WO2000071070A1

WO2000071070A1 - Method and device for raising loads

Info

Publication number: WO2000071070A1
Application number: PCT/GB2000/001850
Authority: WO
Inventors: Thomas Matthew Caveney
Original assignee: Stafford Rubber Company Limited
Priority date: 1999-05-20
Filing date: 2000-05-12
Publication date: 2000-11-30
Also published as: GB0221213D0; GB2377214A; GB9911627D0; GB2350099A

Abstract

A method of raising a patient (or other load) comprises use of an expandable cellular body in an at least partially collapsed or deflated condition, locating said body under the load and expanding said body in at least a vertical direction so as to exert an upward force on the load and thereby raise it in a vertical direction. The method conveniently uses a device which comprises: an expandable cellular body (10) (for example an open-cell polyurethane foam) in an at least partially collapsed or deflated condition; means (12, 12, 13, 14) to prevent unwanted ingress of air into the cellular body (10); and means (17, 18, 19, 20) to permit, in use, ingress of air into the cellular body when said load is supported by the device, thereby to raise the load.

Description

METHOD AND DEVICE FOR RAISING LOADS

This invention relates to a method of raising loads and to a device for use in that method. In particular, though not exclusively, it relates to a method and device for use in raising hospital and other patients, for example from floor level to the level of a bed or trolley or from normal bed level to a higher level to facilitate movement of the patient by hospital staff .

In nursing and other medical practice there is a problem in the frequent need to raise the position of patients from one level to a higher level. Usually this lifting is done manually, and is the cause of much back pain suffered by medical staff . Although mechanical lifting devices have been used to some extent to meet this problem, they suffer from various disadvantages. For example, they usually themselves require physical effort on the part of medical staff, in their operation; they are expensive; and, being of substantial size, occupy valuable floor space whether in use, awaiting use or in storage. Moreover, such devices are not convenient for use away from hospital premises, for example by ambulance personnel attending patients in their homes or at road accidents .

The present invention provides a method and device for use therein which overcome the problem referred to above. According to a first aspect of the present invention there is provided a method of raising patients and other loads by use of a reversibly expandable cellular body of resilient material, in which the cellular body, in a collapsed or deflated condition, is located under the load and expanded in at least a vertical direction so as to exert an upwards force on the load and thereby raise it in a vertical direction.

In a second aspect the present invention provides a device for use in the method of said first aspect of the invention, which comprises : a reversibly expandable cellular body of resilient material which is in a deflated but expandable condition wherein all or a substantial proportion of air has been expelled from the cells of the material;

a container in which the cellular body is encased, the dimensions of the container being such that the container can accommodate the cellular body when said body is in an expanded condition; and

a valve or valves located in the wall of the container, whereby air can be permitted to enter into the container and into said cells thereby permitting the cellular body to expand, and whereby air can be withdrawn or expelled from the container thereby causing the cellular body to become deflated. Although the following description relates, in particular, to the use of a single block of cellular plastics material as the "body" of resilient material, the term "body" also includes two, three, four or more pieces of cellular material, whether or not contiguous and whether or not composed of the same or similar material. If desired, the "body" can be comprised of a mass of plastics material in granular, crumb or other comminuted form.

The cellular material used in the present invention should permit ready egress of air from, and ingress of air into, voids in the material. This requirement is well satisfied by the use of an open-cell foam in which at least a substantial proportion of the cells interconnect with adjacent cells. However, if desired, the voids in the cellular material can be of a size greater than that normally attributed to open-cell foam. Where an open-cell foam is used, its density should be such that, in a desired expanded condition, it is sufficiently strong to support the weight of the patient or other load and permit the necessary ingress and egress of air referred to above. Polyurethane foam is an excellent material for use in this invention. A suitable open-cell polyurethane foam is one having a density in the range 18 to 45 kg/m3, for example 20, 25, 30, 35 or 40 kg/m3.

The shape of the member or members composing the cellular body is usually not critical . For the sake of general convenience the overall shape of the body, as seen in plan view, is rectangular and can be composed, for example, of a single rectangular block or of two or more blocks of square or other rectangular shape or of triangular shape.

With a view to facilitating rapid transfer of air to and from the cellular body, the latter can be provided with channels of a cross-section substantially greater than the size of the cells of the cellular body, the channels extending from an exterior surface of the body into its interior. These channels can be in any convenient disposition within the body, for example extending in the general direction in which the body, in use, expands and contracts.

