GB2280105A - Back support - Google Patents

Abstract

A back support, in the form of a separate cushion or chair back, comprises an outer cover (4) enclosing a foam pad (5) at the front, behind which is a semi-rigid backing member (8) and a lumbar support element (9) mounted to the rear of the backing member (8). The lumbar support element comprises a framework of resilient members whose shape is variable by means of a cam mechanism. The element is enclosed in a fabric pocket (12) which is detachably fastened to the rear of the backing member (8) by means of VELCRO (trade mark) strips, whereby the height of the support element may be varied within the back support. <IMAGE>

Description

BACK SUPPORT The present invention relates to back supports which provide support for a person's back when sitting in a chair. Such supports can either constitute or comprise part of a chair back or they may take the form of separate units which may be placed between a chair back and a person's back. One particular application for the invention is in a separate back support cushion for use with wheelchairs.

It is generally known that the lumbar region of the back should be supported in the sitting position and chair back design in recent years has reflected this.

Accordingly, it is known to provide chairs with backs having a convex, or protruding portion corresponding to the position of the user's lumbar region.

Recently, a device has been developed which provides a lumbar support of variable shape, to accommodate different shaped spines. This device comprises a network of resilient members which may be adjustably bowed outwards to provide a support of variable curvature.

Such a support may be incorporated within a chair back, behind a layer of padding such as plastics foam. A rubber lumbar support of adjustable shape is also known.

When a person sits in the chair and leans against the chair back, the foam layer will compress and the user's back will be supported in the lumbar region by the support device.

Since back sizes vary as well as back shapes, it is known to provide a chair back incorporating such a support device where the chair back is movable in the vertical direction, so that lumbar support is provided at the correct height.

A problem with this device is that either a gap must be left between the chair back and seat to allow for movement of the chair back with respect to the seat or, if the chair back extends behind the seat, an unnecessarily long chair back must be provided.

Furthermore, a robust adjusting mechanism is needed to withstand the stresses placed on the chair back in use.

Clearly, such an arrangement is not suitable for a separate cushion for improving the back support characteristics of a conventional chair or wheelchair.

The present invention has as its objectives the solving or alleviating of the above and other problems.

According to the present invention, a back support for providing support for a person's back when sitting in a chair, comprises a padded front layer which, in use, lies adjacent the person's back behind or within which layer is a lumbar support element which extends over a region of the padded layer to give support, in use, to the lumbar region of the back, the lumbar support element being adjustably secured with respect to the padded layer by securing means which allow the position of the lumbar support element (preferably within the plane of the padded layer) to be adjusted.

Accordingly, the position of the region of lumbar support is adjustable, without the necessity of movably mounting a chair back on a chair, or of providing cushions of different sizes or cushions with the lumbar support mounted in different places within them. Instead, it is possible to adjust the back support to give support in the correct place very simply and easily, without the necessity for providing a range of sizes.

It is preferred that the back support includes a backing member situated behind the padded front layer to which backing member the lumbar support element is adjustably secured. The backing member provides a certain amount of rigidity to the cushion or chair back and provides a secure mounting for the lumbar support element. The shape of the lumbar support element is preferably variable to accommodate different back shapes and, in this case, the backing member is preferably sufficiently flexible to deform around and adopt the shape of the lumbar support element. Accordingly, support can be given to any shape of spine, without the necessity of providing a range of cushions/chair backs of different shape.

The lumbar support element is preferably mounted to the rear of the backing member and should preferably be secured to the backing member along the entire length of the lumbar support in the vertical direction, so that the backing member takes up the shape of the lumbar support element in the region to which the lumbar support element is secured.

The lumbar support element is preferably enclosed in a pocket of flexible material, such as fabric, and the pocket is then adjustably secured to the backing member, preferably by means of a fabric hook and loop fastening system, e.g. in strips. This method is exceptionally simple and cheap to manufacture and provides for exceptionally simple adjustment of the position of the lumbar support element in the back support.

The lumbar support' preferably comprises resilient material whose shape may be adjusted to vary the amount, position and/or type of support imparted by the element.

