This invention relates to a support cushion particularly for relieving pressure for bed-ridden or chair-bound patents.
Support cushions of this kind usually comprise pads of for example foamed or cellular synthetic material, and/or an inflatable air cushion, contained within hard wearing washable covers for example of polyurethane-coated textiles.
A problem encountered with prior art cushions or support pads is that air cushions, because they have to be air tight, are not breathable and as they comprise two panels of flexible material joined only by a seam around the periphery of the panels, tend to bulge to form a convex surfaced body rather than a flat surfaced panel suitable for rectangular cushions.
A prior art document corresponding to the preamble of appended claim 1 is
It is an object of the invention to provide a support cushion and an inflatable pad for a support cushion which enable a fully breathable cushion to be obtained with an inflatable pad as its core, and also enable control of the geometry of the fully inflated pad to be achieved.
From a first aspect, the invention provides an inflatable pad for a support cushion, the pad comprising an airtight outer membrane providing upper and lower surfaces of the pad, and an array of tubes extending through the pad between said upper and lower surfaces, and providing air passages passing through the pad, characterised in that the tubes are each provided with a flange at each end, each said flange engaging with a respective outer face of the air-tight membrane in contact with the upper and lower surfaces and in that each tube is associated with a respective tension spring which extends between said upper and lower surfaces so that the spring tends to draw the upper and lower surfaces towards each other.
Each tube means is associated with a respective tension spring means between said upper and lower surfaces, whereby the spring means tends to draw the upper and lower surfaces towards each other, thereby countering the pressure of air within the pad to prevent bulging of the pad when inflated.
The tension spring means may be concentrically disposed about respective tube means. The springs may be welded polyurethane discs.
The invention also provides, from a second aspect, a support cushion including an inflatable pad according to the first aspect of the invention as part of the internal structure of the cushion.
The support cushion may additionally comprise one or more pads of foamed or expanded plastics material, e.g. polyurethane, and one or more thereof may be shaped to provide a recess or recesses to accommodate the inflatable pad.
The support cushion may be covered with a cover of polyurethane coated fabric, such as a jersey knit. This may comprise two parts, such as a flat base, and a shallow pouch, which can be separated for removal for washing or replacement.
The cover preferably has a nozzle formed therewith to accommodate an inflation tube for the inflatable cushion.
A preferred embodiment of inflatable pad for a support cushion, according to the invention, and of a cushion according to the invention incorporating the pad, will now be described by way of example with reference to the accompanying drawings, wherein:-
Referring first to
The cushion 10 also has a tubular spigot 13 projecting from one face thereof, to accommodate the inflation tube of an inflatable pad within the cushion as described below.
As shown in
The inflatable pad is as shown in more detail in
The upper web 21 of the airtight skin 20 provides for a micro climate between the foam pad 16 and the upper part 11 of the outer cover, This assists the circulation of air within the cushion enabled by the use of the foam pads 14 and 16 and the inflatable pad 15.
The pad 15 has a plurality of tube means 23 which pass through the pad between the upper and lower surfaces of the pad, so that air can pass through the pad, and the pad be rendered 'bxeathable'.
The tube means 23 are arranged in an array of 4 x 4 (sixteen in total) in the embodiment shown, and each consist of a tubular member which is open at each end, and is provided at each end with a respective flange 24 which is sealed e.g. by thermal welding to the skin 20 around the edges of the aperture. The number and distribution thereof may be varied as required by the shape and size of the cushion.
The tube means 23 are each surrounded by a respective tension spring 25 In the form of a welded polyurethane disc which acts to bias the respective opposed surfaces 21 and 22 together against the expansive force of air under pressure introduced from the inflation tube 17. This acts to prevent bulging of the pad 15, so that even when fully inflated it can fit within the geometry of the core of the cushion 10.
The springs 25 are distributed so that they each are associated with a respirative tube means 23, 20.
The cover 11 and 12 of the cushion 10 is a polyurethane coated jersey knit which has good washability properties, and is effectively impervious thereby preventing soiling of the core of the cushion , in particular the polyurethane foarn pads 14, 16 and the inflatable pad 15.
A cushion of the kind described, in accordance with the invention provides good support and comfort for bed-ridden or chair bound patents and will help to prevent or limit pressure sores and ulcers when and facilitate the healing of injuries and operation scars, and the cushion will preferably be manufactured to suit specific bedding users and domestic furniture (such as chairs, settees etc as part of the upholstery, and for wheel chairs).
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.