WO2007069912A1

WO2007069912A1 - A bed elevator

Info

Publication number: WO2007069912A1
Application number: PCT/NZ2006/000316
Authority: WO
Inventors: Bruce Norton Moller; Anthony John Batley
Original assignee: Howard Wright Ltd
Current assignee: Howard Wright Ltd
Priority date: 2005-12-13
Filing date: 2006-12-06
Publication date: 2007-06-21
Anticipated expiration: 2008-06-13

Abstract

An elevator mechanism for varying the height and/or orientation of a frame or platform (14) of a bed. The elevator mechanism includes a head end linkage assembly (1 7) and a foot end linkage assembly (1 8) each of which is adapted for sliding coupling (23) to the frame or platform (14). The head end linkage assembly (17) being coupled to an axle or shaft (20) ('head axle'). The foot end linkage (18) is coupled to an axle or shaft (35) ('foot axle'). A first actuator (31) is coupled to the foot axle (35) and to a lever (28) extending from the head axle (20). A second actuator (41) coupled to the head axle (20) and a lever (43) extending from the foot axle (35). In use operation of the first and second actuators (31, 41) cause the head and foot axles (20, 35) to rotate about their longitudinal axes and thereby result in movement of the head and foot link assemblies (17, 18).

Description

TITLE OF THE INVENTION

A BED ELEVATOR BACKGROUND TO THE INVENTION

This invention relates to a bed elevator.

A bed elevator mechanism is commonly incorporated in beds where the height of the mattress support/frame is required to be at least raised and lowered (generally relative to a bogie or base) such that the height of the bed can be adjusted. Such an elevator mechanism is, therefore, commonly to be found in hospital beds where, for example, the height of the bed needs to be adjusted to suit one or more people carrying out work in relation to a patient in the bed or to have the height of the bed adjusted to the same as the height of some other equipment to which the patient is to be transferred e.g. an operating table, shower trolley or the like. With hospital beds it is commonly required that the mattress deck or platform not only be capable of being raised and lowered relative to a bogie or base but also the deck or mattress platform be capable of tilting in either head down or foot down directions.

It is not uncommon for bed elevator mechanisms to be of a complex construction. This can give rise to complexities in manufacture of the elevator mechanism as well as to maintenance and reliability issues. Some of the complexity arises from the need to include limit switches, stops and like control apparatus to control the extent of raising and lowering and tilting as well as to prevent collisions between moving components of the elevator mechanism.

Known bed elevator mechanisms have sometimes been of a geometry or layout that results in elevator linkages being closely spaced, which can give rise to instability. Also the geometry or layout of the elevator mechanism can limit the degree of tilt of the bed. SUMMARY OF THE INVENTION

It is one object of the present invention to provide a bed elevator mechanism which is of a straight forward yet effective construction.

It is a further object of the present invention to provide an elevator mechanism which is capable of tilting a mattress deck or platform of a bed in a stable manner yet is of a simple straight forward construction.

It is a further object of the invention to provide an elevator mechanism capable of tilting a mattress deck or platform with the ability to provide increased angle of tilt than is normally achievable with known mechanisms.

According to one broad aspect of the invention there is provided an elevator mechanism for varying the height and/or orientation of a frame or platform of a bed the elevator mechanism including a head end linkage assembly and a foot end linkage assembly each of which is adapted for sliding coupling to the frame or platform, the head end linkage assembly being coupled to an axle or shaft ("head axle"), the foot end linkage being coupled to an axle or shaft ("foot axle"), a first actuator coupled to the foot axle and to a lever extending from the head axle and a second actuator coupled to the head axle and a lever extending from the foot axle, whereby in use operation of the first and second actuators cause the head and foot axles to rotate about their longitudinal axes and thereby result in movement of the head and foot link assemblies.

In the preferred form of the invention the foot and head linkage assemblies are formed from common componentry. Preferably, at least, one stabiliser arm is connected between the frame or platform and a linkage assembly preferably the head end linkage assembly.

