EP2978398B1

EP2978398B1 - Hoist for lifting a patient

Info

Publication number: EP2978398B1
Application number: EP14717222.5A
Authority: EP
Inventors: Maurice Petrus Wilhelmus Tak
Original assignee: Indes Holding BV
Current assignee: Indes Holding BV
Priority date: 2013-03-28
Filing date: 2014-03-28
Publication date: 2024-12-04
Anticipated expiration: 2034-03-28
Also published as: EP2978398C0; EP2978398A1; WO2014158023A1; NL2010535C2

Description

FIELD

The invention relates to a hoist for raising a patient from a seated to a standing position and for lowering a patient from a standing to a seated position. In practice, such a hoist is also known as stand-up hoist.

BACKGROUND

US-3 629 880 (Van Rhyn, 1971 ) describes a stand-up hoist provided with pivotable lifting arms with armpit supports. The armpit supports engage the patient in the armpits and pivot up to bring the patient from a seated position into a standing position. With this stand-up hoist the patient himself can operate a crank for adjusting the pivoting arms. By means of a coupling, the crank drive can also be coupled with wheels of the hoist, so that the patient can independently ride the hoist. A use of this hoist in practice is not known to applicant.
In the field of patient stand-up hoists, the device according to GB2 140 773 (James, 1984 ) was experienced as a considerable improvement. Instead of lifting with lifting arms provided with armpit supports, with the hoist known from the British publication the patient is raised with the aid of a support belt (sling) which is connected with lifting arms designed as simple pivoting arms. The patient's knees then rest against a knee support, so that the patient, so to speak, is confined between the sling and the knee support, which provides to the patient a sense of safety. Operation of the hoist can be performed exclusively by a care provider.
EP 0 782 430 (Bouhuijs, 1996 ) is a variant thereon, involving an articulated pivoting arm whose motion is controllable with electric motors and a control. The articulated lifting arm which carries the support belt, can be controlled with greater freedom, so that the ends of the articulated arm that are connected with the support belt can be displaced according to a particular path. Operation of the hoist can be performed exclusively by a care provider. Depending on the patient's need, the path followed by the ends of the lifting arms can be adjusted by the care provider operating the hoist. Also, in a claim of the publication concerned, mention is made of the fact that during raising the lifting device can exert lifting force that is less than 50% of the force necessary to displace the weight of the person concerned. What is meant by this and how this is to be realized is not disclosed in any way.
EP 2 291 162 (Altena, 2009 ) provides a stand-up hoist which in turn need not be provided with a support belt. Instead, the stand-up hoist is provided with a clamping device which is provided with clamping arms disposed in a manner movable towards each other and away from each other, which are each provided with a "clamping pad" which engages the sides of the patient's chest. The clamping arms with pads, so to speak, hold the patient by his chest. In an upwardly and downwardly translatable manner, the clamping arms are connected with a column, which in turn is pivotably connected with a base. It holds true of the hoist described in this publication as well that the operation thereof can exclusively be performed by a care provider.
WO 9611658 discloses a hoist with a parallelogram type lifting arm at the free end of which a chest pad is attached. The patient is supported by a sling attached to the lifting arm, the chest pad and fixed knee pads. A foot support supports the feet of the patient. According to the publication, a more natural way of standing up is obtained by virtue of the fact that the patient is also supported at the front side by the chest pad. WO'658 also discloses that the lifting arm can be controlled by pressing a raising button and a lowering button in a portable switch selectively. This portable switch is movable so that the attendant may manipulate its buttons or the patient himself/herself may manipulate the buttons.
US20120023661 discloses a hoist with an human machine interface that is operable by the user of the hoist himself/herself. The human machine interface is used to input a desired destination. In this way, the patient/user himself/herself can make the hoist to drive to a desired destination, for example, the loo or the bathroom (see [0034] of the publication). Additionally, information specific to the user may also be entered via the human machine interface and stored in the electronic memory. Such information, or user parameters, may be utilized by the electronic control unit to customize the movement or functionality of the hoist. For example, the elevation rate or the lifting power may be tailored to the condition, length and weight of the patient which have been inputted into the human machine interface. Thus, the movements of the robotic human transport device may be customized to the needs and desires of particular users. The rotation of the drive wheel of this known lift may be controlled at least in part based upon a steering force detected by a force sensing device, e.g. a steering force applied to the handle or a weight shift measured by a force sensing device disposed on or within a footstep on which a user may be positioned.