Although the device of the present invention could be one intended only for a single use, it is much more preferable for it to be one suitable for multiple, successive uses and, in that event, it is necessary for the cellular body to be deflated after use so as to put it in a condition for subsequent use and/or storage. The expanded device can be deflated by various means, for example by applying a vacuum to the interior of the container thereby to draw out air or by applying pressure to the block. Removal of the air under suction can be effected, for example, by use of a vacuum cylinder or by means of a venturi arrangement using a jet of compressed air. On the other hand, if the air is to be expelled by direct mechanical pressure, this can conveniently be effected by means of a vertically acting platen or piston acting on the upper (or lower) surface of the device. The use of vacuum or venturi means is particularly valuable where the device of the present invention is to be used at locations, for example by ambulance personnel, where the use of a compression means might not be convenient.

If the device is intended for single-use only, it can be in a very simple form in which the cellular body, encased in a deflated condition in the container, is expanded simply by piercing the container thereby to allow the ingress of air into the container and into the voids in the cellular material . In this arrangement the container needs no valve. On the other hand, in the more general form of the invention, intended for multiple, successive uses, it is necessary for the device to be provided with means which keep the cellular material in a deflated form either prior to its next use or during storage. This can be effected, for example, by providing the container with one or more valves which at least prevent unwanted ingress of air into the container. Where a valve or valves is used, they can take any convenient form. However, in a very simple form of the device of the invention the means to prevent ingress of air into the container can be a patch or like member applied to the exterior of the container so as to cover an aperture or apertures through which air has been extracted to deflate the cellular material. In this embodiment, simple removal of the patch or like member permits air to flow through the container and into the cellular material .

If desired, the flexible container can be secured to, or be integral with, at least part of the body of cellular material, for example the surface or surfaces that, in use, constitute the bottom and/or top of that body. Thus, the bottom surface of the cellular body or the bottom surface of the container can be secured, by means of bonding or otherwise, to a base sheet, board or other base member whose shape and dimensions conveniently correspond to the bottom of the cellular body.

This base member can protect the bottom of the cellular body

(and/or the container) from abrasion and enhance the dimensional stability of at least the lower portion of that body. Thus, it will be seen that the term "flexible container" as used herein includes, but is not limited to, a container whose flexibility is provided by its side region and whose bottom and/or top is substantially inflexible.

EXAMPLE There are now described, by way of example and with reference to the accompanying diagrammatic drawings, preferred embodiments of the method and device aspects of the present invention.

In the drawings:

FIGURE 1 is a top view of the device in a deflated condi ion;

FIGURE 2 is an end view of the device in the deflated condition shown in Fig. 1;

FIGURE 3 is a perspective view of the device in an expanded condition;

FIGURE 4 is a front view of the device in the expanded condition shown in Figure 3 ;

FIGURE 5 is a top view of the device in the expanded condition shown in Figure 3; and

FIGURE 6 is an end view of the device in the expanded condition shown in Fig. 3.

The device comprises a body of open-cell polyurethane foam having a density of 35kg/m , a flexible, air-tight container in the form of a bag formed from sheets of reinforced PVC, the sheets being secured together by welded seams, and valves located in opposed end portions of the bag. The foam body is an elongate block having a length of 1800 mm, a width of 600mm and a depth of 600mm; and the foam is an open-cell polyurethane foam obtained from British Vita Ltd under trade mark CALIGEN (Grade XE22 FR) . CALIGEN is a Trade Mark. Properties of CALIGEN Grade XE22 FR are shown below under the heading "Preferred embodiment" . A wider range of suitable properties of open cell polyurethane foam is shown under the heading "Range" .

TABLE I

CALIGEN (Grade XE22 FR)

Property Preferred Embodiment Range

To From To

Density (Kg/πT) 20.0 22.0 19.0 24.0 Tensile Strength (kPa) 120 500 80 500 Elongation at Break (%) 150 600 120 600 Cell Count (per inch) 40 50 35 55 50% Compression Set (%) 0.0 8.0 0.0 10.0 Cell Count (per cm) 16 20 14 22 10% CLD Hardness (kPa) 2.5 3.5 2.0 4.0 Porosity (BS4443) (l/min)50 250 40 300 FMVSS 302 Flammability 2 3 1 3

The PVC is a medical grade containing an anti-microbial agent which provides protection against bacterial and fungal attack, obtained from Flexible Reinforcements Ltd under trade mark Bondwave grade NFl/103 TS, supplied in lengths having a width of 1270mm. Bondwave is a Trade Mark. This PVC product has the following physical properties: TABLE II:

BONDWAVE NF 1/103TS

The table includes the following abbreviations : "MIN" = Minimum "MAX" = Maximum

Thus, for example, the burst strength of Bondwave NF1/103TS is at least 620 kN/m as measured according to BS 3424, Part 6, Method 8B.