In the preferred form the head and foot axles are mounted to a bogie or trolley assembly.

According to one preferred construction the axles are mounted transversely to longitudinal rails and each linkage assembly includes a pair of spaced apart parallel links which are fixedly coupled to the axle, the ends of the links distal from the axle being coupled together by a cross member.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following more detailed description of the invention according to one preferred embodiment reference will be made to the accompanying drawings in which:-

Figure 1 is a perspective view of the elevator mechanism in conjunction with a trolley or bogie and a frame which forms part of or is attached to a mattress platform or deck,

Figure 2 is a side elevation view of the arrangement as shown in Figure 1 but with a patient/ mattress frame attached to the frame and with the closest side rail of the bogie and closest side member of the frame having been removed in the interests of better illustrating the components and layout of components of the elevator mechanism,

Figure 3 is a side elevation view of the same as Figure 2 but showing the frame lowered down to its lowermost point of travel relative to the bogie, Figure 4 is a side elevation view similar to Figure 2 but showing a further embodiment of the invention, and

Figure 5 is a side elevation view similar to Figure 3 but showing the further embodiment.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

Referring to the figures 1 to 3 of the drawings there is shown a bogie assembly 10 which essentially comprises a pair of spaced apart and parallel side rails 1 1 which are coupled at their ends to cross members 12. Each of the cross members 12 carry a pair of spaced apart wheels 1 3. As is common with hospital beds one or more of the wheels are lockable so that when the bed is in a desired position the bed is not readily moveable.

Coupled to the bogie assembly 10, as will hereinafter be described, is a frame 14 which can form part of or be attached to a mattress platform. A typical patient/ mattress platform or support S is shown in Figures 2 and 3. In the illustrated form the frame 14 comprises a pair of spaced apart parallel side members 1 5 which are joined at each end to cross members 1 6. The frame 14 is largely constructed in accordance with normal techniques for hospital beds and, therefore, further description of the detailed construction of the frame 14 and patient support platform S is not required for the purposes of the present invention.

The frame 14 is mounted to the bogie 10 by the elevator mechanism which includes a head end elevator link assembly 17 and a foot end elevator link assembly 18. As can be seen assemblies 1 7 and 18 are mounted at a lower end to the bogie 10 and at an upper end to the side members 1 5 of the frame 14.

The head end link assembly 17 incorporates, according to a preferred construction, a pair of spaced apart parallel elevator links 19 which are joined at their lower ends by an elevator axle 20. The axle 20 is journalled in bearings or pivot blocks 21 coupled to the side rails 1 1 of the bogie 10.

The upper end of the elevator links 19 are joined by a cross member 22. A roller 23 is rotatably coupled to each of the elevator links 19 or to the ends of the cross member 22. Rollers 23 are slidingly engaged in roller channels 24 mounted to the frame side member 1 5.

Stabilizer arms are preferably coupled to one of the linkage assemblies. Preferably this is the head end link assembly 1 7. Thus, pivotally coupled in the length of each link 1 9 is a stabiliser arm 25. The arm 25 is pivotally coupled to the link 19 by a bottom pivot 26 and coupled by a top pivot 27 to the side member 15 of the top frame 14. This link 19 keeps the rollers 23 in the channels 24. Also because link 25 is half the length of arm 19 the frame 14 does not translate either towards the head end or the foot end when the frame 14 is raised or lowered.

The lower ends of the links 19 are preferably fixed to the ends of the axle 20. Thus, the links 19 can pivot relative to the bogie 10 as the axle 20 rotates about it's longitudinal in the bearings 21 .

Attached to the axle 20 (preferably at a point between the bearings 21) is an arm 28. As can be seen more clearly in Figure 2 this arm 28 extends downwardly so that its lower end is below the side rails 1 1 of the bogie 10.

