TILTING BED

Abstract: A sub-mattress assembly for a tilting bed comprises a base (3), two leaves (5a/5b) each overlying a respective lateral portion of the base (2) and connected by a hinge, bladders (8a & 8b) for independently raising each leaf (5a,5b) so as to roll a bed occupant lying on a mattress (1) supported by the assembly partially from one side to the other side. The leaves (5a,5b) are contained in a loose flexible sheath (13) on which the mattress (1) is retained, such that when one of the leaves (5a,5b) is raised to tilt the mattress (1) it is laterally displaced up the inclined leaf (5a) thus reducing the tendency for an occupier to be rolled out of bed. The base (2) and leaves (5a,5b) are divided into transversely articulated panels to provide head and knee rests.

Description: This invention relates to a sub-mattress assembly. Such a sub-mattress assembly is disclosed in the US-A-4 225 988. Any conventional bed mattress may be tilted at will by the bed occupant or automatically in order to prevent or alleviate pressure sores caused by stagnation of the blood flow in the outer layers of the skin resulting from long-term contact pressures between the occupant's skin and the bed mattress. The assembly may also be used to allow change of position by the frail or paralysed. Currently these objectives are achieved by purpose made surgical or hospital beds which are articulated longitudinally so that portions of the bed mattress may be inclined in one direction or another by electro-mechanical means; this type of bed is cumbersome and expensive. In UK Patent Specification No. 1,024,312 there is described an inflatable sub-mattress assembly comprising an inflatable back rest member, an inflatable knee rest member, a control valve, flexible tubing leading from the control valve to the inflatable members, and an inlet on the valve for connection to an air supply, the valve being manually operable to control inflation and deflation of the inflatable members. The assembly may have two further inflatable members each in the form of an elongate bag and extending side-by-side along the assembly over or under the back rest and the knee rest. Such an arrangement tends to roll the patient out of bed. The disadvantages of the prior art arrangements are overcome or mitigated by the present invention according to which there is provided a sub-mattress assembly for a tilting bed, the assembly comprising a base, two leaves each overlying a respective lateral portion of the base and hinged at its inner edge, means for independently raising each leaf so as to roll a bed occupant lying on a mattress supported by the assembly partially from one side to the other side, as disclosed in the US-A-4 225 988, and further characterised in that the leaves are contained in a loose flexible sheath which is wider than and secured to the base, and on the central portion of which the mattress is retained, whereby the surface of the flexible sheath facing the mattress has a high co-efficient of friction such that when one of the leaves is raised, to tilt the overlying mattress portion, the sheath (13) is sliding across the upper board assembly (5) and the mattress is laterally displaced up the inclined leaf thus reducing the tendency for an occupant to be rolled out of bed. Preferably, the elevating means comprise two bladders each arranged to elevate one of the leaves. Thus, when one of the bladders is inflated not only is the overlying mattress portion inclined but the mattress as a whole moves sideways, climbing the inclination created. A person lying on the mattress is also correspondingly moved thereby inclining the body as a whole in the lateral direction and also moving it away from the edge of the bed, thus reducing the possibility of the person being rolled off the bed. By inflating the other bladder and correspondingly exhausting the former the angle of inclination can be reversed. This change in position, either at will purely for relief, or arranged to take place over long periods as a gradual change during sleep, has beneficial results in the reduction of the causes of pressure sores. The assembly may be supplied with either high volume or low volume, low pressure air which can be fed to, and exhausted from, each of the bladders alternately by means of a suitable pump and valve system. High volume air is supplied when rapid movement is required. Low volume is preferably employed when an imperceptible movement is required so that sleep remains undisturbed. In the latter case the pump may be controlled by a timing device to reverse the motion at a predetermined rate and the air metered to give the desired rate of motion. In the former case, the high volume air distribution may be controlled at will by means of one of various types of switch