GB2286430A - Lifting devices - Google Patents

Abstract

Apparatus particularly for injured or disabled persons comprises a lifting device 10 and pneumatic control means 68. The lifting device comprises a stack of substantially rectangular bags 11, 12 and 13 secured together which bags contain internal flexible links to limit the inflated thickness thereof. The pneumatic control means 68 has valve controlled outputs 69 which are connected or connectable by respective hoses 16 individually to the bags and is arranged to pressurise the outputs sequentially, from a supply of compressed air 70, to automatically fully inflate each bag in turn. <IMAGE>

Description

LIFTING DEVICES This invention concerns lifting devices, e.g. for lifting injured or disabled persons in confined spaces.

It is known to raise a person by means of a pneumatically inflatable apparatus comprising a platform which is disposed on a bellows and is stablised by a mechanism contained in the bellows. Such apparatus provides stable lifting, but is expensive to construct, is cumbersome to carry and in its lowermost condition is too thick to be slid easily under a person without the person being raised significantly by hand.

For emergency use, it is known to employ stretchers comprising a pneumatically inflatable mattress slung between poles. Such apparatus is bulky because of its length, and the maximum thickness of the mattress is very small and thus provides insufficient lift, so that the stretcher has to be raised manually by means of the poles.

It is also known to employ a large inflatable bag for lifting purposes. Such bags are inherently unstable during lifting, and are not therefore suitable for lifting disabled persons.

Stability of lifting is most important where disabled persons are concerned, and in particular in circumstances where only one or two helpers or attendants are available to assist such a person.

Forms of apparatus such as hoists, employing large frameworks and requiring operators to continuously operate complex controls, are not suitable for use in confined spaces, and are inconvenient to transport and operate under emergency conditions because of their weight, bulk and complexity.

The invention seeks to avoid or reduce these problems of cost, overly restricted lift, bulk and stability.

According to the present invention there is provided a lifting apparatus comprising a lifting device and pneumatic control means; wherein the lifting device comprises a stack of substantially rectangular bags secured together, in which the fully inflated thickness of each bag is less than the width and breadth of the bag, at least the bag or bags below the uppermost bag of the stack containing internal flexible links to limit the inflated thickness thereof; and wherein the pneumatic control means has valve controlled outputs which are connected or connectable by respective hoses individually to the bags and is arranged to pressurise the outputs sequentially, from a supply of compressed air, to automatically fully inflate each bag in turn.

The inflated thickness of the lowermost bag is preferably greater than, e.g. about double, the inflated thickness of the uppermost bag, but the bags may be of any combination of thickness to achieve a desired lift.

The bags are preferably made from a "drop thread" material which integrally incorporates the links.

The stack preferably comprises three or four bags.

Adjacent bags are preferably secured together by webs which extend along at least two sides thereof and are bonded to side walls of the bags.

The lowermost bag may have an abrasion resistant base or underside.

The hoses are preferably permanently attached by integral inlets of the bags, which inlets may be arranged on one side of the stack and may be offset from one another to reduce the overall thickness of the device when the bags are deflated.

The overall plan dimensions of the stack are preferably at least 0.3 metres by 0.3 metres up to 0.8 metres by 2.0 metres.

The fully inflated height of each bag is preferably less than half of its smallest plan dimension, e.g. about a third or a quarter.

The device is light, is thin when deflated for ease of insertion under a person, gives substantial stability during sequential inflation, is stable when fully inflated and is relatively inexpensive to construct.

The pneumatic control means preferably comprises a plurality of solenoid actuated flow control valves and a plurality of pressure actuated switching arrangements, wherein each valve controlled output is controlled by a respective one of the valves and is pneumatically connected to a respective one of the switching arrangements so that the valve is closed by the switching arrangement when the pressure at that output reaches a predetermined pressure, and wherein the switching arrangements are electrically connected to open the valves sequentially to a pneumatic pressure supply line.