SUMMARY OF THE INVENTION

The present invention contemplates the provision of a hoist which is provided with an electric, mechanical, hydraulic or pneumatic drive and which provides control over at least a part of the lifting movement to the patient himself.
To that end, the invention provides a hoist according to claim 1.
The hoist being provided with a signal receiver which is arranged for receiving an input signal delivered by the patient, the patient himself can exert an influence on the action of the hoist. The patient, so to speak, is in control. Here, an input signal is to be understood to mean not only a consciously delivered input signal. The input signal can also be a force produced by the patient, such as a standing force which is exerted or a force which is exerted on the lifting arms. A movement of the patient can also constitute an input signal. Being in control is of great importance because the patient is brought from a passive role into an active role. This means the patient will be able to tension his muscles at the right moment. When a care provider operates the hoist, the patient is actually always surprised by the onset of the raising movement and the onset of the lowering. When the patient is in control himself/herself, he/she can tension his/her muscles and then actuate the hoist. Thus, automatically, via the patient's brain, the link between the moment of onset of the raising movement and the tensioning of the muscles is established and an optimum tuning of the timing of these two actions is obtained.
Where in the claims and description reference is made to "a drive" or "the drive", this is understood to cover an assembly of drives. This can involve an electrical drive, a mechanical drive in which potential energy can be stored, a pneumatic drive, a hydraulic drive or a combination thereof. The drive should provide at least a part of the energy that is necessary to generate a lifting force during standing up. The energy may originate, for instance, from a battery or the electricity grid in the case of an electrical drive or an electrically energized hydraulic or pneumatic drive, or from a pressure chamber in the case of a pneumatic or hydraulic drive. In a particularly simple embodiment the drive may be formed by a spring, such as a spiral spring or a gas spring, or by a counterweight which is raised during the patient's sitting down and which lowers during the patient's standing up. In that case the energy needed to generate a lifting force during raising is potential energy which is stored in a depressed or extended spring, or potential energy which is stored in the compressed gas in the gas pressure chamber of a gas spring, or potential energy which is stored in the counterweight brought to a higher level, which comes down during the raising of the patient. In such simple embodiments, the force that is produced by the spring or the counterweight may by itself be insufficient to raise the patient. Without cooperation of the patient, that is, without lifting force that is produced by the patient himself, the lifting mechanism will not come into motion then. Thus the patient is compelled to come into action himself to raise himself. In that sense, therefore, he is in control.
It is possible that the movement of the lifting arms is realized by a composite of movements of different parts. For instance, a configuration as described in the above-mentioned European application EP `430 which has an articulated arm with two electric motors which jointly effect a movement of the ends of the lifting arms. The earlier-mentioned EP' 162 has a column which is pivotably connected with a basic frame and along which a lifting arm assembly is translatable up and down. Both for the pivoting of the column and for the translation of the lifting arms assembly along the column, a separate drive is present. The pivoting and the translation together provide to the lifting arms the desired path that is to be followed during raising and lowering.
In an embodiment, the hoist may additionally include a signal receiver that is embodied as an operating switch which is so positioned on the basic frame and/or the lifting arms that the patient can operate it himself.
The input signal is then the operating force that is exerted on the operating switch and the output signal is, for instance, contact or no contact.
The input signal can additionally be a force that is exerted on a lever and the output signal can be the blocking or deblocking of a blocking mechanism.
For that matter, in an embodiment, it may be that the patient is not raised when he has set the operating switch in the active position. After all, as already indicated above, the drive may be so weak that it provides too little force to raise the patient. Thus, the patient is then compelled to produce force himself as well and to be in control that way. In such an embodiment, the operating switch is only a kind of release switch which prevents the patient being raised unexpectedly, if he produced sufficient standing force while he has no intention of standing up.
Being in control need not be limited to the moment of onset of the raising movement or the moment of onset of the lowering movement. Optionally, the patient can interrupt the movement during raising or lowering through operation, or release, of the operating switch. If during raising or lowering the patient changes his mind for any reason, for instance for a physical reason such as pain or for a psychological reason such as anxiety, then the patient himself can intervene directly and thus remains in control. This knowledge alone already gives the patient an improved sense of security.
The hoist may additionally include at least one signal receiver that is embodied as a regulator which is so positioned on the basic frame and/or the lifting arms that the patient can operate it himself.
The input signal is the action by which the patient sets the regulator in a particular position. The output signal of the regulator can be, for instance, a variable electrical resistance of the regulator or a variable voltage.
The output signal delivered by the signal receiver designed as regulator can be processed by the control in different manners to influence the behavior of the hoist. Different possibilities are discussed hereinafter on the basis of a few embodiments. Briefly summarized, in a further elaboration the regulator can be used, for instance, to influence the speed of the lifting movement or the lowering movement. In an alternative further elaboration the regulator can also be used to set the force produced by the lifting arms. Thus, for instance, a lifting force can be set, such that the patient is maximally stimulated to make use of his own muscular strength. Further, the regulator can also be used to set the path followed by the lifting arms. Depending on the position of the regulator a different path can be followed.
According to claim 1, the at least one signal receiver comprises a lifting force signal receiver which measures an input signal and generates an output signal that is indicative of a lifting force exerted by the lifting arms during raising and/or lowering of the patient, while the lifting force signal receiver is included in the basic frame and/or the lifting arms, wherein the lifting force signal receiver is connected with the control, wherein the control is configured for controlling the drive depending on at least the output signal generated by the lifting force signal receiver.
The lifting force that is observed is indicative of the amount and possibly manner of support provided by the hoist during raising. The term lifting force may relate exclusively to the lifting force magnitude. However, the lifting force contains information not only about the lifting force magnitude but also about the lifting force direction. The lifting force signal receiver can therefore deliver an output signal that contains information about the lifting force magnitude. In an embodiment, the lifting force signal receiver may also be configured for delivering an output signal which contains information on both the lifting force magnitude and the lifting force direction. By measuring the lifting force, the control can adjust the behavior of the hoist. Thus, in an embodiment, for instance, the speed of the lifting movement or lowering movement can be influenced depending on the measured lifting force. In an embodiment, instead or additionally, also the path of the lifting arms may be influenced depending on the measured lifting force. The behavior of the hoist may, for instance, be so controlled that the lifting force during raising or lowering is adjusted to a desired level.
