GB2359063A - Load handling apparatus - Google Patents

Abstract

A device (10) for displacing a load such as a patient, comprising a body (11) of resilient open cell foam material encased within a gas-impermeable envelope (14) having an outlet (15) for connecting the interior of the envelope to a gas evacuation pump (19 Fig 3) by means of which the open cell foam can be collapsed to the reduced dimensions within the outer envelope (14) by evacuation of all air within it. At least one control valve (16) is provided at an inlet to the envelope (14) to allow gas to be reintroduced into the envelope (14) so that the body of resilient open cell foam can regain its original dimensions, lifting or moving the patient in doing so. Two or more of the devices (10) can be combined to form a wedge shaped device for sitting up or transferring a patient eg. onto a bed (Fig 5).

Description

2359063 1 LOAD RANDLING APPARATUS The present invention relates generally

to load handling apparatus, and particularly to a device for displacing a load.

As used in this specification, the term "displacing" will be understood to refer to linear or rotating physical displacement in any direction, including elevating and descending movement, lateral rectilinear movement, curvilinear movement and turning or rotary movement in any directional sense.

The present invention finds a major application in the handling of patients, which is a field in which the " load" comprises a human being and, therefore, there are special requirements as to security and delicacy (that is the lack of forcefulness) of handling. It is important, for example, that load handling apparatus for patients be fail safe in the sense that any foreseeable failure of the apparatus to perform should not result in any sudden loss of support which may cause an injured person to drop or jolt. It is also important that any movements applied to a patient, particularly one with physical injuries, must be introduced gradually without any risk of sudden 2 or unexpected jerks or jolts since, even if these are in a rising rather than a falling direction they may cause exacerbation of the patient's injuries.

In this field of use considerable consideration has been given in recent times to the techniques by which carers are able to move patients from one position to another, for example from a prone to a supine position, from a supine to a sitting position, or from sitting to standing or vice versa, as well as more radical movements such as lateral transfer of a patient from one bed to another. It is recommended that special techniques and equipment are utilised in order to reduce as much as possible, if not entirely avoid, the need for carers to exert physical lifting forces on the patient either to cause the displacement or to reduce the frictional contact between the patient and the supporting surface in order to facilitate lateral transfer.

Various items of equipment have in the past been designed for facilitating such movements, including hydraulic and pneumatic hoists with slings for lifting patients, roller and other slides for facilitating lateral transfer (which are especially useful in transferring patients from a transport trolley to an operating table) and similar such 3 items.

Known hoists for raising patients from one horizontal level to another are large, cumbersome, complicated and expensive items which, apart from their physical size and shape, which precludes their use in circumstances where access is restricted, cannot always be made available for all patient movements since it would be necessary to convey the equipment from one place to another rapidly and this is not easily achieved in a working environment such as a hospital.

The present invention seeks to provide an additional item of equipment which is of value in load handling situations, and is especially valuable in connection with the handling of live loads such as human beings, which meets the requirements of security and gentleness of displacement necessary for the safe handling of patients, which is economical to produce and which uses very little energy in operation.

According to one aspect of the present invention, therefore, there is provided a device forming at least part of apparatus for displacing a load, comprising a body of resilient, open cell foam material encased within 4 a gas-impermeable envelope having means for connecting the interior thereof to gas evacuation means whereby in use to create a subatmospheric pressure within the envelope, and at least one control valve for selectively allowing the admission of gas into the envelope when the interior thereof is at a sub-atmospheric pressure.

