Support appliances

Abstract

In a bed for example for hospital use in which the mattress comprises a plurality of separate air cells at different pressures, means for mounting the air cells so as to render them easily removable but at the same time with an effective air seal between the air cell and the bed even when the air cells are flexed in use.

Description

BACKGROUND OF THE INVENTION

This invention relates to support appliances such as a bed, mattress or chair which incorporates a plurality of inflatable cells.

Experience with inflatable mattresses, particularly in hospitals, has shown that mattresses which are composed of a number of individual air cells have pronounced advantages over mattresses of more conventional construction and interest has arisen in recent years in the development of matresses of this type.

As described in British Patent Specifications 949,652 and 1,273,342, the provision of a plurality of cells which can be individually inflated to differential pressures increases the comfort and well being of hospital patients and other people who are obliged to lie on beds, chairs or other support appliances for long periods of time.

In using inflatable mattresses of the kind described in the above two Patent Specifications it is necessary from time to time to remove individual cells for cleaning or replacement. As the individual cells have flexible walls and are contiguously arranged in these prior constructions removal of an individual cell is virtually impossiblle without deflating the cell and its immediate neighbours. This can be a serious disadvantage in practice since it means that the patient has to be transferred to another bed while the necessary adjustments and replacement are made.

Furthermore, in using cells in beds of which various sections can be tilted to support the patient, for example, in an upright sitting position compression fittings and other types of connection between the air cells and the frame of the bed have in the past been found to be unsuitable as the air connection very often pulls out from the frame and the cells deflate. This has been a considerable problem in practice.

The present invention is concerned with methods of locating and anchoring a plurality of cells in an inflatable mattress which facilitates replacement of individual cells as desired and which provides an air tight seal even when the inflatable cells flex relative to the base of the support appliance

SUMMARY OF THE INVENTION

According to one aspect of the present invention there is provided a support appliance which comprises a plurality of inflatable cells mounted on a bar arranged parallel to the length of the cells, inlet and/or outlet means for air being provided between the bar member and each associated air cell.

In this way, the air cell is able to pivot about the bar as the patient moves or as the various sections of the bed are hinged relative to one another. As the air cell pivots about the bar and the air connection for the air cell is provided in the bar, there is less likelyhood of air leaks caused by pivoting and movement of the air cell since the degree of relative movement is greatly reduced.

In a preferred arrangement the bar is provided in the form of a tubular member.

Preferably a layer of resilient material is provided on the top surface of each bar or tubular member, and the air inlet and/or outlet in the bar or tubular member comprises an aperture through the resilient material and the top surface of the bar or tubular member. The resilient material may comprise a layer of foam rubber about 1 inch thick. The inlet and/or outlet for the air cell then preferably comprises a rigid nozzle member which tightly engages the aperture through the resilient material to provide a seal. Preferably the bar or tubular member has two inlet and/or outlets adjacent opposite ends, one being for air supply to the air cell and one for exhaust of air from the air cell. If the bar is a tubular member then this will necessitate an internal stop between the two apertures in the tubular member.

If the support appliance is in the form of a bed, then preferably the bar or tubular member extends transverse to the length of the bed and rests on frame members along each side of the bed. The frame members are preferably hollow and cooperating apertures are provided in the frame members and the bar and air may be passed from one frame member through each bar to the interior of an associated air cell and out from the interior of the associated air cell through the other aperture in the bar to the other frame member.

According to a further aspect of the invention the inflatable cells are connected to inlet and/or outlet means for air by forming holes in the base of the individual cells which are located over corresponding holes in the base of the support appliance, the support appliance in the areas of the holes providing a firm surface so that pressure of air in the cells effectively seals the base of the individual cells around the inlet and/or outlet means.

According to an additional aspect of the invention, there is provided an inflatable cell primarily, for use in a support appliance of the type described and having internal means for restraining expansion under the influence of pressure of a gas introduced therein. The means for restraining expansion conveniently takes the form of strips, ribbons, webs or the like which are connected at their ends to opposed walls of the cell and which have a dimension which prevents expansion of the cells by more than a predetermined amount under internal air pressure. The strips, ribbons, or webs may be of the same or different material as the cells and may be attached to the walls of the cells by welding, stitching riveting bonding or other convenient means. It will be appreciated that by restraining expansion of the cells in this way in a desired direction, removal of an individual cell is facilitated since adjacent cells will not exert significant lateral force on a cell to be removed.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation from one side of one section of a bed in accordance with the invention;

FIG. 2 is a section taken along line A--A in FIG. 1;