The pneumatic control means may be constructed as a pressure sensitive control unit which is arranged to receive a single compressed air supply and to distribute the compressed air sequentially to the plurality of outlets so that each outlet, starting with a predetermined one thereof, is supplied with compressed air until a predetermined pressure is reached and is isolated from the supply before the next outlet commences to receive compressed air.

The pneumatic control means may also include or be combined into a portable compressed air supply unit which includes a compressor to provide a compressed air supply, and, optionally, a rechargeable battery to power the compressor.

The air supply unit may include a switch to switch off the compressor when all outlets have reached a predetermined pressure or respectively predetermined pressures.

The invention will be described further by way of example, with reference to the accompanying diagrammatic drawings, wherein FIGURE 1 shows a first embodiment of apparatus of the invention in side elevation with a lifting device in an inflated condition; FIGURE 2 is a schematic circuit diagram of the control unit of that apparatus; FIGURE 3 shows a second embodiment of the apparatus; FIGURE 4 is a circuit diagram of a pneumatic supply and control unit of the apparatus; and FIGURE 5 shows the lifting device, deflated, in end elevation.

The lifting device 10, in both embodiments, comprises a stack of three bags 11, 12 and 13, each of which is about 0.4 metres in width, and about 0.35 metres in breadth. The top bag 11 has an inflated thickness of about 0.1 metres, whereas the bags 12 and 13 therebelow are about 0.2 metres thick.

Each bag comprises a body of drop thread material in which upper and lower panels are linked internally by a multiplicity of inelastic threads, and the panels are connected peripherally by flexible inelastic side walls 17 bonded to said panels. The panels and side walls are preferably made of woven fabric/reinforced plastics material, e.g. nylon reinforced butyl rubber material.

Webs 18 are bonded to the side walls 17 along junctions at at least two sides of the stack between adjacent bags, to secure the bags together.

Each bag is provided with a hose 16 secured at an inlet 19 to the bag, and each hose has a terminal connector 15. The inlets 19 may be horizontally offset from each other, at one end of the stack, and the device is arranged so that, in the fully deflated condition, the thickness of the device is not much more than the thickness of a single hose e.g. is of the order of one or two centimetres, so that it can be slid below a person who has to be lifted in a confined space, e.g. in a bath, in a toilet compartment or between a bed and a wall.

Thereafter, the bags can be inflated sequentially to maximum thickness to raise the person, as hereinafter described.

Referring to FIGURE 2, the control unit 68 provides connections 69 for the three hoses 16, and has an input hose 70 and electrical lead 71 for connecting the unit to a compressed air supply line and a 12DC power supply (not shown) to receive compressed air and a 12V DC electrical supply. The unit 68 has, internally, an air supply line 70A connected to three solenoid actuated valves 72, 73 and 74, and has three pressure sensitive switching arrangements 75, 76 and 77 represented in FIGURE 2 as three pressure sensitive switches, all shown in FIGURE 2 in a de-energised condition.

When pressure is first supplied to the unit and the latter is electrically energised, switch 75 energises the valve 72 which opens to supply compressed air from line 70 to the bottom bag 13, and valves 73 and 74 remain closed.

When the bag 13 is inflated to a predetermined pressure, switch 75 responds to de-energise (and thus closes) valve 72 and to energise switch 76 via which valve 73 is opened for inflating the middle bag 12 until it reaches a predetermined pressure at which the switch 76 responds to de-energise valve 73 and energise valve 74 via switch 77 for inflating the top bag 11. When the top bag is inflated to a predetermined pressure at which switch 77 responds to de-energise valve 74, inflation of the device is automatically halted, and the device is held inflated by the closed valves. The person operating the apparatus is free, during inflation of the device, to attend the person being lifted.

The switching arrangements have considerable hysteresis, e.g. the said predetermined pressure is considerably higher than the pressure at which the switches revert to their normal conditions; and may be constructed in a manner similar to that hereinafter described with reference to FIGURE 4. The device is deflatable by disconnection of the hoses 16 after the person has been transferred to a support such as a wheelchair.

