggy back actuator includes a first hydraulic cylinder having a first rod, a second hydraulic cylinder having a second rod, a third hydraulic cylinder having a third rod, and a fourth hydraulic cylinder having a fourth rod. It should be noted that although the embodiments described herein often refer to a master-slave system including four hydraulic cylinders, the master-slave system hydraulic circuit described herein can include any even number of hydraulic cylinders.

6 , the front actuator 16 and the rear actuator 18 each include a rigid support frame 180 that is substantially H-shaped (i.e., two vertical sections connected by a transverse section). The rigid support frame 180 includes a transverse member 182 that is coupled to the two vertical members 184 approximately midway between each of the two vertical members 184. The pump motor 160 and the fluid reservoir 162 are coupled to the transverse member 182 and are in fluid communication. In one embodiment, the pump motor 160 and the fluid reservoir 162 are positioned on opposite sides of the transverse member 182 (e.g., the fluid reservoir 162 is positioned above the pump motor 160). Specifically, the pump motor 160 may be a brushed, dual-rotation motor with a peak output of approximately 1400 watts. The rigid support frame 180 may include additional transverse members or backing plates to provide additional rigidity and resist twisting or lateral movement of the vertical members 184 relative to the transverse members 182 during actuation.

Each vertical member 184 includes a pair of piggyback hydraulic cylinders (i.e., a first hydraulic cylinder and a second hydraulic cylinder or a third hydraulic cylinder and a fourth hydraulic cylinder), wherein the rod of the first cylinder extends in a first direction and the rod of the second cylinder extends in a substantially opposite direction. When the cylinders are arranged in a master-slave configuration, one of the vertical members 184 includes an upper master cylinder 168 and a lower master cylinder 268. The other of the vertical members 184 includes an upper slave cylinder 169 and a lower slave cylinder 269. It should be noted that although the master cylinders 168, 268 are piggyback and extend the rods 165, 265 in substantially opposite directions, the master cylinders 168, 268 can be located in alternate vertical members 184 and/or extend the rods 165, 265 in substantially the same direction.

6A-6D , the cylinder housing 122 may include an upper cylinder 168 and a lower cylinder 268. The upper piston 164 may be confined within the upper cylinder 168 and configured to travel within the upper piston 164 when acted upon by hydraulic fluid. The upper rod 165 may be coupled to the upper piston 164 and move with the upper piston 164. The upper cylinder 168 may be in fluid communication with a rod-extend fluid path 312 and a rod-retract fluid path 322 on opposite sides of the upper piston 164. Thus, when a greater pressure is supplied to the hydraulic fluid via the rod-extend fluid path 312 than the rod-retract fluid path 322, the upper piston 164 may extend and may force fluid out of the upper piston 164 via the rod-retract fluid path 322. When the hydraulic fluid is supplied at a greater pressure via the rod-retract fluid path 322 than the rod-extend fluid path 312 , the upper piston 164 may retract and may force fluid out of the upper piston 164 via the rod-extend fluid path 312 .

Similarly, lower piston 264 can be confined within lower cylinder 268 and can be configured to travel within lower piston 264 when acted upon by hydraulic fluid. Lower rod 265 can be coupled to lower piston 264 and move with lower piston 264. Lower cylinder 268 can be in fluid communication with rod-extend fluid path 314 and rod-retract fluid path 324 on opposite sides of lower piston 264. Thus, when the pressure of hydraulic fluid supplied via rod-extend fluid path 314 is greater than the pressure of rod-retract fluid path 324, lower piston 264 can extend and can force fluid out of lower piston 264 via rod-retract fluid path 324. When the pressure of hydraulic fluid supplied via rod-retract fluid path 324 is greater than the pressure of rod-extend fluid path 314, lower piston 264 can retract and can force fluid out of lower piston 264 via rod-extend fluid path 314.

In some embodiments, the hydraulic actuator 120 actuates the upper rod 165 and the lower rod 265 in a self-balancing manner, thereby allowing the upper rod 165 and the lower rod 265 to extend and retract at different speeds. Applicants have discovered that when the upper rod 165 and the lower rod 265 are self-balancing, the hydraulic actuator 120 can extend and retract with greater reliability and speed. Without being bound by theory, it is believed that the differential speed of actuation of the upper rod 165 and the lower rod 265 allows the hydraulic actuator 120 to dynamically respond to a variety of loading conditions. For example, the rod extend fluid path 312 and the rod extend fluid path 314 can be in direct fluid communication with each other without any pressure regulating device disposed therebetween. Similarly, the rod retract fluid path 322 and the rod retract fluid path 324 can be in direct fluid communication with each other without any pressure regulating device disposed therebetween. Thus, when hydraulic fluid is simultaneously pushed through rod-extend fluid path 312 and rod-extend fluid path 314, upper rod 165 and lower rod 265 can be extended differentially based on the difference in resistance acting on each of upper rod 165 and lower rod 265, such as, for example, applied load, displacement volume, connecting rod motion, etc. Similarly, when hydraulic fluid is simultaneously pushed through rod-retract fluid path 322 and rod-retract fluid path 324, upper rod 165 and lower rod 265 can be retracted differentially based on the difference in resistance acting on each of upper rod 165 and lower rod 265.

Still referring to Figures 6A-6D, the hydraulic circuit housing 150 can form a hydraulic circuit 300 for transmitting fluid through an extend fluid path 310 and a retract fluid path 320. In some embodiments, the hydraulic circuit 300 can be configured such that, through selective operation of the pump motor 160, hydraulic fluid can be pushed or pulled in each of the extend fluid path 310 and the retract fluid path 320. Specifically, the pump motor 160 can be in fluid communication with the fluid reservoir 162 via a fluid supply path 304. The pump motor 160 can also be in fluid communication with the extend fluid path 310 via a pump extend fluid path 326, and with the retract fluid path 320 via a pump retract fluid path 316. Thus, the pump motor 160 can pull hydraulic fluid from the fluid reservoir 162 and push the hydraulic fluid through the pump extend fluid path 326 or the pump retract fluid path 316 to extend or retract the hydraulic actuator 120. It should be noted that while the embodiments of the hydraulic circuit 300 described herein with respect to Figures 6A to 6D specifically describe the use of certain types of components, such as solenoid valves, check valves, balancing valves, manual valves, or flow regulators, the embodiments described herein are not limited to the use of any particular components. In fact, the components described with respect to the hydraulic circuit 300 can be replaced with equivalent components that, in combination, perform the functions of the hydraulic circuit 300 described herein.

6A , pump motor 160 can push hydraulic fluid (generally indicated by arrows) along extend path 360 to extend upper rod 165 and lower rod 265. In some embodiments, extend fluid path 310 can be in fluid communication with rod extend fluid path 312 and rod extend fluid path 314. Retract fluid path 320 can be in fluid communication with rod retract fluid path 322 and rod retract fluid path 324. Pump motor 160 can pull hydraulic fluid from fluid reservoir 162 via fluid supply path. Hydraulic fluid can be pushed toward extend fluid path 310 via pump extend fluid path 326.

The pump extend fluid path 326 may include a check valve 332 configured to prevent hydraulic fluid from flowing from the extend fluid path 310 to the pump motor 160 and to allow hydraulic fluid to flow from the pump motor 160 to the extend fluid path 310. Thus, the pump motor 160 may force hydraulic fluid through the extend path into the rod extend fluid path 312 and the rod extend fluid path 314. The hydraulic fluid may flow along the extend path 360 into the upper cylinder 168 and the lower cylinder 268. When the upper rod 165 and the lower rod 265 are extended, the hydraulic fluid flowing into the upper cylinder 168 and the lower cylinder 268 may cause hydraulic fluid to flow into the rod retract fluid path 322 and the rod retract fluid path 324. The hydraulic fluid may then flow along the extend path 360 into the retract fluid path 320.

The hydraulic circuit 300 may further include an extend return fluid path 306 in fluid communication with each of the retract fluid path 320 and the fluid reservoir 162. In some embodiments, the extend return fluid path 306 may include a balancing valve 334 configured to allow hydraulic fluid to flow from the fluid reservoir 162 to the retract fluid path 320 and prevent hydraulic fluid from flowing from the retract fluid path 320 to the fluid reservoir 162 unless an appropriate pressure is received via a guide line 328. The guide line 328 may be in fluid communication with the pump extend fluid path 326 and the balancing valve 334. Thus, when the pump motor 160 pumps hydraulic fluid through the pump extend fluid path 326, the guide line 328 may cause the balancing valve 334 to modulate and allow hydraulic fluid to flow from the retract fluid path 320 to the fluid reservoir 162.

Optionally, extend-return fluid path 306 may include a check valve 346 configured to prevent hydraulic fluid from flowing from fluid reservoir 162 to retract fluid path 320 and to allow hydraulic fluid to flow from extend-return fluid path 306 to fluid reservoir 162. Thus, pump motor 160 may force hydraulic fluid through retract fluid path 320 to fluid reservoir 162. In some embodiments, a relatively large amount of pressure may be required to open check valve 332 compared to the relatively small amount of pressure required to open check valve 346. In other embodiments, the relatively large amount of pressure required to open check valve 332 may exceed approximately twice the relatively small amount of pressure required to open check valve 346, such as, for example, approximately three times or more of the pressure in another embodiment, or approximately five times or more of the pressure in yet another embodiment.

In some embodiments, the hydraulic circuit 300 may further include a regeneration fluid path 350 configured to allow hydraulic fluid to flow directly from the retraction fluid path 320 to the extension fluid path 310. Thus, the regeneration fluid path 350 can allow hydraulic fluid supplied from the rod retraction fluid path 322 and the rod retraction fluid path 324 to flow along a regeneration route 362 toward the rod extension fluid path 312 and the rod extension fluid path 314. In other embodiments, the regeneration fluid path 350 can include a logic valve 352 configured to selectively allow hydraulic fluid to flow along the regeneration route 362. The logic valve 352 can be communicatively coupled to a processor or sensor and configured to open when the bed is in a predetermined state. For example, the logic valve 352 can open when the hydraulic actuator 120 associated with the leg is in a second position relative to the first position (which, as described herein, can represent an unloaded state). Opening the logic valve 352 during extension of the hydraulic actuator 120 may be desirable to accelerate the extension process. Regeneration fluid path 350 may further include a check valve 354 configured to prevent hydraulic fluid from flowing from retraction fluid path 320 to extension fluid path 310. In some embodiments, the amount of pressure required to open check valve 332 is approximately the same as the amount of pressure required to open check valve 354.

6B , the pump motor 160 can push hydraulic fluid (generally indicated by arrows) along a retract path 364 to retract the upper rod 165 and the lower rod 265. The pump motor 160 can pull hydraulic fluid from the fluid reservoir 162 via the fluid supply path 304. The hydraulic fluid can be pushed toward the retract fluid path 320 via the pump retract fluid path 316. The pump retract fluid path 316 can include a check valve 330 that is configured to prevent hydraulic fluid from flowing from the retract fluid path 320 to the pump motor 160 and to allow hydraulic fluid to flow from the pump motor 160 to the retract fluid path 320. Thus, the pump motor 160 can push hydraulic fluid through the retract fluid path 320 into the rod retract fluid path 322 and the rod retract fluid path 324.

Hydraulic fluid can flow into the upper cylinder 168 and the lower cylinder 268 along the retract route 364. As the upper rod 165 and the lower rod 265 retract, the hydraulic fluid flowing into the upper cylinder 168 and the lower cylinder 268 can cause hydraulic fluid to flow into the rod extend fluid path 312 and the rod extend fluid path 314. The hydraulic fluid can then flow into the extend fluid path 310 along the retract route 364.

The hydraulic circuit 300 may further include a retract return fluid path 308 in fluid communication with each of the extend fluid path 310 and the fluid reservoir 162. In some embodiments, the retract return fluid path 308 may include a balancing valve 336 configured to allow hydraulic fluid to flow from the fluid reservoir 162 to the extend fluid path 310 and prevent hydraulic fluid from flowing from the extend fluid path 310 to the fluid reservoir 162 unless an appropriate pressure is received via a guide line 318. The guide line 318 may be in fluid communication with the pump retract fluid path 316 and the balancing valve 336. Thus, when the pump motor 160 pumps hydraulic fluid through the pump retract fluid path 316, the guide line 318 may cause the balancing valve 336 to modulate and allow hydraulic fluid to flow from the extend fluid path 310 to the fluid reservoir 162.

6A-6D , while the hydraulic actuator 120 is typically powered by the pump motor 160, it can also be manually actuated after bypassing the pump motor 160. Specifically, the hydraulic circuit 300 may include a manual supply fluid path 370, a manual retract return fluid path 372, and a manual extend return fluid path 374. The manual supply fluid path 370 may be configured to supply fluid to the upper cylinder 168 and the lower cylinder 268. In some embodiments, the manual supply fluid path 370 may be in fluid communication with the fluid reservoir 162 and the extend fluid path 310. In other embodiments, the manual supply fluid path 370 may include a check valve 348 configured to prevent hydraulic fluid from flowing from the manual supply fluid path 370 to the fluid reservoir 162 and to allow hydraulic fluid from the fluid reservoir 162 to flow to the extend fluid path 310. Thus, manual manipulation of the upper piston 164 and the lower piston 264 may cause hydraulic fluid to flow through the check valve 348. In some embodiments, a relatively small amount of pressure may be required to open check valve 348 compared to the relatively large amount of pressure required to open check valve 346. In other embodiments, the relatively small amount of pressure required to open check valve 348 may be less than or equal to approximately 1/2 of the relatively large amount of pressure required to open check valve 346, such as, for example, less than or equal to approximately 1/5 in another embodiment, or less than or equal to approximately 1/10 in yet another embodiment.

The manual retract return fluid path 372 can be configured to return hydraulic fluid from the upper and lower cylinders 268 to the fluid reservoir 162, back to the upper and lower cylinders 168, 268, or in both directions. In some embodiments, the manual retract return fluid path 372 can be in fluid communication with the extend fluid path 310 and the extend return fluid path 306. The manual retract return fluid path 372 can include a manual valve 342 that can be actuated from a normally closed position to an open position, and a flow regulator 344 that is configured to limit the amount of hydraulic fluid that can flow through the manual retract return fluid path 372, i.e., the volume per unit time. Thus, the flow regulator 344 can be used to provide controlled lowering of the couch 10. It should be noted that although the flow regulator 344 is depicted in Figures 12A to 12D as being located between the manual valve 342 and the extension fluid path 310, the flow regulator 344 can be located in any position in the hydraulic circuit 300 suitable for limiting the retraction speed of the upper rod 165, the lower rod 265, or both elements.

The manual extend return fluid path 374 can be configured to return hydraulic fluid from the upper cylinder 168 and the lower cylinder 268 to the fluid reservoir 162, back to the upper cylinder 168 and the lower cylinder 268, or in both directions. In some embodiments, the manual extend return fluid path 374 can be in fluid communication with the retract fluid path 320, the manual retract return fluid path 372, and the extend return fluid path 306. The manual extend return fluid path 374 can include a manual valve 343 that can be actuated from a normally closed position to an open position.

In some embodiments, the hydraulic circuit 300 may further include a manual release assembly (e.g., a button, tension member, switch, linkage, or pull rod) that actuates manual valves 342 and 343 to allow the upper and lower rods 165, 265 to extend and retract without using the pump motor 160. Referring to the embodiment of FIG. 6C, the manual valves 342 and 343 may be opened, for example, via the manual release assembly. A force may act on the hydraulic circuit 300 to extend the upper and lower rods 165, 265, such as, for example, gravity or manual articulation of the upper and lower rods 165, 265. With the manual valves 342 and 343 open, hydraulic fluid may flow along the manual extension route 366 to facilitate extension of the upper and lower rods 165, 265. Specifically, when upper rod 165 and lower rod 265 extend, hydraulic fluid can move from upper cylinder 168 and lower cylinder 268 into rod retract fluid path 322 and rod retract fluid path 324. Hydraulic fluid can travel from rod retract fluid path 322 and rod retract fluid path 324 into retract fluid path 320.

Hydraulic fluid can also travel toward extend return fluid path 306 and manual retract return fluid path 372 via manual extend return fluid path 374. Depending on the speed or force applied to extend upper and lower rods 165 and 265, hydraulic fluid can flow through extend return fluid path 306, past check valve 346, and into fluid reservoir 162. Hydraulic fluid can also flow toward extend fluid path 310 via manual retract return fluid path 372. Hydraulic fluid can also be supplied from fluid reservoir 162 to extend fluid path 310 via manual supply fluid path 370, i.e., when manual operation generates sufficient pressure to cause hydraulic fluid to flow through check valve 348. Hydraulic fluid at extend fluid path 310 can flow to rod extend fluid path 312 and rod extend fluid path 314. Manual extension of upper and lower rods 165 and 265 can cause hydraulic fluid from rod extend fluid path 312 and rod extend fluid path 314 to flow into upper and lower cylinders 168 and 268.

6D , when manual valves 342 and 343 are open, hydraulic fluid can flow along manual retract path 368 to facilitate retracting upper rod 165 and lower rod 265. Specifically, when upper rod 165 and lower rod 265 are retracted, hydraulic fluid can move from upper cylinder 168 and lower cylinder 268 into rod extend fluid path 312 and rod extend fluid path 314. Hydraulic fluid can travel from rod extend fluid path 312 and rod extend fluid path 314 into extend fluid path 310.

Hydraulic fluid can also travel through the manual retract return fluid path 372 toward the flow regulator 344, which operates to limit the flow rate of the hydraulic fluid and the retraction speed of the upper and lower rods 165, 265. The hydraulic fluid can then flow toward the manual extend return fluid path 374. The hydraulic fluid can then flow through the manual extend return fluid path 374 into the retract fluid path 320. Depending on the retraction speed of the upper and lower rods 165, 265 and the permissible flow rate of the flow regulator 344, some hydraulic fluid may leak past the check valve 346 into the fluid reservoir 162. In some embodiments, the permissible flow rate of the flow regulator 344 and the opening pressure of the check valve 346 can be configured to substantially prevent hydraulic fluid from flowing through the check valve 346 during manual retraction. Applicants have discovered that by prohibiting flow through the check valve 346, the upper and lower cylinders 168, 268 can be ensured to remain primed at all times, and air penetration during manual retraction can be reduced.

Hydraulic fluid in the retraction fluid path 320 can flow to the rod retraction fluid path 322 and the rod retraction fluid path 324. Manual retraction of the upper rod 165 and the lower rod 265 can cause hydraulic fluid from the rod retraction fluid path 322 and the rod retraction fluid path 324 to flow into the upper cylinder 168 and the lower cylinder 268. It should be noted that although the manual embodiment described with respect to Figures 6C and 6D depicts extension and retraction as separate operations, it is contemplated that manual extension and manual retraction can be performed within a single operation. For example, after opening manual valves 342 and 343, the upper rod 165 and the lower rod 265 can extend, retract, or perform both actions sequentially in response to an applied force.