A device such as that def ined above may be made to a specific shape suitable for a specific purpose, or may be made as a rectangular body or other regular shape such as square or circle for general purpose use. The resilient, open cell foam material must be one having sufficient inherent stiffness to support the intended load when at atmospheric pressure. By evacuating the interior of the envelope, however, atmospheric pressure causes compression of the open cell foam material allowing this to occupy a very much reduced volume. In this configuration of reduced volume the device may be introduced beneath the load to be handled, and thereafter the valve means operated to allow gas to be admitted into the envelope gradually so that the compression of the open cell foam by atmospheric forces is progressively released allowing the foam to expand to its natural state compressed only by the weight of the load (which, naturally, will only act to compress the foam material to a minimum extent and then only in places where particular load-bearing contact takes place).

is In order to spread the load of, for example, a patient over the entire area of the closed cell foam there may be provided at least one closed cell foam or rather impermeable (and preferably relatively stiff) layer adjacent a major face of the said body of open cell foam material. Closed cell foam may be made in a wide range of stiffness and resilience, and a patient sitting or lying on a surface comprising such material, and actually in contact with such material over relatively limited areas, such as at the feet, hips and shoulders, will nevertheless have the entire weight of the patient spread over the entire surface of the open cell foam material by the closed cell foam layer.

Indeed, the said at least one closed cell foam or other impermeable layer may form part of the said impermeable envelope, in which case the skin,, or impermeable envelope may be attached to the closed cell foam layer at or adjacent the periphery thereof or even between the contact region between the closed cell foam layer and the open cell foam layer as part of the connection, which may be made by adhesive or welding such as ultrasonic welding 6 techniques. In a typical embodiment for use as a bed having a capability for raising the patient, therefore, the body of resilient open cell foam material may have closed cell foam layers on each of two opposite major faces and a flexible laminar sealing layer around the sides and ends. A completely encasing laminar envelope may, of course, be provided either instead of, or as an addition to, the edge and end sealing membrane.

Moreover, there may be further provided one or more layers or elements of a different density and/or cell structure within the body of open cell foam material whereby to determine the physical behaviour thereof as the envelope is evacuated and/or as gas is readmitted thereto. In more general terms the layers or elements within the body of open cell foam material may have any physical property different from that of the open cell foam material to achieve any desired effect, such as a change in shape, variation in resistance or the like.

For this purpose the said body of open cell foam material may be formed as a structure comprising a plurality of layers with intervening intermediate layers of material having different physical properties. These physical properties may include the fact that the layers are 7 rigid, that they are thicker at one point than another, especially tapered from one edge to the other, have cavities or humps or comprise a material or materials which are reactive to pressure, particularly thixotropic and reverse thixotropic materials. The latter may have particular advantages as a -sub-surface layer in varying the pressure applied to a person lying thereon, especially in reducing the risk of pressure sores.

Embodiments of the invention may be formed in which the said body of open cell foam material has two major substantially parallel faces or may be made in other shapes, particularly curved shapes which, in the relaxed state, match or accommodate the curvature of the part of the human body intended to come into contact therewith. This is of particular significance in relation to structures which may form a cradle or sling for a human body, or a seat on which a person may rest in a seated position.

Moreover, embodiments of the invention may be formed in which the body and/or the said envelope includes at least one substantially rigid panel extending over at least part of at least one of the said faces thereof. Such rigid panel may serve in particular to spread a load 8 applied over a relatively small area, such as by a hand or foot, in order to ensure that the foam body is capable of applying sufficient force to maintain support of the whole weight of the person even though the weight may be applied through a single small area such as when a person is standing on the surface.

The said body of open cell foam material and/or the or an intervening intermediate layer may be of varying thickness in the relaxed state.

This is of particular value in providing a structure capable of causing lateral displacement of a patient when gas is admitted to the envelope or removed therefrom.

Preferably, in such an embodiment, the thickness of the said body and/or outer or intermediate layer is greater towards one longitudinal edge and/or towards one end thereof. When compressed by evacuation of gas from the envelope such embodiments may have a tapered or wedge- like shape and, when expanded by readmission of gas, can adopt a much more inclined or strongly tapered wedgeshape. In order to compensate for this in the compressed state the body may have outer layers (which may be rigid foam, closed cell foam or other material) having a tapering shape in the opposite direction and an 9 inclination such as will match that of the taper of the open cell foam when compressed. In this way the opposite major faces of the device will be substantially parallel in the compressed state, facilitating handling and storage. Visual indication of the direction of slope upon release, however, would be advisable in such embodiments.