In the second embodiment, lifting device 10 is powered by a pneumatic supply and control unit 30 (FIGURE 3) which can be manually actuated from a remote control unit 31.

The unit 30 also provides the three outlets 69. The outlets are connected to the respective control valves 72, 73 and 74 connected to the common compressed air supply line 70 (not shown in FIGURE 4) as in the first embodiment, but unlike that embodiment, the line 70 is connected to a compressor 20 driven by a motor 32 in the unit 30, which unit also houses a rechargeable battery 79.

The motor 32 and the solenoids 72S, 73S and 74S of the valves 72, 73 and 74 are controlled by three pressure sensitive switching arrangements 75A, 76A and 77 via relays K1 to K7 in control circuitry shown in FIGURE 4.

The remote control unit 31 provides switches 35 and 35A (FIGURE 4) having a normal "off" position and an "up" switching position or a "down" switching position respectively, and is releasably connected to the control circuitry by a lead 36 (FIGURE 3).

The circuitry is arranged so that the bags can be inflated sequentially. When the switch 35 is initially moved to and held in its "up" position (closing on contact C2 in FIGURE 4) the motor 32 is energised via relay K1, and relay K5 is energised to energise solenoid 72S (via relay K4) to open the valve 72 for inflating bag 13.

When air bag 13 reaches its predetermined pressure, pressure switch PIH of switching arrangement 75A closes and latches relay K4 such that its terminal 3 is isolated and its terminal 16 connected, this action closes valve 72 and opens valve 73 via terminals 3 and 5 of relay K3 for inflating the bag 12.

When the bag 12 reaches its predetermined pressure, switch P2H of switching arrangement 76A closes and latches relay K3 such that its terminal 3 is isolated and its terminal 16 is connected, and this action closes the valve 73 and opens the valve 74, for inflating bag 11.

When the bag 11 reaches its predetermined pressure, switch 77 closes and through relay K2 switches off the compressor motor 32. On releasing the inflate switch 35 to the off position, valve 74 closes maintaining bag 11 at pressure.

If the switch 35A is operated to its down position closing on contact C4 relay K5 opens valve 74 allowing compressed air from bag 11 to escape to atmosphere via the air system pipes and back feeding through the compressor.

This facility is included to allow minor adjustment of the height of the top bag 11 and to provide some comfort to the occupant.

When the bags are disconnected from the unit 30, pressure switches P1L and P2L of switching arrangements 75A and 76A operate and, via relays K6 and K7, reset relays K3 and K4 back into their normally closed states ready to start again.

The switches P1L and P2L are set at a lower predetermined pressure fractionally smaller than the aforementioned predetermined pressure. The provision of higher and lower pressure switches controlling latching relays is to prevent the diversion of air into an already inflated bag if a minimal decrease in pressure occurs in that bag, possibly caused by movement of the occupant, i.e. to provide pressure switching hysteresis as previously mentioned.

In both embodiments, switching off the supply of compressed air will only allow deflation of that bag which was in the process of being inflated.

The invention is not confined to details of the foregoing examples, and many variations are possible within the scope of the invention. For example, the bags, or at least one thereof, may be releasably secured in the stack, e.g. by means of fasteners or fastening tape such as "Velcro" (a Registered Trade Mark).

Where the bags are permanently connected, the abutting faces of the panels may be bonded together.

The stack is preferably of modular construction e.g.

in which the lowermost bag is the same as the next bag.

The inlets may be offset, e.g. to allow an inverted duplicate of the bag 11 to be superimposed on the bag 11 without significantly increasing the deflated thickness.

The upper and/or lower surface or surfaces of the stack may be provided by a rigid or stiff laminate panel or panels.

The switch 35 may be able to be locked in its "on" or "up" position to free the operator to attend the person being lifted.

The unit 68 may contain a rechargeable or renewable battery in circuit with an energisation switch instead of, or as well as, the lead 71, as indicated in broken lines in FIGURE 2.