Referring again to Figures 1 and 2, to determine whether the couch 10 is level, sensors (not depicted) can be used to measure distance and/or angle. For example, the front actuator 16 and the rear actuator 18 can each include an encoder that determines the length of each actuator. In one embodiment, the encoder is a real-time encoder that is operable to detect movement of the total length of the actuator or changes in the length of the actuator while the couch is powered or unpowered (i.e., manually controlled). While various encoders are contemplated, in one commercial embodiment, the encoder can be an optical encoder manufactured by Midwest Motion Products, Inc. of Watertown, MN, U.S.A. In other embodiments, the couch includes an angle sensor that measures actual angle or change in angle, such as, for example, a potentiometer rotation sensor, a Hall effect rotation sensor, or the like. The angle sensor can be operable to detect the angle of any pivotally coupled portion of the load-end leg 20 and/or the control-end leg 40. In one embodiment, an angle sensor is operably coupled to the loading-end leg 20 and the control-end leg 40 to detect a difference (angle Δ) between the angle of the loading-end leg 20 and the angle of the control-end leg 40. The loaded state angle can be set to an angle, such as approximately 20°, or any other angle generally indicating that the couchette 10 is in a loaded state (indicating loading and/or unloading). Thus, when the angle Δ exceeds the loaded state angle, the couchette 10 can detect that it is in a loaded state and perform certain actions based on being in the loaded state.

7 , in one embodiment, the control cartridge 50 is communicatively coupled (generally represented by lines marked with arrows) to one or more processors 100. Each of the one or more processors 100 can be any device capable of executing machine-readable instructions, such as, for example, a controller, an integrated circuit, a microchip, etc. As used herein, the term “communicatively coupled” means that the components are capable of exchanging data signals with each other, such as, for example, exchanging electrical signals via a conductive medium, exchanging electromagnetic signals via air, exchanging optical signals via optical waveguides, etc.

The one or more processors 100 may be communicatively coupled to one or more memory modules 102, which may be any device capable of storing machine-readable instructions. The one or more memory modules 102 may include any type of memory, such as, for example, read-only memory (ROM), random access memory (RAM), secondary storage (e.g., a hard drive), or a combination thereof. Suitable examples of ROM include, but are not limited to, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), electrically alterable read-only memory (EAROM), flash memory, or a combination thereof. Suitable examples of RAM include, but are not limited to, static RAM (SRAM) or dynamic RAM (DRAM).

The embodiments described herein can automatically implement the methods by executing machine-readable instructions with one or more processors 100. The machine-readable instructions can include logic or algorithms written in any programming language of any generation (e.g., 1GL, 2GL, 3GL, 4GL, or 5GL), such as, for example, machine language that can be executed directly by a processor, or assembly language, object-oriented programming (OOP), scripting language, microcode, etc., which can be compiled or assembled into machine-readable instructions and stored. Alternatively, the machine-readable instructions can be written in a hardware description language (HDL), such as logic implemented via a field programmable gate array (FPGA) configuration or an application-specific integrated circuit (ASIC) or its equivalent. Therefore, the methods described herein can be implemented in any conventional computer programming language, implemented as pre-programmed hardware elements, or implemented as a combination of hardware and software components.

2 and 7 , the front actuator sensor 62 and the rear actuator sensor 64 are configured to detect whether the front actuator 16 and the rear actuator 18, respectively, are in a first position, the first position positioning each actuator relatively closer to a bottom surface of a corresponding one of a pair of cross members 63, 65 ( FIG. 2 ), or a second position positioning each actuator further from the corresponding one of the cross members 63, 65 relative to the first position, and transmit the detection to the one or more processors 100. In one embodiment, the front actuator sensor 62 and the rear actuator sensor 64 are coupled to a corresponding one of the cross members 63, 65; however, other positions or configurations on the support frame 12 are contemplated herein. The sensors 62, 64 can be distance measuring sensors, string encoders, potentiometer rotation sensors, proximity sensors, Reed switches, Hall effect sensors, combinations thereof, or any other suitable sensors operable to detect when the front actuator 16 and/or rear actuator 18 are in and/or pass through the first position and/or second position. In further embodiments, other sensors can be used with the front and rear actuators 16, 18 and/or cross members 63, 65 to detect the weight of a patient positioned on the bed 10 (e.g., via strain gauges). It should be noted that the term "sensor," as used herein, means a device that measures a physical quantity, state, or property and converts it into a signal related to the measured value of the physical quantity, state, or property. Additionally, the term "signal" means an electrical, magnetic, or optical waveform capable of being transmitted from one location to another, such as current, voltage, luminous flux, DC, AC, sine wave, triangle wave, square wave, etc.

Referring to FIG3 and FIG7 simultaneously, the sleeper 10 may include a front angle sensor 66 and a rear angle sensor 68, which are communicatively coupled to one or more processors 100. The front angle sensor 66 and the rear angle sensor 68 may be any sensor that measures an actual angle or a change in angle, such as, for example, a potentiometer rotation sensor, a Hall effect rotation sensor, or the like. The front angle sensor 66 may be operable to detect a front angle _αf of the pivotal connection of the loading-end leg 20. The rear angle sensor 68 may be operable to detect a rear angle _αb of the pivotal connection of the control-end leg 40. In one embodiment, the front angle sensor 66 and the rear angle sensor 68 are operably coupled to the loading-end leg 20 and the control-end leg 40, respectively. Thus, the one or more processors 100 may execute machine-readable instructions to determine the difference (angle Δ) between the front angle _αf and the rear angle _αb . The loaded state angle may be set to, for example, approximately 20° or any other angle generally indicating that the sleeper 10 is in a loaded state (representing loading and/or unloading). Thus, when the angle Δ exceeds the loaded state angle, the sleeper 10 can detect that it is in a loaded state and perform certain actions based on being in this loaded state. Alternatively, distance sensors can be used to perform angular measurements similar to those used to determine the front angle _αf and the rear angle _αb . For example, the angles can be determined from the positioning of the loading-end legs 20 and/or the control-end legs 40 relative to the side members 15. For example, the distance between the loading-end legs 20 and a reference point along the side members 15 can be measured. Similarly, the distance between the control-end legs 40 and a reference point along the side members 15 can be measured. Additionally, the distances between the front actuator 16 and the rear actuator 18 can be measured. Thus, any of the distance measurements or angle measurements described herein can be used interchangeably to determine the positioning of components of the sleeper 10.

Furthermore, it should be noted that the distance sensor can be coupled to any portion of the bed 10 such that the distance between the lower surface and components such as, for example: the front end 17, the rear end 19, the front loading wheel 70, the front wheel 26, the middle loading wheel 30, the rear wheel 46, the front actuator 16, or the rear actuator 18 can be determined.

Referring to FIG3 and FIG7 simultaneously, the front end 17 may include a pair of front loading wheels 70 configured to assist in loading the cot 10 onto a loading surface (e.g., the floor of an ambulance). The cot 10 may include a loading-end sensor 76 communicatively coupled to the one or more processors 100. The loading-end sensor 76 is a distance sensor operable to detect the position of the front loading wheels 70 relative to the loading surface (e.g., the distance from the detected surface to the front loading wheels 70). Suitable distance sensors include, but are not limited to, ultrasonic sensors, touch sensors, proximity sensors, or any other sensor capable of detecting the distance to an object. In one embodiment, the loading-end sensor 76 is operable to directly or indirectly detect the distance from the front loading wheels 70 to a surface substantially directly below the front loading wheels 70. Specifically, the loading-end sensor 76 can provide an indication when a surface is within a definable distance range from the front loading wheels 70 (e.g., when the surface is greater than a first distance but less than a second distance), and is also referred to herein as the loading-end sensor 76 "seeing" the loading surface. Thus, the definable range can be set so that a positive indication is provided by the loading end sensor 76 when the front loading wheels 70 of the cot 10 contact the loading surface. Ensuring that both front loading wheels 70 are on the loading surface can be important, particularly in an environment where the cot 10 is loaded into the ambulance at an incline.

The loading-end leg 20 may include an intermediate loading wheel 30 attached to the loading-end leg 20. In one embodiment, the intermediate loading wheel 30 may be positioned on the loading-end leg 20 adjacent to the front crossbar 22 ( FIG. 2 ), with the front actuator 16 mounted to the lower end of the front crossbar ( FIG. 6 ). As shown in FIGS. 1 and 3 , the control-end leg 40 is not provided with any intermediate loading wheel adjacent to the rear crossbar 42, with the rear actuator 18 mounted to the lower end of the rear crossbar ( FIG. 6 ). The berth 10 may include an intermediate load sensor 77 communicatively coupled to the one or more processors 100. The intermediate load sensor 77 is a distance sensor operable to detect the distance between the intermediate loading wheel 30 and the loading surface 500. In one embodiment, the intermediate load sensor 77 may provide a signal to the one or more processors 100 when the intermediate loading wheel 30 is within a set distance of the loading surface. While the intermediate loading wheel 30 is depicted as being located solely on the loading-end leg 20, it is further contemplated that the intermediate loading wheel 30 may also be located on the control-end leg 40 or any other location on the couch 10, such that the intermediate loading wheel 30 cooperates with the front loading wheel 70 to facilitate loading and/or unloading (e.g., supporting the frame 12). For example, the intermediate loading wheel may be located at any location that is likely to be a fulcrum or center of balance during the loading and/or unloading processes described herein.

The sleeper 10 may include a rear actuator sensor 78 that is communicatively coupled to the one or more processors 100. The rear actuator sensor 78 is a distance sensor operable to detect the distance between the rear actuator 18 and a loading surface. In one embodiment, the rear actuator sensor 78 is operable to directly or indirectly detect the distance from the rear actuator 18 to a surface substantially directly beneath the rear actuator 18 when the control end legs 40 are substantially fully retracted (Figures 4, 5D, and 5E). Specifically, the rear actuator sensor 78 can provide an indication when the surface is within a definable distance range of the rear actuator 18 (e.g., when the surface is greater than a first distance but less than a second distance).

Still referring to Figures 3 and 7, the couch 10 may include a front driving light 86 communicatively coupled to the one or more processors 100. The front driving light 86 may be coupled to the front actuator 16 and configured to pivot therewith. Thus, when the couch 10 is rolled with the front actuator 16 extended, retracted, or any position therebetween, the front driving light 86 may illuminate the area directly in front of the front end 17 of the couch 10. The couch 10 may also include a rear driving light 88 communicatively coupled to the one or more processors 100. The rear driving light 88 may be coupled to the rear actuator 18 and configured to pivot therewith. Thus, when the couch 10 is rolled with the rear actuator 18 extended, retracted, or any position therebetween, the rear driving light 88 may illuminate the area directly behind the rear end 19 of the couch 10. The couch 10 may also include a pair of surround lights 89 communicatively coupled to the one or more processors 100. Each of the surround lights 89 can be coupled to a respective one of the pair of substantially parallel side members 15, thereby illuminating an area directly to the side of the couch 10. The one or more processors 100 can receive input from any of the operator controls described herein and cause the front driving lights 86, the rear driving lights 88, the surround lights 89, or any combination thereof to be activated.

In some embodiments, the front driving lights 86, rear driving lights 88, and surround lights 89 together define a safety lighting system for the bed 10. In this safety lighting system for the bed 10, the front driving lights 86, rear driving lights 88, and surround lights 89 turn on or off simultaneously and can be controlled by two buttons, such as two buttons arranged in the button array 52, each of which defines a different illumination mode. For example, one of the buttons in the button array 52, when pressed, can define a "scene" light mode, in which the front driving lights 86, rear driving lights 88, and surround lights 89 turn on/off, and in which the surround lights 89 illuminate a steady white light when on. Another button in the button array 52, when pressed, can define an "emergency" light mode, in which the front driving lights 86, rear driving lights 88, and surround lights 89 turn on/off, and in which the surround lights 89 illuminate a red-red-white light sequence when on.

1 and 7 , the couch 10 may include a line indicator 74 communicatively coupled to the one or more processors 100. The line indicator 74 may be any light source configured to project a linear indication on a surface, such as, for example, a laser, a light emitting diode, a projector, or the like. In one embodiment, the line indicator 74 may be coupled to the couch 10 and configured to project a line on a surface beneath the couch 10 such that the line is aligned with the intermediate loading wheel 30. The line may extend from a point beneath or adjacent to the couch 10 to a point offset from the side of the couch 10. Thus, when the line indicator projects the line, an operator at the back end 19 may maintain visual contact with the line during loading, unloading, or both, and use the line as a reference for the location of the center of balance of the couch 10 (e.g., the intermediate loading wheel 30).

The rear end 19 may include operator controls 57 for the couch 10. As used herein, operator controls 57 include input components for receiving commands from an operator and output components for providing instructions to the operator. Thus, an operator can use operator controls when loading and unloading the couch 10 by controlling the movement of the loading-end legs 20, the control-end legs 40, and the support frame 12. The operator controls 57 may include a control pod 50 positioned at the rear end 19 of the couch 10. For example, the control pod 50 may be communicatively coupled to one or more processors 100, which in turn are communicatively coupled to the front and rear actuators 16, 18. The control pod 50 may include a visual display component or graphical user interface (GUI) 58 configured to communicate to the operator whether the front and rear actuators 16, 18 are activated or deactivated. The visual display component or GUI 58 may include any device capable of emitting an image, such as, for example, a liquid crystal display, a touch screen, or the like.

2 , 7 , and 8 , the operator controls 57 can be operable to receive user input indicating a need to perform a bed rest function. The operator controls 57 can be communicatively coupled to the one or more processors 100 so that input received by the operator controls 57 can be converted into control signals, which are then received by the one or more processors 100. Thus, the operator controls 57 can include any type of tactile input capable of converting a physical input into a control signal, such as, for example, a button, switch, microphone, knob, etc. It should be noted that while the embodiments described herein refer to automatic operation of the front and rear actuators 16 , 18 , the embodiments described herein can include operator controls 57 configured to directly control the front and rear actuators 16 , 18 . That is, the automatic process described herein can be overridden by the user, and the front and rear actuators 16 , 18 can be actuated independently of input from the controls.

In some embodiments, operator controls 57 can be located on the rear end 19 of the bed 10. For example, the operator controls 57 can include a button array 52 positioned adjacent to and below the visual display assembly or GUI 58. The button array 52 can include a plurality of buttons used, for example and without limitation, to turn lights and lighting modes on and off, such as scene lights, emergency lights, etc., to select a particular operating mode of the bed, such as one of a plurality of "direct power" modes explained later in this section, and to select a predetermined position/arrangement of the bed, such as a "seat position" that is automatically configured upon pressing the associated button and explained later in this section. Each button of the button array 52 can include an optical element (i.e., an LED) that can emit optical energy in a visible wavelength when the button is activated. Alternatively or additionally, the operator controls 57 can include a button array 52 positioned adjacent to and above the visual display assembly or GUI 58. It should be noted that while each button array 52 is depicted as consisting of four buttons, the button array 52 can include any number of buttons. Additionally, the operator controls 57 may include a concentric button array 54 ( FIG. 8 ) comprising a plurality of arcuate buttons concentrically arranged around a central button. In some embodiments, the concentric button array 54 may be located above the visual display assembly or GUI 58. In still other embodiments, one or more buttons 53 may be provided on either or both sides of the control pod 50, which may provide the same and/or additional functionality as any of the buttons in the button arrays 52 and/or 54. It should be noted that while the operator controls 57 are depicted as being located at the rear end 19 of the couch 10, it is further contemplated that the operator controls 57 may be located at alternative locations on the support frame 12, such as at the front end 17 or sides of the support frame 12. In yet further embodiments, the operator controls 57 may be located in a removably attachable wireless remote control that can control the couch 10 without being physically attached to the couch 10.

The operator controls 57 may further include a raise button 56 operable to receive an input indicating a need to raise ("+") the couch 10, and a lower button 60 operable to receive an input indicating a need to lower ("-") the couch 10. It should be appreciated that in other embodiments, the raise and/or lower command functions may be assigned to other buttons, such as buttons in the button arrays 52 and/or 54, in addition to the buttons 56 and 60. As explained in greater detail herein, each of the raise and lower buttons 56 and 60 may generate a signal that actuates the load-end legs 20, the control-end legs 40, or both to perform a couch function. A couch function may require raising, lowering, retracting, or releasing the load-end legs 20, the control-end legs 40, or both, depending on the position and orientation of the couch 10. In some embodiments, each of the lower and raise buttons 60 and 56 may be analog buttons (i.e., a button press and/or displacement may be proportional to a parameter of a control signal). Thus, the actuation speed of the load end leg 20, the control end leg 40, or both, may be proportional to the parameter of the control signal.Alternatively or additionally, each of the lower button 60 and the raise button 56 may be a backlit button.

In the illustrated embodiment of FIG8 , two button groups 161 and 163 are also shown, providing buttons 56 and 60. The first button group 161 is positioned in a fixed position on the support frame 12, adjacent to or adjacent to the end frame member 165. The second button group 163 is positioned on a retractable handle 167, which can be positioned adjacent to the first button group 161. As indicated by the arrows in FIG8 , the retractable handle 167 is movable between a first position, in which the second button group 163 is positioned relatively close to or proximate to the first button group 161, and a second position, in which the second button group 163 extends relatively away from or away from the first button group 161. In one embodiment, the distance between the first and second positions is 225 mm; in other embodiments, the distance can be selected from a range of 120 to 400 mm. It should be understood that the retractable handle 167 is movable between the first and second positions, as well as a plurality of positions therebetween, and can be locked in these positions. Pressing the release button 169 unlocks the retractable handle 167 so that the second button set 163 can be extended or retracted relative to the first button set 161. In another embodiment, as best depicted in FIG14A, the end frame member 165 can be configured to be angled downward and deflected from the plane in which the pair of retractable handles 167 extend and retract. In still other embodiments, either or both of the sides of the end frame member 165 and either or both of the retractable handles 167 can be provided with a respective one of the first and second button sets 161, 163 (FIG. 8).

Turning now to an embodiment in which the couch 10 is actuated simultaneously, the couch 10 of FIG2 is depicted as being extended so that the front actuator sensor 62 and the rear actuator sensor 64 detect that the front actuator 16 and the rear actuator 18 are in a first position, i.e., the front and rear actuators 16, 18 are in contact with and/or in close proximity to their respective cross members 63, 65, such as when the loading-end legs 20 and the control-end legs 40 are in contact with a lower surface and loaded. When the front and rear actuator sensors 62, 64 detect that the front and rear actuators 16, 18, respectively, are in the first position and can be lowered or raised by the operator using the lower button 60 and the raise button 56, both the front and rear actuators 16, 18 are active.