In addition, the at least one signal receiver comprises a standing force signal receiver which measures an input signal and generates an output signal that is indicative of a standing force that is exerted by the patient on a footplate during raising and/or lowering the patient, wherein the standing force signal receiver is connected with the control, wherein the control is configured for controlling the at least one drive depending on at least the output signal generated by the standing force signal receiver.
The term standing force may relate exclusively to the standing force magnitude. However, the standing force contains information not only about the standing force magnitude but also about the standing force direction, that is, the direction of the standing force exerted by the patient with his feet on the footplate. The standing force signal receiver can therefore deliver an output signal that contains information about the standing force magnitude. In an embodiment, the standing force signal receiver may also be configured for delivering an output signal which contains information about both the standing force magnitude and the standing force direction. With the standing force signal receiver, for instance, it can be observed whether the patient is exerting additional force on the footplate on which he has placed his feet. Exerting such an additional force may be indicative of the circumstance that the patient wants to stand up. The standing force sensor is used in combination with a lifting force signal receiver. Thus, the control can observe what part of the weight of the patient is carried by the lifting arms and what part of the weight of the patient is carried by the footplate. The control is configured to determine on the basis of both output signals a a desired lifting speed and/or a desired path of the lifting arms and, in accordance therewith, control the at least one drive. Optionally, the control may be configured to additionally determine on the basis of both output signals a desired lifting force and/or a desired path of the lifting arms and, in accordance therewith, control the at least one drive. Optionally, the standing force signal receiver and/or the lifting force signal receiver can be combined with an earlier-mentioned operating switch or regulator. With that, the patient can for instance arrange for the hoist not to enter into operation until the operating switch or the regulator has been brought into a position corresponding to action. Whether the hoist actually proceeds to raise can then, in an embodiment, be made dependent on, for instance, the standing force signal and/or the lifting force signal.
In an embodiment, the signal receiver may be implemented as a strain gauge, or an assembly of strain gauges, which measures an elastic deformation of a part of the lifting arms, the basic frame or the footplate. Such an elastic deformation may be particularly small and may even be imperceptible to the user.
In an embodiment, the signal receiver may be implemented as a load cell.
Such signal receivers may be relatively simple in construction and reliable in their operation. Moreover, the costs of such signal receivers are relatively low.
In addition to the lifting force signal receiver and the standing force signal receiver, the at least one signal transducer can comprise an acceleration sensor which measures an input signal and generates an output signal which is indicative of an acceleration of the lifting arms, wherein the control is configured for controlling the drive depending on the output signal generated by the acceleration sensor.
Acceleration sensors can provide an indication of the amount of a patient's force contribution and of the patient's behavior in the hoist. Thus, for instance, patient vibration or swinging can be observed by such acceleration sensors. Also output signals coming from the acceleration sensors can thus contribute to a control of the hoist that gives the patient more of a sense of being in control.
In addition to the lifting force signal receiver and the standing force signal receiver discussed above, in yet another embodiment, the at least one signal receiver can comprise a motion sensor or speed sensor which measures an input signal and generates an output signal which is indicative of a movement or speed of the lifting arms, wherein the control is configured for controlling the drive depending on the output signal generated by the motion or speed sensor. Such sensors may be implemented, for instance, as a gyroscope or an angle sensor. In fact, any sensor type that can measure, as input signal, a motion, a speed or acceleration, or a change of those quantities and can generate an output signal related thereto which is indicative of those quantities, is suitable for use as signal receiver.
The signal receivers which have been discussed above are all connected with the control. In this control, the output signals of the signal receivers may be processed in different manners and can lead to a different manner of control of the at least one drive. Generally, the control will be implemented as an electronic control, but, as will be described hereinafter, may also involve a mechanical control.
The control is configured for processing the at least one output signal of the at least one signal receiver and for, on the basis thereof, controlling the at least one drive such that the speed of the lifting arms depends on the at least one output signal. Thus, for instance, the signals generated by the lifting force signal receiver and the standing force signal receiver and optionally the acceleration sensor serve to control the motion speed of the lifting arms.
In an embodiment, the control may additionally be configured for processing the at least one output signal of the at least one signal receiver and for, on the basis thereof, controlling the at least one drive such that the lifting force which the lifting arms exert on the patient via the armpit supports, the clamping pads and/or the support belt depends on the at least one output signal.
With such an embodiment, it can be effected that the control involves the output signals generated by the lifting force signal receiver and the standing force signal receiver and optionally the acceleration sensor in controlling the at least one drive such that the lifting force during the raising and/or lowering of the patient has a desired value. This leads to a kind of power assist.
In yet another embodiment, the control may additionally be configured for processing the at least one output signal of the at least one signal receiver and for, on the basis thereof, controlling the at least one drive such that the path that the lifting arms follow depends on the at least one output signal.
With such an embodiment it can be effected that the control involves the output signals generated by the lifting force signal receiver and the standing force signal receiver and optionally the acceleration sensor in controlling the at least one drive such that the movement path that the lifting arms follow is optimally tuned to the force contribution of the patient. Thus, the patient can always be held in an optimum attitude to produce a largest possible part of the get-up force. In determining the path, not just the vertical force components need to play a role. Especially the horizontal force components can constitute an important input for adjusting the movement path of the lifting arms. For that matter, horizontal force components can also be a reason to adjust the lifting force and/or lifting speed. In other words, not only the magnitude of the force or forces produced can serve as input but so may the direction of the force or forces produced.
As mentioned, the control may further be arranged to combine the different regulations with each other, such that a desired course of the speed, a desired course of the lifting force, and a desired path of the lifting arms during raising and/or lowering of the patient are obtained.
In an embodiment, the lifting force in a position of the lifting arms corresponding to a seated position of the patient may be in the range of 40-70% of the total weight of the patient and the lifting force in a position of the lifting arms corresponding to a standing position of the patient may be in the range of 0-10% of the total weight of the patient. Such a course of the force leads to a decreasing support during standing up and to an increasing support during sitting down. Such a refine manner of power assist is experienced by the patient as agreeable.
In a further elaboration, the control may be configured such that, in positions of the lifting arms that are between the positions corresponding to the seated position and the standing position, the lifting force exerted by the lifting arms decreases gradually when the lifting arms move from the position corresponding to the seated position to the position corresponding to the standing position.