The element may comprise a single resilient member of adjustable shape, made from e.g. resilient plastics or rubber (such devices are known in themselves), but it preferably comprises a network of resilient (e.g. spring steel) members which is generally planar in the relaxed state and which includes a mechanism by means of which the network may be caused to bow outwards towards the front of the cushion.

Further features and advantages of the invention will be apparent from the following description of one specific embodiment which is given by way of example only. The description makes reference to the accompanying drawings, in which: Figure 1 is a schematic perspective view of the front of a cushion in accordance with the invention; Figure 2 is a schematic vertical section through a cushion in accordance with the invention, showing the internal elements in an uncompressed state; Figure 3 is a schematic perspective view from the rear of the cushion of Figure 1, with the rear flap raised; Figure 4 is a schematic rear perspective view of the lumbar support device and means for securing it within the cushion of Figure 1; Figure 5 is a schematic perspective view of the upper support member within the cushion; and Figure 6 is a schematic perspective view of the lumbar support element used in a cushion of Figure 1.

Referring firstly to Figure 1, the cushion takes the form of a generally flattened cuboid with a "dome"-shaped protrusion 1 in the centre of the front face, adjacent the upper edge. This protrusion is designed to give support between the shoulder blades. On the rear of the upper edge of the cushion are located fastenings, which may comprise hook and loop tape, such as is marketed under the trade mark VELCRO. The fastenings are included in the cushion particularly for wheelchair applications, where the upper edge of the cushion is desirably fastened to the wheelchair frame to keep it in position. The cushion has a tapered region 3 at its base.

Turning now to Figure 2, the construction of the cushion is shown. Encompassing the entire cushion is a flexible covering of, e.g. fabric. Inside the cover, at the front of the cushion (the right hand side of Figure 2), is a foam block 5 with a bevelled portion at the bottom rear edge. To the front face of the block is glued a layer of fabric 6. To the rear of the foam block, adjacent the upper edge, is an upper support member 7 (see Figure 5), which in this embodiment is constituted by a further foam block or blocks of carefully selected density and resilience. The protrusion on the front face of the cushion (Figure 1) is formed by the upper support member 7 deforming the foam block 5.

To the rear of the upper support element and extending over the entire area of the rear face of the front foam block 5 is a semi-rigid, resilient backing member 8.

This member is normally polypropylene and imparts stiffness to the cushion, giving overall support to a user's back and yet being sufficiently flexible to allow it to bow out in a given area under the influence of a lumbar support device 9 located behind it. The upper support member 7 and foam block 5 are glued to the backing member 8, whereby the member 7 creates the protrusion 1 on the front face. The bevel on the front face of the cushion is created in a simlar way as the bevelled portion of the rear face of the block 5 is glued to the backing member 8.

To the rear of the backing member is glued a fabric backing layer 10. Detachably mounted on the backing layer 10 is the lumbar support device 9. In the embodiment shown in the figures, the lumbar support device 9 comprises a lumbar support element 11 (see Figure 6) enclosed in a pocket 12 of e.g fabric, the device 9 being mounted on the backing layer 10 via the fabric pocket 12. The pocket 12 may be mounted on the backing layer 10 by means of a hook and loop fastening system such as is marketed under the trade mark VELCRO (Figure 4). In this case two parallel vertical strips 13 of VELCRO of one type are fastened to the backing layer 10, whilst two parallel vertical strips 14 of VELCRO of the complimentary type (shown in broken lines) are fastened to the device pocket. 12.

Access to the lumbar support device is provided via a flap 16 in the rear of the cover 4.

The lumbar support element itself comprises a generally planar framework of spring steel members connected to a cam-operated tensioning mechanism whereby the shape of the element may be adjusted between a generally flat configuration and one in which the framework is bowed out of the general plane of the element. The extent to which the framework is bowed is infinitely adjustable by means of a detachable handwheel 15 which operates the cam mechanism. Normally, the mechanism consists of a cam member at the bottom of the element (not shown) which acts on a strip 19 extending over the length of the element and fastened at the top. Actuating the cam pulls the strip downwards, thereby causing the element to bow.