available for use by the infirm or disabled. Because the assembly can be fitted to any type of bed its use is beneficial in the home where the majority of the infirm or disabled are cared for. One current arrangement for sitting up bed occupants comprises a pneumatic sub-mattress assembly which when fitted to a conventional bed can be used to raise the head of the bed when inflated with low pressure air. The advantage of this type of arrangement is that it can be conveniently fitted to the bed occupant's existing bed. Alternatively there are various purpose-made electro-mechanical beds which are arranged to raise the head of the bed and may also provide a variety of other movements automatically such as raising or lowering the level of the bed legs. It is important that a bed occupant who benefits from a longitudinally-articulated bed can also be sat up readily for the normal welfare activities such as, for example, eating and drinking. According to a preferred feature of the present invention the sub-mattress assembly described above is transversely articulated so that it may be readily used in conjunction with a pneumatic sub-mattress bed raiser or an electro-mechanically adjustable bed, or incorporate such elevating means. Preferably the base and leaves of the assembly are made up of flat panels which are hinged along two transverse axes such that there may be raised both an end portion of the mattress to sit an occupant up, and an intermediate portion to raise the occupant's knees and prevent him from slipping down the bed. Although the invention may be carried out in a variety of ways, one embodiment thereof will now be described, by way of example, with reference to the accompanying drawings in which Figure 1 is an isometric view from the foot end of a conventional bed (or an electro-mechanical bed) incorporating the assembly of the invention with parts omitted and with one side of the bed mattress tilted; Figure 2 is a view similar to that of Fig. 1 but with the bed mattress and the enveloping sheath omitted for clarity; Figure 3 is a side view of the bed with the assembly in an unelevated condition; Figure 4 is a side view of the assembly in a sitting-up position under the influence of an electro-mechanical bed; Figure 5 is a side view of the assembly in a sitting-up position under the influence of a pneumatically-actuated inflatable bed raiser; and Figure 6 is an isometric view similar to that of Fig. 1 but from the foot end of the bed and with both sides of the bed mattress tilted. A conventional bed shown in the drawings comprises a bed mattress 1 supported on a base 2. Sandwiched therebetween is a sub-mattress assembly having a lower board assembly 3 comprising a head board 3(1), a centre board 3(2) which is hinged to a foot board 3(3) by an inferior hinge 4 formed of tape. Above the lower board assembly 3 is located an upper board assembly 5, comprising a head board 5(1), a centre board 5(2) hinged thereto by a superior tape hinge 6 and a foot board 5(3). Each of the boards 5 is subdivided along the centre line into leaves a and b which are hinged together by separate hinges 7. Between the upper and lower board assemblies 3 and 5 is interposed an inflatable bladder 8 longitudinally divided into two compartments 8 a and 8 b , each compartment being anchored to respective leaves of the board assemblies and having at its slightly projecting head end a port 9a,9b connected via a duct 10a,10b to a dual-outlet inflator 11 controlled by a switch device 12. Secured to the outer side edges of the lower board assembly 3 is an enveloping flexible sheath 13 having a lateral extent greater than that of the assembly 3 and covering the upper board assembly 5. The sheath 13 is provided with straps 14 by which the mattress 1 may be retained over the medial area of the sheath 13. Figure 4 shows the bed and sub-mattre ss assembly used in conjunction with an electro-mechanical system 140 for raising the assembly to a sitting-up position. Figure 5 shows an alternative to the system of Figure 4, being a pneumatically-actuated mattress raiser 15 having a head bladder 16 supplied through a valve 17 and connected to a knee-raising bladder 18. When the inflator 11 is operated to admit air to the bladder compartment 8 a the thrust generated by the bladder reacts on the lower board assembly 3 causes the leaves 5(1) a , 5(2) a and 5(3) a of the upper board assembly to pivot about the hinges 7 towards the inclined position shown in Figures 1 and 6. As the leaves are raised the slack in the fabric of the sheath 13 initially present at that side of the bed 1 is progressively taken up. Subsequently continued elevation of the leaves causes the sheath 13 to slide across the upper board assembly 5 until all the initial slack on the other side