FIG. 3 is an elevation from one side of a modified bed section in accordance with the invention;

FIG. 4 is a section taken along the line B--B in FIG. 3, and,

FIG. 5 is a section similar to FIG. 4 of an alternative embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, the Figures show a section of a bed including a base portion 1 and inflatable cells 2 (of which only the lower portions are shown) forming a mattress section. A number of bed sections, e.g. 3 or 4, are coupled together with articulated connections to form a complete bed as described in our copending British Patent application no. 11942/73 or in the "Lancet" Oct. 23rd, 1971 pages 885 to 888. The base portion comprises a pair of tubular frame members 3 which form both the frame of the bed and also serve as the supply and exhaust conduits for the air for the inflatable cells. Supported on the frame members 3 are a series of cross members or bars 4 (one for each cell) which are constructed from wood, steel or other substantially rigid material and which are bolted to the frame members 3 by bolts 5 or loosely located by locating ears on the frame member 3. Pairs of blocks 6, of substantially rigid material (one pair for each cell) are mounted opposite each other on each side of the bed and at spaced intervals along its length. Holes 7 and 8 respectively are formed in each block 6 and are aligned with corresponding holes 9 and 10 in the bar 4 and in the upper wall of tubular members 3. These holes provide for supply of air at low pressure e.g. up to about 5-15 inches water gauge, to the cells and removal of air therefrom. The air may be heated.

Cross member 4 is formed with slots 11 and 12 on each side of blocks 6 and these slots extend across the width of the bed section. Slots 11 and 12 communicate with tubular cavities 13 and 14 formed partly by a hollowed out portion of the bar 4 and partly by a plate 15. An inflatable cell 2 (which is approximately sausage shaped) extends across the width of the bed section and is in contact at its ends with blocks 6. Each cell 2 is anchored to the bed section 1 by an anchoring arrangement including a pair of ropes 16 and 17 which are received respectively in tubular cavities 13 and 14. Attached to ropes 16 and 17 is a web of material 18 which is in the form of a loop, the ends of the web being connected to the ropes 16 and 17 while the middle portion is attached to or forms the base of cell 2. Each inflatable cell 2 is formed with holes 19 and 20 which are aligned with holes 7 and 8 in the blocks 6.

Excess material is provided in the base portion of the inflatable cell 2 in the regions of the holes 19 and 20 so that on inflation of the cell, pressure of air in the cell presses the base of the cell, in the vicinity of holes 19 and 20, firmly into contact with the blocks 6 and thereby forms an air tight seal. Individual cells can be removed from the bed section by slightly deflating the appropriate cell and drawing the cell outwardly i.e., from the plane of the paper in FIG. 2. In order to locate the cell widthwise of the bed, downwardly extending web portions 21 and 22 are provided which may be secured by Velcro or similar quick release system to a part of the bed section 1, e.g. to the frame members 3.

Conveniently the spaces between blocks 6 are filled with a rubber or plastic foam material 23.

In order to limit lateral expansion of the cells 2, a membrane similar to membrane 24 in FIGS. 4 and 5 divides each cell longitudinally and is attached by any suitable means to the cell walls. The membrane is apertured to allow air to circulate through the entire interior of the cells. The dimensions of the membrane are chosen so that undue lateral force is not exerted by the cells on neighbouring cells.

It will be appreciated that in the arrangement illustrated in FIGS. 1 and 2, the pressure and through flow of air will normally be identical in each cell. In some circumstances it may be desirable to vary the flow of air through one individual cell and this can be achieved by fitting a bush 25 in hole 19 having a greater or smaller orifice than those in the other cells in the bed section depending on whether a larger or smaller through flow is desired.

Removal of a cell in the arrangement illustrated in FIGS. 1 and 2 is exceedingly simple. A blanking plate may be slidably mounted on the top surface of each block 6 so that it can be moved from an inoperative position to an operative position where it blanks off the inlet hole 8 and depressurises its associated cell without interfering with the air supply to the remaining cells in the section. Web portions 21 and 22 are freed from their fastenings and the selected cell can then be drawn out. Replacement of a cell is achieved by the reverse of these operations.