With reference to Figures 4A-4C simultaneously, an embodiment of a cot 10 that is raised (Figures 4A-4C) or lowered (Figures 4C-4A) via simultaneous actuation is schematically depicted (note that, for clarity, the front actuator 16 and the rear actuator 18 are not depicted in Figures 4A-4C). In the depicted embodiment, the cot 10 includes a support frame 12 that is slidably engaged with a pair of loading-end legs 20 and a pair of control-end legs 40. Each of the loading-end legs 20 is rotatably coupled to a front hinge member 24, which is rotatably coupled to the support frame 12. Each of the control-end legs 40 is rotatably coupled to a rear hinge member 44, which is rotatably coupled to the support frame 12. In the depicted embodiment, the front hinge member 24 is rotatably coupled toward the front end 17 of the support frame 12, and the rear hinge member 44 is rotatably coupled to the support frame 12 toward the rear end 19.

FIG4A depicts the cot 10 in its lowest transport position. Specifically, the rear wheels 46 and the front wheels 26 are in contact with a surface, the loading-end legs 20 are slidingly engaged with the support frame 12 such that the loading-end legs 20 contact a portion of the support frame 12 toward the rear end 19, and the control-end legs 40 are slidingly engaged with the support frame 12 such that the control-end legs 40 contact a portion of the support frame 12 toward the front end 17. FIG4B depicts the cot 10 in an intermediate transport position, i.e., the loading-end legs 20 and the control-end legs 40 are in an intermediate transport position along the support frame 12. FIG4C depicts the cot 10 in its highest transport position, i.e., the loading-end legs 20 and the control-end legs 40 are positioned along the support frame 12 such that the front loading wheels 70 are at a maximum desired height, which can be set to a height sufficient for loading the cot, as described in more detail herein.

The embodiments described herein can be used to raise a patient from a position below a transport vehicle in preparation for loading the patient into the transport vehicle (e.g., from the ground to above the loading surface of an ambulance). Specifically, the bed 10 can be raised from a lowest transport position ( FIG. 4A ) to an intermediate transport position ( FIG. 4B ) or a highest transport position ( FIG. 4C ) by simultaneously actuating the loading-end legs 20 and the control-end legs 40 and sliding them along the support frame 12 . When being raised, actuation causes the loading-end legs to slide toward the front end 17 and rotate about the front hinge member 24 , and causes the control-end legs 40 to slide toward the rear end 19 and rotate about the rear hinge member 44 . Specifically, a user can interact with the operator controls 57 ( FIG. 8 ) and provide input indicating the need to raise the bed 10 (e.g., by pressing the raise button 56 ). The bed 10 is raised from its current position (e.g., the lowest transport position or the intermediate transport position) until it reaches the highest transport position. When the uppermost transport position is reached, actuation may stop automatically, ie, further additional input is required to raise the bed 10. Input may be provided to the bed 10 and/or operator controls 57 in any manner, such as electronically, audibly, or manually.

The couch 10 can be lowered from the intermediate transport position ( FIG. 4B ) or the highest transport position ( FIG. 4C ) to the lowest transport position ( FIG. 4A ) by simultaneously actuating the loading-end leg 20 and the control-end leg 40 and causing them to slide along the support frame 12. Specifically, when lowering, the actuation causes the loading-end leg to slide toward the rear end 19 and rotate about the front hinge member 24, and causes the control-end leg 40 to slide toward the front end 17 and rotate about the rear hinge member 44. For example, the user can provide input indicating the need to lower the couch 10 (e.g., by pressing the lower button 60). When the input is received, the couch 10 is lowered from its current position (e.g., the highest transport position or the intermediate transport position) until it reaches the lowest transport position. Once the couch 10 reaches its lowest height (e.g., the lowest transport position), the actuation can automatically cease. In some embodiments, the control box 50 provides a visual indication of the activity of the loading-end leg 20 and the control-end leg 40 during movement.

In one embodiment, when the sleeper 10 is in the uppermost transport position ( FIG. 4C ), the loading-end legs 20 contact the support frame 12 at the front loading index 221, and the control-end legs 40 contact the support frame 12 at the rear loading index 241. Although FIG. 4C depicts the front loading index 221 and the rear loading index 241 as being located near the middle of the support frame 12, alternative embodiments are contemplated in which the front loading index 221 and the rear loading index 241 are located anywhere along the support frame 12. For example, the uppermost transport position can be set by actuating the sleeper 10 to a desired height and providing input indicating the need to set the uppermost transport position (e.g., pressing and holding the “+” and “-” buttons 56, 60 simultaneously for 10 seconds).

In another embodiment, each time the couch 10 is raised above the uppermost transport position for a set period of time (e.g., 30 seconds), the control box 50 provides an indication that the couch 10 has exceeded the uppermost transport position and needs to be lowered. The indication may be a visual indication, an audible indication, an electronic indication, or a combination thereof.

When the sleeper bed 10 is in the lowest transport position ( FIG. 3A ), the loading-end leg 20 may contact the support frame 12 at a forward, flat index 220 located proximate the rear end 19 of the support frame 12, and the control-end leg 40 may contact the support frame 12 at a rearward, flat index 240 located proximate the front end 17 of the support frame 12. Furthermore, it should be noted that the term “index” as used herein means a position along the support frame 12 that corresponds to a mechanical or electrical stop, such as, for example, a block in a channel formed in the side member 15, a locking mechanism, or a servo-controlled stop.

The front actuator 16 is operable to raise or lower the front end 17 of the support frame 12 independently of the rear actuator 18. The rear actuator 18 is operable to raise or lower the rear end 19 of the support frame 12 independently of the front actuator 16. By independently raising the front end 17 or the rear end 19, the sleeper 10 is able to maintain the support frame 12 level or substantially level when the sleeper 10 is moved over an uneven surface, such as steps or a ramp. Specifically, if one of the front actuator 16 or the rear actuator 18 is in a second position relative to the first position, the set of legs that are not in contact with the surface (i.e., the set of legs that are in tension, such as when one or both ends of the sleeper are raised) is activated by the sleeper 10 (e.g., to move the sleeper 10 away from a curb). Other embodiments of the sleeper 10 are operable to automatically adjust to a level position. For example, if the rear end 19 is lower than the front end 17, pressing the "+" button 56 will raise the rear end 19 to a horizontal position before raising the bed 10, and pressing the "-" button 60 will lower the front end 17 to a horizontal position before lowering the bed 10.

In one embodiment depicted in FIG. 2 , the couch 10 receives a first position signal from the front actuator sensor 62 indicating the detected position of the front actuator 16 and a second position signal from the rear actuator sensor 64 indicating the detected position of the rear actuator 18. The first and second position signals may be processed by logic executed by the control pod 50 to determine the couch 10's response to input received by the couch 10. Specifically, user input may be input into the control pod 50. The user input is received as a control signal instructing the control pod 50 to change the height of the couch 10. Generally speaking, when the first position signal indicates that the front actuator is in a first position and the second position signal indicates that the rear actuator is in a second position relative to the first position (the first and second positions indicating a distance, angle, or position between two predetermined relative positions), the front actuator actuates the loading-end legs 20 and the rear actuator 18 remains substantially stationary (e.g., not actuated). Thus, when only the first position signal indicates the second position, the loading-end leg 20 can be raised by pressing the “-” button 60 and/or lowered by pressing the “+” button 56. Generally speaking, when the second position signal indicates the second position and the first position signal indicates the first position, the rear actuator 18 actuates the control-end leg 40 and the front actuator 16 remains substantially stationary (e.g., not actuated). Thus, when only the second position signal indicates the second position, the control-end leg 40 can be raised by pressing the “-” button 60 and/or lowered by pressing the “+” button 56. In some embodiments, the actuators can be actuated relatively slowly after initial movement (i.e., a slow start) to mitigate rapid jostling of the support frame 12 before actuating relatively quickly.

With reference to both Figures 4C through 5E , embodiments described herein can utilize independent actuation to load a patient into a transport vehicle (note that, for clarity, the front actuator 16 and rear actuator 18 are not depicted in Figures 4C through 5E ). Specifically, the couch 10 can be loaded onto the loading surface 500 according to the process described below. First, the couch 10 can be placed in its highest transport position (Figure 3), or any position where the front loading wheels 70 are positioned at a height greater than the loading surface 500. When loading the couch 10 onto the loading surface 500, the couch 10 can be raised via the front and rear actuators 16 and 18 to ensure that the front loading wheels 70 are positioned above the loading surface 500. In some embodiments, the front and rear actuators 16, 18 can be actuated simultaneously to maintain the couch level until the couch reaches a predetermined height. Once the predetermined height is reached, the front actuator 16 can raise the front end 17, causing the couch 10 to angle in its highest loading position. Thus, the cot 10 can be loaded with the rear end 19 lower than the front end 17. The cot 10 can then be lowered until the front loading wheels 70 contact the loading surface 500 (FIG. 5A).

As depicted in FIG5A , the front loading wheels 70 are above the loading surface 500. In one embodiment, after the loading wheels contact the loading surface 500, the pair of loading-end legs 20 can be actuated using the front actuator 16 because the front end 17 is above the loading surface 500. As depicted in FIG5A and FIG5B , the middle portion of the cot 10 is clear of the loading surface 500 (i.e., a sufficiently large portion of the cot 10 has not yet been loaded beyond the loading edge 502 such that the majority of the weight of the cot 10 can be suspended and supported by the wheels 70, 26, and/or 30). When the front loading wheels are sufficiently loaded, the cot 10 can be maintained level with a reduced amount of force. Furthermore, in this position, the front actuator 16 is in the second position relative to the first position, and the rear actuator 18 is in the first position relative to the second position. Thus, for example, if the "-" button 60 is activated, the loading-end legs 20 are raised ( FIG5B ). In one embodiment, after the loading-end legs 20 have been raised sufficiently to trigger the loading state, the operation of the front actuator 16 and the rear actuator 18 is dependent on the position of the self-actuated bed. In some embodiments, a visual indication is provided on the visual display assembly or GUI 58 of the control pod 50 ( FIG. 2 ) when the loading-end legs 20 are raised. The visual indication can be color-coded (e.g., green for activated legs and red for inactivated legs). The front actuator 16 can automatically cease operation when the loading-end legs 20 have fully retracted. Furthermore, it should be noted that during the retraction of the loading-end legs 20, the front actuator sensor 62 may detect a second position relative to the first position, at which point the front actuator 16 can raise the loading-end legs 20 at a faster rate; for example, fully retracting them in approximately two seconds.

Referring simultaneously to FIG3 , FIG5B , and FIG7 , after the front loading wheel 70 has been positioned on the loading surface 500 to assist in loading the cot 10 onto the loading surface 500, the one or more processors 100 can automatically actuate the rear actuator 18. Specifically, when the front angle sensor 66 detects that the front angle _αf is less than a predetermined angle, the one or more processors 100 can automatically actuate the rear actuator 18 to extend the control-end legs 40 and raise the rear end 19 of the cot 10 above the original loading height. The predetermined angle can be any angle indicative of a loading state or percentage of extension, such as, for example, less than approximately 10% of the extension of the loading-end legs 20 in one embodiment, or less than approximately 5% of the extension of the loading-end legs 20 in another embodiment. In some embodiments, before automatically actuating the rear actuator 18 to extend the control-end legs 40, the one or more processors 100 can determine whether the loading-end sensor 76 indicates that the front loading wheel 70 is touching the loading surface 500.

In another embodiment, the one or more processors 100 can monitor the rear angle sensor 68 to confirm that the rear angle _αb is changing in response to actuation of the rear actuator 18. To protect the rear actuator 18, if the rear angle _αb indicates improper operation, the one or more processors 100 can automatically suspend actuation of the rear actuator 18. For example, if the rear angle _αb fails to change within a predetermined amount of time (e.g., approximately 200 ms), the one or more processors 100 can automatically suspend actuation of the rear actuator 18.

Referring simultaneously to Figures 5A-5E , after the loading-end legs 20 have been retracted, the couch 10 can be pushed forward until the intermediate loading wheels 30 have been loaded onto the loading surface 500 (Figure 5C). As depicted in Figure 5C, the front end 17 and the middle portion of the couch 10 are above the loading surface 500. Therefore, the pair of control-end legs 40 can be retracted along with the rear actuator 18. Specifically, an ultrasonic sensor can be positioned to detect when the middle portion is above the loading surface 500. When the middle portion is above the loading surface 500 during the loading state (e.g., the loading-end legs 20 and the control-end legs 40 have an angle Δ greater than the loading state angle), the rear actuator can be actuated. In one embodiment, the control box 50 (Figure 2) can provide an indication (e.g., an audible beep) when the intermediate loading wheels 30 are sufficiently beyond the loading edge 502 to permit actuation of the control-end legs 40.

It should be noted that the middle portion of the cot 10 is above the loading surface 500, and any portion of the cot 10 that could serve as a fulcrum is sufficiently beyond the loading edge 502 so that the control-end legs 40 can be retracted, reducing the amount of force required to lift the rear end 19 (e.g., less than half of the weight of the loaded cot 10 needs to be supported on the rear end 19). Furthermore, it should be noted that the position of the cot 10 can be detected by sensors located on the cot 10 and/or sensors located on or adjacent to the loading surface 500. For example, an ambulance may have sensors that detect the position of the cot 10 relative to the loading surface 500 and/or the loading edge 502, and have communication means to transmit this information to the cot 10.

5D , after the console legs 40 are retracted, the cot 10 can be pushed forward. In one embodiment, during the retraction of the rear legs, the rear actuator sensor 64 can detect that the console legs 40 are unloaded, at which point the rear actuator 18 can raise the console legs 40 at a higher speed. When the console legs 40 are fully retracted, the rear actuator 18 can automatically stop operating. In one embodiment, the control box 50 ( FIG. 2 ) can provide an indication when the cot 10 is sufficiently extended beyond the loading edge 502 (e.g., fully loaded or loaded such that the rear actuator extends beyond the loading edge 502).

Once the bed is loaded onto the loading surface (FIG. 5E), the front and rear actuators 16, 18 can be deactivated by releasably locking/coupling to the ambulance. The ambulance and bed 10 can each be equipped with components suitable for coupling, such as male-female type connectors. In addition, the bed 10 can include a sensor that registers when the bed is fully positioned in the ambulance and sends a signal that causes the actuators 16, 18 to lock. In yet another embodiment, the bed 10 can be connected to a bed fastener that locks the actuators 16, 18 and is further coupled to the ambulance's power system, which charges the bed 10. A commercial example of such an ambulance charging system is the Integrated Charging System (ICS) produced by Ferno-Washington, Inc.

Referring concurrently to Figures 5A-5E , embodiments described herein can unload the couch 10 from the loading surface 500 using independent actuation as described above. Specifically, the couch 10 can be unlocked from the fasteners and pushed toward the loading edge 502 (Figures 5E-5D). When the rear wheels 46 are released from the loading surface 500 (Figure 5D), the rear actuator sensors 64 detect that the control-end legs 40 are unloaded and allow the control-end legs 40 to be lowered. In some embodiments, the control-end legs 40 can be prevented from being lowered, for example, if a sensor detects that the couch is not in the correct position (e.g., the rear wheels 46 are above the loading surface 500, or the intermediate loading wheels 30 are away from the loading edge 502). In one embodiment, the control pod 50 (Figure 2) can provide an indication when the rear actuator 18 is activated (e.g., the intermediate loading wheels 30 are near the loading edge 502 and/or the rear actuator sensors 64 detect a second position relative to the first position).

Referring to FIG. 5D and FIG. 7 simultaneously, the one or more processors can automatically activate the line indicator 74 to project a line on the loading surface 500 indicating the center of balance of the sleeper 10. In one embodiment, the one or more processors 100 can receive input from the intermediate load sensor 77 indicating that the intermediate loading wheel 30 is in contact with the loading surface. The one or more processors 100 can also receive input from the rear actuator sensor 64 indicating that the rear actuator 18 is in a second position relative to the first position. When the intermediate loading wheel 30 is in contact with the loading surface and the rear actuator 18 is in the second position relative to the first position, the one or more processors can automatically cause the line indicator 74 to project the line. Thus, when the line is projected, a visual indication can be provided to the operator on the loading surface, which can be used as a reference for loading, unloading, or both operations. Specifically, when the line approaches the loading edge 502, the operator can slow down the removal of the sleeper 10 from the loading surface 500, thereby allowing additional time to lower the control end legs 40. This action can minimize the amount of time the operator needs to support the weight of the sleeper 10.

5A-5E , when the couch 10 is properly positioned relative to the loading edge 502, the control-end legs 40 can be extended ( FIG. 5C ). In some embodiments, when the rear actuator sensor 64 detects a second position relative to the first position, the control-end legs 40 can be relatively quickly extended by opening the logic valve 352 to activate the regeneration fluid path 350 ( FIG. 12A-12D ). For example, the control-end legs 40 can be extended by pressing the "+" button 56. In one embodiment, a visual indication is provided on the visual display assembly or GUI 58 of the control cassette 50 when the control-end legs 40 are lowered ( FIG. 2 ). For example, a visual indication can be provided when the couch 10 is in the loading state and the control-end legs 40 and/or the loading-end legs 20 are actuated. This visual indication can signal that the couch should not be moved (e.g., pulled, pushed, or rolled) during actuation. When the control end leg 40 contacts the floor ( FIG. 5C ), the control end leg 40 becomes loaded and the rear actuator sensor 64 deactivates the rear actuator 18 .

When the sensor detects that the loading-end legs 20 are not in contact with the loading surface 500 ( FIG. 5B ), the front actuator 16 is activated. In some embodiments, when the front actuator sensor 62 detects a second position relative to the first position, the loading-end legs 20 can be relatively quickly extended by opening the logic valve 352 to activate the regeneration fluid path 350 ( FIG. 12A - FIG. 12D ). In one embodiment, the control pod 50 can provide an indication when the intermediate loading wheel 30 is at the loading edge 502 ( FIG. 2 ). The loading-end legs 20 are extended until they contact the base plate ( FIG. 5A ). For example, the loading-end legs 20 can be extended by pressing the "+" button 56. In one embodiment, a visual indication is provided on the visual display assembly or GUI 58 of the control pod 50 when the loading-end legs 20 are lowered ( FIG. 2 ).

7 and 8 , actuation of any operator control 57 can cause one or more processors 100 to receive a control signal. The control signal can be encoded to indicate that one or more of the operator controls has been actuated. The encoded control signal can be associated with a preprogrammed bed function. Upon receiving the encoded control signal, the one or more processors 100 can automatically execute the bed function. In some embodiments, the bed function can include a door opening function that transmits a door opening signal to a vehicle. Specifically, the bed 10 can include a communication circuit 82 that is communicatively coupled to the one or more processors 100. The communication circuit 82 can be configured to exchange communication signals with a vehicle, such as an ambulance. The communication circuit 82 can include a wireless communication device, such as, but not limited to, a personal area network transceiver, a local area network transceiver, a radio frequency identification (RFID), an infrared transmitter, a cellular transceiver, and the like.