Embodiments of this form will be particularly suitable for use in conjunction with so-called roller slide sheets which are currently used for lateral transfer of patients without lifting. Roller slide sheets are used for displacing a patient longitudinally of a bed, particularly between a lying and a sitting position, or to raise the patient to a higher sitting position; they are also used for lateral transfer of a recumbent patient from one bed to another or to assist in turning the patient from a prone to a supine position or vice versa.

Embodiments of the invention may also be formed in which the said varying thickness of the said body and/or the outer or intermediate layer forms a profiled mattress or bed capable of elevating one or other part of the patient lying thereon in dependence on selective admission of gas to parts of the envelope partitioned from one another.

For this purpose a structure comprising several individual bodies of foam material each encased in a separate gas-impermeable envelope may be joined together to form a common structure. Such a structure may, furthermore, be used to form a chair or like support, such a chair having at least a seat and a seat back, but possibly also having side arms.

The present invention may be seen to comprehend apparatus comprising two or more structures as herein defined, with independently operable valves to allow evacuation and/or readmission of gas from or to the interior chambers thereof.

The invention may also be understood to comprehend apparatus comprising a structure as herein def ined in which two opposite major faces are inclined at a non-zero angle with respect to one another, in combination with a transfer aid in the form of an element of flexible laminar material having a low coefficient of friction between itself and the surface of the structure, or in which the transfer aid is in the form of a closed or open loop of flexible laminar material the facing surfaces of which have a low coefficient friction whereby to encourage lateral movement of a load resting on the structure with the transfer aid interposed between itself and the surface of the structure as gas is admitted to or evacuated from the interior of the envelope.

The nature of the valve used in controlling the admission of gas to the envelope, and through which gas may be evacuated in order to compress the device, is preferably such that it does not occupy greater than the thickness of the body when compressed by atmospheric forces upon evacuation of gas valve means, such is from the envelope. Suitable resilient as elastomeric lip valves, may be used for this purpose although more robust slide valves or rotary control valves made from plastics or metal may be designed with a suitable shape to permit their use in these circumstances. A slot-like of flattened shape is particularly appropriate for this purpose.

The gas evacuation means may be one of several types, including a vacuum pump which may be a positive displacement type or one acting indirectly, particularly an ejector valve type of pump, and in any event may be driven by an electric motor or other form of prime mover. Alternatively, the gas evacuation means may comprise or include means for varying the volume of gas as a result of a chemical reaction. Such chemical reaction may 12 result in a release of gas to allow expansion of the foam, or a consumption or reduction of gas (for example by utilising the oxygen content and/or the nitrogen content of the air, resulting in effective removal of the gas content of a sealed envelope thereby allowing the surrounding atmospheric pressure to compress it to a very flat condition.

In its application as a patient handling device the present invention offers a number of significant advantages, not least of which is the security of support offered by the open cell foam material. It will be appreciated that rupture of the gas-impermeable membrane will not result in a loss of support since this is provided by the resilience of the open cell foam material. Accidents or vandalism will. therefore, not render the device ineffective. Likewise, because the open cell foam material takes a certain time for gas to permeate throughout the cells due to the pressure differential between the surrounding atmospheric pressure and the reduced pressure within the material when collapsed, even a sudden and catastrophic loss of seal will result only in the gradual and relatively slow expansion of the foam material to its expanded state so that, should this happen inadvertently, no sudden or 13 dangerous change in position of a patient will occur.

Various embodiments of the present invention will now be more particularly described, by way of example, with 5 reference to the accompanying drawings, in which:

Figure 1 is a perspective view of a first embodiment of the invention formed as a bed for receiving a recumbent patient and raising or lowering the patient over a certain vertical height range; Figure 2 is a perspective view similar to that of Figure 1 showing the embodiment of Figure 1 in the collapsed or lowered condition; Figure 3 is a sectional view through the embodiment of Figure 1 illustrating it connected to a vacuum pump for withdrawal of the air contained therein; Figure 4 is a schematic diagram illustrating the use of the embodiment of Figure 1 in transferring a patient from a trolley to a bed; Figure 5 is a schematic diagram similar to that of Figure 4, showing an alternative embodiment allowing automatic transfer of a patient from trolley to bed; Figure 6 is a schematic perspective view of an alternative embodiment of the present invention suitable for use in elevating a stretcher for facilitating introduction of a patient into an ambulance;

14 Figure 7 is a schematic sectional view of an alternative embodiment usable for lifting a patient from a lying to a sitting position; Figure 7a is a sectional view through the embodiment of Figure 7 illustrated in its collapsed form; and Figure 8 is a schematic view of an assembly forming a further embodiment of the present invention.