of the bed base 1 has been taken up. At that point when the Fig. 1 position is reached the sheath 13 imposes a limit on upward movement of the leaves. It will be appreciated that, because the mattress 1 is secured to the sheath 13, the mattress 1 is caused to move up the inclined leaves during inflation, and a person lying longitudinally on the mattress 1 is both rolled to an inclined position and moved laterally through a pre-determined distance across the bed base 2. If now the switch is operated to allow air to exhaust from the bladder compartment 8a and the other compartment 8b to be inflated, the process hereinbefore described will be repeated on the other side of the bed and the mattress 1 raised on its other side. If the sequence is partially reversed again the condition can be returned to that shown in Figure 1. The occupant can thus be placed in either of the extreme or intermediate positions (e.g. that shown in Fig. 6) at will without danger of falling out of bed and the assembly can be readily used with any type of bed of the appropriate size. It has been found that the intermediate position of Figure 6 is useful for elevating the occupant to a convenient height for attending to various tasks such as washing or changing. By operation of the switch device 12 alternate inflation and deflation of the bladder compartments 8 a and 8 b can be effected so as gently to roll the occupant from one side to the other. An additional benefit can be gained from the sub-mattress assembly if a bed sheet (not shown), positioned under the occupant, is anchored, by means of clips, to the underside of the base 2 before one side of the mattress is tilted; when the side of the mattress is raised the additional lateral transport of the occupant will greatly facilitate turning the body. Means may be provided to fix the lower board assembly 3 permanently to the bed base 2 and straps or other restraining devices attached to the upper board 5(1) and board 5(2) should this be necessary where, for example, a patient is likely to go into muscular spasm with the attendant danger of falling inadvertently out of the bed. The mattress 1 may be retained in place not only positively, as by straps, but alternatively or additionally by providing the sheath 13 with an upper surface having a high co-efficient of friction or with "Velcro" (registered trademark) touch-and-close pads.

Claims: A sub-mattress assembly for a tilting bed, the assembly comprising a base (3), two leaves (5a,5b), each overlying a respective lateral portion of the base and hinged (7) at its inner edge, means for independently raising each leaf (5a,5b) so as to roll a bed occupant lying on a mattress (1) supported by the assembly partially from one side to the other side, characterised in that the leaves (5a,5b) are contained in a loose flexible sheath (13) which is wider than and secured to the base (3), and on the central portion of which the mattress (1) is retained, with the surface of the flexible sheath facing the mattress having a high co-efficient of friction such that when one of the leaves (5a,5b) is raised to tilt the overlying mattress portion (1), the sheath (13) slides across the upper board assembly (5) and the mattress (1) is laterally displaced up the inclined leaf (5a) thus reducing the tendency for an occupier to be rolled out of bed. An assembly as claimed in claim 1, in which the inner edges of the leaves (5a,5b) are hinged together. An assembly as claimed in claim 1, in which the inner edge of each leaf (5a,5b) is hinged to a respective outer edge of a central panel. An assembly as claimed in claims 1, 2 or 3, in which the elevating means comprise a bladder (8) disposed between each leaf (5a,5b) and the base (3). An assembly as claimed in any preceding claim, in which the base (3) comprises a thin panel for enabling the assembly to be placed between a conventional bed base (2) and a mattress (1). An assembly as claimed in any preceding claim, wherein the assembly is articulated transversely to allow an end portion of the mattress (1) to be inclined with respect to the remaining portion. An assembly as claimed in claim 6, in which the remaining portion is also transversely articulated to allow it to assume an inverted V-elevation to provide a knee rest. An assembly as claimed in claim 6 or 7, in which the articulated portions are detachably connected. An assembly as claimed in claims 6, 7 or 8, in which inflatable means (15) are provided for inclining one or more of said portions of the assembly. A sub-mattress as claimed in any preceding claim, in which the mattress (1) is retained on the sheath (13) by one or more straps (14).

Inventors: RICHARDSON, MICHAEL ALEXANDER
Applicants: TURNBLADE LTD.
Application year: 1987
Main classification: A61G7
IPC codes: A61G7