The control signal from one or more of the operator controls 57 can be associated with a door opening function. Upon receiving a control signal associated with the door opening function, the one or more processors 100 can cause the communication circuit 82 to transmit a door opening signal to any vehicle within range of the door opening signal. Upon receiving the door opening signal, the vehicle can open its door to receive the cot 10. Furthermore, the door opening signal can be encoded to identify the cot 10, such as via a classification, a unique identifier, or the like. In another embodiment, the control signal from one or more of the operator controls 57 can be associated with a door closing function, which operates similarly to the door opening function and causes the vehicle's door to close.

3 , 7 , and 8 , the bed's functions may include an automatic leveling function that automatically levels the front end 17 and rear end 19 relative to gravity. Thus, the front angle _αf , the rear angle _αb , or both angles can be automatically adjusted to compensate for uneven terrain. For example, if the rear end 19 is lower than the front end 17 relative to gravity, the rear end 19 can automatically rise to level the bed 10 relative to gravity, the front end 17 can automatically lower to level the bed 10 relative to gravity, or both. Conversely, if the rear end 19 is higher than the front end 17 relative to gravity, the rear end 19 can automatically lower to level the bed 10 relative to gravity, the front end 17 can automatically raise to level the bed 10 relative to gravity, or both.

2 and 7 , the couch 10 may include a gravity reference sensor 80 configured to provide a gravity reference signal indicative of an Earth reference frame. The gravity reference sensor 80 may include an accelerometer, a gyroscope, an inclinometer, and the like. The gravity reference sensor 80 may be communicatively coupled to the one or more processors 100 and coupled to the couch 10 at a location suitable for detecting the level of the couch 10 relative to gravity (such as, for example, the support frame 12).

Control signals from one or more of the operator controls 57 can be associated with the automatic leveling function. Specifically, any operator control 57 can transmit a control signal associated with activating or deactivating the automatic leveling function. Alternatively or additionally, other bed functions can selectively activate or deactivate the bed leveling function. When the automatic leveling function is activated, the one or more processors 100 can receive a gravity reference signal. The one or more processors 100 can automatically compare the gravity reference signal with a terrestrial reference system indicating the level of the Earth. Based on this comparison, the one or more processors 100 can automatically quantify the difference between the terrestrial reference system and the current level of the bed 10 indicated by the gravity reference signal. This difference can be converted into a desired adjustment to level the front end 17 and rear end 19 of the bed 10 relative to gravity. For example, this difference can be converted into an angular adjustment to the front angle α _f , the rear angle α _b , or both angles. Accordingly, the one or more processors 100 can automatically actuate the actuators 16 and 18 until the desired adjustment is achieved, i.e., feedback can be provided using the front angle sensor 66 , the rear angle sensor 68 , and the gravity reference sensor 80 .

Referring simultaneously to FIG1 , FIG9 , and FIG10 , one or more of the front wheels 26 and the rear wheels 46 may include a wheel assembly 110 for automatic actuation. Thus, while the wheel assembly 110 depicted in FIG9 is coupled to the connecting rod 27 , the wheel assembly may be coupled to the connecting rod 47 . The wheel assembly 110 may include a wheel steering module 112 for guiding the orientation of the wheels 114 relative to the bed 10 . The wheel steering module 112 may include a control shaft 116 defining a rotational axis 118 for steering; a steering mechanism 90 for actuating the control shaft 116; and a fork 121 defining a rotational axis 123 for the wheels 114 . In some embodiments, the control shaft 116 may be rotatably coupled to the connecting rod 27 such that the control shaft 116 rotates about the rotational axis 118 . The rotational motion may be facilitated by a bearing 124 located between the control shaft 116 and the connecting rod 27 .

The steering mechanism 90 can be operably coupled to the control shaft 116 and can be configured to push the control shaft 116 about the rotation axis 118. The steering mechanism 90 can include a servo motor and an encoder. Thus, the steering mechanism 90 can directly actuate the control shaft 116. In some embodiments, the steering mechanism 90 can be configured to rotate freely to allow the control shaft 116 to rotate about the rotation axis 118 when the couch 10 is moved by being pushed. Optionally, the steering mechanism 90 can be configured to lock in place and resist movement of the control shaft 116 about the rotation axis 118.

7 and 9-10 , the wheel assembly 110 may include a rotational locking module 130 for locking the fork 121 in a substantially fixed orientation. The rotational locking module 130 may include a screw member 132 for engaging a latch member 134, a biasing member 136 for biasing the screw member 132 away from the latch member 134, and a cable 138 for transmitting mechanical energy between the locking actuator 92 and the screw member 132. The locking actuator 92 may include a servo motor and an encoder.

The channel formed by the connecting rod 27 can accommodate the screw component 132. The screw component 132 can be advanced into the channel so that the screw component 132 disengages from the locking component 134 and exits the channel into an interference position within the locking component 134. The biasing component 136 can bias the screw component 132 toward the interference position. The cable 138 can be coupled to the screw component 132 and operably engaged with the locking actuator 92 so that the locking actuator 92 can transmit a force sufficient to overcome the biasing component 136 and translate the screw component 132 from the interference position to disengage the screw component 132 from the locking component 134.

In some embodiments, the lock component 134 can be formed in the fork 121 or coupled to the fork 121. The lock component 134 can include a rigid body that forms an aperture that is complementary to the screw component 132. Thus, the screw component 132 can travel in and out of the lock component via the aperture. The rigid body can be configured to interfere with the movement of the lock component 134 caused by the movement of the control shaft 116 about the rotation axis 118. Specifically, when in the interference position, the screw component 132 can be constrained by the rigid body of the lock component 134, so that the movement of the control shaft 116 about the rotation axis 118 is largely mitigated.

Referring to FIG7 and FIG9-10 simultaneously, the wheel assembly 110 may include a brake module 140 for resisting rotation of the wheel 114 about the rotation axis 123. The brake module 140 may include a brake piston 142 for transmitting a braking force to a brake pad 144; a biasing member 146 for biasing the brake piston 142 away from the wheel 114; and a brake mechanism 94 for providing the braking force to the brake piston 142. In some embodiments, the brake mechanism 94 may include a servo motor and an encoder. The brake mechanism 94 may be operably coupled to a brake cam 148 such that actuation of the brake mechanism 94 causes the brake cam 148 to rotate about the rotation axis 151. The brake piston 142 may act as a cam follower. Thus, the rotational motion of the brake cam 148 is converted into linear motion of the brake piston 142, which in turn moves the brake piston 142 toward and away from the wheel 114 depending on the direction of rotation of the brake cam 148.

Brake pad 144 can be coupled to brake piston 142 such that movement of brake piston 142 toward and away from wheel 114 engages and disengages brake pad 144 from wheel 114. In some embodiments, brake pad 144 can be contoured to match the shape of the portion of wheel 114 that brake pad 144 contacts during braking. Optionally, the contact surface of brake pad 144 can include protrusions and grooves.

7 , each of the steering mechanism 90, the locking actuator 92, and the braking mechanism 94 can be communicatively coupled to one or more processors 100. Thus, any operator control 57 can be coded to provide a control signal operable to automate any operation of the steering mechanism 90, the locking actuator 92, the braking mechanism 94, or a combination thereof. Alternatively or additionally, any bed rest function can automate any operation of the steering mechanism 90, the locking actuator 92, the braking mechanism 94, or a combination thereof.

3 and 7 to 10 simultaneously, any operator control 57 can be coded to provide a control signal operable to cause the steering mechanism 90 to actuate the fork 121 to an outboard position (depicted as a dashed line in FIG10 ). Alternatively or in addition, a bed function (e.g., a seat function) can be configured to selectively cause the steering mechanism 90 to actuate the fork 121 to an outboard position. When arranged in the outboard position, the fork 121 and the wheels 114 can be oriented vertically relative to the length of the bed 10 (direction from the front end 17 to the rear end 19). Thus, the front wheels 26, the rear wheels 46, or both can be arranged in the outboard position so that the front wheels 26, the rear wheels 46, or both are oriented toward the support frame 12.

With reference to both FIG8 and FIG11-12, the bed function may include an escalator function configured to maintain a patient supported by the patient support 14 horizontally while the bed 10 is supported by the escalator. Accordingly, any operator control 57 may be coded to provide a control signal operable to activate, deactivate, or both the escalator function. In some embodiments, the escalator function may be configured to orient the bed 10 so that the patient faces the same direction relative to the escalator ramp when riding the ascending escalator 504 or the descending escalator 506. Specifically, the escalator function may ensure that the rear end 19 of the bed 10 faces the downward slope of the ascending escalator 504 and the descending escalator 506. In other words, the bed 10 may be configured so that the rear end 19 of the bed is ultimately loaded onto the ascending escalator 504 or the descending escalator 506.

Referring now to FIG. 13 , elevator functionality can be implemented according to method 301 . It should be noted that while method 301 is depicted in FIG. 13 as including a plurality of enumerated processes, any process of method 301 may be performed in any order or omitted without departing from the scope of the present invention. At process 303 , the support frame 12 of the bed 10 may be retracted. In some embodiments, the bed 10 may be configured to automatically detect that the support frame 12 is retracted before continuing the elevator functionality. Alternatively or additionally, the bed 10 may be configured to automatically retract the support frame 12.

Referring simultaneously to Figures 7, 8, 11, and 13, a bed can be loaded onto the ascending escalator 504. The ascending escalator 504 can form an elevator slope θ relative to the platform immediately in front of the ascending escalator 504. In process 305, the front wheels 26 can be loaded onto the ascending escalator 504. When the front wheels 26 are loaded onto the ascending escalator 504, the raise button 56 can be actuated. When the escalator function is activated, a control signal transmitted from the raise button 56 can be received by the one or more processors 100. In response to the control signal transmitted from the raise button 56, the one or more processors can execute machine-readable instructions to automatically actuate the brake mechanism 94. As a result, the front wheels 26 can be locked to prevent them from rolling. While the raise button 56 remains activated, the one or more processors can automatically cause the visual display assembly to provide an image indicating that the loading end legs 20 are activated.

At process 307, the raise button 56 may remain active. In response to the control signal transmitted from the raise button 56, one or more processors may execute machine-readable instructions to automatically activate the bed leveling function. Thus, the bed leveling (equalization) function may dynamically actuate the load-end legs 20 to adjust the front angle _αf . Thus, as the bed 10 is gradually pushed onto the ascending escalator 504, the front angle _αf may change to keep the support frame 12 substantially level.

At process 309, after the rear wheels 46 are loaded onto the ascending escalator 504, the raise button 56 can be deactivated. In response to a control signal transmitted from the raise button 56, one or more processors can execute machine-readable instructions to automatically actuate the brake mechanism 94. Consequently, the rear wheels 46 can be locked to prevent them from rolling. With the front wheels 26 and the rear wheels 46 loaded onto the ascending escalator 504, the bed-leveling function can adjust the front angle _αf to match the escalator angle θ.

At process 311, as the front wheels 26 approach the end of the ascending escalator 504, the raise button 56 can be activated. In response to a control signal transmitted from the raise button 56, one or more processors can execute machine-readable instructions to automatically actuate the brake mechanism 94. Consequently, the front wheels 26 can be unlocked to allow the front wheels 26 to roll. As the front wheels 26 exit the ascending escalator 504, the bed-leveling function can dynamically adjust the front angle _αf to keep the support frame 12 of the bed 10 level.

At process 313, the one or more processors 100 can automatically determine the position of the loading-end legs 20. Consequently, when the front end 17 of the cot 10 exits the ascending escalator 504, the front angle _αf can reach a predetermined angle, such as (but not limited to) the angle corresponding to full extension of the loading-end legs 20. When the predetermined level is reached, the one or more processors 100 can execute machine-readable instructions to automatically actuate the braking mechanism 94. Consequently, the rear wheels 46 can be unlocked to allow them to roll. Consequently, when the rear end 19 of the cot 10 reaches the end of the ascending escalator 504, the cot 10 can roll away from the ascending escalator 504. In some embodiments, escalator mode can be deactivated by actuating one of the operator controls 57. Alternatively or additionally, elevator mode can be deactivated for a predetermined period of time (e.g., approximately 15 seconds) after the rear wheels 46 are unlocked.

Referring simultaneously to Figures 7, 8, 12, and 13, the cot 10 can be loaded onto the descending escalator 506 in a manner similar to loading onto the ascending escalator 504. At process 305, the rear wheels 46 can be loaded onto the descending escalator 506. After the rear wheels 46 are loaded onto the descending escalator 506, the lowering button 60 can be actuated. When the escalator function is active, a control signal transmitted from the lowering button 60 can be received by the one or more processors 100. In response to the control signal transmitted from the lowering button 60, the one or more processors can execute machine-readable instructions to automatically actuate the braking mechanism 94. Consequently, the rear wheels 46 can be locked to prevent them from rolling. While the lowering button 60 remains active, the one or more processors can automatically cause the visual display assembly to provide an image indicating that the loading-end legs 20 are active.

At process 307, the lower button 60 may remain active. In response to the control signal transmitted from the lower button 60, one or more processors may execute machine-readable instructions to automatically activate the bed-leveling function. Consequently, the bed-leveling function may dynamically actuate the load-end legs 20 to adjust the front angle _αf . Thus, as the bed 10 is gradually pushed onto the descending escalator 506, the front angle _αf may change to keep the support frame 12 substantially level.

At process 309, after the front wheels 26 are loaded onto the descending escalator 506, the lower button 60 can be deactivated. In response to a control signal transmitted from the lower button 60, the one or more processors 100 can execute machine-readable instructions to automatically actuate the brake mechanism 94. Consequently, the front wheels 26 can be locked to prevent them from rolling. With the front wheels 26 and the rear wheels 46 loaded onto the descending escalator 506, the bed-leveling function can adjust the front angle _αf to match the escalator angle θ.

At process 311, when the rear wheels 46 approach the end of the descending escalator 506, the lower button 60 can be activated. In response to the control signal transmitted from the lower button 60, one or more processors can execute machine-readable instructions to automatically actuate the brake mechanism 94. As a result, the rear wheels 46 can be unlocked to allow the rear wheels 46 to roll. When the rear wheels 46 leave the descending escalator 506, the bed-leveling function can dynamically adjust the front angle _αf to keep the support frame 12 of the bed 10 substantially level.

At process 313, the one or more processors 100 can automatically determine the position of the loading-end legs 20. Consequently, when the rear end 19 of the cot 10 exits the descending escalator 506, the front angle _αf can reach a predetermined angle, such as (but not limited to) an angle corresponding to full extension of the loading-end legs 20. When the predetermined level is reached, the one or more processors 100 can execute machine-readable instructions to automatically actuate the braking mechanism 94. Consequently, the front wheels 26 can be unlocked to allow the front wheels 26 to roll. Consequently, when the front end 17 of the cot 10 reaches the end of the descending escalator 506, the cot 10 can roll away from the descending escalator 506. In some embodiments, after unlocking the front wheels 26, the elevator mode can be deactivated for a predetermined period of time (e.g., approximately 15 seconds).

4B , 7 , and 8 , the bed rest function may include a cardiopulmonary resuscitation (CPR) function operable to automatically adjust the bed rest 10 to an ergonomic position for medical personnel to perform effective CPR in the event of cardiac arrest. Any operator control 57 may be coded to provide a control signal operable to activate, deactivate, or both the CPR function. In some embodiments, the CPR function may be automatically deactivated when the bed rest is in an ambulance, connected to the bed rest fastener, or both.

In some embodiments, the control signal of the present invention can be transmitted to one or more processors 100 and received by one or more processors 100. In response to the control signal, one or more processors can execute machine-readable instructions to automatically actuate the brake mechanism 94. Therefore, the front rotating wheel 26, the rear rotating wheel 46 or the two can be locked to prevent the bed 10 from rolling. The bed 10 can be configured to provide the audio indication of the activated CPR function. In addition, the height of the support frame 12 of the bed 10 can be slowly adjusted to the intermediate transport position (Fig. 4 B), and this intermediate transport position corresponds to the substantially horizontal height (such as, for example, seat height, sofa height) for giving CPR between about 12 inches (about 30.5cm) and about 36 inches (about 91.4cm), or any other predetermined height that is suitable for giving CPR. In certain embodiments, one or more of the operator controls 57 can be configured to lock or unlock the front rotating wheel 26, the rear rotating wheel 46 or the two. Actuating the operator control 57 to lock or unlock the front wheels 26, the rear wheels 46, or both can automatically deactivate the CPR function. Thus, normal operation of the bed 10 via the lowering button 60 and the raising button 56 can be restored.

3 , 7 , and 8 , the bed rest function may include an extracorporeal membrane oxygenation (ECMO) function, which is operable to automatically maintain the front end 17 of the bed rest 10 at a higher height than the rear end 19 during operation of the bed rest 10. After the ECMO function is activated, a control signal may be transmitted to and received by the one or more processors 100. In response to the control signal, the one or more processors 100 may execute machine-readable instructions to automatically actuate the locking actuator 92. This prevents the front wheels 26 , the rear wheels 46 , or both from rotating or turning. Furthermore, the front angle α _f , the rear angle α _b , or both may be adjusted so that the support frame 12 is at a predetermined downward tilt angle from the front end 17 to the rear end 19. This adjustment may be implemented substantially similarly to the bed leveling function, except that the support frame 12 is adjusted to a downward tilt angle relative to gravity, rather than being horizontal relative to gravity. Furthermore, when the ECMO function is activated, the lower button 60 and the raise button 56 may be used to adjust the average height of the support frame 12 while automatically maintaining the downward tilt angle. After deactivating the ECMO function, the bed 10 can resume normal operation.

14A and 14B , an embodiment of the reclining bed 10 may include a patient support 400 for supporting a patient on the reclining bed 10. In some embodiments, the patient support 400 may be coupled to the support frame 12 of the reclining bed 10. The patient support 400 may include a head support portion 402 for supporting the patient's back, head, and neck, and a foot support portion 404 for supporting the patient's lower extremity region. The patient support 400 may further include a middle portion 406 located between the head support portion 402 and the foot support portion 404. Optionally, the patient support 400 may include a support cushion 408 for providing cushioning for patient comfort. The support cushion 408 may include an outer layer formed of a material that is non-reactive to biological fluids and materials.

Referring now to Figures 14A and 14B simultaneously, the patient support member 400 can be operable to pivot relative to the support frame 12 of the recliner 10. For example, the head support portion 402, the foot support portion 404, or both can be rotated relative to the support frame 12. The head support portion 402 can be adjusted to elevate the patient's torso relative to a flat position (i.e., substantially parallel to the support frame 12). Specifically, a head offset angle _θH can be defined between the support frame 12 and the head support portion 402. As the head support portion 402 rotates away from the support frame 12, the head offset angle _θH can increase. In some embodiments, the head offset angle _θH can be limited to a substantially acute maximum angle, such as, for example, approximately 85° in one embodiment or approximately 76° in another embodiment. The foot support portion 404 can be adjusted to elevate the patient's lower extremity region relative to a flat position (i.e., substantially parallel to the support frame 12). A foot offset angle _θF can be defined between the support frame 12 and the foot support portion 404. As the foot support portion 404 rotates away from the support frame 12, the foot offset angle _θF can increase. In some embodiments, the foot offset angle _θF can be limited to a substantially acute maximum angle, such as, for example, approximately 35° in one embodiment, approximately 25° in another embodiment, or approximately 16° in another embodiment.