Referring now to the drawings, and in particular to 10 Figures 1, 2 and 3 thereof the invention in its simplest form comprises, as shown in Figure 1, a body 11 of open cell foam material which, in this embodiment, is of sufficient dimensions to be suitable as a bed or mattress, namely in the region of 2 metres long, 1 metre wide and 0. 5 metres thick. Other dimensions are, of course, readily usable and the dimensions given here by way of example are non-limitative.

The body 11 of open cell foam material has two opposite major faces to which are secured correspondingly dimensioned relatively thin layers of closed cell foam material 12, 13 with the entirety of the structure being encased in a surrounding gas-impermeable membrane 14, shown cut away in Figure 1 for clarity.

is At one end of the body 11 the membrane 14 has a connector 15 incorporating, within it a controllable unidirectional valve operable by a control wheel 16 on the connector 15. In correspondence with this valve the upper and lower layers 12, 13 of relatively rigid closed cell foam material have respective notches 17 (the notch in the lower layer 13 being concealed in Figure 1, but visible in Figure 2) allowing these two layers closely to approach one another, as shown schematically in Figure 2, when the air from within the membrane 14 is evacuated.

Figure 1 illustrates the device in its relaxed or expanded form, and Figure 2 shows the configuration adopted by the device if the valve connector 15 is connected to a gas-evacuation device indicated schematically 19 in Figure 3, for example by means of a short length of connector hose 20. In Figure 3 the gas evacuation device 19 is shown as a vacuum pump although, as discussed above, other means for evacuating gas from the interior of the membrane 14 may be utilised.

As the gas is evacuated from the body 11 of open cell foam material surrounding atmospheric pressure causes this to collapse. Because of the rigid supporting effect of the two closed cell foam layers 12, 13 the device 16 retains its generally rectangular configuration with the two layers 12, 13 remaining f lat and approaching one another until the evacuation of gas has reached its limit, at which point the evacuation is discontinued.

The unidirectional valve in the connector 15 maintains the vacuum providing the control wheel 16 remains in its closed position. In this configuration the device 10 is in the form of a stiff board-like element which can be stacked with other such elements, stood on end or otherwise stored until needed. This is particularly useful as a store of emergency beds for a hospital, since they occupy little room when compressed. In Figure 4 there is illustrated a situation where a patient B is to be transferred from a trolley generally indicated 21 onto a bed generally indicated 22. In which a situation a collapsed handling device 10 is taken from the store (which may conveniently be beneath a trolley or bed), and introduced beneath a patient generally indicated P.

As will be appreciated the trolley 21 is substantially lower than the bed 22 and, consequently, transfer of the patient P from the trolley 21 to the bed 22 would require lifting the patient a significant distance. Once the handling device 10 has been introduced under the patient a lateral transfer aid in the form of a loop 23 of 17 material having a low coefficient of friction, such as that described in the applicant's earlier patent GB 2 282 126 is also introduced under the patient. By operating on the control wheel 16 air can be allowed into the open cell foam body 11 causing the patient to rise until the upper surface of the device 10 is substantially level with the upper surface of the bed 22. At this point it is a simple matter, by acting on the roller loop 23, to cause the patient to slide laterally across from the trolley 21 to the bed 22.