Property Method of Test to BS 3424 Weight 320+/- 7.5% Part 3, Method 5A

Burst strength (kN/m²) 620 MIN Part 6, Method 8B

Breaking load (longitudinal) (N/5cm) 280 MIN

Breaking load (transverse) Part 4, Method 6 (N/5cm) 150 MIN Tongue tear (longitudinal) (N) 75 MIN Tongue tear (transverse) (N) 60 MIN Part 5, Method 7B Resistance to flex cracking (Cycles) 250,000 MIN Part 9, Method IB

Cold Crack (°C) -20 MAX Part 8, Method 10A Flame resistance COMPLIES BS5852: Part 1: 1979

Match test

Special properties Complies with BS 3878: 1992 (flexible PVC sheeting for hospital use) as regards extraction by soap solution and oily media. Contains an antimicrobial treatment which provides protection against bacterial and fungal attack

With reference to Figures 1 and 2, the block (10) is in a deflated condition in which all, or at least a substantial proportion, of the air has been expelled from the open cells of the foam.

The container comprises upper and lower walls (11,12) which conform substantially and are in contact with, or closely adjacent, the upper and lower, substantially parallel, surfaces of the foam block. The upper and lower walls of the container extend, respectively, outwardly and meet at edge portions. (13,14). Thus, the portions of the container which lie outwardly of the side edges (15,16) of the block (10) provide a means whereby the container can accommodate the block when the latter is in an expanded condition.

Valves (17,18,19,20) provide a means by which air can be allowed to enter the container and/or be expelled from the container. In one alternative, the valves each have an inlet and an outlet function, that is, they are adapted both to permit the ingress of air into the container and to permit egress of air from the container; in an alternative form some of the valves can be inlet valves and some can be outlet valves .

Figure 3 is a perspective view in which the foam block is in an expanded condition and substantially entirely fills the container. Thus, the container closely conforms to the shape of the expanded block which has expanded in an upward direction.

With further reference to Figures 1 and 2, in the deflated condition shown in those drawings the thickness of the polyurethane block is typically in the range 40 to 70 (for example 50 to 60) mm. The width and length of the block are substantially the same as when the block is in its fully expanded condition, that is a length of about 1800 mm and a width and depth of about 600 mm.

Figures 4, 5 and 6 show respectively front view, plan and end view of the device where the block is a fully expanded condition, and they correspond to the perspective view shown in Figure 3.

Mode of Operation

The following description, given by way of example, describes the use of the device illustrated in Figures 1 to 6 in the raising of a load, for example a hospital patient.

The device, in the deflated condition illustrated in Figures 1 and 2, is laid on the floor at a location where it is wished to raise the patient. The patient is then placed on the upper surface (11) of the container, care being taken that the extension portions (13,14) are not trapped beneath the patient and thereby inoperative . Once the patient is comfortably and safely located on the device ambient air is allowed to enter the container through the inlet valve or valves, the air thereby flowing into the open cells of the foam and causing the foam to expand, especially in an upwards direction. As the effective height of the foam thus increases the container extension portions (13,14) are drawn inwardly so that the container as a whole accommodates the increasing height of the foam. The upwards expansion of the foam is usually limited by the maximum height of the container available after the slack provided by the extension portions (13,14) has been taken up. The device is then substantially in the condition illustrated in Figure 3 of the drawings.

Normally, the dimensions of the device are such that, on expansion of the foam the upper surface of the device can be raised to a height permitting easy transfer of the patient from the device to a desired new location such as a bed or trolley.

In normal conditions of use it will then be necessary or desirable to return the device to a collapsed or contracted condition in which it is ready for subsequent further use or storage. This contraction can be effected, for example, by deflating the bag, for example by use of a probe and vortex to remove the air from the foam and bag through the outlet valve or valves . Once the air has been removed the valve or valves are closed and the device then remains in a collapsed condition. Alternatively, the air can be evacuated from the container by vacuum means . Another way of evacuating the device is by applying a compressive force thereby to reduce the operating height of the foam by a requisite amount. Of course, whichever method is used to evacuate the device it is necessary to prevent subsequent accidental ingress of air into the device, for example by closing the inlet valve or valves .

