IE892125L - Chair - Google Patents

Description

IE 892125 - 2 - The invention relates to a chair and in particular to an improved construction of chair to give maximum pelvic and spinal support.

Backache is to a large extent a biomechanical problem. When a person is sitting in a chair which lacks proper back support, 5 the pelvis tends to tilt backwards causing the lumbar spine to flex, thus losing its protective mechanism and causing the back of the disc spaces to open. The attempt to keep the lumbar spine in an optimum position by muscular effort causes posture stress and aching. Constant use of chairs lacking pelvic support can 10 lead to lumbar disc prolapse generally referred to as a "slipped disc".

It is an object of the invention to provide a chair with a properly designed back and pelvic support which holds the back in a correct sitting position. 15 According to the invention there is provided a chair having a seat portion and a back portion extending upwardly from the seat portion, the back portion having a lower portion, a central IE 892125 - 3 - portion, and an upper portion, the lower portion including a pair of pelvis supporting portions to engage the iliac bones of the pelvis, in use, the pelvis supporting portions being spaced-apart to define therebetween a recess to receive the sacrum and the 5 fifth lumbar spinous process to support the pelvis and relieve pressure on the sacrum and fifth lumbar process, in use, the back portion being of curved shape in longitudinal cross-section, the lower portion being of concave shape, the central portion being of convex shape and the upper portion being of convex shape to 10 guide and support the contour of the spine, in use.

In one embodiment of the invention the pelvis supporting portions extend upwardly for a distance of from 25 to 30 centimetres, most preferably approximately 28 centimetres from the seat portion when sat upon. 15 Preferably the width of the recess between the pelvis supporting portions is from 8 to 12 centimetres, most preferably approximately 10 centimetres.

In one embodiment of the invention the back portion includes a pair of side support portions extending upwardly from the pelvis 20 supporting portions adjacent the side edges of the back portion to guide, retain and support the spine in use approximately centrally in the chair.

Preferably the seat comprises a raised front portion to guide a user into a correct sitting portion in the chair. 892125 - 4 - In a preferred embodiment of the invention the seat portion includes a slightly raised rear portion, adjacent the back portion to support the pelvis, in use.

Preferably the seat portion includes a pair of side support portions to guide, retain and assist in supporting the pelvis approximately centrally in the chair.

In a preferred aspect of the invention the seat portion includes a raised portion approximately centrally arranged towards the front of the chair to guide and support the inside of the thighs, in use.

In one embodiment of the invention the seat portion includes a pair of curved cut-out portions to guide and support the thighs and receive the legs, in use.

In one arrangement the seat portion is supported on ground engaging legs.

In one case the back portion is movable relative to the seat portion to facilitate reclining of the back portion, in use.

In another embodiment of the invention the seat portion is supported on a pair of spaced-apart profiled arcuate arms which are rockable upon a base platform, and return spring means are provided between the arms and the platform.

IE 892125 - 5 - Preferably the spring means comprises a coil spring means extending between the platform and the profiled areas.

Typically there are two coil springs associated with each arm.

The invention will be more clearly understood from the following 5 description thereof given by way of example only with reference to the accompanying drawings, in which; Fig. 1 is a perspective view of a rocking chair according to the invention.

Fig. 2 is a top plan view of the chair, 10 Fig. 3 to a side partially cross-sectional view of the chair, Fig. 4 is a front, partially cross-sectional enlarged view of portion of the chair, and Fig. 5 is a perspective view of an alternative construction 15 of chair.

Referring to the drawings and initially to Figs. 1 to 4 there is illustrated a chair according to the invention in this case a rocking chair indicated generally by the reference numeral 1. The chair 1 comprises a platform formed by two spaced-apart IE 892125 - 6 - support legs 3, 4 each of which has a generally flat upper surface 5, a rear flat foot portion 6 and a front foot 7 having a castor 8. The chair has a seat portion 10 and a back portion 11 extending upwardly from the seat portion 10 and is supported 5 by a pair of spaced-apart profiled arcuate arms 13, 14 on the legs 3, 4. The arms 13, 14 are shaped as illustrated and engage the flat portion 5 of the legs 3, 4 for rocking movement of the chair relative the platform, in use.

Return spring means for the rocking motion is in this case 10 provided by four coil springs 15, two associated with each support arm 13, 14 and the associated support legs 3, 4 respectively. The springs 15 are attached to brackets 20, 21 which are in turn attached to the support arms 13, 14 and support legs 3, 4 respectively. 15 The back portion 11 has a lower portion 30, a central portion 31 and an upper portion 32. The lower portion 30 includes a pair of pelvis supporting portions 33, 34 to engage the iliac bones of the pelvis, in use. The pelvis supporting portions 33, 34 are spaced-apart to define therebetween a recess 35 to receive the 20 sacrum and fifth lumbar process to support the pelvis and relieve pressure on the sacrum and fifth lumbar process, in use. The pelvis supporting portions extend upwardly for a distance of from 25 to 30, most preferably approximately 28 centimetres from the seat portion 10 when sat upon to provide pelvic support for the 25 average range of users. The recess 35 has a width of from 8 to IE 892125 - 7 - 12, most preferably approximately 10 centimetres to accommodate the average range of users.

