SPECIFICATIONCushionThis invention relates to a cushion for supporting the back of the user when sitting in a chair or perhaps in a car seat.
Although many people have painful backs and require some sort of supporting cushion to enable them to sit comfortably, it is believed that all people will be able to benefit from a back cushion giving localised support adjacent the spine.
Many back supports have been proposed in the past, but have not been found to give the completely relaxed feeling achieved from adequate support.
According to the present invention, a cushion for supporting the user's back has a support surface in the form of two cheeks or hills separated by a valley where the user's spine will be.
Most of the cushions and supports already proposed are of generally concave form in horizontal section, to correspond approximately with the general curve of a patient's back but the present invention derives from the discovery that special support is needed adjacent the spine, and that that can be achieved by providing the valley referred to above for accommodating the spine with the cheeks or hills on either side of it which lead generally in a convex manner away from the valley to give good support for the part of the user's back immediately on each side of the spine.
Thus, the shape of the cushion in horizontal sections can at least at the centre part be generally convex apart from the valley. In vertical sections it is most convenient if the sections are generally convex with the convexity at the valley being much less pronounced than at the cheeks or hills.
The cushion may have a minimum thickness of about one inch to give a fairly stable base portion, and the maximum thickness at the curved summits of the cheeks or hills might be about three inches.
All around the cheeks the surface of the cushion may merge smoothly into a rim which is at about the minimum thickness of the cushion.
Conveniently the cushion is an injection moulding perhaps made from a flexibly resilient material, for example a foam plastics material.
The invention has various aspects and from one of those aspects it might be considered to be a cushion generally in accordance with the accompanying drawings.
From another point of view the invention may be considered as a cushion having a support surface in the form of a convex shape interrupted by a valley for accommodation of the sitter's spine.
The invention may be carried into practice in various ways, and one embodiment will now be described by way of example, with reference to the accompanying drawings, in which: FIGURE lisa plan view of an orthopaedic cushion embodying the invention; andFIGURES 2, 3, 4, and 5 are respectively an end elevation, a front elevation, and sections on the lines IV--IV and V-V of the cushion shown in FIGURE 3.
The cushion is an injection mouldirig from a fairly firm foam plastics material providing good support for the back of a user while having sufficient elastic resilience to permit some conformation with the individual shape of the user's back.
The drawings show how in the end view the cushion has a generally convex section, although it is slightly concave near the top and the bottom merging into a base block, perhaps 3 inch or 1 inch thick. In the median section shown in FIGURE 5 the curve is also convex but very much shallower in accordance with what may be described as a valley extending from top to bottom, as seen in the front view of FIGURE 3, and in the plan of FIGURE 1 and the corresponding cross section of FIGURE 4.
On either side of the valley there is a small hiil which is smoothly convex in both directions.
The valley conforms generally with the spine of the user, and the cheeks on either side are for supporting the lumber region of the spine on either side. The convexity is more pronounced than is necessaryto conform with the user's back, but since it is firmly elastically resilient, each cheek gives good support for its side of the back independently of the spine which runs downs the valley.
The cushion is at variance with the general design of such cushions already proposed or available which are generally of concave form as seen in horizontal section, in accordance with the general shape of a horizontal section of the patient's back.
This novel double convex form on either side of the valley gives surprisingly effective support and great comfort for the user when sitting.
In a preferred cushion the dimensions are about 15" in height and 14" width with a maximum thickness of about 3". The base is flat, although it could be curved to conform with a particular seat, and the bottom and sides are straight, whereas the top has symmetrical slight concavities roughly in accordance with the sitter's shoulder blades.
1. A cushion for supporting the back of a user having a support surface in the form of two cheeks or hills separated by a valley where the user's spine will be.
2. A cushion as claimed in Claim 1 in which the cheeks or hills on either side of the valley lead generally in a convex manner away from the valley to give good support for the part of the user's back immediately on each side of the spine.
3. A cushion as claimed in either of the preceding claims, in which the shape of the cushion in sections which will be horizontal when the cushion is generally vertical behind the user's back are of generally convex form apart from the valley.
4. A cushion as claimed in any of the preceding claims in which in sections which will be vertical and perpendicular to the general plane of the cushion when the cushion is in use the sections of the cushion are generally convex with a much less pronounced convexity than the convexity at the cheeks or hills.
5. A cushion as claimed in any of the preceding claims having a minimum thickness of one inch.
6. A cushion as claimed in any of the preceding claims having a maximum thickness at the curved
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