1 and 14 , the couch 10 can be configured to automatically actuate to a seated loading position (also referred to hereinafter as a "seating position"). Specifically, the front actuator 16 can actuate the loading-end legs 20, the rear actuator 18 can actuate the control-end legs 40, or both the front actuator 16 and the rear actuator 18 can actuate to lower the rear end 19 of the couch 10 relative to the front end 17 of the couch 10. When the rear end 19 of the couch 10 is lowered, a seated loading angle α can be formed between the support frame 12 and the substantially horizontal surface 503. In some embodiments, the seated loading angle α can be limited to a maximum angle that is substantially acute, such as, for example, approximately 35° in one embodiment, approximately 25° in another embodiment, or approximately 16° in another embodiment. In some embodiments, the seated loading angle α can be substantially the same as the foot offset angle _θF , such that the foot support portion 404 of the patient support member 400 is substantially parallel to the horizontal surface 503.

Referring again to Figures 14A and 14B, before the reclining bed 10 is automatically actuated to the sitting loading position, the head support portion 402 and the foot support portion 404 of the patient support member 400 can be raised away from the support frame 12. In addition, the front wheels 26 and the rear wheels 46 can be oriented in substantially similar directions. Once aligned, the front wheels 26 and the rear wheels 46 can be locked in place. In some embodiments, the reclining bed 10 can include an input terminal that is configured to receive a command to actuate the reclining bed to the sitting loading position. For example, the visual display assembly or GUI 58 can include a touch screen input terminal for receiving tactile input. Alternatively or in addition, various other buttons or audio input terminals can be configured to receive a command to actuate the reclining bed 10 to the sitting loading position.

Once the control box 50 receives this command, the sleeper 10 can be placed in the sitting stowage position (seat position) mode. In some embodiments, the sleeper 10 can automatically actuate to the sitting stowage position without additional input upon entering the sitting stowage position mode. Alternatively, the sleeper 10 may require additional input before translating to the sitting stowage position. For example, while in the sitting stowage position mode, the rear end 19 of the sleeper 10 can be lowered by pressing the "-" button 60 ( FIG. 2 ). In other embodiments, a time limit can be imposed on the sitting stowage position mode to limit the total time that the mode remains in effect. Thus, upon expiration of the time limit, the sitting stowage position mode can be automatically deactivated, such as, for example, approximately 60 seconds in one embodiment, approximately 30 seconds in another embodiment, or approximately 15 seconds in yet another embodiment. In further embodiments, upon entering the sitting stowage position mode, a confirmation indicating that the sleeper 10 is in the sitting stowage position mode can be provided, such as, for example, an audible indication or a visual indication on the visual display assembly or GUI 58.

Referring now to FIG. 15 , in another embodiment, the bed 10 (generally depicted in a block diagram) includes an onboard, networked bed control system, generally designated by reference numeral 1000. The bed control system 1000 enables electronic messages to be transmitted to and received from various electronic control circuits or digital controllers provided on the bed 10. It should be understood that the digital controllers can each be a microprocessor or microcontroller, such as processor 100 ( FIG. 7 ), which includes a central processing unit, memory, and other functional elements, all disposed on a single semiconductor substrate, or an integrated circuit that provides the specialized operations disclosed below. Additionally, it should be understood that while certain disclosed embodiments of the controller utilize programmed processors and/or application-specific integrated circuits, these devices can be implemented using discrete devices, or using any analog or hybrid corresponding integrated circuit, including logic or software implementations (e.g., emulations) of any of these devices.

In some embodiments, the bed control system 1000 includes one or more controllers, such as a motor controller 1002, a graphical user interface (GUI) controller 1004, and/or a battery unit or controller 1006. Those skilled in the art will appreciate that the number of controllers may be fewer (e.g., one or more processors 100 depicted in FIG. 7 ) or greater than those shown in FIG. It should also be understood that the numbering of the controllers in FIG. 15 is arbitrary and is intended solely to illustrate the specific functionality of each controller for illustrative purposes. That is, in some embodiments of the bed 100, the specific functionality of each controller may be altered and/or combined with other controllers and/or eliminated. For example, in one embodiment, the bed control system 1000 includes at least one controller, a sensor, a user display unit, a battery unit 1006, and a wired communication network 1008 configured to transmit messages between the at least one controller, the sensor, the user display unit, and the battery unit. In one embodiment, the battery unit 1006 is a battery management system integrated with a battery pack (i.e., battery) that provides portable power to the bed 10, wherein the battery management system controls charging and discharging of the battery pack and communicates with at least one controller via a communication network.

In other embodiments, the various controllers 1002, 1004, 1006 can be communicatively connected via a wired network 1008, such as, for example, a controller area network (CAN), a LONWorks network, a LIN network, an RS-232 network, a Firewire network, a DeviceNet network, or any other type of network or fieldbus that provides a communication system for communication between these electronic control circuits. Regardless of the specific type of wired network 1008, a wired link can exist between the physical network nodes (i.e., active electronic devices or circuits attached to the bed control system 1000 and capable of sending, receiving, or forwarding information via the wired network 1008) and the electronic control circuits (controllers) that are programmed and/or designed to control movement of at least the leg actuators of the bed, and optionally control bed drive and/or lighting of height indicators, locking and unlocking of wheel locks, unlocking of external bed fasteners, data logging and error monitoring, calibration, and signal transmission.

Each physical network node typically includes a circuit board that includes the electronics needed to control a user interface, one or more actuators, one or more sensors, and/or one or more other electrical components, as well as the associated electronics needed to allow each node to communicate within the bed control system 1000. For example, in FIG15 , the first node in the bed control system 1000 may be a motor controller 1002 for controlling one or more motors, actuators, and/or each movable caster lock (brake) of the bed 10 (e.g., actuators 16, 18, steering mechanism 90, locking actuator 92, and/or braking mechanism 94 ( FIG1 and FIG7 )). The motor controller 1002 includes the associated electronics needed to allow the controller to communicate with any other networked electronics using a wired network 1008. In one embodiment, one or more processors may be embodied as the motor controller 1002.

The GUI controller 1004 can be a second node configured to control a graphical user interface 1005 and, in one embodiment, can be embodied as a control box 50 having a visual display assembly or GUI 58, i.e., as a user display unit. The graphical user interface 1005 can include one or more buttons or switches, such as any of the buttons in the button arrays 52 and/or 54 ( FIG. 8 ), or it can include a touch screen or other such device for allowing the patient or caregiver to control one or more aspects of the bed 10 and an output display to provide visual/graphical feedback of the bed's status, along with corresponding audio and/or tactile output from an included audio and/or tactile output generating device. The GUI controller 1004 includes the associated electronics necessary to allow the GUI controller 1004 to communicate with any other networked electronics using a wired network 1008.

A third node in the bed control system 1000 may be a battery unit or controller 1006 for controlling one or more battery-based power supplies for the bed 10. The battery controller 1006 also includes the associated electronics necessary to allow the controller 1006 to communicate with any other networked electronics using the wired network 1008. In other embodiments, other nodes in the bed control system 1000 are, for example, one or more sensors that can be connected to the wired network 1008 and/or directed to any of the controllers 1002, 1004, and 1006.

In the illustrated embodiment, corresponding outputs of the sensors described below are connected to inputs of the motor controller 1002. The one or more sensors may include one or more position sensors 1010 for detecting the relative position/orientation of components of the cot 10, such as whether the loading-end legs and the control-end legs are in an open position (i.e., the cot is raised above its lowest position by the associated legs) or in a closed position (i.e., the associated legs are in their lowest position, thereby placing the cot in its lowest position). The one or more sensors may also include one or more temperature sensing sensors 1012 for detecting the operating temperature of the motor. The one or more sensors may include one or more proximity sensors 1014 and/or 1016 for detecting the position/orientation of a first component of the cot 10 relative to an external support surface (such as a ground or ambulance transport compartment) and/or relative to another component of the cot, such as for detecting the proximity of the intermediate loading wheel to another external surface and the relative orientation of the operator (control-end) leg actuator bracket to the support frame. The one or more sensors may include one or more angle sensors 1018 for detecting the angular orientation of one or more components of the bed 10, such as the angles of the loading end legs and the control end legs. The one or more sensors may include one or more detection sensors 1020 for detecting proximity and/or connection to external bed fasteners, such as those provided in an emergency transport. The one or more sensors may include one or more voltage sensing sensors 1022 for detecting a voltage, such as a charging voltage. It will be appreciated that in the illustrated embodiment, the motor controller 1002 is responsible for processing the output of these sensors 1010, 1012, 1014, 1016, 1018, 1020, and/or 1022 and forwarding messages containing the sensed information via the wired network 1008 to other networked electronics in the bed control system 1000, such as controllers 1004 and 1006.

In yet another embodiment, the bed control system 1000 of the bed 10 may further include a wireless controller 1024, which is networked to the other controllers 1002, 1004, and 1006 via a wired network 1008 to provide at least forwarded messages and any other messages transmitted via the wired network 1008 to an external wireless receiver as needed. For example, if a hospital begins using music to help relieve pain, a music player application 1009 may be loaded into the GUI controller 1004, synchronized with the hospital network via the wireless controller 1024, and play the same music transmitted/broadcast/streamed via the hospital network. In this embodiment, an operator can use the GUI 1005 to operate the music player application 1009 (to automatically synchronize with the hospital music system, stop, select, change, etc. when necessary) and play music through the audio speakers 1011 using the volume controls provided on the bed 10. If desired, the music player application 1009 can also select and play a preloaded selection of music from the memory 102 ( FIG. 7 ). It should be appreciated that the wireless controller 1024 includes and/or is electronically coupled to a wireless transceiver 1126 that provides a wireless communication link 1028 to an external wireless receiver 1030. The wireless communication link 1028 may be a Bluetooth connection, a ZigBee connection, a RuBee connection, a WiFi (IEEE 802.11) connection, an infrared (IR) connection, or any other suitable wireless communication connection.

The couch 10 has multiple modes of operation, five (5) of which are operator-selected powered motion modes of operation: wake-up, direct power - both legs, direct power - load-end leg mode, direct power - control-end leg mode, and seat position mode. In one embodiment, these five (5) modes can be selected from the GUI 1005 via button 53 and/or via button arrays 52 and/or 54, and in another embodiment, can be selected from the control box 50. The GUI 1005 can provide visual and/or auditory cues regarding the current operation of the couch 10, such as audibly saying "raise" or "lower" through the speaker 1011 when the couch is operating in the powered mode of raising or lowering the couch 10. The five operator-selected powered motion modes of operation are now discussed below.

The "wake-up" mode is a fully operational mode of the bed 10, allowing independent leg movement of the control-end legs and the load-end legs. Depending on the state of the bed 10, one or both legs may respond to "+/raise/extend" and "-/lower/retract" operator control buttons 1035 and 1037, respectively, which may be provided, for example, via a user interface 1039. The user interface 1039 may also include power controls 1041, such as buttons, toggle switches, selectors, and the like, to provide "power on/off" and "power off" to the bed control system 1000 of the bed 10 upon operator command. Manipulating the power controls 1041 to turn the bed control system 1000 into an active state (i.e., wake-up mode) sends a supply voltage (PWR) signal to the motor controller 1002. Control buttons 1035, 1037 may also be provided as selector positions or toggle positions of a selector or toggle switch, such as may be provided by buttons 56, 60, button arrays 52, and/or 54 depicted in Figure 8. Furthermore, in other embodiments, the GUI controller 1004, GUI 1005, and/or user interface 1039 may be provided as an integral part of or separate from the control cartridge 50 (Figure 1).

The direct power modes allow the operator to directly (and independently) control the movement of the couch's legs via the user interface 1039 and/or the GUI 1005. For example, by selecting one of the direct power modes, the operator can independently control one or both sets of legs to raise, lower, load, or unload the couch. In the following direct power modes, the couch 10 will not use any of its sensors to determine which leg should be moved in response to a button press of one of the operator control buttons 1035, 1037 (such as the raise button 56 or the lower button 60). The "direct power - both legs" mode allows the operator to directly power the control and loading leg motors by selecting "direct power mode - both legs" with a direct power mode button (e.g., a button in the button array 52 and/or button 53 on the GUI 1005) and then pressing the raise/extend operator control ("+") button 1035 or the retract/lower operator control ("-") button 1037, regardless of other sensor values. "Direct Power - Loading Leg Mode" allows the operator to directly power the loading (loading) leg motors by pressing the "+" button 1035 or the "-" button 1037, regardless of other sensor values. "Direct Power - Control Leg Mode" allows the operator to directly power the control (operator) leg motors by pressing the "+" button 1035 or the "-" button 1037, regardless of other sensor values. "Seating Position Mode" allows the operator to easily move the couch 10 to a position in which the patient surface is angled to allow the patient to more easily sit on the couch, as explained in more detail earlier in the text with reference to Figures 13 and 14. The couch 10 can be set up with a single loading height that matches the height at which it can be loaded onto an external support surface, such as above the ground (e.g., the floor of a vehicle). When the operator raises the couch 10 using the "+" button 1035, the couch 10 will automatically stop at this height. It should be understood that in each direct power mode, after the operator places the bed in a particular direct power mode, a countdown timer counts down from a predetermined amount of time (e.g., 15 seconds). If the operator does not perform further action (i.e., press one of buttons 1035 or 1037) after selecting the direct power mode, the motor controller 1002 reverts to its standard operating mode upon expiration of the countdown timer. In some embodiments, a graphical image showing the countdown timer 59 ( FIG. 8 ) and the corresponding count can be provided on the GUI 1005.

"Sleep Mode" is a state of reduced power consumption during periods of sleep when the bed 10 is asleep. "Manual Operation" is used to retract the bed legs without the need for electrical control. Manual Operation exists independently of any motor controller operation or input signal. The motor controller 1002 will be unaware that a manual operation has been performed and will behave exactly as if no manual operation has been performed. Operation in this mode requires no software. When the bed's power controls 1041, such as those provided by one of the button arrays 52 or 54 ( FIG. 8 ), are in the off position/state ("Off Mode"), the motor controller 1002 is powered off (off), and the display, position indicator, and drive lights 1032 , 1034 of the GUI 1005, as well as the load and control end solenoid actuators 1036 , 1038, are not powered. Operation in this mode also requires no software. "Charge Mode" is used when the bed 10 is connected to the charger 1040 to charge the battery, which is detected by the charge voltage sensor 1022. A graphical image can be provided to the GUI 1005 or 58 to display the corresponding voltage/charge level of the battery 1007 and a visual indication of whether the battery is currently charging, such as via a color change and/or pulsation of the battery voltage/charge level graphical image 61 ( FIG. 8 ). It should be understood that the charger is external to the bed 10 and can be connected to an outlet within the emergency transport or directly to the vehicle's power system. In other embodiments, when the bed 10 is docked into a bed fastener (not shown) that can be detected by the bed fastener detection sensor 1020, a wireless remote vehicle control (not shown) can become active for controlling the extension and retraction of the legs of the bed via command messages received by the wireless controller 1024 and sent to the motor controller 1002 for execution (if desired) via the wired network 1008.

16 , a communication messaging protocol for motor controller 1002 is shown, illustrating information provided from motor controller 1002 via wired network 1008. Each message according to this protocol consists of a header frame, which indicates the origin and type of the message provided via bed control system 1000, a byte frame, and a data frame. The header frame indicates the origin and type of the message provided via bed control system 1000, and the byte frame indicates the length of the message for message error detection. The data frame in a message from motor controller 1002 may include a B1 bit, a B2 bit, a C1 floor condition bit, a C2 floor condition bit, a D1 bit, a D2 bit, a wake-up bit, a light-off bit, a record bit, a charging voltage present bit, a light-on bit, a fastener detected bit, a USB activity bit, an A1 extension bit, an A2 extension bit, a motor status bit, a voltage range bit, and/or a motor controller error code bit.

When the "+" button 1035 is pressed, the B1 bit is set by the motor controller 1002 and the B1 bit is broadcast via the wired network 1008. When the "-" button 1037 is pressed, the B2 bit is set by the motor controller 1002 and the B2 bit is broadcast via the wired network 1008. When the C1 backplane condition bit of the input code signal is set, the C1 backplane condition bit is set by the motor controller 1002 and the C1 backplane condition bit is broadcast via the wired network 1008. When the C2 backplane condition bit of the input code signal is set, the C2 backplane condition bit is set by the motor controller 1002 and the C2 backplane condition bit is broadcast via the wired network 1008. When D1 is set (when closed), the D1 bit is set by the motor controller 1002 and the D1 bit is broadcast via the wired network 1008. When D2 is set (when closed), the D2 bit is set by the motor controller 1002 and the D2 bit is broadcast via the wired network 1008. When the operating mode is wakeup or charging, or if a "stuck button error" is active (even when motor controller 1002 is in sleep mode), the wakeup bit is set by motor controller 1002 and broadcast via wired network 1008. When the battery voltage is less than the minimum lamp voltage threshold, the lights-off bit is set by motor controller 1002 and broadcast via wired network 1008. In one embodiment, the minimum lamp voltage threshold is 5 volts, but can be set to any other desired voltage level by changing this value set in configuration file 1106 or script 1100 (Figure 19). When the motor controller is configured to log to a removable flash memory card (e.g., such as a memory stick, SD card, compact flash, etc.), the logging bit is set by motor controller 1002 and broadcast via wired network 1008.

When the motor controller detects a non-zero voltage (Charge+) via the charge voltage sensor 1022, the charge voltage present bit is set by the motor controller 1002 and broadcast via the wired network 1008. When the light is commanded to turn on via a button on the button array 52 and/or 54 and/or a remote control signal received via the wireless controller 1024, the light on bit is set by the motor controller 1002 and broadcast via the wired network 1008. When a software utility is connected to the controller (e.g., for programming, diagnostics, updates, etc.), the USB activity bit is set by the motor controller 1002 and broadcast via the wired network 1008. The A1 extension (32-bit) is set by the motor controller 1002 and broadcast via the wired network 1008 to indicate the amount of extension of the load (load-end) outrigger actuator rod. The A1 extension is expressed in mils, ranging from 0 to 18,000, with 0 mils being fully retracted and 18,000 mils being fully extended. A2 Extension (32 bits) is set by the motor controller 1002 and broadcast over the wired network 1008 to indicate to the operator (control end) the extension of the outrigger actuator rod. A2 Extension is expressed in mils and ranges from 0 to 18,000, where 0 mils is fully retracted and 18,000 mils is fully extended.