In yet another embodiment, the control may be configured for processing the at least one output signal of the at least one signal receiver and for, on the basis thereof, controlling the at least one drive such that the acceleration of the lifting arms depends on the at least one output signal. This form of control can also be combined with speed control and force control. Thus, a particularly refined regulating behavior can be obtained that provides to the patient an optimum sense of being in control.
In an embodiment, in addition to the at least one signal receiver, the hoist may be provided with at least one position sensor which delivers a position signal which is indicative of the position of the lifting arms, wherein the control is configured for controlling the drive on the basis of a speed function, and optionally additionally a position, force, path and/or acceleration function, which has as input parameters both the at least one output signal of the at least one signal receiver and the at least one position signal of the at least one position sensor.
As by virtue of the at least one position sensor also the position of the lifting arms is known, at least the speed and optionally the lifting force, the movement path and/or the acceleration of the lifting arms can also be regulated depending on the position of the lifting arms. It will be clear that right before assuming the seated position from a standing position, the descending movement speed of the lifting arms should decrease, so that the patient can sit down gently and does not plop down. During raising, in a path located between the two end positions, the speed may be somewhat higher than near the two end positions. The control can contain different control programs and has at least the lifting force and the standing force as input data, and optionally additionally the position of an operating switch and/or a regulator as input data. In addition thereto, also the position signals of the lifting arms can be involved in the control program as input parameter for determining the control signals for the at least one drive of the hoist. Thus, the hoist may, for instance, mainly have a lifting force control, whereby the control will attempt to keep the lifting force as low as possible. In this regard, however, use can also be made of the position signal to observe whether the patient is still making an ascending movement or is still making a descending movement with sufficient speed. When for instance such an ascending movement is not made or when the speed thereof falls below a particular threshold value, the control may be arranged to raise the lifting force a bit, so that the patient starts moving again or starts moving a bit faster. When during sitting down the speed of the descending movement is too high, for instance because the patient himself is producing insufficient standing force, the control may be arranged to raise the lifting force a bit, so that the descending movement of the patient is decelerated. What is thus accomplished is not only that the patient is in control but also that he is stimulated to use his own muscles. This has a favorable influence on the condition of the patient.
In an embodiment, the control can be an electronic control. Such an electronic control generally contains a memory and a central processor unit with the aid of which a program having different input and output parameters can be executed. Such an electronic control provides a great flexibility in respect of the functions that can be performed by the electronic control. Thus, as described above, different control functions for controlling the at least one drive can be programmed. Moreover, the electronic control can also be used for other functions, for instance, storing the use of the hoist or even automatically storing individual patient data such as data on the amount of power assist that the patient needs and the course of the amount of power assist over time.
In an embodiment, the at least one drive comprises a stepping motor, a servo motor or a like controllable electric motor which is controllable on the basis of force and/or position control and/or a derivative thereof.
In this connection, "a derivative" is to be understood to mean speed or acceleration. Such motors can be accurately controlled by means of the electronic control. Different signals may then be used as input for the control, as already described at length hereinbefore.
In an embodiment of the hoist, the control may be configured to determine, on the basis of the at least one output signal and the at least one position signal, a physique, such as height and/or weight, and/or posture of the patient, and, on the basis thereof, to automatically tune the lifting path, the lifting force, the lifting speed and/or the lifting acceleration of the lifting arms to the physique and/or posture.
With such a design, the hoist can be directly put into use by different patients, the behavior of the hoist then being automatically tuned to the physique and/or posture of the patient. This refined, patient-specific behavior can then be obtained without manual input of data concerning physique and posture in the control of the hoist needing to take place. For that matter, an embodiment where a manual input of such data is possible and desirable is also within the scope of the present invention.
In an embodiment, the at least one drive can comprise a gas spring and the control can comprise a blocking mechanism which in a first position blocks the gas spring and in a second position deblocks the gas spring.
The blocking mechanism may be provided, for instance, with a lever, for bringing the blocking mechanism from the blocked position to the deblocked position and vice versa. In an embodiment, the gas spring may be designed as a passive gas spring. That is, it will extend in the deblocked condition of the blocking mechanism when the patient himself exerts sufficient force to stand up and hence the gas spring is loaded less. The gas spring then provides to the patient a particular support and hence a form of power assist. However, when the patient exerts a stand up force that is below a defined minimum value, the gas spring, in the deblocked position of the blocking mechanism, will under the influence of the weight of the patient be pressed together, whereby the gas is compressed. Such a blockable gas spring is generally known per se for desk chairs with height-adjustment. It is also possible, however, that the gas spring is of the active type and is energized by an external gas source of high pressure which can be set into communication with the interior of the gas spring for extending the gas spring upon raising of the patient even when he is resting his full weight on the lifting arms. When the patient wants to be lowered, a valve in the gas spring may be operated, whereby gas is released from the gas spring, so that the pressure in the gas spring lowers and the gas spring can be compressed under the influence of the force exerted thereon. Clearly, in this way, gas under high pressure will be lost and now and then the external gas source will have to be replaced or replenished.
Instead of making use of a mechanically operated blocking mechanism which has been described above in connection with the embodiment with the gas spring, use can also be made of an electronic or electrically operated blocking mechanism.
Instead of or in addition to a gas spring, in an embodiment the at least one drive can comprise a spring or a counterweight, while the at least one signal receiver comprises an operating knob or lever, wherein the control comprises a blocking mechanism which is operatively connected with the operating knob or the lever and which in a first position blocks the lifting arms and in a second position deblocks the lifting arms. The spring can for instance be a draw spring or compression spring which may for instance be designed as a helical spring. Such an embodiment is likewise relatively simple and advantageous from a viewpoint of costs.
In an embodiment the hoist may be provided with a blocking device which is configured to block the lifting arms in the end positions thereof, and preferably also in at least a number of intermediate positions. This is important during the displacement of the hoist. Then the lifting arms are to be prevented from coming into action suddenly or unexpectedly.
Presently, on the basis of a number of exemplary embodiments, and with reference to the drawings, the invention will be further clarified.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows a perspective view of an example of a first embodiment of a hoist with armpit supports;
Figure 2 shows a perspective view of an example of a second embodiment of a hoist with support belt;
Figure 3 shows a graph in which on the X axis the angle of the upper legs with the horizontal is plotted and on the Y axis the produced lifting force as a percentage of the body weight is plotted; and
Figure 4 shows a graph in which on the X axis the angle of the upper legs with the horizontal is plotted and on the Y axis the speed of the free ends of the lifting arms is plotted.