The device of the present invention, as described above with reference to the accompanying drawings, has the advantages of being simple to use, having no mechanical moving parts, being of light weight and, in its deflated condition, occupying a small volume facilitating storage, either flat or rolled into a coil .

Claims

l. A method of raising a patient or other load by use of an expandable cellular body, in which the cellular body, in an at least partially collapsed or deflated condition, is located under the load and expanded in at least a vertical direction so as to exert an upward force on the load and thereby raise it in a vertical direction.

2. A method according to Claim 1, wherein the cellular body, in said at least partially collapsed or deflated condition, is expanded by ingress of air or other gas into said body.

3. A method according to Claim 1 or 2, wherein said cellular body comprises one, two, three, four or more pieces of resilient cellular material.

4. A method according to Claim 3, wherein the structure of the cellular material has an open-cell characteristic.

5. A method according to Claim 3 or 4, wherein said cellular material is a plastics material.

6. A method according to Claim 5, wherein said plastics material is a polyurethane foam.

7. A method according to Claim 6, wherein the polyurethane foam is an open-cell foam having a density in the range from 18 to 45 kg/m³-

8. A method according to Claim 3 or 4, wherein said cellular material is an elastomeric material .

9. A device for raising a patient or other load, which comprises :

an expandable cellular body (10) in an at least partially collapsed or deflated condition; means (11,12, 13, 14) to prevent unwanted ingress of air into the cellular body (10) ; and means (17, 18, 19, 20) to permit, in use, ingress of air into the cellular body when said load is supported by the device, thereby to raise the load.

10. A device according to Claim 9, wherein the expandable cellular body comprises one, two, three, four or more pieces of resilient cellular material.

11. A device according to Claim 10, wherein the structure of the cellular material has an open-cell characteristic.

12. A device according to Claim 10 or 11, wherein said cellular material is a plastics material .

13. A device according to Claim 12, wherein said plastics material is a polyurethane foam.

14. A device according to Claim 13, wherein the polyurethane foam is an open-cell foam having a density in the range from 18 to 45 kg/m³.

15. A device according to Claim 10 or 11, wherein said cellular material is an elastomeric material .

16. A device according to any of Claims 9 to 15, wherein the means to prevent unwanted ingress of air comprises:

a container (11, 12, 13, 14) in which the cellular body is encased, the dimensions of the container being such that the container can accommodate the cellular body when said body is in an expanded condition.

17. A device according to Claim 16, wherein said container is of a flexible, substantially air-impermeable material.

18. A device according to any of Claims 9 or 17, wherein said means to permit, in use, ingress of air, comprises: a valve or valves (17, 18, 19, 20) located in a wall of the container (11, 12, 13, 14), whereby air can be permitted to enter into the container and into said cells thereby permitting the cellular body to expand, and whereby air can be withdrawn or expelled from the container thereby causing the cellular body to become deflated.

19. A device according to any of Claims 9 to 18, which comprises : a reversibly expandable cellular body which is in an at least partially collapsed or deflated but expandable condition wherein all or a substantial proportion of air has been expelled from the cells of the material.

20. A device according to any of Claims 9 to 19, wherein the means to prevent unwanted ingress of air comprises a container

(11, 12, 13, 14) in which the cellular body is encased, the dimensions of the container being such that the container can accommodate the cellular body when said body is in an expanded condition; and said means to permit, in use, ingress of air, comprises a readily-puncturable portion of the container.

21. A device according to any of Claim 9 to 19, wherein the means to prevent ingress of unwanted air comprises a container (11, 12, 13, 14) in which the cellular body is encased, the dimensions of the container being such that the container can accommodate the cellular body when said body is in an expanded condition; and said means to permit, in use, ingress of air, comprises an aperture in the container sealed by a plug, patch or other temporary sealing means which can readily be removed from said aperture.

22. A device according to any of Claims 9 to 21, wherein the cellular body is in an expanded condition.

23. A method according to Claim 1, said method being substantially as described herein with reference to the accompanying drawings .

24. A method of raising a patient or other load by use of an expandable cellular body, said method being substantially as described in the foregoing Example with reference to the accompanying drawings .

25. A device for raising a patient or other load by use of an expandable cellular body, said device being substantially as described herein with reference to the accompanying drawings.

26. A device for raising a patient or other load by use of a expandable cellular body, said device being substantially as described in the foregoing Example with reference to the accompanying drawings .