Figure 5 illustrates an alternative configuration of the device 10, in which the open cell foam body 110 is tapered or wedge shape, but otherwise similar to the embodiment of Figure 1. Upon introduction of air by opening the valve 15, therefore, the expansion of the open cell foam 110 causes the upper layer 12 of the device 110 to adopt an inclined orientation as illustrated in Figure 5 so that the patient P rolls automatically on the roller loop 23 from the trolley 21 to the bed 22. Naturally, means are provided to ensure that the upper and lower layers 12, 13 of the device 110 are substantially parallel to one another when the device is compressed by evacuation of air from the interior of the enclosing membrane. This may be achieved, for 18 example, by introduction of oppositely tapered intermediate layers in a manner similar to that which will be described in relation to Figure 7 hereafter.

Figure 6 illustrates a structure comprising two devices 10 placed one above the other and used for elevating a patient P on a stretcher 24 from ground level to the floor level of an ambulance 25. It will be appreciated that patient handling devices 10 in a configuration ready for use, that is the collapsed board-like state as illustrated in Figure 2, may be stored within an ambulance 25, for example along the side walls thereof, ready for use in a situation such as that shown in Figure 6 where a patient, collapsed on the roadway and too seriously physically injured to be manhandled, can be safely and easily raised by gently introducing beneath him a thin, collapsed patient handling device 10 and allowing introduction of air by opening the valve 15. Gradual induction of air allows the patient to be raised slowly and gently. Greater height can be achieved by using several devices one above the other as illustrated in Figure 6. Then it is a simple matter to slide the stretcher 24 straight onto the floor 26 of the ambulance 25 without requiring any significant lifting by the ambulance crew, or they my grasp the handle and carry the 19 patient to the ambulance if it has not been possible to bring it up as close as shown in Figure 6.

After use the devices 10 may be collapsed by using a portable vacuum pump driven by the ambulance's engine or, for example, by a turbine-driven device connectable to the exhaust and utilising the vehicle's exhaust gases either to drive a positive displacement pump or an ejector pump. If time is of the essence and the crew decide that there is insufficient time to delay before transferring the patient P to hospital, the devices 10 may be slung on the cradles from the roof of the ambulance in their inflated condition and collapsed by withdrawal of air at a later time.

is Figure 7 illustrates a further alternative embodiment comprising several sectors 31, 32 of open cell foam material sandwiched between tapering layers 33, 34, 35 of closed cell foam material. Each of the open cell foam bodies 31, 32 has its own individual manually operable valve 36, 37 and, as illustrated in Figure 7a, when air is evacuated from the open cell foam bodies 31, 32 the opposite inclination of the closed cell foam layers 33, 34, 35 results in a flat package in which the opposite major faces 38, 39 are substantially parallel to one another. In this collapsed configuration the device 40 may be introduced under a patient lying on a bed, with the valve end nearest the patient's head and the opposite end adjacent the lower part of the patient's trunk. Then, by opening the valves 36, 37 air is allowed into the open cell foam bodies 31, 32 which expand to the shape illustrated in Figure 7 lifting the patient from the horizontal to a sitting position.

Figure 8 illustrates a structure comprising several rectangular bodies, four in number, 41, 42, 43 and 44 respectively assembled to form the side arms, back and seat of a chair generally indicated 45. Such a chair may be equipped with a tapered device 40 such as that shown in Figure 7 which may turn from a position in which the upper surface 38 is horizontal to one in which it is vertical so that a patient (not shown) sitting on the seat 44 may be raised from a sitting to a standing position with the aid of the device.

Collapse of the elements 41, 42, 43, 44 allows the chair to be reduced in dimensions for storage.

In another embodiment (not illustrated) the expansion of 25 an open cell foam element placed to one side of a 21 patient, between the patient and a rigid support such as a wall, can be used to displace the patient laterally without requiring any force to applied by the carers.

Although described with particular reference to the application to patient handling, the load displacement device of a present member is applicable to load handling generally. For example, a supermarket trolley may be equipped with such a device to allow the merchandise to be lifted to the same level as the checkout conveyor to facilitate transfer. Another embodiment may be formed as a 11 library steps" or lifting stool device for use by people to reach higher shelves.

For security in the compressed state a system of safety straps may be provided to encircle the device.