Pivotally coupled at pivot 29 to the arm 28 is the distal end of the piston rod 30 of a linear actuator 31. The body of the linear actuator 31 is pivotally coupled at pivot 32 to a lug or other mounting 33 which is fixed to the axle 35 of the foot end elevator link assembly 1 8. The foot end elevator link assembly 18 is of generally the same construction as the head end elevator link assembly 17. It thus comprises spaced apart parallel links 34 coupled to axle 35 which is journalled in bearings or pivot blocks 21 . The links 34 are coupled by a cross member 37 and rollers 38 of the link assembly 18 are slidingly engaged in channels 39 carried by the side members 1 5 of the top frame 14.

Once again, as with the previous described head end elevator link assembly 1 7, a linear actuator 40 has its piston rod 41 coupled by pivot 42 to arm 43 which extends downwardly from and is fixed to the axle 35. The body of the linear actuator 40 is pivotally coupled at pivot 44 to the axle 20 of the head elevator link assembly 1 7.

There are no stabliser arms coupling the foot end elevator assembly links 34 to the side members 1 5 of the top frame 14.

In accordance with known construction, the bogie 10 includes a power pack, a hydraulic pump for powering the linear actuators, and an electrical control which is switched using a pendant handset or other control elements generally carried by the top frame 14. As the means of powering and controlling the linear actuators 31 and 40 is in accordance with normal techniques, further description is not required for the purposes of describing the present invention.

To achieve raising and lowering of the top frame 14 the head end actuator 31 and foot end actuator 40 are actuated simultaneously. They, therefore, push on the arms 28 and 43 through the connecting pivots 29 and 42 thereby inducing a torque to rotate the arms 28 and 43. This causes the respective axles 20 and 35 to rotate to thereby raise or lower (relative to the bogie 10) the links 19 and 34. This raising and lowering of the links 1 9 and 34 results in the rollers 23 and 38 moving along the channel rails 24 and 39. The stabiliser arms 25 enable the top frame 14 to move precisely vertically when the top frame 14 is raised. The nature of the layout of the elevator link assemblies 1 7 and 1 8 and the manner in which torque is applied to the axles 20 and 35 thereof by the linear actuators 31 and 40 is such that no limit switches are required as each of the elevator link assemblies 1 7 and 1 8 operate within a specific locus. It will be appreciated by those skilled in the art that this is achieved by way of elevator link assemblies 1 7 and 18 which (except for arms 25) are identical in their make-up and geometry. This thereby makes manufacture simple and reduces the manufacturers stock holding of componentry.

Tilting of the top frame 14 into either head down or foot down configuration is achievable. This is carried out by differing the displacement of the head end actuator 31 and foot end actuator 40 as appropriate in order to obtain a head down or foot down configuration.

As disclosed above, the actuator body of each linear actuator 31 and 40 is pivotally mounted to the axle of the opposite elevator link assembly 17 or 18. As a result of this a greater tilt (up to 1 6°) can be achieved without the need of limit switches, stops or collisions occurring between the opposing elevator link assemblies.

The present invention thus provides a simple yet extremely effective bed elevator arrangement. The construction is such that no limit switches are required with each of the elevator arm assemblies. The extent of movement of each elevator arm assembly is controlled by the extent of movement possible with the linear actuators.

The use of common components for each of the elevator link assemblies 1 7 and 1 8 provide for not only manufacturing simplicity but also reduced tooling and jigging as well as stockholding of componentry by the manufacturer. Also cross member (to support the linear actuators 31 and 40) are not required on the bogie. The mounting of the linear actuator of each actuator arm assembly with the axle of the opposite actuator arm assembly means that tilting of the upper frame 14 to an angle of up to 16° is possible. This is advantageously achieved without the need for limit switches and/or stops. Furthermore, the tilting is achievable without collisions between moving components of the two actuator arm assemblies.

The design of having the elevator actuators linked together by the body mount of each actuator attached to the axle of the opposite elevator link assembly provides an advantage in that there is wider elevator spacing which results in the mattress platform being more stable. Also it means that each elevator arrangement is not able to operate totally independently of the other and allows tilt of up to 16° to be achieved.