The invention further includes and provides a lifting apparatus having any novel part or feature or novel combination of the parts or features disclosed herein or in the accompanying drawings.

Claims (18)

1. Lifting apparatus comprising a lifting device and pneumatic control means; wherein the lifting device comprises a stack of substantially rectangular bags secured together, in which the fully inflated thickness of each bag is less than the width and breadth of the bag, at least the bag or bags below the uppermost bag of the stack containing internal flexible links to limit the inflated thickness thereof; and wherein the pneumatic control means has valve controlled outputs which are connected or connectable by respective hoses individually to the bags and is arranged to pressurise the outputs sequentially, from a supply of compressed air, to automatically fully inflate each bag in turn.

2. Apparatus as claimed in Claim 1 wherein the pneumatic control means comprises a plurality of solenoid actuated flow control valves and a plurality of pressure actuated switching arrangements, wherein each valve controlled output is controlled by a respective one of the valves and is pneumatically connected to a respective one of the switching arrangements so that the valve is closed by the switching arrangement when the pressure at that output reaches a predetermined pressure, and wherein the switching arrangements are electrically connected to open the valves sequentially to a pneumatic pressure supply line.

3. Apparatus as claimed in Claim 1 or 2 wherein the pneumatic control means is constructed as a pressure sensitive control unit which is arranged to receive a single compressed air supply and to distribute the compressed air sequentially to the plurality of outlets so that each outlet, starting with a predetermined one thereof, is supplied with compressed air until a predetermined pressure is reached and is isolated from the supply before the next outlet commences to receive compressed air.

4. Apparatus as claimed in Claim 1, 2 or 3 wherein the pneumatic control means includes or is combined into a portable compressed air supply unit which includes a compressor to provide a compressed air supply, and, optionally, a rechargeable battery to power the compressor.

5. Apparatus as claimed in Claim 4 wherein the air supply unit includes a switch to switch off the compressor when all outlets have reached a predetermined pressure or respectively predetermined pressures.

6. Apparatus as claimed in any preceding claim wherein the pneumatic control means is arranged so that switching off of the supply of compressed air during inflation will only allow deflation of that bag which was in the process of being inflated.

7. Apparatus as claimed in Claim 2 or any one of Claims 3 to 6 as appended to Claim 2 wherein the switching arrangements provide switching hysteresis so that a valve closed by the respective switching arrangement is not reopened until the pressure at the respective output falls to a lower predetermined pressure.

8. Apparatus as claimed in any preceding claim wherein the inflated thickness of the lowermost bag is greater than the inflated thickness of the uppermost bag.

9. Apparatus as claimed in any preceding claim wherein the bags are made from a "drop thread" material which integrally incorporates the links.

10. Apparatus as claimed in any preceding claim wherein the stack comprises three or four bags.

11. Apparatus as claimed in any preceding claim wherein adjacent bags are secured together by webs which extend along at least two sides thereof and are bonded to side walls of the bags.

12. Apparatus as claimed in any preceding claim wherein the lowermost bag has an abrasion resistant base or underside.

13. Apparatus as claimed in any preceding claim wherein the hose are permanently attached by integral inlets of the bags and wherein the inlets are arranged on one side of the stack and are offset from one another to reduce the overall thickness of the device when the bags are deflated.

14. Apparatus as claimed in any preceding claim wherein the overall plan dimensions of the stack are at least 0.3 metres by 0.3 metres up to 0.8 metres by 2.0 metres.

15. Apparatus as claimed in any preceding claim wherein the fully inflated height of each bag is less than half of its smallest plan dimension.

16. Apparatus as claimed in any preceding claim wherein the upper and/or lower surface or surfaces of the stack is or are provided by a rigid or stiff laminate panel or panels.

17. Apparatus as claimed in any preceding claim wherein the pneumatic control means is substantially as hereinbefore described with reference to FIGURE 2 or 4 of the accompanying drawings.

18. Apparatus substantially as hereinbefore described with reference to FIGURES 1 and 2 or FIGURES 3 and 4 of the accompanying drawings.