DETAILED DESCRIPTION

In the figures corresponding parts are designated with the same reference numerals. The figures show examples of hoists in which a large number of embodiments of the invention are combined. However, the embodiments can also be used separately from each other.
Figs. 1 and 2 show examples of hoists in which a number of embodiments of the invention are incorporated. There is a hoist 10 for raising a patient P from a seated to a standing position. Evidently, the hoist can also be used for lowering a patient P from a standing position to a seated position. In a most general sense, the hoist 10 is provided with a basic frame 12 and two lifting arms 14, 14' which are each provided, at a free end thereof, with an armpit support 16, 16', clamping pads and/or a fixing for a support belt 18. With the aid of an adjusting mechanism 20, 22, the lifting arms 14, 14' are displaceably connected with the basic frame 12. Further, at least one drive 24, 26 is provided, which is arranged for driving the adjusting mechanism 20, 22 for the purpose of displacing the lifting arms 14, 14' relative to the basic frame 12, such that the lifting arms 14, 14' follow a path which guides the patient P, who is supported by the armpit supports 16, 16', the clamping pads and/or the support belt 18, from a seated position to a standing position.
The hoist 10 is characterized by at least one signal receiver 28, 30, 32, 34, 36 which is arranged for receiving an input signal which is delivered by the patient P and for generating an output signal S1, S2, S3, S4. The at least one signal receiver 28, 30, 32, 34, 36 is in communication with a control 38. This control 38 is also connected with the at least one drive 24, 26 and is arranged for controlling the at least one drive 24, 26 depending on the output signal S1, S2, S3, S4 delivered by the at least one signal receiver 28, 30, 32, 34, 36.
The exemplary embodiment of Fig. 1, which incorporates different embodiments of the invention, is provided with a basic frame 12 with a footplate 40 on which the patient can place his feet. In the example shown, the basic frame is provided with swiveling wheels 56. Optionally, the basic frame 12 may be provided with one or more driving wheels which are provided with a drive motor. Such driving wheels, too, can be regulated by an operating element. Preferably, the operating element is so positioned that the patient P can operate this operating element himself and thus can regulate himself where the hoist 10 is ridden to. The operating element for driving the driving wheels may be designed, for instance, as a joystick. The basic frame 12 of the example of Fig. 1 is further provided with a fixed column 46 in which a movable column 48 is received so as to be telescopically movable. On the fixed column 46, as shown in the example of Fig. 1, knee supports 52 may be mounted. The movable column 48 forms a part of the adjusting mechanism 20 with the aid of which the lifting arms 14, 14' can be displaced. The telescopic movement of the movable column 48 is effected by the drive motor 24. This drive motor 24 may be designed as a simple gas spring with a blocking mechanism as control and a lever as signal receiver. The drive motor 24 may also be designed as an electric motor which is controllable in the manner described hereinbefore by the control 38.
In the exemplary embodiment of Fig. 1 a yoke 50 is fixedly connected with the movable column 48. To the yoke 50 the lifting arms 14, 14' may be connected, optionally each pivotable about a substantially vertically extending axis or, instead of vertical axes, axes slightly inclined towards each other. On the yoke 50, as shown in the example of Fig. 1, a first signal receiver in the form of an operating switch 28 may be arranged. The operating switch 28 generates an output signal S1. Further, as shown in the example of Fig. 1, a second signal receiver in the form of a regulator 30 may be arranged. In an embodiment, the operating switch 28 and the regulator 30 may also be integrated in a single signal receiver. The operating switch 28 and the regulator 30 can generate an output signal S1. Both the operating switch 28 and the regulator 30 are so positioned as to be easily accessible for the patient P. Accordingly, positioning may also be on a part of the hoist 10 other than the yoke 50. The exemplary embodiment of Fig. 1 is provided with two lifting force signal receivers 32, 32' which are arranged on the yoke 50. These lifting force signal receivers 32, 32' generate an output signal S2 which is indicative of the lifting force exerted by the hoist 10 on the patient P. Further, in the basic frame 12, for instance under the footplate 40, a standing force signal receiver 34 may be provided. This standing force signal receiver 34 generates an output signal S3 which is indicative of the standing force exerted by the patient P on the footplate. The lifting force signal receivers 32, 32'and the standing force signal receiver 34 may be designed as a strain gauge or an assembly of strain gauges. Further, these signal receivers 32, 32', 34 may be designed as a load cell, different implementations of which are known per se. In addition thereto, the exemplary embodiment of Fig. 1 is further provided with an acceleration sensor 36. In the example shown, it is mounted near the upper end of movable column 48. For this acceleration sensor it also holds that it may be mounted on other parts of the hoist 10. The acceleration sensor generates an output signal S4. The exemplary embodiment of Fig. 1 is further provided with a position sensor 42 which delivers a position signal SP1 which is indicative of the position of the lifting arms 14, 14'. In the exemplary embodiment shown, the position sensor 42 is accommodated in the fixed column 46 adjacent the drive 24. All signal receivers 28, 30, 32, 32', 34, 36 are in communication with the control 38. The control 38 in turn is in communication with the drive 24. The different functions according to which the control 38 can process the output signals S1, S2, S3 and S4 have already been described in the introduction to the description. Thus, the functions can regulate, for instance, the lifting force, the speed, the acceleration and/or the positions and hence the movement paths of the lifting arms 14, 14' on the basis of at least one of the different output signals S1, S2, S3, S4 possibly in combination with a position signal SP1. With such a hoist 10, the patient P is `in control' and particular embodiments thereof may involve power assist during the raising and lowering of the patient P. In an alternative embodiment, the fixed column 46 may be designed as a pivotable column which near a lower end thereof is connected with the mobile base so as to be pivotable about a horizontal axis. For controlling the pivotability of the column 46, a second drive (not shown) may be provided which is also controlled by the control 38.