The motor state bits (32 bits in one embodiment, other desired bit lengths in other embodiments) are set by the motor controller 1002 and broadcasted over the wired network 1008 to indicate the current motor state using the following count: 0 = motor state 0; 1 = motor state 1; 2 = motor state 2; 3 = motor state 3; 4 = motor state 1-; 5 = motor state 2-; 6 = motor state 3-; 7 = motor state 4; 8 = motor state 5; 9 = motor state 6; 10 = motor state 7; 11 = motor state 8; and 12 = motor state 9. Each of these motor states is discussed in more detail in the following sections. For any condition where leg movement is locked, the motor controller 1002 will report motor state 0 to the GUI controller 1004 for indication on the display 1005. The voltage range bits (32 bits in one embodiment, other desired bit lengths in other embodiments) are set by the motor controller 1002 and broadcasted over the wired network 1008 to indicate the current voltage range. When a motor controller error code bit is detected, the motor controller error code bit is set by the motor controller 1002 (64 bits in one embodiment, other desired bit lengths in other embodiments) and broadcast via the wired network 1008. The conditions that cause a particular motor controller error code to be provided are discussed in more detail in a later section.

Referring to FIG. 17 , the communication messaging protocol for the battery controller 1006 is shown, illustrating information provided from the battery controller 1006 via the wired network 1008. Each message according to this protocol consists of a header frame, indicating the origin and type of the message provided via the bed control system 1000, a byte frame, and a data frame. The header frame indicates the origin and type of the message provided via the bed control system 1000, and the byte frame indicates the length of the message for error detection. The data frame in messages from the battery controller 1006 may include a charge bit, a full charge level, a battery error code bit, a high temperature bit, a battery temperature byte, a battery voltage byte, and/or an undervoltage bit. While the battery 1007 is being charged via the charger 1040, the charge bit is set in messages by the battery controller 1006 and periodically broadcast via the wired network 1008. The motor controller 1002 uses this information to detect charging errors when compared with the value of the charge voltage sensor 1022, which should also indicate that the battery 1007 voltage is below a level indicating the required charging current. When the battery 1007 is at the fully charged voltage, the battery controller 1006 sets the full charge level in the message and broadcasts the full charge level via the wired network 1008. The motor controller 1002 uses this information to detect charging errors when compared to the value of the charge voltage sensor 1022, which should also indicate that the battery is no longer below a voltage level indicating the current required for charging.

In response to detecting an error in the current and/or voltage provided by the battery 1007 while powering the operation of the bed 10, the battery controller 1006 sets a battery error code bit (16 bits in one embodiment, other desired bit lengths in other embodiments) in a message and broadcasts the battery error code bit via the wired network 1008. The motor controller 1002 uses the battery error code to set a motor controller error code for the display 1005, as discussed later. When the battery 1007 is at a temperature greater than 55°C, the battery controller 1006 sets a high temperature bit in a message and broadcasts the high temperature bit via the wired network 1008. The motor controller 1002 also uses this information to set a motor controller error code for the display 1005. After reading the battery temperature and voltage, the battery controller 1006 sets a battery temperature byte and a battery voltage byte in a message and periodically broadcasts the temperature byte and battery voltage byte via the wired network 1008. If the least significant bit in the message from the battery controller 1006 does not change after a certain time, the motor controller 1002 will read the battery voltage (ChargeV) from the input of the charge voltage sensor 1022. In one embodiment, when the total battery voltage 1007 is below 33.5V, the battery controller 1006 sets the undervoltage bit in the message and broadcasts the undervoltage bit via the wired network 1008. In other embodiments, the total battery voltage can be higher or lower as needed and as set in the configuration file 1106. At this voltage and while it remains below this voltage, the motor controller 1002 will read the battery voltage (ChargeV) from the input of the charge voltage sensor 1022 instead of reading it from the message from the battery controller 1006.

18 , a communication messaging protocol for GUI controller 1004 is shown, illustrating information provided from GUI controller 1004 via wired network 1008. Each message according to this protocol consists of a header frame, which indicates the origin and type of the message provided via bed control system 1000; a byte frame, which indicates the length of the message for error detection; and a data frame. The data frame in messages from GUI controller 1004 includes a lamp driver bit, a direct power mode code bit, a display software version bit, a display configuration version bit, and a display graphics version bit.

When the operator commands activation of the driving lights 1034 (such as lights 86, 88, and 89) of the bed 10 via the GUI 1005, the GUI controller 1004 sets the driving light bit in a message and broadcasts the driving light bit via the wired network 1008. The motor controller 1002 turns on the driving lights 1034, such as lights 86, 88, and 89, in response to reading the message from the GUI controller that the driving light bit is set. As explained in the following sections, the motor controller 1002 reads and uses the direct power mode code bits (3 bits in one embodiment, other desired bit lengths in other embodiments) when selecting an operating mode. The direct power mode code bits are set in a message by the GUI controller 1004 in response to the operator's input via the GUI 1005 and broadcast via the wired network 1008. The remaining data provided by the GUI controller 1004 (such as the display software version bits, the display configuration version bits, and the display graphics version bits) are set by the GUI controller 1004 in the message in response to the query and are used by the motor controller 1002 to set these version values and provide these version values to an external utility issuing the query connected to the motor controller via USB for diagnostic/update purposes.

Table 1: Motor Controller I/O and I/O signals between motor controller 1002 and the rest of system 1000 are shown in FIG. 15 .

Table 1: Motor Controller I/O

The motor controller 1002 selects a mode based on the input signals received, see Table 1 and Figure 19. In this illustrated embodiment, the motor controller 1002 follows program instructions provided via one or more scripts 1100. Each script provides program code or bytecode that is saved to and executed from a memory of the motor controller 1002 (such as memory 102 (Figure 7)). Each bytecode can be, for example and without limitation, a logical expression, a statement, or a value input to the motor controller 1002 for execution. For example, in one embodiment, a wake-up timer 1104 (Figure 19) is implemented via a script that uses one or more timer registers of the controller 1002. The timer register is a counter that can be loaded with a value using a script command from the script 1100. The counter then counts down every millisecond regardless of the execution state of any other script. The program code of the script includes the following functions: loading the timer, reading its current count value, pausing and resuming the count, and checking whether the count has reached zero (0).

Many other scripts 1100 are provided in the controller's memory 1102, which enable the bed 10 to provide all of the aforementioned movements, operations, and instructions. These scripts are discussed in more detail in the following sections. The motor controller 1002 also uses a configuration file 1106, also stored in memory (e.g., memory 102), to read from and compare and/or set specific preset/predetermined parameters/variables discussed herein. It should be understood that any preset parameter discussed herein can be provided in a configuration file 1106 or script 1100 and read from by the motor controller 1002, and if provided in the configuration file 1106, can be customized by the operator. Once a particular script is stored in the controller's memory (e.g., memory 102), it can be executed manually or automatically whenever the controller 1002 is powered on. Manual activation is performed by sending a command via the USB port. Scripts can be automatically activated after the controller is powered on, for example, via a PWR signal from the user interface 1039, or after enabling, for example, a bootloader in the controller's configuration memory by setting an automatic script configuration. When enabled, if a script is detected in memory after a reset, script execution is enabled and the script will be run.

FIG20 illustrates, via a flowchart, a main script (i.e., program instructions) 2000 executed by the motor controller 1002 to automatically determine the motor mode selection based on the above-described inputs and issue motor commands in real time (i.e., in less than 1 second). In process step 2002, the motor controller 1002 checks whether the PWR signal from the user interface 1039 is low. If so, the mode maintained by the motor controller 1002 is "off" mode 2004. If the PWR signal from the user interface 1039 is high in process step 2002, the motor controller 1002 checks whether the charge voltage (ChargeV) from the charger is non-zero in process step 2006. If so, the mode selected by the motor controller 1002 is "charge" mode 2008. If the ChargeV voltage is zero in process step 2006, the motor controller 1002 checks whether the previous mode was "charge" mode 2008 in process step 2010. If so, the motor controller 1002 checks in step 2012 whether the wake-up timer 1104 running on the motor controller 1002 has expired. If so, the motor controller 1002 places the bed 10 in "sleep" mode 2014. If the motor controller 1002 determines in process step 2012 that the wake-up time of the wake-up timer 1104 has not expired, the motor controller 1002 places the bed in "wake-up" mode 2016. It should be understood that the wake-up time can be configured via the configuration file 1106, but in one embodiment, the wake-up time can be, for example, selected from a range of 0 to 10,000 seconds, and in one specific embodiment, is 600 seconds. However, if in process step 2010 the previous mode was not charging mode 2008, the motor controller 1002 checks in process step 2018 whether the previous mode was "off" mode 2004. If so, the motor controller 1002 places the bed in "sleep" mode 2014. In other words, after a preset amount of time of non-use, the motor controller 1002 will enter a "sleep" mode 2014 to conserve power.

In process step 2018, if it is determined that the previous mode was not the "off" mode 2004, then in process step 2020, the motor controller 1002 checks whether the time specified by the wake-up time has passed since the last press of the "+" or "-" button 1035 or 1037. If so, the motor controller 1002 places the bed in the "sleep" mode 2014. If the "+" or "-" button 1035 or 1037 is pressed while the bed is in the sleep mode 2014 in step 2022, the motor controller 1002 will then place the bed in the wake-up mode 2016. If the time specified by the wake-up time has not passed since the last press of the "+" or "-" button 1035 or 1037 in process step 2020, the motor controller 1002 checks in step 2024 whether the direct power mode code is 0 (i.e., selected via the "wake-up" button on the control box 50 and/or GUI 1005). If the direct power mode code is 0, the motor controller 1002 checks in step 2026 whether the "+" or "-" button 1035 or 1037 has been pressed, and if not, the motor controller 1002 places the bed in the "wake-up" mode 2016. If the direct power mode code is not 0 in process step 2024, the motor controller 1002 checks in process step 2028 whether the direct power mode code is 1 (i.e., via selection of a "direct power - both legs" button on the control box 50, for example, by pressing the button array 52, 54 or button 53 and/or a button of the GUI 1005), and if so, actuates the bed in the "direct power - both legs" mode. If the direct power mode code is not 1 in process step 2028, the motor controller 1002 checks in process step 2030 whether the direct power mode code is 2 (i.e., via selection of the "direct power - load end legs" button on the control box 50, button 53, and/or GUI 1005), and if so, activates the couch in the "direct power - load end legs" mode. If the direct power mode code is not 2 in process step 2030, the motor controller 1002 checks in process step 2032 whether the direct power mode code is 3 (i.e., via selection of the "direct power - control end legs" button on the control box 50, button 53, and/or GUI 1005), and if so, activates the couch in the "direct power - control end legs" mode. If the direct power mode code is not 3 in process step 2032, the motor controller 1002 checks in process step 2034 whether the direct power mode code is 4 (i.e., via selection of the "Set Loading Height" button on the control box 50, button 53, and/or GUI 1005), and if so, activates the cot in "Set Loading Height" mode. If the direct power mode code is not 4 in process step 2034, the motor controller 1002 checks in process step 2036 whether the direct power mode code is 5 (i.e., via selection of the "Seat Position" button on the control box 50, button 53, and/or GUI 1005), and if so, activates the cot in "Seat Position" mode. If the direct power mode code is not 5 in process step 2036, the motor controller 1002 places the cot in wake-up mode. If, in process step 2026, the motor controller 1002 detects a press of the "+" or "-" button 1035 or 1037, the motor controller 1002 determines and selects a motor state command based on the received input in process step 2038, as explained in more detail in a later section below. It should be understood that in some embodiments, one of the buttons of the button array 52, 54, or button 53 can be used as a mode selection button that allows the user to cycle through a sequence of mode selections, each mode selection having an associated one of the direct power mode code values discussed herein. For example, in some embodiments, each button press cycles to the next mode and causes the motor controller 1002 to display a matching image for the selected mode on the GUI 58 or 1005. For example, FIG24A depicts a matching image for selecting the direct power-two leg mode displayed on GUI 1005, FIG24B depicts a matching image for selecting the direct power-load-side leg mode displayed on GUI 1005, and FIG24C depicts a matching image for selecting the direct power-control-side leg mode displayed on GUI 1005. FIG24D depicts a matching image for selecting the seat position mode displayed by motor controller 1002 on GUI 1005, which will be discussed in a later section. In some embodiments, the button press sequence is: direct power - both legs, corresponding to direct power mode code = 1; direct power - loading end legs, corresponding to direct power mode code = 2; direct power - control end legs, corresponding to direct power mode code = 3; set loading height, corresponding to direct power mode code = 4; and standard (normal) operating mode, putting the motor controller 1002 back into control of the following sequence of automatic operations: moving the legs based on sensor input, and pressing other buttons on the control box 50, and/or pressing the "+" or "-" button 1035 or 1037, as discussed herein.

Off-mode and Charge-mode operation

In the off mode and the charging mode of operation, the motor controller 1002 is powered, but power is not delivered to the actuators 16, 18, and the lights 86, 88, 89 do not provide illumination. The motor controller 1002 ignores any input from the "+" and "-" operator control buttons 1035, 1037. The following sections will continue to describe error detection, error logging, and error code updating. As described above, if the PWR signal from the user interface 1039 is high, and then if the charge voltage (ChargeV) from the charger 1040 is not zero, the mode is "Charge", which sets the charge voltage present bit in the message sent from the motor controller 1002 via the wired network 1008.

Sleep mode operation

In sleep mode operation, the motor controller 1002 is powered off to minimize power consumption of the battery's energy. In this mode, no power is delivered to the actuators, and the lights 1032 and 1034 do not provide illumination. If an input occurs, i.e., a press of the raise/extend operator control ("+") button 1035 or the lower/retract operator control ("-") button 1037, then upon releasing the press of either button 1035 or 1037, the motor controller 1002 is placed into wake mode operation. As long as the wake timer 1104 has not expired, the next "+" or "-" button press will then operate the bed 10 as described below, thereby returning the motor controller 1002 to "sleep" mode as described above. In sleep mode, the motor controller 1002 continues to monitor for error conditions. Any detected errors are logged in the error log file, but no further error handling occurs to minimize power consumption of the battery's energy.

Direct power supply - two outriggers, load-end outrigger or control-end outrigger

In Direct Power - Two Leg Mode, Direct Power - Load Leg Mode, and Direct Power - Control Leg Mode, the motor controller 1002 continues to monitor for error conditions. Any detected errors are recorded in the error log file. The associated error code bit is set for any detected error. No other error handling occurs in this mode. The motor controller 1002 ignores all sensors (including angle sensors, proximity sensors, and leg status sensors) to control leg motion in these modes. The motor status is 5 for Direct Power - Control Leg Mode. The motor status is 6 for Direct Power - Two Leg Mode. The motor status is 7 for Direct Power - Load Leg Mode.

Seat position mode

In the seat position mode, the motor controller 1002 displays the image depicted in FIG. 24D on the GUI 1005 and ignores the "+" button 1035. While the "-" button 1037 is held, the motor controller 1002 moves the couch 10 in a horizontal position to the seat position height parameter preset in the configuration file 1106. Once the couch has reached the seat position height, the load-end legs 20 will stop moving, and the control-end legs 40 will retract to the operator seat height using controlled electrical power. If the load-end legs 20 are already at the seat position height when the "-" button 1037 is pressed, the motor controller 1002 will directly retract the control-end legs 40 to the operator seat height preset in the configuration file 1106 using controlled electrical power speed if the load-end legs 20 are not moving. The motor state for the seat position mode is 9.

Setting the loading height

When the set load height is selected in the setup mode, the motor controller 1002 stores the current A1 value in memory (e.g., memory 102) as the preset load height provided in the configuration file 1106. The setting is stored in the configuration file 1106 relative to the extension of the actuator rod, rather than the raw voltage reading. When in this mode, the motor controller 1002 ignores the operator control buttons 1035, 1037.

Wake-up mode

Wake-up mode is the standard (full) operating mode of the bed. This mode allows independent leg movement of the control end legs and the loading end legs.

21 , the motor controller 1002 automatically determines the motor state in process step 2038 ( FIG. 20 ) using the values of the bits in the input code signal according to the mapping shown. The motor state commands are defined in the following section provided below. The bits of the input code signal are defined as follows: Bit 0 = D1, Bit 1 = D2. Referring also to FIG. 22 and FIG. 23 , a cross-section of the cross member 64 (taken along the section line A-A depicted in FIG. 2 ) is shown, to which the upper actuator cross member 299 ( FIG. 6 ) is rotatably attached. As shown in FIG. 22 and FIG. 23 , the cross member 64 provides a pivot plate 2200 within a cavity 2202 defined by its bottom surface 2203. The pivot plate 2200 is rotatably attached to the cross member 64 adjacent a first end 2204 and is rotatably attached to the upper actuator cross member 299 adjacent a second end 2206 that is spaced apart (ie, distal) from and below the first end 2204 .

As shown in FIG23 , the pivot plate 2200 can rotate about the first end 2204 through an angle r ranging from 0 to 15 degrees in one embodiment, from 0 to 30 degrees in other embodiments, and from 0 to 45 degrees in yet another embodiment, or any other value between 0 and 90 degrees. As shown in FIG22 , the pivot plate 2200 is in a first position X1 when the side 2208 of the pivot plate is spaced (i.e., away from) and above the actuator cross member 299, in close proximity (i.e., angle r < 3 degrees), parallel to, or against the bottom surface 2203 of the cross member 64. The open/close sensor 1010 ( _FIG15 ), which can be, for example, a reed switch sensor, a Hall effect sensor, an angle sensor, or a contact switch, detects the first position _X1 and communicates it to the motor controller 1002. Thus, bit D1 is set to 1 when sensor 1010 detects that the pivot plate 2200 loading the legs is in the first position _X1 orientation as shown in FIG. 22 , and is set to 0 when the pivot plate 2200 is in the second position _X2 orientation as shown in FIG. 23 .

In one embodiment, sensor 1010 indicates the second position _X2 when angle r is greater than 3 degrees. In yet another embodiment, sensor 1010 indicates the second position X2 when upper actuator cross member 299 is lowered to 2.5 mm below its relative position when pivot plate 2200 is in the first position _X1 . Similarly, because the pivot plate (not shown) of the control end leg is identical to pivot plate 2200, bit D2 is set to ₁ when the pivot plate of the control end leg is in the first position _X1 as shown in FIG. 22, and is set to 0 when the pivot plate of the control end leg is in the second position _X2 as shown in FIG. 23.