Referring to FIGS. 3 and 4, the construction shown therein represents a modified arrangement for mounting and anchoring the cells to the bed section. The frame of the bed section is formed from a pair of longitudinally extending tubular frame members 33 upon which are mounted a plurality of cross members 34 which are spaced apart lengthwise of the bed section. Interposed between each pair of adjacent cross members is tubular secondary member 35 having closed ends and a blocked off central portion to prevent air flowing therethrough. Secondary members 35 are clamped at each end to tubular members 33 so that holes in members 33 align with corresponding holes in members 35 in an air-tight manner by means of a seal 41. Air is supplied to each cell 36 from its associated member 35 via a nipple 37 screwed into member 35. Each cell 36 is formed with a hole into which nipple 37 is received and the material surrounding the hole is reinforced with a rubber annulus 38. Sealing of the cells onto the member 35 is achieved by the pressure of air in the cells. Rimilar provision is made at the other end of the cell for lfow of air from the cell. Each cell 36 is anchored to the member 35 by webs 39 and 40 extending lengthwise of the cell which are secured to each other by press studs, Velcro or similar material. The tops of the cross members 34 are padded with plastics or rubber foamed strips 42.

An important advantage of the construction described in the figures is that the cells show little tendency to leak at their points of connection to the air inlet and return conduits even when the cells are deflected by articulation of the individual bed sections to contour the upper surface of the mattress as shown in the Figures of the "Lancet" article referred to above.

It may not be essential in all instances to provide an outlet 19 for escape of air from the cells 2 where the cells are provided with pores since the flow of air may be controlled through such pores.

Lateral expansion of the cells is preferably controlled by membranes 24 as shown in FIGS. 4 and 5 since this enables the shape of the cells to be retained more easily in their expanded condition independently of adjacent cells. It will be appreciated that there may be more than one membrane in each cell and the membranes are not necessarily parallel to the top surface of the bed section. For example the membranes may divide the interior of each cell into a number of honeycomb compartments or may induce the air to flow in a tortuous path through the cell. Air in the cell may be induced in this way to flow generally parallel to the upper surfaces of the cell and this may facilitate control of the temperature of the user of the bed or, by provision ofporous cell fabric, extraction of water vapour or other gases released by wounds or injuries.

The embodiment shown in FIG. 5 is generally similar to FIG. 4. However, it has been found a bed can be produced without the cross members 34 or strips 42, if the tubular members 35 are increased in size. In the embodiment of FIG. 5 the tubular members 35 have been enlarged and are constructed of steel tubes coated with a plastic material. It will be seen that each tublar member 35 includes a layer on its top surface of 1 inch thick sponge rubber 50. The air cells 36 each include two apertures, one adjacent each end with rigid nozzles 51, the rigid nozzles 51 including a collar 52 around their inner end for easy attachment of the nozzles 51 to the air cells. The air inlet and/or outlet in the member 35 is provided by an aperture 53 through the sponge rubber layer 50 and through the top surface 54 of the tubular member 35. The diameter of the aperture through the sponge rubber layer 50 is narrower than the outer diameter of the nozzle 51 so that an air seal is provided. However, as with the previous embodiments, as a safeguard there is provided a loose layer of material around the nozzle 51 in each air cell and betwen the webs 39 and 40 which under the influence of the air pressure within the air cell will provide a seal around each aperture.

It has been found preferable to delete the presence of members 34, 42 since this simplifies the cleaning of the bed, a matter of paramount importance in the use of such beds in hospitals.

Furthermore, by the use of simple plug connections between the air cell and the members 35 the removal and insertion of the air cells is greatly facilitated. Further, the members 35 support the air cells and each member 35 provides a pivot about which the associated air cells may to a limited extent rotate as the patient moves on the bed or if the bed is provided in sections which hinge relative to one another.

Various means may be provided for anchoring the webs 39, 40 to the member 35. In the arrangement shown in FIG. 5 there is provided along each side of the member 35 further bars 55, 56 which are clamped to the side faces of the member 35 by clamping means which are releasable from each end of the member 35. The webs 39, 40 are wrapped around the bars 55, 56 and anchored thereto by frictional clamping between the bars 55,56 and the side surfaces of the member 35.

Claims

I claim:

1. A support appliance which comprises

a. a plurality of elongated tubular members;

b. a plurality of elongated inflatable cells, each arranged parallel to one of said tubular members;

c. means mounting each said cell on the respective tubular member;

d. separate inlet and outlet apertures extending through the wall of said cell and through the adjacent wall of the respective tubular member; and

e. a layer of foam rubber positioned between each said cell and said respective tubular member, said inlet and outlet apertures extending through the wall of said cell, through said foam rubber and through the adjacent wall of the respective tubular member;

f. whereby a continuous flow of pressurized air may be maintained in each of said cells between the inlet and outlet apertures thereof.

2. A support appliance as claimed in claim 1 further comprising a rigid nozzle member in tight sealing engagement with each of said inlet and outlet apertures.