Fig. 2 shows another exemplary embodiment of a hoist 10. The hardware of this hoist 10 is based on the lift described in detail in WO96/28125 . Corresponding parts are designated with the same reference numerals as in Fig. 1. Instead of armpit supports, this hoist 10 is provided with a support belt 18. Instead of a telescopically movable column 48 as adjusting mechanism, the adjusting mechanism 22 of the hoist 10 of Fig. 2 is provided with an articulated arm 54, 14, 14' which is connected with a fixed frame part 46 of the basic frame 12. The first member 54 of the articulated arm has one end pivotably connected with the fixed frame part 46. At the other end of the first member 54, the lifting arms 14, 14' are pivotably connected with the first member 54 and these lifting arms 14, 14' form a second member of the articulated arm. The position of the first member 54 relative to the fixed frame part 46 is controlled with a first drive 24 and the position of the lifting arms 14, 14' relative to the first member 54 is controlled with a second drive 26. In a practical embodiment, these drives 24, 26 are designed as controllable electric motors. The first drive 24 is provided with a first position sensor 42 which generates a first position signal SP1. The second drive 26 is provided with a second position sensor 44 which generates a second position signal SP2. One of the lifting arms 14 is provided with an acceleration sensor 36. Both lifting arms 14, 14' may, as shown in the example of Fig. 2, be provided with lifting force signal receivers 32. At the footplate 40 a standing force signal receiver 34 may be provided. For the example of Fig. 2, it also holds that the functions provided by the control 38 regulate, for instance, the lifting force, the speed, the acceleration and/or the positions and hence the movement paths of the lifting arms 14, 14' on the basis of at least one of the different output signals S1, S2, S3, S4 possibly in combination with the position signals SP1 and SP2. With the hoist 10 of Fig. 2, too, the patient P is `in control' and particular embodiments thereof may involve `power assist' during the raising and lowering of the patient P.
In an alternative embodiment, the hoist may be a ceiling lift, where the basic frame has no wheels but is suspended from a ceiling lift.
Fig. 3 shows an example of a possible regulation of the at least one drive 24, 26 of the hoist 10. The angle of the upper legs with the horizontal - this angle is obviously related to the position of the lifting arms 14, 14'- is plotted against the amount of lifting force produced by the hoist 10 through control of the at least one drive 24, 26 for positioning the lifting arms 14, 14'. It is clearly visible that the amount of support, or power assist, depends on the position in which the patient P is. The more the patient P is in the standing position, the less the lifting force produced by the hoist. In this graph, along the X-axis, the angle of the upper legs with the horizontal is now plotted, but this is not the only parameter that needs to determine the lifting force. Thus, the lifting force exerted may also serve as input for the control 38. Further, the lifting force, as already described before, may, instead of being determined by the angle of the upper legs, or in addition thereto, also be determined by the standing force exerted on the footboard 40 and/or by the output signal S4, observed with the acceleration sensor, which is representative of the acceleration.
Fig. 4 shows another example of a possible regulation of the at least one drive 24, 26 of the hoist 10. The speed of the free ends of lifting arms 14, 14"is here plotted against the angle included by the upper legs of the patient P and the horizontal. Raising starts gradually and free of shock. Next, the speed is raised to a maximum. Before the end of the lifting movement the lifting speed is rapidly reduced and right before the end of raising, the amount of deceleration of the movement is reduced again, so that a stop without shock is effected. In realizing such a control, the control 38 will in each also take into account the output signals S1, S2, S3, S4 which are provided by the at least one signal receiver 28, 30, 32, 32', 34, 36. What can thus be effected is, for instance, that the lifting force never exceeds a particular threshold value, while this threshold value may also vary with the position of the lifting arms 14, 14' relative to the basic frame 12 and hence with the position of the patient P.
It will be clear that the graphs shown in Figs. 3 and 4 are given only by way of example and that a multitude of variants of regulations are possible. For instance, as already indicated earlier, various regulations may be combined with each other, so that for instance the lifting speed and the exerted lifting force and possibly the lifting acceleration and/or lowering acceleration remain(s) within particular limits, whereby the patient P is optimally stimulated to utilize his own muscular strength as much as possible. Also, the lifting path may be influenced, so that the patient is optimally stimulated each time to utilize his own muscular strength as much as possible.
While the invention has been represented and described in detail with reference to the figures, these figures and this description should only be regarded as an example. The reference numerals in the claims should not be construed as limitations of the claims but serve only for clarification.