Such lumbar support elements are known in themselves and one such element is marketed under the trade mark SCHUKRA. Such elements are the subject of patent numbers EP-B-6840, US-A-3490084, US-A-3724144, US-A-4452485 and US-A-4354709, whose contents are incorporated herein by reference.

Access for adjusting the curvature of the lumbar element is provided by a hole 17 in the flap 16 of the cover 4 and via a hole 18 in the pocket 12 containing the lumbar support element 11.

Although the above arrangement for attaching the lumbar support element 11 to the backing member 8 is the preferred one because of its simplicity, security and easy adjustment, other arrangements are envisaged which are within the scope of the invention. For example, the lumbar element, enclosed in a pocket, could be fastened to the backing member/backing layer by means of a zip or zips, press studs, etc. Alternatively the element 11 might be fastened directly to the backing member by means of straps. The element could equally be slidably mounted on semi-rigid strips or rails mounted to the backing member. In this case friction grip mechanisms could be provided on the lumbar element to lock it at a given position, or the strip/rails could carry teeth which engage with releasable locking members on the element.

The support element 11 may be provided in different sizes to accommodate different back sizes.

In use, the cushion is placed against the back of a chair or wheelchair, with the foam block front layer of the cushion facing outwards. The person who is to use the back support cushion sits in chair and an appropriate height for the lumbar support device is selected. The lumbar device is then moved to the correct height by pulling apart the VELCRO strips holding the device in place and then repositioning it by re-engaging the VELCRO strips at the appropriate position.

The degree of curvature provided by the support device is then varied by removing the cushion from the chair and inserting the handwheel 15 into a socket on the support element 11, through the holes 17 and 18 in the flap 16 and pocket 12. The degree of curvature is determined according to the shape of the user's spine, according to known methods and principles.

The handwheel 15 is then removed and the cushion replaced. If possible, the fastening straps 2 are then attached to the framework of the chair or wheelchair. It is of course a simple matter to re-adjust the cushion if necessary for maximum comfort and support.

It will be appreciated that the invention is applicable to a chair back as well as to a separate cushion. The structure of the chair back would be essentially the same as the above described cushion, with fastening straps 2 being omitted and means for mounting the chair back permanently or semi-permanently into a chair structure being provided.

Claims (13)

1. A back support for providing support for a person's back when sitting in a chair, the support comprising a padded front layer which, in use, lies adjacent the person's back behind or within which layer is a lumbar support element which extends over a region of the padded layer to give support, in use, to the lumbar region of the back, the lumbar support element being adjustably secured with respect to the padded layer by securing means which allow the position of the lumbar support element to be adjusted.

2. A back support as claimed in Claim 1 wherein the position of the lumbar support element is adjustable only in the plane of the padded layer.

3. A back support as claimed in Claim 1 or Claim 2 including a backing member behind the padded front layer to which the lumbar support element is adjustably secured.

4. A back support as claimed in Claim 3 in which the shape of the lumbar support element is variable to accommodate different back shapes.

5. A back support as claimed in Claim 4 in which the backing member is sufficiently flexible to deform around and adopt the shape of the lumbar support element.

6. A back support as claimed in any of Claims 3 to 5 in which the lumbar support element is mounted to the rear of the backing member.

7. A back support as claimed in any of Claims 3 to 6 in which the lumbar support element is enclosed in a pocket of flexible material which pocket is adjustably secured to the backing member.

8. A back support as claimed in Claim 7 in which the pocket is secured to the backing member by means of a fabric hook and loop fastening system.

9. A back support as claimed in Claim 4 or any claim dependent thereon, wherein the lumbar support element comprises resilient material, the shape of the element being adjustable to vary the amount, position and/or type of support imparted by the element.

10. A back support as claimed in Claim 9, wherein the lumbar support element comprises a network of resilient members which is generally planar in the relaxed state and which includes a mechanism by means of which the network may be caused to bow outwards towards the front of the cushion.

11. A cushion comprising a back support as claimed in any preceding claim.

12. A chair having a back comprising a back support as claimed in any preceding claim.

13. A back support substantially has herein specifically described with reference to Figures '1 to 6 of the accompanying drawings.