3. A support appliance which comprises

a. a plurality of elongated tubular members;

b. a plurality of elongated inflatable cells, each arranged parallel to one of said tubular members and including a pair of spaced parallel web members attached generally along the length of the exterior of the air cell, said web members extending along opposite sides of the respective tubular member;

c. means for anchoring said web members to the respective tubular members, said adjacent wall of said tubular members being between said pair of web members; and

d. separate inlet and outlet apertures extending through the wall of said cell and through the adjacent wall of the respective tubular member;

e. whereby a continuous flow of pressurized air may be maintained in each of said cells between the inlet and outlet apertures thereof.

4. A support appliance as claimed in claim 3 wherein said means for mounting each said cell comprises means for anchoring said web portions to the opposite sides of each of said elongated tubular members such that the elongated portion of said cell between said web portions and adjacent the surface of said tubular member is maintained relatively slack whereby the air pressure within each air cell presses said slack portion against the surface of said tubular member to provide a seal about said inlet and outlet apertures between the surface of the tubular member and said cell.

5. A support appliance as claimed in claim 3 wherein said mounting means comprises fixed members spaced on said opposite sides of said tubular members forming narrow elongated slots between said fixed members and said opposite sides of said tubular members, a hem along the free end of each of said web portions and rigid elongated means having a width greater than said slot mounted in each hem whereby each said web member is anchored in one of said slots, movement through said slot being prevented by said rigid elongated means in said hem.

6. A support appliance as claimed in claim 3 wherein said mounting means comprises a plurality of rigid elongated members mounted adjacent said opposite sides of each of said tubular members, each said web member passing around one of said rigid elongated members to secure said web member between one of said bars and the respective side of a tubular member.

7. A support appliance which comprises

a. a base having a firm surface thereon,

b. at least one air cell mounted on said base,

c. air inlet and outlet means extending between said air cell and said base, said air inlet and outlet means comprising holes in said firm surface of said base aligned with holes in the wall of said cell,

d. means attached to the wall of said cell at at least two positions spaced from the holes in the wall of said cell for attaching said cell to the base such that a relatively slack portion of the cell wall is provided about each hole,

e. whereby air pressure in said air cell causes the slack portion of said cell to effectively seal with said firm surface of said base about said holes.

8. A support appliance which comprises

a. a plurality of elongated tubular members;

b. a plurality of elongated inflatable cells, each arranged parallel to one of said tubular members;

c. means mounting each said cell on the respective tubular member;

d. separate inlet and outlet apertures extending through the wall of said cell and through the adjacent wall of the respective tubular member;

e. a layer of resilient material positioned between each said cell and said respective tubular member, said inlet and outlet apertures extending through the wall of said cell, through said resilient material and through the adjacent wall of the respective tubular member; and

f. a rigid tubular nozzle member extending through and in tight sealing engagement with each of said inlet and outlet apertures;

g. whereby a continuous flow of pressurized air may be maintained in each of said cells between the inlet and outlet apertures thereof.

9. A support appliance in the form of a bed which comprises

a. a pair of elongated hollow frame members extending the length of the bed along opposite sides thereof;

b. a plurality of elongated tubular members extending transversely to the length of the bed and being supported on said frame members adjacent the opposite ends thereof;

c. cooperating apertures extending from a wall in each of said hollow frame members to a wall in each of said tubular members;

d. a plurality of elongated inflatable cells, each arranged parallel to one of said tubular members;

e. means mounting each said cell on the respective tubular members; and

f. separate inlet and outlet apertures extending through the wall of said cell and through the adjacent wall of the respective tubular member;

g. whereby a continuous flow of pressurized air may flow from the interior of one of said hollow frame members through one of said cooperating apertures to all of said tubular members, through said inlet apertures to all of said cells, through said outlet apertures to all of said tubular members and finally through the other of said cooperating apertures to the other of said hollow frame members.

10. A support appliance which comprises

a. a plurality of elongated tubular members;

b. a plurality of elongated inflatable cells, each arranged parallel to one of said tubular members;

c. means mounting each said cell on the respective tubular member;

d. separate inlet and outlet apertures extending through the wall of said cell and through the adjacent wall of the respective tubular member; and

e. a layer of resilient material positioned between each said cell and said respective tubular member, said inlet and outlet apertures extending through the wall of said cell, through said resilient material and through the adjacent wall of the respective tubular member;

f. said plurality of cells being arranged in a plurality of groups, all the cells in one group being adapted to be maintained at one air pressure while the pressure of the remaining groups are independently controllable;

g. whereby a continuous flow of pressurized air may be maintained in each of said cells between the inlet and outlet apertures thereof.