Claims

A hoist (10) for raising a patient (P) from a seated to a standing position and for supporting the patient during sitting down, the hoist (10) being provided with:
• a basic frame (12);

• two lifting arms (14, 14') each provided at a free end thereof with an armpit support (16, 16'), a clamping pad and/or a fixing for a support belt (18);

• an adjusting mechanism (20, 22) which connects the lifting arms (14, 14') displaceably with the basic frame (12);

• at least one drive (24, 26) arranged for driving the adjusting mechanism (20, 22) for the purpose of displacing the lifting arms (14, 14') relative to the basic frame (12), such that the lifting arms (14, 14') follow a path which guides the patient (P), who is supported by the armpit supports (16, 16'), the clamping pads and/or the support belt (18), from a seated position to a standing position;

• at least one signal receiver (28, 30, 32, 34, 36) arranged for receiving an input signal delivered by the patient (P) and for generating an output signal;

• a control (38) which is connected with the at least one signal receiver (28, 30, 32, 34, 36) and which is connected with the at least one drive (24, 26) and which is arranged for controlling the at least one drive (24, 26) depending on the output signal (S1, S2, S3, S4) delivered by the at least one signal receiver (28, 30, 32, 34, 36).

wherein the at least one signal receiver comprises a standing force signal receiver (34) which measures an input signal and generates an output signal (S3) which is indicative of a standing force which is exerted by the patient (P) on a footplate (40) during raising and/or lowering of the patient (P), wherein the standing force signal receiver (34) is connected with the control (38),
characterized in that

the at least one signal receiver additionally comprises a lifting force signal receiver (32) which measures an input signal and generates an output signal (S2) which is indicative of a lifting force which is exerted by the lifting arms (14, 14') during raising and/or lowering of the patient (P), wherein the lifting force signal receiver (32) is included in the basic frame and/or the lifting arms (14, 14'), wherein the lifting force signal receiver (32) is connected with the control (38),

wherein the control (38) is configured for controlling the at least one drive (24, 26) for driving the adjusting mechanism (20, 22) for displacing the lifting arms (14, 14') relative to the basic frame (12) depending on at least the output signal generated by the standing force signal receiver (34) and the output signal generated by the lifting force signal receiver (32),