In yet other embodiments, it will be appreciated that the bed actuation system 34 interconnects the support frame 12 and each of the pair of legs 20, 40 under the automatic control of the bed control system 1000 and is configured to vary the height of the support frame 12 relative to the wheels 26, 46 of each of the legs 20, 40 as described in the preceding sections. The bed control system 1000 controls activation of the bed actuation system 34 and, as described above, is configured to detect when one or both actuators 16, 18 of the bed actuation system 34 are in a first orientation or position _X1 relative to the support frame 12, wherein the first orientation is distal from a second orientation or position _X2 , and to position the ends of the actuators 16 and/or 18 distal from the wheels 26, 46 (i.e., the cross member 299) closer to the support frame 12. When there is a signal requesting a change in the height of the support frame 12 relative to the wheels 26, 46 of each of the legs 20 and/or 40 (such as pressing a control button 56 or 60 and/or an input code signal indicating this height change as shown in the following section), the bed actuation system 1000 causes one or both actuators 16, 18 of the bed actuation system 34 to direct the support frame 12 and legs 20 and/or 40 closer or farther apart based on input received from one or more sensors regarding the sensed conditions discussed above in this document.

Referring back to FIG. 21 , bit 2 of the input code signal indicates to the motor controller 1002 the state of the C1 floor condition and is determined according to the following equation: C1&&A1<5%, where C1 is 1 when the load wheel proximity sensor detects the floor and C1 is 0 when the load wheel proximity sensor does not detect the floor. When the load end actuator rod is extended less than 5%, the expression A1<5% holds true (1). Bit 3 of the input code signal indicates to the motor controller 1002 the state of the C2 floor condition and is determined according to the following equation: C2&&A1<1%&&A2<5%, where C2 is 1 when the control end leg mounted proximity sensor detects the floor and C2 is 0 when the proximity sensor does not detect the floor. When the load end actuator rod is extended less than 1%, the expression A1<1% holds true. When the control end actuator rod is extended less than 5%, the expression A2<5% holds true. Bit 4 of the input code signal indicates to the motor controller 1002 that the intermediate loading condition or loading angle is present and is determined by the following equation: A2-A1>37%&&A1<5%, where the expression A2-A1>37% holds true when the extension of the control-end actuator rod relative to the total possible extension is 37% greater than the extension of the load-end actuator rod. The expression A1<5% holds true when the load-end actuator rod is less than 5% extended. Bit 5 of the input code signal indicates to the motor controller 1002 that the bed height is at the maximum value and is determined by the following equation: A2&&A1>99% horizontal range, which indicates that the extension of both the control-end actuator rod and the load-end actuator rod is greater than 99%.

As shown in FIG21 , when the input code signal bit has a decimal value in the range of 24-63, the motor control 1002 automatically selects motor state 0. When the input code signal bit has a decimal value selected from 2, 6, 10, 14, and 18, the motor control 1002 automatically selects motor state 1. When the input code signal bit has a decimal value of 19, the motor control 1002 automatically selects motor state 1-. When the input code signal bit has a decimal value selected from 1, 4, 5, 9, 17, 20, and 21, the motor control 1002 automatically selects motor state 2. When the input code signal bit has a decimal value selected from 22 and 23, the motor control 1002 automatically selects motor state 2-. When the input code signal bit has a decimal value selected from 3, 7, 11, and 15, the motor control 1002 automatically selects motor state 3. When the input code signal bit has a decimal value selected from 8, 12, and 13, the motor control 1002 automatically selects motor state 3-. Motor control 1002 automatically selects motor state 8 when the input code signal bits have a decimal value selected from 0 and 16. It will be appreciated that the operator manually selects motor states 5-9 as described above with reference to the seat position mode and the direct power mode.

Automatic Stop Due to Leg State Change: When the input code signal changes due to a change in the D1 or D2 state, the motor controller 1002 stops moving the bed's legs until either button 1035 or 1037 is pressed again.

Position indicator light. The position indicator light 1032 (such as implemented as the line indicator 74 (Figure 7) in one example) is illuminated (on) when the bed 10 is not attached to the charger 1040 and the conditions in two situations have been met. For the first situation, the following conditions need to be met: the loading position of the input code signal is set, and the control end leg is in the first position _X1 . The loading position is set when the extension of the loading leg is <5%, and the difference between the loading end leg and the control end leg is ≥40%. For the second situation, the following conditions need to be met: when the loading end sensor 76 "sees" the loading surface, and the control end leg is in the extended state (>5%).

Movement within the motor state

Motor State 0: In this motor state, the motor controller 1002 ignores any presses of the buttons 1035, 1037, so that neither the load-end solenoid actuator 1036 nor the control-end solenoid actuator 1038 is activated, so that the legs 20, 40 are neither extended nor retracted.

Motor State 1: When the "+" button 1035 is pressed, the motor controller 1002 causes the load-end solenoid actuator 1036 to extend the load-end leg 20 in an open-loop mode at the maximum possible speed. The control-end solenoid actuator 1038 is not activated by the motor controller 1002, so that the control-end leg 40 does not move. When the "-" button 1037 is pressed, the motor controller 1002 causes the load-end solenoid actuator 1036 to retract the load-end leg 20 in an open-loop mode at the maximum possible speed. The control-end solenoid actuator 1038 is not activated by the motor controller 1002, so that the control-end leg 40 does not move unless the kickup mode conditions described below are met.

Upshift Mode: When the input code signal transitions from 2 to 18 (i.e., the loading-end legs 20 are fully retracted to establish an intermediate loading condition), the motor controller 1002 automatically extends the control-end legs 40 to the upshift height defined in the configuration file 1106. If the control-end legs 40 have not been extended to the upshift height after the upshift time (a countdown timer predefined in the configuration file 1106) expires, the motor controller 1002 stops attempting to extend the control-end legs 40. This action prevents the motor controller 1002 from continuing to attempt to extend the control-end legs 40, which are already at their maximum possible extension. As long as the "-" button 1037 is pressed and the loading-end legs 20 have not yet reached their maximum retraction, the loading-end legs 20 will continue to be retracted by the motor controller 1002 during the upshift mode. After the upshift time timer expires and when the loading-end legs 20 have reached their maximum retraction, the motor controller 1002 deactivates the loading actuator 18.

Motor State 1-: In this motor state, pressing the "+" button 1035 does not cause the motor controller 1002 to activate the solenoid actuators 1036, 1038. However, pressing the "-" button 1037 causes the motor controller 1002 to activate the load-end solenoid actuator 1036, thereby retracting the load-end leg 20 in open-loop mode at the maximum possible speed. Furthermore, the control-end solenoid actuator 1038 does not move, causing the control-end leg 40 to remain at the same height.

Motor State 2: In this motor state, pressing the "+" button 1035 causes the motor controller 1002 to activate only the control end solenoid actuator 1038, causing the control end leg 40 to extend in open loop mode at the maximum possible speed. When pressing the "-" button 1037, the motor controller 1002 activates only the control end solenoid actuator 1038, causing the control end leg 40 to retract in open loop mode at the maximum possible speed.

Motor State 2-: In this motor state, the motor controller 1002 ignores any presses of the "+" button 1035, causing neither the load-side solenoid actuator 1036 nor the control-side solenoid actuator 1038 to be activated, causing the legs 20, 40 to not extend. When the "-" button 1037 is pressed, the motor controller 1002 activates the control-side solenoid actuator 1038, causing the control-side leg 40 to retract in open-loop mode at the power setting specified by the KickDownPower parameter provided in the configuration file 1106.

Motor State 3: When the "+" button 1035 is pressed and the extension of the load-end legs 20 and control-end legs 40 are equal within 2% of the operating range, the motor controller 1002 causes the load-end solenoid actuator 1036 to extend the load-end legs 20 at the power setting specified by the "Raise Power" in the configuration file 1106. Furthermore, the motor controller 1002 activates the control-end solenoid actuator 1038, causing the control-end legs 40 to extend in tracking mode (tracking the position of the load-end legs). When the legs 20, 40 reach the first stop position determined by the transport height parameters preset in and read from the configuration file 1106 or script 1100, the motor controller 1002 stops extension of the legs 20, 40. To continue extension of the legs 20, 40, the "+" button 1035 must be released and re-pressed. When the "+" button 1035 is pressed again after stopping at the transport height stop position, the motor controller 1002 will extend the legs 20, 40 again until the legs reach the loading height stop position. In order to continue extending the legs 20, 40 beyond the loading height stop position to their maximum possible extension (the highest horizontal stop position (A1=99%, A2=99%)), the "+" button 1035 will again have to be released and pressed again.

It will be appreciated that if the loading height stop position is set within 0.2 inches (5.08 mm) of the transport height stop position (measured on the actuator stem), the motor controller 1002 ignores stops at the loading height stop position. This feature is useful during field operation when the loading height stop position may have to be deactivated due to an error and/or for current care needs. When the motor controller 1002 begins moving the legs 20, 40 via activation of the solenoid actuators 1036, 1038, the leg extension speed will ramp from the starting raise power speed (i.e., the first power setting parameter) to the raise power parameter setting (a second power setting parameter that is greater than the first power setting parameter so that the bed is raised faster than when raised at the first power setting parameter) over the time period specified by the soft start acceleration raise parameters, all of which are preset and read by the motor controller 1002 from the configuration file 1106 or script 1100. After the operator releases the "+" button 1035, the motor controller 1002 will ramp the leg extension speed down to the start raise power speed (i.e., the first power rating parameter) over the time period specified by the soft stop parameters, all of which are also preset and read by the motor controller 1002 from the configuration file 1106 or script 1100. If the ChargeV signal value from the sensor 1022 (or as reported by the battery controller 1006 via battery communication messages) is less than the start raise power, the motor controller 1002 will set the output power to the solenoid actuators 1036, 1038 to zero (0) volts. When approaching the transport height stop position, the motor controller 1002 will ramp the leg retraction speed (i.e., the power output to the solenoid actuators 1036, 1038) to zero (0) over the distance specified by the Raise Distance Correction Value parameter preset in the configuration file 1106 or script 1100. The motor controller 1002 will not move the load or control end legs beyond the maximum level parameter. If the loading or control end legs are already outside the highest level range when entering motor state 3, the motor controller 1002 will not retract the legs into the horizontal range until the "-" button 1037 is pressed.

When the "-" button 1037 is pressed and the extension of the loading-end legs 20 and the control-end legs 40 are equal within 2% of the operating range, the motor controller 1002 will activate the loading-end solenoid actuator 1036 to retract the loading-end legs 20 at the power setting specified by the reduced power parameters preset and read from the configuration file 1106 or script 1100. The motor controller 1002 also causes the control-end solenoid actuator 1038 to retract the control-end legs 40 in a tracking mode (tracking the position of the loading legs). The motor controller 1002 will stop retracting the legs 20, 40 when they reach the transport height stop position and will not continue to retract below the transport height stop position until the "-" button 1037 has been released and repressed.

When the motor controller 1002 begins to move the legs 20, 40 by activating the solenoid actuators 1036, 1038, the leg retraction speed will ramp from the start lowering power speed (third power setting parameter) to the speed set by the lowering power speed (fourth power setting parameter, which is greater than the third power setting parameter so that the bed lowers faster than when it is lowered at the third power setting parameter) over a period of time specified by the soft lowering acceleration reduction parameter, wherein all parameters are preset in the configuration file 1106 or script 1100 and read by the motor controller 1002 from the configuration file 1106 or script 1100. After the operator releases the "-" button 1037, the motor controller 1002 will ramp the leg retraction speed back to the start lowering power speed parameter over a period of time specified by the soft stop parameter. As described above, if the power reported by the sensor 1002 or the battery controller 1006 is less than the soft lowering power parameter, the motor controller 1002 sets the output power to the solenoid actuators 1036, 1038 to zero (0) volts. When approaching the lowest level stop (preset and read by the motor controller 1002 from the configuration file 1106 or script 1100), the motor controller 1002 will ramp the leg retraction speed down to zero (0) volts over the distance specified by the lowering distance correction value parameter, which is also preset in the configuration file 1106 or script 1100 and read by the motor controller 1002 from the configuration file 1106 or script 1100. The motor controller 1002 will not move either the load end leg 20 or the control end leg 40 beyond the lowest level stop. If either the load end leg 20 or the control end leg 40 is already outside the lowest level stop range when entering motor state 3, the motor controller 1002 will not retract the legs into the horizontal range until the "+" button 1035 is pressed. When the "+" or "-" button 1035 or 1037 is held and the legs 20, 40 are extended to unequal degrees exceeding 2% of the operating range of the respective solenoid actuators 1036, 1038, the motor controller 1002 automatically moves only the leg (i.e., leg 20 or 40) that needs to travel in the direction of the button press to equalize leg extension. Once the angle sensor 1018 senses that the legs 20, 40 have reached equal extension (A1 = A2), the motor controller 1002 will then simultaneously extend/retract the legs 20, 40 as described above in the previous section. The controller 1002 performs the aforementioned automatic equalization function to ensure that the level of the couch 10 is raised or lowered. It should be understood that the lowest level stop position is a set value, and the couch 10 will stop lowering at this height based on feedback from the angle sensor. If the couch 10 stops lowering above this height, pressing the "-" button 1037 will lower the unit to the stop position height. At this height, further pressing of the "-" button 1037 will do nothing, whereas pressing of the "+" button 1035 will raise the bed 10 if the extension conditions discussed herein are met. This functionality of the bed 10 prevents the buttons 1035 or 1037 from moving the bed 10 when it is fully retracted and stowed in an emergency transport.

Motor State 3-: When in this motor state, the motor controller 1002 will not respond to any presses on the "+" button 1035, so that neither the load-end leg 20 nor the control-end leg 40 moves. When the "-" button 1037 is pressed and the extension of the load-end leg 20 and the control-end leg 40 is equal within 2% of the operating range (e.g., 10 mm), the motor controller 1002 will cause the load-end solenoid actuator 1036 to retract the load-end leg 20 at the power setting specified by the reduced power parameters provided in the configuration file 1106 or script 1100. In addition, the motor controller 1002 causes the control-end solenoid actuator 1038 to retract the control-end leg 40 in tracking mode (tracking the position of the load-end leg). The motor controller 1002 will stop retracting the legs 20, 40 when they reach the transport height stop position and will not continue to retract the legs 20, 40 until the "-" button 1037 has been released and re-pressed. After the "-" button 1037 has been released and re-pressed, when the legs 20, 40 begin to move again, the motor controller 1002 will ramp the leg retraction speed from the start lowering power speed to the speed set by the lowering power speed parameter over the time period specified by the soft lowering acceleration reduction parameter. After the operator releases the "-" button 1037, the motor controller 1002 will ramp the leg retraction speed back to the start lowering power speed parameter over the time period specified by the soft stop parameter. If the power indicated by the ChargeV signal from the sensor 1022 or the power indicated by the battery controller 1006 in the communication message is less than the start lowering power speed, the output power provided by the motor controller 1002 to the solenoid actuators 1036, 1038 is set to zero (0) volts. When approaching the lowest level stop, the motor controller 1002 will ramp the leg retraction speed down to zero (0) volts over the distance specified by the decrease distance correction value parameter. The motor controller 1002 will not move either the load-end leg 20 or the control-end leg 40 beyond the lowest level stop.

The motor controller 1002 will not move the legs 20, 40 beyond the lowest level stop. If either or both legs 20, 40 are already outside the lowest level range when entering motor state 3, the motor controller 1002 will not retract the legs into the horizontal range until the "+" button 1035 is pressed. If the "-" button 1037 is held and the legs are extended to unequal degrees exceeding 2% of the operating range, only the pair of legs 20 or 40 that need to be retracted to equalize leg extension will move. Once the legs have reached equal extension (i.e., A1 = A2), they will be retracted by the motor controller 1002 as described above in the previous section.

Motor State 5: In this motor state, when the "+" button 1035 is pressed, the motor controller 1002 responds by activating only the control end solenoid actuator 1038, causing the control end leg 40 to extend at a power level set by the reduced power parameter, which is preset in the configuration file 1106 or script 1100 and read by the motor controller 1002 from the configuration file 1106 or script 1100. When the motor controller 1002 begins moving the control end leg 40, the leg extension speed ramps from the start power speed to the speed set by the reduced power parameter over the time period specified by the soft start acceleration parameter. When the "-" button 1037 is pressed, the motor controller 1002 activates only the control end solenoid actuator 1038, causing the control end leg 40 to retract at a power level set by the reduced power parameter. When the motor controller 1002 begins to move the control end leg 40, the leg retraction speed is ramped from the start reduced power speed to the speed set by the reduced power parameter over the time period specified by the soft reduce acceleration reduction parameter.

Motor State 6: When in this motor state, when the "+" button 1035 is pressed, the motor controller 1002 activates both solenoid actuators 1036, 1038, causing both legs 20, 40 to extend at the power level set by the Reduced Raise Power parameter. When the motor controller 1002 begins moving the legs 20, 40, the motor controller 1002 ramps the leg extension speed from the start-up power speed to the speed set by the Reduced Raise Power parameter over the time period specified by the Soft Start Acceleration Raise parameter. When the "-" button 1037 is pressed, the motor controller 1002 activates the solenoid actuators 1036, 1038, causing both legs 20, 40 to retract at the power level set by the Reduced Lower Power parameter. When the motor controller 1002 begins moving the legs 20, 40, the motor controller 1002 ramps the leg extension speed from the start-down power speed to the speed set by the Reduced Lower Power parameter over the time period specified by the Soft Start Acceleration Decrease parameter.

Motor State 7: In this motor state, when the "+" button 1035 is pressed, the motor controller 1002 responds by activating only the load-end solenoid actuator 1036, causing the load-end legs 20 to extend at a power level set by the Reduce Raise Power parameter, which is preset in the configuration file 1106 or script 1100 and read by the motor controller 1002 from the configuration file 1106 or script 1100. When the motor controller 1002 begins moving the load-end legs 20, the leg extension speed ramps from the start raise power speed to the speed set by the Reduce Raise Power parameter over the time period specified by the Soft Start Acceleration Raise parameter. When the "-" button 1037 is pressed, the motor controller 1002 activates only the load-end solenoid actuator 1036, causing the load-end legs 20 to retract at a power level set by the Reduce Raise Power parameter. When the motor controller 1002 begins moving the load end legs 20, the leg retraction speed is ramped from the start reduced power speed to the speed set by the reduced power parameter over the time period specified by the soft reduce acceleration reduction parameter.

Motor State 8: When in this motor state, when the "+" button 1035 is pressed, the motor controller 1002 activates the solenoid actuators 1036, 1038, causing the legs 20, 40 to extend at full power. When the "-" button 1037 is pressed, the motor controller 1002 activates both solenoid actuators 1036, 1038, causing the legs 20, 40 to retract at full power.

