The present invention relates to a body support such as a mattress or cushion and in particular to a body support or mattress which is comprised of a fluid fillable chamber provided with a fluid pressure detection system associated with means for automatic repressurization.

It is well recognized in the medical field that patients who are bedridden or confined to a seated or reclined position for one reason or another, commonly develop decubitus ulcers or bedsores. These bedsores result from the continuous pressure and irritation on areas of the body such as the hips, buttocks, knees, elbows, heels and shoulders, or other weight bearing points of a persons body. Bedsores often form at bony protuberances of the body and are difficult to heal due to the lower capillary blood flow in these areas, along with the further reduction in such blood flow due to weight bearing pressure exerted on these points.

It is therefore necessary when dealing with bedridden or immobilized patients such as for example, geriatrics, quadraplegics, paraplegics or unconscious patients that they be regularly moved from position to position in order to distribute the weight bearing pressure about various body parts, as well as also keeping the patient clean and dry. The necessity of regularly moving patients obviously creates an enormous work load for nursing staff or carers of the patients concerned, which work is often difficult and even dangerous to the nurse/carer's health due to the necessity to regularly lift quite heavy and awkward weights.

In the past these problems have been addressed to some extent by the provision of body supports such as, for example, mattresses or cushions provided with a number of inflatable air cells, which air cells are in communication so that a load or weight placed upon the body support will result in an equalization of pressure within the body support throughout the numerous cells. This is quite distinct from the situation of a normal

spring-type mattress wherein each spring of the mattress is independent from the others and as an increasing force is exerted upon each spring the spring in turn exerts an increasing force upon its load. It is therefore to be seen that inflatable cell-type body supports will markedly reduce the pressure exerted by the support upon the body resting thereon, and thereby reduce the tendency for the patient to develop bedsores, and at the same time improve the patient's comfort support, reduce pain and aid healing of any existing bedsores.

There are however problems associated with the inflatable cellular body supports known to-date, as they are necessarily manufactured from a flexible, elastomer ic-type material which is prone to puncture and deflation. Also these inflatable cellular body supports are generally comprised of top and lower portions which are sealed together using a bonding agent, to form a chamber. Reductions in the pressure within the chamber can therefore also result if weaknesses in the bonding material occur, or alternatively if a leakage occurs at an inlet/outlet valve. As a result of these types of leakages the pressure within the chamber can be reduced to such an extent that the patient is no longer being adequately supported and discomfort, pain and bedsores can therefore develop.

It is also a problem associated with inflatable cellular body supports known to date that it is difficult to ensure a correct level of inflation. Naturally, if the body support is overinflated the support surface will be hard and contribute to discomfort, pain and/or bedsore formation, with the same problems associated with under- inflation. In the past the pressure has been adjusted by testing the distance between a bony point of the patient's body (for example, the hip) and the base of the body support. This would be done, for example, by inserting a finger beneath the body support and then inflating the body support until the patient's body no longer bears weight upon the carer's fingers. This process is, however, quite tedious and difficult to carry out effectively.

It is therefore an object of the present invention to at least substantially ameliorate the problems associated with the cellular body supports known to-date, and in particular it is an object of the present invention to provide a cellular body support wherein pressure reductions within the chamber can be detected, and the pressure can automatically be corrected, in order that the body supported by the body support should be evenly supported.

It is also an object of the present invention to provide a body support which can easily and conveniently be adjusted to optimal pressure.

It is a further object of the present invention to provide a body support which is easy and economical to manufacture and operate.

Therefore, in accordance with a preferred embodiment of die present invention there is provided a body support comprising a base portion and a support portion which are sealed together to form a chamber therebetween, part of which is comprised of a plurality of flexible cells formed within the support portion; said chamber is adapted to be filled by fluid such that pressure of the fluid can support a body resting on said support portion and such that pressure exerted by said body on said chamber will be equalized throughout said chamber; also provided are one or more pressure sensing devices within said chamber, adjacent to said base portion such that if a cell or cells should collapse onto said base portion under pressure from a body resting upon said support portion, a warning will register and/or a pump will be activated to increase the pressure of the fluid and thereby expand the collapsed cell or cells.

According to another embodiment of the present invention said warning comprises a visual and/or sound alarm.

According to a further embodiment of the present invention, between said pump and said chamber there is provided a one-way valve which will prevent fluid passing out of said chamber.

According to a still further embodiment of the present invention there is provided a timing mechanism which will detect whether cells of the body support are collapsing at a regular rate, thereby raising a second warning to indicate that there is a consistent leak within the chamber.

According to a still further embodiment of the present invention said fluid is air, water or another non-toxic and non-environmentally damaging gas or liquid.

The present invention will now be described by way of example only and with reference to the following figures wherein:

Figure 1 is a perspective sectional view of the body support;

Figure 2 is a perspective sectional view of the body support showing one or more cells in the collapsed state.

Referring to Figure 1 it can be seen that the body support of the present invention is comprised of an upper portion 1 and a base portion 2. Although not essential, it is most preferred that the upper portion 1 and base portion 2 will be separate pieces of material which are fused, bonded or sealed together about their respective peripheries. For example sealing may be achieved by using a bonding agent such as a known adhesive, a heat sealing method or other known method of joining or fastening. It is important however that the sealing, bonding or fastening be complete about the periphery between the upper and base portions in order that a fluid tight chamber is formed between these two portions. While the base portion 2 may be formed of a wide range of materials, it is important that' the upper portion 1 be comprised of a flexible and preferably

able to expand when pressurized and then resiliently contract to its original shape. Most preferably the base portion 2 will also be formed of a similar material, although the base need not be so flexible, and may be formed of a slightly thicker and stronger material than the upper portion 1.