A pair of side support portions 38, 39 extending upwardly from the pelvis supporting portions 33, 34 adjacent the side edges of 5 the back portion 11 to guide, retain and support the spine in use approximately centrally in the chair.

The back portion 11 is of curved shape in longitudinal cross-section, the lower portion 30 being of generally convex shape, the central portion 31 being of generally concave shape and the 10 upper portion 32 being of generally convex shape to guide and support the contour of the spine, in use.

The seat portion 10 comprises a raised front portion 40, a slightly raised rear portion 41 and a pair of side support portions 42, 43 to guide, retain and assist in supporting the 15 pelvis approximately centrally in the chair. A raised front portion 44 is also provided which is arranged approximately centrally towards the front of the chair to guide and support the inside of the thighs, in use.

In this case the seat portion 10 includes a pair of arcuate cut-20 out portions 51, 52 to guide and support the thighs and receive the legs, in use.

Referring to Fig. 5 there is illustrated another chair 50 according to the invention. The back portion 11 and seat portion IE 892125 - 8 - 10 are of the same general shape and construction as the chair 1 described above with reference to Figs. 1 to 4 and like parts are assigned the same reference numerals. The seat 10 is in this case supported on ground engaging legs 55. 5 It will be appreciated that the back portion may be movable relative to the seat portion to allow the chair to be reclined, in use.

The chair according to the invention is not only comfortable to sit in and use but most importantly guides, retains and supports 10 the user in a correct sitting position with the pelvis fully supported relieving pressure on the sacrum and fifth lumbar process.

The invention is not limited to the embodiments hereinbefore described which may be varied in both construction and detail.

Claims (17)

1. IE 892125 - 9 -CLAIMS

2. A chair having a seat portion and a back portion extending upwardly from the seat portion, the back portion having a lower portion, a central portion and an upper portion, the lower portion comprising a pair of pelvis supporting portions to engage the iliac bones of the pelvis, in use, the pelvis supporting portions being spaced-apart to define therebetween a recess to receive the sacrum and the fifth lumbar spinous process to support the pelvis and relieve pressure on the sacrum and fifth lumbar spinous process, in use, the back portion being of curved shape in longitudinal cross-section, the lower portion being of concave shape, the central portion being of convex shape to guide and support the contour of the spine, in use. 15 2. A chair as claimed in claim 1 wherein the pelvis supporting portions extend upwardly for a distance of from 25 to 30 centimetres from the seat portion when sat upon.

3. A chair as claimed in claim 2 wherein the distance is approximately 28 centimetres. 1. 5 10 20 4.

4. A chair as claimed in claim 1 or 2 wherein the width of the recess between the pelvis supporting portions is from 8 to 12 centimetres. IE 892125 - 10 -

5. A chair as claimed in claim 4 wherein the width is approximately 10 centimetres.

6. A chair as claimed in any preceding claim wherein the back portion includes a pair of side support portions extending 5 upwardly from the pelvis supporting portions adjacent the side edges of the back portion to guide, retain and support the spine in use approximately centrally in the chair.

7. A chair as claimed in any preceding claim wherein the seat comprises a raised front portion to guide a user into a 10 correct sitting portion in the chair.

8. A chair as claimed in any preceding claim wherein the seat portion includes a slightly raised rear portion, adjacent the back portion to support the pelvis, in use.

9. A chair as claimed in any preceding claim wherein the seat 15 portion includes a pair of side support portions to guide, retain and assist in supporting the pelvis approximately centrally in the chair.

10. A chair as claimed in any preceding claim wherein the seat portion includes a raised portion approximately centrally 20 arranged towards the front of the chair to guide and support the inside of the thighs, in use. - 11 -

11. A chair as claimed in any preceding claim wherein the seat portion includes a pair of curved cut-out portions to guide and support the thighs and receive the legs, in use.

12. A chair as claimed in any preceding claim wherein the seat portion is supported on ground engaging legs.

13. A chair as claimed in any preceding claim wherein the back portion is movable relative to the seat portion to facilitate reclining of the back portion, in use.

14. A chair as claimed in any of claims 1 to 11 wherein the seat portion is supported on a pair of spaced-apart profiled arcuate arms which are rockable upon a base platform, and return spring means are provided between the arms and the platform.

15. A chair as claimed in claim 14 wherein the spring means comprises a coil spring means extending between the platform and the profiled areas.

16. A chair as claimed in claim 15 wherein there are two coil springs associated with each arm.

17. A chair substantially as hereinbefore described with reference to the accompanying drawings. mc\spe\l0402han.cp