Motor State 9: In this motor state, when the “-” button 1037 is pressed, if the control end leg 40 is not within the seat position tolerance distance parameter of the seat position height parameter (both parameters are preset in the configuration file 1106 or script 1100 and read from the configuration file 1106 or script 1100 by the motor controller 1002), and if the extension of the load end leg 20 and the control end leg 40 are equal within 2% of the operating range, and the extension of the load end leg 20 is less than the result of the seat position height parameter - seat position tolerance distance, then the motor controller 1002 causes the load end solenoid actuator 1036 to extend the load end leg 20 at the power setting specified by the raise power parameter, which is preset in the configuration file 1106 or script 1100 and read from the configuration file 1106 or script 1100 by the motor controller 1002. In addition, the motor controller 1002 causes the control-end solenoid actuator 1038 to extend the control-end leg 40 in tracking mode (tracking the position of the loaded leg). The motor controller 1002 stops extending the leg 20, 40 when it reaches the seat height position. As in other modes, when the leg begins to move, the motor controller 1002 causes the leg extension speed to ramp from the start-up power speed to the speed set by the increase power parameter over the time period specified by the soft start acceleration increase parameter. After the operator releases the "-" button 1037, the motor controller 1002 ramps the leg extension speed back to the start-up power speed parameter over the time period specified by the soft stop parameter. If the power reported by the sensor 1022 or the battery controller 1006 is less than the start-up power speed parameter, the motor controller 1002 sets the output power to the solenoid actuators 1036, 1038 to zero (0) volts.

As the seat height is approached, the motor controller 1002 causes the leg retraction velocity to ramp down to zero (0) volts over the distance specified by the Raise Distance Correction Value parameter. If the extension of the load-end legs 20 and the control-end legs 40 is equal within 2% of the operating range (?), and the extension of the load-end legs 20 exceeds the seat height + seat position tolerance, the motor controller 1002 causes the load-end solenoid actuator 1036 to retract the load-end legs 20 at a power setting specified by the Reduce Power parameter provided in the configuration file 1106 or script 1100. In addition, the motor controller 1002 causes the control-end solenoid actuator 1038 to retract the control-end legs 40 in a tracking mode (tracking the position of the load legs). The berth legs stop retracting when the position of the seat height parameter is reached.

As in other modes, when the motor controller 1002 begins to move the outriggers 20, 40, the outrigger retraction speed ramps from the start power reduction speed to the speed set by the reduce power parameter over the time period specified by the soft reduce acceleration reduction parameter. After the operator releases the "-" button 1037, the outrigger retraction speed will ramp down to the start power reduction speed over the time period specified by the soft stop parameter. If the power reported by the sensor 1022 or the battery controller 1006 is less than the power required for the soft reduce power speed, the motor controller 1002 sets the output power to zero (0) volts. As the position of the seat position height parameter is approached, the outrigger retraction speed will ramp down to zero (0) over the distance specified by the reduce distance correction value parameter. If the unequal extension of the outriggers 20, 40 exceeds 2% of the operating range (?), further outrigger movement will depend on the position of the load-end outrigger 20 relative to the control-end outrigger 40 and the seat position height. If the bed 10 is in a position such that the loading end legs 20 are above the seat position height and the control end legs 40 are below the loading end legs 20 and below the seat position height, the motor controller 1002 retracts the loading end legs 20 to their seat position height and then retracts the control end legs 40 to their operator seat height.

If the berth 10 is in a position such that the loading-end legs 20 are above seat height and the control-end legs are lower than the loading-end legs 20 but above seat height, the motor controller 1002 retracts the loading-end legs 20 to be flush with the control-end legs 40, then the motor controller 1002 retracts the legs 20, 40 evenly to seat height, and then the motor controller 1002 retracts the control-end legs 40 to their operator seat height. If the berth is in a position such that the loading-end legs are above seat height and the control-end legs 40 are above the loading-end legs 20, the motor controller 1002 retracts the control-end legs 40 to be flush with the loading-end legs 20, then the motor controller 1002 retracts both legs evenly to seat height, and then the control-end legs 40 to their operator seat height.

If the berth is in a position such that the loading-end legs 20 are below seat height and the control-end legs are below the loading-end legs 20, the control-end legs 40 are extended to be flush with the loading-end legs 20, both legs are then extended evenly to seat height, and the control-end legs 40 are then retracted to operator seat height. If the berth 10 is in a position such that the loading-end legs 20 are below seat height and the control-end legs 40 are above the loading-end legs 20 but below seat height, the loading-end legs 20 are extended to be flush with the control-end legs 40, both legs 20, 40 are then extended evenly to seat height, and the control-end legs 40 are then retracted to their operator seat height.

If the berth is in a position such that the loading end legs 20 are below seat height and the control end legs 40 are above the loading end legs 20 and also above seat height, the loading end legs 20 are extended to seat height and then the control end legs 40 are retracted to operator seat height. If the loading end legs 20 are within the seat position tolerance of seat height, the motor controller 1002 will not cause the loading end solenoid actuator 1036 to move the loading end legs 20 when the control end solenoid actuator 1038 is activated by the motor controller 1002 to retract the control end legs 40 to the operator seat height at a reduced power level.

Mode-independent operations

The following operating modes are independent of any motor mode operation: USB data transfer status, battery voltage monitoring, data logging, error detection, and configuration file execution and updating. While in USB data transfer mode, an external controller utility, such as one provided on a personal computer or intelligent electronic device, can read the motor controller log file. A suitable example of such a controller utility is Roborunt from RoboteQ (Scottsdale, AZ). From the controller utility, software version updates can be applied to the controller and the maximum and minimum heights for the angle sensor can be calibrated. The controller utility can also display the status and values of the analog/digital inputs and outputs of the motor controller 1002 depicted in FIG15.

For battery voltage monitoring, motor controller 1002 is responsible for monitoring the battery voltage level. The voltage level is read after a predefined idle time, defined by the Voltage Read Idle Time parameter, which begins counting down after pressing the "+" button 1035 or the "-" button 1037. The Voltage Read Idle Time parameter is preset to 15 seconds, but this can be configured via configuration file 1106. If the idle voltage level is less than the actuator minimum voltage threshold (preset and read from configuration file 1106 or script 1100), the actuator is disabled. After the actuator has been disabled for low voltage, the battery voltage must exceed the actuator minimum voltage threshold by one volt (1V) before the actuator is enabled. If the idle voltage level is less than the light minimum voltage threshold (preset and read from configuration file 1106 or script 1100), the lights off position is set. After the low voltage has disabled the lamp, the battery voltage must become one volt (1V) above the lamp minimum voltage threshold before the lamp will be enabled.

Voltage Interval: If the idle voltage is >= VThresh3, the interval is 3. If the idle voltage is < VThresh3 and >= VThresh2, the interval is 2. If the idle voltage is < VThresh2 and >= VThresh1, the interval is 1. If the idle voltage is < VThresh1, the interval is 0.

Data Recording

A text-readable log file is written to a memory device, such as memory 102, or to a flash memory card, such as a USB memory stick, SD card, and/or Compact Flash card connected to the motor controller. The log file will include a specific entry that records each occurrence or clearing of an error code. The log file will include a specific entry during bed rest operation that records the bed rest status every 50 milliseconds (50 ms). The log file will include entries during idle periods at a period controlled by the idle log time. The motor controller provides the following bed rest status fields in the data log file: battery voltage, A1, A2, D1, D2, C1, C2 values, timestamp, + button status display, - button status display, + button telescoping handle, - button telescoping handle, motor controller error code, motor 1 current, motor 2 current, motor command 1, motor command 2, direct power code, motor status, battery message, A1 speed, A2 speed, motor 1 temperature, motor 2 temperature, controller channel temperature, controller IC temperature, fault flag, battery temperature, and error detection.

Error Conditions

The motor controller 1002 monitors the following error/warning conditions and takes actions specified by the error's associated priority category. The discussion provided below also provides the "error code bit" value for the detected "condition" and the "clear" action (if any). Additional actions may be listed for specific errors, which are also discussed below. It should be understood that the motor controller 1002 sets the associated error code bit in the message and broadcasts the error code bit via the wired network 1008. For each error code, an associated error icon 51 ( FIG. 8 ) is provided to the GUI 58 to alert the operator to possible functional or safety issues associated with the associated error code. In some embodiments, the associated error icon 51 may be color-coded, with high-priority error codes displayed in a first color (such as red) and all other error codes displayed in a second color (such as yellow). Error conditions and their associated priorities will now be discussed.

Error Condition - Priority Category: None.

- Condition: Low Battery (battery voltage is less than the battery bin 1 voltage specified in configuration file 1106 or script 1100) = Error code bit 0. Cleared: Cleared when the battery voltage becomes higher than battery bin 1.

- Condition: Battery below actuator minimum voltage threshold after inactivity in voltage read inactivity time = Error code bit 1. Additional actions: Disable actuator. Clear: Cleared when battery voltage becomes above actuator minimum voltage + 1V.

- Condition: Battery falls below lamp minimum voltage threshold after being idle for voltage read idle time = Error code bit 2. Additional actions: Set lights off bit Clear: Cleared when battery voltage becomes above lamp minimum voltage + 1V.

- Condition: Detected that the button is on (ON) in excess of the maximum button press = Error code bit 3. Cleared: Cleared when the button is detected to be off (OFF).

- Condition: During leveling operation |A1-A2| outside horizontal operating range for more than maximum leveling time = Error code bit 4. Cleared: Cleared when outriggers are extended and become horizontal.

- Condition: Battery Charge Detect Failure (zero voltage detected on Charge+ pin when battery's charge position is set) = Error Code Bit 5.

- Condition: "+" and "-" buttons detected simultaneously = Error code bit 6. Additional Actions: Ignore both buttons (motor controller 1002 will not command legs 20, 40 to extend or retract). Clear: Cleared when one or both buttons are released.

Error condition - Priority category: Low. Error handling - Priority category: Low, takes precedence over all non-priority error class handling.

- Condition: Improper charge voltage detected on Charge+ (>1.48mV on Charge+; equal to >44.1V charger voltage) = Error code bit 16. Clear: Cleared when voltage on Charge+ is <1.48mV.

- Condition: Bed becomes above transport height (A1 or A2 extends beyond transport height when both D1 and D2 are closed) = Error code bit 17. Cleared: Cleared when bed is no longer above transport height or after a high priority above transport height error becomes active.

- Condition: Charging Fault (non-zero voltage detected on Charge+ pin when the battery's charge or full potential is not set) = Error Code Bit 19. Cleared: Cleared when the voltage on the Charge+ pin disappears or the battery's charge or full potential is set.

- Condition: Battery High Temperature (Battery Charger High Temperature Error Bit is set) - Error Code Bit 21. Cleared: Cleared when the Battery's High Temperature Error Bit is cleared.

Error Condition - Priority Class: Medium. Error Handling - Priority Class: Medium overrides all None and Low priority error class handling and causes deactivation of the solenoid actuators 1036, 1038 (eg, within 50 milliseconds) and prevents actuation until this error condition clears.

- Condition: The motor temperature is detected to be above Motor Over Temperature = Error Code Bit 32. Additional Actions: The sensor temperature will continue to be monitored and recorded while the overtemperature error occurs. Clear: The error will be cleared when the motor temperature becomes below the motor restart temperature.

- Condition: Motor sensor disconnected = Error code bit 33. Clear: This error is cleared when the motor temperature sensor is detected.

Error Condition - Priority Category: High. Error Handling - Priority Category: High overrides all None, Low, and Medium priority error handling and causes deactivation of solenoid actuators 1036, 1038 (e.g., within 50 milliseconds) and prevents actuation until the error condition clears. A power cycle will clear all errors. Transitioning to sleep mode will suspend all alarms. If the current in either motor exceeds 40A for more than 500 milliseconds, the actuator is disabled.

- Condition: Outrigger movement state speed error (exceeds maximum speed or falls below minimum speed) = Error code bit 48. Clear: Cleared after outrigger speed error timeout.

- Condition: Outrigger Movement Status Speed Error (Below Minimum Speed) = Error Code Bit 49. Actuator and - button disabled during button deactivation time. Error icon displayed during this time. Cleared: Cleared if + button pressed and/or after outrigger speed error timeout.

- Condition: Angle sensor fault (A1 or A2 has any of the following conditions: Ch1 or Ch2 voltage is outside the sensor's rated range of 0.5V to 4.5V; or Ch1+Ch2 is not 5V+/-0.5V) = Error code bit 50. Clear: Clears after voltage returns to expected range.

- Condition: Couch already above transport height (A1 or A2 extended beyond transport height, with both D1 and D2 closed) > 30 seconds = Error code bit 51. Additional Action: Do not deactivate "-" button 1037 (allow actuator to retract, but not extend). Clear: Clears after the couch is no longer above transport height.

It should now be understood that the embodiments described herein can be used to transport patients of various sizes by coupling a support surface, such as a patient support surface, to a support frame. For example, a lift-off stretcher or incubator can be removably coupled to the support frame. Thus, the embodiments described herein can be used to load and transport a variety of patients, from infants to bariatric patients. Furthermore, the embodiments described herein allow an operator to load and/or unload the cot onto and/or from an ambulance by pressing a single button to actuate the independently articulated legs (e.g., pressing the "-" button 1037 to load the cot onto an ambulance, or pressing the "+" button 1035 to unload the cot from an ambulance). Specifically, the cot 10 can receive an input signal, such as from an operator control. The input signal can indicate a first direction or a second direction (lowering or raising). When the signal indicates the first direction, the pair of loading-end legs and the pair of control-end legs can be lowered independently, or when the signal indicates the second direction, the pair of loading-end legs and the pair of control-end legs can be raised independently.

It is also noted that words such as "preferably," "generally," "typically," and "generally" are not used herein to limit the scope of the claimed embodiments, or to imply that certain features are critical, required, or even essential to the structure or function of the claimed embodiments. Rather, these words are simply used to highlight alternative or additional features that may or may not be utilized in a particular embodiment of the present invention.

For the purposes of describing and defining the present invention, please also note that the word "substantially" is used herein to represent the degree of uncertainty that may be associated with any quantitative comparison, value, measurement, or other representation. The word "substantially" is also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.

After reference to the specific embodiments, it will be apparent that modifications and variations are possible without departing from the scope of the invention as defined in the appended claims. More specifically, although some aspects of the invention are indicated herein as being preferred or particularly advantageous, the invention is not intended to be limited to these preferred aspects of any specific embodiment.

Claims (15)

1. An electric ambulance bed for transporting a patient above a surface, comprising: Supporting framework; Four legs, each leg having a caster for supporting the bed on the surface; An actuator for a bed actuation system, the actuator interconnecting the support frame with a pair of legs and changing the height of the support frame relative to the wheels of each leg; and A bed-staying control system operatively connected to the bed-staying actuation system to control the activation of the bed-staying actuation system, and detecting that the actuator is in a first orientation relative to the support frame, wherein the first orientation is away from a second orientation, and positioning the end of the actuator away from each wheel closer to the support frame, and the presence of a specific signal requesting a change in the height of the support frame relative to the wheel of each of the outriggers, such that the bed-staying actuation system moves the pair of outriggers relative to the support frame at a first speed, the first speed being different from a second speed at which the bed-staying actuation system moves the pair of outriggers relative to the support frame when the end of the actuator is in the second orientation. 2. The electric ambulance bed according to claim 1, wherein the bed control system includes at least one controller, a sensor, a user display unit, a battery unit, and a wired communication network, the wired communication network being configured to transmit messages between the at least one controller, the sensor, the user display unit, and the battery unit. 3. The electric ambulance bed according to claim 2, wherein the wired communication network is selected from Controller Area Network (CAN), LONWorks network, LIN network, RS-232 network, Firewire network and DeviceNet network. 4. The electric ambulance bed according to claim 2, wherein the battery unit is a battery management system integrated with a battery pack that provides portable power to the bed, wherein the battery management system controls the charging and discharging of the battery pack and communicates with the at least one controller via the wired communication network. 5. The electric ambulance bed according to claim 2, wherein the at least one controller is a first controller, and the bed control system includes a second controller, wherein the first controller is a motor controller for controlling the raising and lowering of the support frame relative to each wheel, and the second controller is a graphical user interface controller for receiving input from and providing output to the operator. 6. The electric ambulance bed according to claim 5, wherein the bed control system includes a third controller selected from a wireless controller for transmitting and receiving wireless communications, a battery controller for controlling the power supply of batteries to all electric components of the electric ambulance bed, and combinations thereof. 7. The electric ambulance bed according to claim 5, wherein the motor controller is programmed via a program logic script to control the activation of the bed actuation system to raise and lower the support frame relative to each wheel of the outriggers. 8. The electric ambulance bed of claim 1, wherein the bed control system includes a manually operable user interface device for providing the bed control system with a signal requesting a change in the height of the support frame relative to the wheels of each of the outriggers; and wherein the bed control system is configured to move the outriggers with maximum power via manual operation of the user interface device in response to detecting that the end of the actuator is in the second orientation and in response to the presence of the signal. 9. The electric ambulance bed of claim 1, wherein the bed control system includes a manually operable user interface device for providing the bed control system with a signal requesting a change in the height of the support frame relative to the wheels of each of the outriggers, the actuator being a first actuator, the pair of outriggers being a first pair of outriggers, wherein the first actuator interconnects the first pair of outriggers with the support frame, and wherein the bed actuation system includes a second actuator interconnecting a second pair of outriggers with the support frame, the bed actuation system being configured to change the height of the support frame relative to the wheels of each of the outriggers via independent operation of the first actuator and the second actuator, and wherein the bed actuation system, in response to the presence of the signal, by manually operating the user interface device, thereby balancing the height of the support frame between the loading end and the control end of the bed through the independent operation of the first actuator and the second actuator, when the end of the first actuator is in the first orientation. 10. The electric ambulance bed of claim 9, wherein the bed control system further includes a mode selection button, which cycles through a plurality of direct power supply modes and selects one of the plurality of direct power supply modes, wherein selecting the direct power supply mode causes the bed actuation system to graphically display the selection of the direct power supply mode on a display of the bed control system, and in response to the presence of the signal, the height of the support frame is balanced between the loading end and the control end of the bed by manually operating the user interface device without independently operating the first actuator and the second actuator. 11. The electric ambulance bed of claim 10, wherein one of the direct power supply modes is a two-leg direct power supply mode, by selecting the mode, causing the bed control system to respond to the presence of the signal by manually operating the user interface device, thereby changing the evaluation of the support frame at both the loading end and the control end. 12. The electric ambulance bed of claim 11, wherein another of the direct power supply modes is a direct power supply mode for the loading end outriggers only, by selecting this mode, causing the bed control system to respond to the presence of the signal by manually operating the user interface device, thereby changing only the evaluation of the support frame at the loading end. 13. The electric ambulance bed according to claim 12, wherein another of the direct power supply modes is a control-end outrigger direct power supply mode, by selecting this mode, causing the bed control system to respond to the presence of the signal by manually operating the user interface device, thereby changing only the evaluation of the support frame at the control end. 14. The electric ambulance bed of claim 13, wherein the bed control system returns to a normal operating state, in which the bed control system responds to the presence of the signal after a countdown timer that begins after the selection of the direct power supply mode expires, and the absence of the signal before the countdown timer expires, by manually operating the user interface device, thereby balancing the height of the support frame between the loading end and the control end of the bed by independently operating the first actuator and the second actuator. 15. A method of transporting a patient above a surface, comprising using an electric ambulance bed as described in claim 1.