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Claims (23)

1. CLAIMS is 1. A device forming part of apparatus for displacing a load,

   comprising a body of resilient open cell foal material encased within a gas-impermeable envelope having means for connecting the interior thereof to gas evacuation means whereby in use to create a sub atmospheric pressure within the envelope, and at least one control valve for selectively allowing the admission of gas into the envelope when the interior thereof is at a sub-atmospheric pressure.
2. 2. A device as claimed in Claim 1, in which there is further provided at least one closed cell foam or other impermeable layer adjacent a major face of the said body of open cell foam material.
3. 3. A device as claimed in Claim 2, in which the said at least one closed cell foam or other impermeable layer 20 forms part of the said impermeable envelope.
4. 4. A device as claimed in any preceding claim, in which there are one or more layers or elements of different density and/or cell structure within the body of open cell foam whereby to determine the behaviour thereof as 23 the envelope is evacuated and/or as gas is readmitted thereto.
5. 5. A device as claimed in Claim 4, in which the said body of open cell foam material is formed as a structure comprising a plurality of layers with intermediate layers of material having different physical properties e.g. rigid, tapered, hollow hump shaped or reactive.
6. 6. A device as claimed in any preceding claim, in which the said body of open cell foam material has two major substantially parallel faces.
7. 7. A device as claimed in Claim 6, in which the said body and/or the said envelope includes at least one substantially rigid panel extending over at least part of at least one of the said major faces.
8. 8. A device as claimed in any preceding claim, in which the said body of resilient open cell foam material and/or the or an intervening intermediate layer is of varying thickness in the relaxed state.
9. 9. A device as claimed in Claim 8, in which the thickness of said body and/or outer or intermediate layer 24 is greater towards one longitudinal edge and/or towards one end thereof.
10. 10. A device as claimed in any of Claims 1 to Claim 9, in which the said varying thickness of the said body and/or outer or intermediate layer forms at least a mattress for a profiled bed.
11. 11. A device as claimed in any of Claims 1 to 9, in which the said body of open cell foam material is shaped as a chair with at least a seat and a seat back.
12. 12. A device as claimed in Claim 11, in which the body of open cell foam material includes parts shaped as chair arms.
13. 13. Apparatus comprising two or more devices as claimed in any preceding claim, with independently operable valves to allow evacuation and/or readmission of gas from or to the interior chambers thereof.
14. 14. Apparatus comprising the combination of a device as claimed in any preceding claim in which two opposite major faces thereof are inclined at a non-zero angle with respect to one another, together with a transfer aid in the form of an element of flexible laminar material having a low coefficient of friction between itself and the surf ace of the structure, or between two layers of the transfer aid itself.
15. is. Apparatus comprising a device as claimed in any of Claims 1 to 13 in which two major faces are inclined at a non-zero angle with respect to one another, and a transf er aid in the form of a closed or open loop of flexible laminar material the facing surfaces of which have a low coefficient of friction whereby to encourage lateral movement of a load resting on the structure with the transfer aid interposed between itself and the surface of the structure as gas is admitted to the interior of the envelope.
16. 16. A device or apparatus as claimed in any preceding claim, in which the shape and dimensions of the valve are such as not to be greater than the thickness of the body when compressed by atmospheric forces upon the evacuation of gas therefrom.
17. 17. A device or apparatus as claimed in any preceding claim, in which the said valve is a lip valve of elastomeric material.

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18. 18. A device or apparatus as claimed in any preceding claim, in which the valve is a slide valve.
19. 19. A device or apparatus as claimed in any of Claims 1 to 17, in which the valve is a rotary control valve.
20. 20. A device or apparatus as claimed in any preceding claim, in which the gas evacuation means comprise or 10 include an ejection valve.
21. 21. A device or apparatus as claimed in any preceding claim, in which the gas evacuation means include a mechanical pump.

    is
22. 22. A device or apparatus as claimed in any preceding claim, in which the gas evacuation means comprise or include means for varying the volume of gas as a result of a chemical reaction.
23. 23. A device or apparatus substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.