The upper portion 1 is comprised of a plurality of cells 7 which extend upwardly and are in communication together such that when a fluid is introduced into the chamber between the base portion 2 and upper portion 1, this fluid will be equally distributed between die cells 7 which effectively comprise part of the chamber.

In a preferred form of the invention the periphery of the base of each cell is bonded to the base portion 2 with gaps provided where there may be placed a flexible channelling pad 3 between the upper portion 1 and the base portion 2 which is either fluid permeable or alternatively simply creates a gap within the bonding at the periphery of the base of each cell to thereby provide channelling in order to ensure that the cells 7 are in communication. The provision cell bases bonded about their periphery aids in maintaining rigidity of the cells. It is to be stressed however that this feature is merely preferred and not essential.

As also shown in Figure 1 there are provided a plurality of pressure detectors 4 which are located adjacent to the base portion 2, between the base portion 2 and the upper portion 1. In the situation where there is also a channelling pad 3, the pressure detectors 4 will preferably be located above the channelling pad 3. Preferably there will be a plurality of pressure detectors 4 positioned adjacent to the base portion 2. While it is possible to have one pressure detector 4 positioned directly beneath each cell 7, it is probably unnecessary to arrange so many pressure detectors and it is more likely that the pressure detectors 4 should be distributed in the ratio of approximately 1 for each group of six cells 7. However, it will be recognized that the apparatus of the present invention

will be far more responsive to pressure fluctuations if a higher ratio of pressure detectors to cells is employed, similarly fewer pressure detectors may be employed if desired.

Each of the pressure detectors 4 are linked via conductors 5 in parallel, and the array of pressure detectors 4 and conductors 5 is then linked via an external connector 6 to a warning device 8. The warning device 8 may comprise any known alarm type device such as for example an audio alarm and/or a visual alarm such as a light or lights. These specific warning devices 8 are mentioned by way of example only, and it is to be recognized that any suitable type of warning device may be employed.

Linked to the warning device 8 is a pump 10 which has a connection 12 from the pump 10 to the chamber of the body support, and in a preferred embodiment of the invention there is a valve 11 between the pump 10 and chamber which will allow a fluid to pass from the pump into the chamber but not in the opposite direction.

The idea of the present invention is that the chamber between the upper portion 1 and the base portion 2 of the body support can be filled with a fluid. Examples of suitable fluids are air, water and other non-toxic and non-environmentally damaging gases or liquids. The most preferred fluid is air. When the chamber is pressurized with fluid (or inflated with air) the cells 7 will expand, and given their close location together the cells will provide a substantially continuous upper surface upon which a body can rest. Because of the fluid pressure within the chamber and specifically within the cells, the body resting thereupon will be supported by the fluid and prevented from resting upon the base portion 2. As a result of the cells being in communication with one another, the pressure upon the cells exerted by the body resting thereupon will result in an even displacement of the fluid throughout the chamber, such that there are no particular points of the body resting thereupon which will be exposed to a higher contact pressure. This is in contrast to the situation with a standard spring mattress wherein the greater the force exerted upon an individual spring, the greater the force the spring exerts upon the body resting

thereon. It is this type of continual contact force or pressure which may result in discomfort, pain and bed sores developing.

Should a leak or pressure drop of the fluid within the chamber occur, this can be detected right away as one or more cells will thereby collapse and a pressure will be exerted onto the pressure detectors 4 by the body resting upon the cells. When the pressure detectors are activated an electrical circuit will be completed in order to activate the warning device 8 and also to activate the pump 10 which will result in fluid being pumped from the pump into the chamber to thereby increase the fluid pressure within the chamber and thereby expand the collapsed cell or cells. This process is shown in Figure 2 where a collapsed cell 9 is contacting the pressure detector 4 in order to activate the alarm and pump.

Although not essential the detection/warning and pump systems can be battery operated, which will be advantageous from the perspective of simplicity of the electrical circuitry required and also from a safety point of view, given that the currents involved will be reduced and so therefore will the possibilities of electrocution. However, it is also possible to have these systems mains-power operated, given necessary safety features such as earthing and/or circuit breaking capacity.

In a preferred embodiment of the invention there will be a timer also incorporated into the warning device such that if the pressure detector 4 and warning device 8 is reactivated within a set time, then a further alarm will be raised in order to notify the carer or user that there is a technical difficulty with the body support. In this way a technician can be contacted in order to attend to what is most probably a slow leak of the body support chamber. Importantly, even in this circumstance the patient or user will not be subjected to undue skin pressure or discomfort as the pump will be continuously operating to maintain the chamber at a pressure sufficient to hold the patient's body above the base portion 2.

Another important feature of the invention is the ease with which the fluid pressure can be optimally adjusted. In this regard, it is merely necessary to rest the user upon die body support and then increase the fluid pressure until just fractionally after the warning device has ceased to register. In this way, the body support will provide a soft support, suspending the user above the base portion.

It is to be recognized that the applications of the body support are wider than simply the use as a mattress or cushion and could extend even as far as providing a soft support for inanimate bodies or objects. Clearly the same arrangement can be utilised on, for example, wheelchairs, or other chairs which may be utilised by persons who for some reason lack mobility. It is also conceivable mat the present invention could be utilised by able-bodied persons either in a sitting or lying capacity, simply to improve their level of comfort. Another application is in the use for animals, and in particular for use with animals that may be recovering from veterinary intervention. A still further adaptation of the invention is a multi-chamber body support which will allow the various chambers to be differentially pressurised, and may for example be useful to support amputee patients. This list of possible applications of the present invention is not intended to be conclusive, but merely exemplary of the possible applications to which this invention can be adapted.

It is to be recognized that the present invention has been described by way of example only, and that modifications and/or alterations can be made thereto which would be within the scope of the knowledge of a person skilled in the art, without departing from the intended scope or spirit of the invention.