wherein the control (38) is configured for processing the at least one output signal (S1, S2, S3, S4) of the at least one signal receiver (28, 30, 32, 34, 36) and for, on the basis thereof, controlling the at least one drive (24, 26) such that the speed of the lifting arms (14, 14') depends on the at least one output signal (S1, S2, S3, S4).
The hoist according to claim 1, wherein the at least one signal receiver comprises an operating switch (28) which is so positioned on the basic frame (12) and/or the lifting arms (14. 14') that the patient (P) can operate it himself.
The hoist according to claim 1 or 2, wherein the at least one signal receiver comprises a regulator (30) which is so positioned on the basic frame (12) and/or the lifting arms (14, 14') that the patient can operate it himself.
The hoist according to any one of claims 1-3, wherein the signal receiver (32, 34) is implemented as a strain gauge or an assembly of strain gauges which measures an elastic deformation of a part of the lifting arms (14, 14'), the basic frame (12) or the footplate (40).
The hoist according to any one of claims 1-3, wherein the signal receiver (32, 34) is implemented as a load cell.
The hoist according to any one of the preceding claims, wherein the at least one signal receiver comprises an acceleration sensor (38) which measures input signal and generates an input signal (S4) which is indicative of an acceleration of the lifting arms (14, 14'), wherein the control (38) is configured for controlling the drive (24, 26) depending on the output signal generated by the acceleration sensor (40).
The hoist according to any one of the preceding claims, wherein the control (38) is configured for processing the at least one output signal (S1, S2, S3, S4) of the at least one signal receiver (28, 30, 32, 34, 36) and for, on the basis thereof, controlling the at least one drive (24, 26) such that the lifting force that the lifting arms (14, 14') exert via the armpit supports (16, 16'), the clamping pads and/or the support belt (18) on the patient (P) depends on the at least one output signal (S1, S2, S3, S4).
The hoist according to claim 7, wherein the lifting force in a position of the lifting arms (14, 14') corresponding to a seated position of the patient (P) is in the range of 40-70% of the total weight of the patient (P) and wherein the lifting force in a position of the lifting arms (14, 14') corresponding to a standing position of the patient (P) is in the range of 0-10% of the total weight of the patient (P).
The hoist according to claim 8, wherein in positions of the lifting arms (14, 14') that are between the positions corresponding to the seated position and the standing position, the lifting force exerted by the lifting arms (14, 14') decreases gradually when the lifting arms (14, 14') move from the position corresponding to the seated position to the position corresponding to the standing position.
The hoist according to any one of the preceding claims, wherein the control (38) is configured for processing the at least one output signal (S1, S2, S3, S4) of the at least one signal receiver (28, 30, 32, 34, 36) and for, on the basis thereof, controlling the at least one drive (24, 26) such that the path that lifting arms follow depends on the at least one output signal (S1, S2, S3, S4).
The hoist according to any one of the preceding claims, wherein the control (38) is configured for processing the at least one output signal (S1, S2, S3, S4) of the at least one signal receiver (28, 30, 32, 34, 36) and for, on the basis thereof, controlling the at least one drive (24, 26) such that the acceleration of the lifting arms (14, 14') depends on the at least one output signal (S1, S2, S3, S4).
The hoist according to any one of claims 1-11, wherein in addition to the at least one signal receiver (28, 30, 32, 34, 36), the hoist (10) is provided with at least one position sensor (42, 44) which delivers a position signal (SP1, SP2) which is indicative of the position of the lifting arms (14, 14'), wherein the control (38) is configured for controlling the drive (24, 26) on the basis of a speed function, and optionally additionally a position, force, path and/or acceleration function, which has as input parameters both the output signals (S1, S2, S3, S4) of the at least one signal receiver (28, 30, 32, 34, 36) and the at least one position signal (SP1, SP2) of the at least one position sensor (42).
The hoist according to any one of the preceding claims, wherein the control (38) is an electronic control.
The hoist according to any one of the preceding claims, wherein the at least one drive (24, 26) comprises a stepping motor, a servo motor or a similar controllable electric motor which is controllable on the basis of force and/or position control and/or a derivative thereof.
The hoist according to claim 12, wherein the control (38) is configured to determine, on the basis of the at least one output signal (S1, S2, S3, S4) and the at least one position signal (SP1, SP2), a physique, such as height and/or weight, and/or posture of the patient (P), and, on the basis thereof, to automatically tune the lifting path, the lifting force, the lifting speed and/or the lifting acceleration of the lifting arms (14, 14') to the physique and/or posture.
The hoist according to claim 1, wherein the at least one drive comprises a gas spring, wherein the at least one signal receiver comprises an operating knob or lever, wherein the control comprises a blocking mechanism which is operatively connected with the operating knob or the lever and which in a first position blocks the gas spring and in a second position deblocks the gas spring.
The hoist according to claim 1, wherein the at least one drive comprises a spring or a counterweight, wherein the at least one signal receiver comprises an operating knob or lever, wherein the control comprises a blocking mechanism which is operatively connected with the operating knob or the lever and which in a first position blocks the lifting arms and in a second position deblocks the lifting arms.
The hoist according to any one of claims 1-17, provided with:
• a blocking device which is configured to block the lifting arms (14, 14') in the end positions thereof, and preferably also in at least a number of intermediate positions.