The invention according to a second embodiment is shown in Figures 4 and 5. this form of the invention includes a fifth wheel 45 which is attached via a lever arm 46 to the axle 20 of the head end elevator assembly 1 7. When the bed is raised to full height (Figure 4) the fifth wheel 45 lowers and makes contact with the floor F. The wheel 45 either telescopically or using a secondary floating linkage is effectively spring loaded so as to make contact with the floor F thereby providing active suspension to keep the wheel 45 in contact with the floor when travelling over uneven flooring. This fifth wheel 45 only comes in contact with the floor F when the bed is at full height which also brings the bed to a height most ergonomic for manoeuvring.

The fifth wheel 45 provides improved ease of steering over a current four wheel bogie design due to the wheel 45 being near the centre of the head of the bed (a more central turning point). This is an alternative to known designs where the bed is steered by locking one castor at the head end longitudinally in line with the bed. An advantage of incorporating a fifth wheel with the present invention is that the actuation (raising and lowering) of the fifth wheel is provided by the head end elevator assembly 1 7. Thus, when the bed is in the fully lowered position the head end linkage 17 causes the arm 46 and hence wheel 45 to be fully raised (Figure 5) while in the fully elevated position of the bed (Figure 4) the fifth wheel comes into contact with the floor.

The invention is open to modification as will be appreciated by those skilled in the art and such modifications are taken to fall within the scope of the present invention as defined in the following claims.

Claims

1. A bed elevator mechanism for varying the height and/or orientation of a frame or platform of a bed the elevator mechanism including a head end linkage assembly and a foot end linkage assembly each of which is adapted for sliding coupling to the frame or platform, the head end linkage assembly being coupled to an axle or shaft ("head axle"), the foot end linkage being coupled to an axle or shaft ("foot axle"), a first actuator coupled to the foot axle and to a lever extending from the head axle and a second actuator coupled to the head axle and a lever extending from the foot axle, whereby in use operation of the first and second actuators cause the head and foot axles to rotate about their longitudinal axes and thereby result in movement of the head and foot link assemblies.

2. The elevator as claimed in claim 1 wherein the foot and head linkage assemblies are formed from common componentry.

3. The elevator as claimed in claim 1 or 2 wherein at least, one stabiliser arm is connected between the frame or platform and a linkage assembly.

4. The elevator as claimed in claim 3 wherein the stabiliser arm is connected to the head end linkage assembly.

5. The elevator as claimed in claim 1 , 2, 3 or 4 wherein the head axle and foot axle are both mounted to a bogie or trolley assembly.

6. The elevator as claimed in claim 4 wherein the axles are mounted transversely to longitudinal rails and each linkage assembly includes a pair of spaced apart parallel links which are fixedly coupled to the axle, the ends of the links distal from the axle being coupled together by a cross member.

7. The elevator as claimed in any one of claims 1 to 5 wherein each linkage assembly includes a pair of spaced apart parallel elevator links which are joined at a lower end to the elevator axle, an upper end of each link being coupled to a roller slidingly engaged in a roller channel mounted to a side member of the frame or platform.

8. The elevator as claimed in any one of claims 1 to 7 wherein the body of each actuator is coupled to the axle or shaft and the piston rod of the actuator is coupled to the lever.

9. A bed incorporating a bogie or trolley assembly and an occupant/mattress platform or support coupled to the bogie or trolley by an elevator mechanism as claimed in any one of claims 1 to 8.

10. The bed as claimed in claim 9 further including a mounting fixedly coupled to the head axle and an additional wheel coupled to a distal end of the mounting said additional wheel being engageable, when the platform or support is fully elevated, with a surface on which wheels of the bogie or trolley are engaged.

1 1 . The bed as claimed in claim 10 wherein the mounting includes or is coupled to suspension means to provide suspension movement to said additional wheel.

12. A bed elevator substantially as herein described with reference to Figures 1 to 3 or 4 and 5 of the accompanying drawings.