EP1983956A1

EP1983956A1 - A chair for a disabled person

Info

Publication number: EP1983956A1
Application number: EP07703382A
Authority: EP
Inventors: James Leckey
Original assignee: James Leckey Design Ltd
Current assignee: James Leckey Design Ltd
Priority date: 2006-02-09
Filing date: 2007-02-09
Publication date: 2008-10-29
Anticipated expiration: 2027-02-09
Also published as: EP1983956B1; WO2007090677A8; WO2007090677A1; PL1983956T3; ES2462390T3; GB0602534D0; DK1983956T3

Abstract

The present invention provides a chair for a physically disabled person which is adapted to accommodate a wide range of physical disabilities though multiple adjustable features, and which chair effects correction of posture while a person, in particular a child, is seated in the chair.

Description

A Chair for a Disabled Person

This invention relates to a chair for a disabled person, and in particular a chair which is designed to provide correct posture while seated, and to be adaptable to a large number of body shapes/sizes and which is particularly intended for use by children.

Background of the Invention

Young children, in particular in the 4-12 year old category, who have physical disabilities will often have difficulty is finding seating which is suited to their needs. Seating can play a very large role in the lives of such children due to their disabilities, and is often an integral part of many daily activities such as feeding, playtime, school, therapy and general interaction with family and friends. Unsuitable seating will cause discomfort and therefore distraction, and due to the length of time spent sitting, can begin to seriously affect the quality of life for such children. There are however a large number of challenges to be faced when trying to accommodate pelvic positioning while seated, for example rotation, pelvic tilt, medial alignment and obliquity.

"Rotation" of the pelvis arises when a child is not sitting with their pelvis square in the chair. The base of their back is not aligned with the chair back. Rotation may present as a shortening of one upper leg or as "wind sweeping". If a chair cannot accommodate shortening the pelvis may be pulled forward on the shorter side. If a chair cannot accommodate a child's wind sweep their upper legs often have to be positioned straight forward in parallel. This also pulls the pelvis out of alignment into rotation.

Many children with such special needs have not been able to benefit from activities such as crawling, sitting or standing. These activities normally help development from the foetal curve to the secondary and tertiary curvatures of the spine. This means they have a tendency to sit on their sacrum, known as "pelvic tilt". They will do this to lock out the spine, which gives them a stable position. Medial alignment of the pelvis is also very important, as is the accommodation or correction of obliquity, where a child presents with pelvis in a lateral tilted position.

Special needs children will often require physical therapy in order to work on postural needs, whether resulting from flexible or fixed deformity.

It is therefore an object of the present invention to provide a chair which is adapted to accommodate individuals with various physical disabilities and therefore postural needs.

It is a further object of the invention to provide a chair which is adapted to maintain or correct flexible deformity and/or accommodate fixed deformity.

Summary of the invention

According to the present invention there is provided a chair for a physically disabled person comprising a seat base; a backrest; and a pad for supporting the sacral region of a person sitting in the chair, the position of the sacral pad being adjustable relative to the base.

Preferably, the height, depth and angular position of the sacral pad about a substantially horizontal transverse axis are independently adjustable relative to the base.

Preferably, lateral edges of the sacral pad can be adjusted to different depths.

Preferably, the chair comprises a resiliently flexible lumber support member fixed at its lower end to, and extending upwardly from, the sacral pad.

Preferably, an upper end of the lumbar support member is slidably captured by the backrest. Preferably, the base comprises a transverse ridge for engaging, in use, the gluteal crease of a person sitting in the chair.

Preferably, the chair comprises a pair of thigh support members slidably and rotatably mounted side-by-side on the base for independent depth adjustment relative to the base and rotation relative to the base about an upright axis.

Preferably, each thigh support is capable of rotation relative to the base such as to overly a front to rear centreline of the base.

Preferably, the substantially horizontal transverse axis passes, in use, at least approximately through a position corresponding to the ischial tuberosity at the base of the pelvis of a person sitting in the chair.

Preferably, the chair comprises a pelvic harness releasably secured to the sacral pad.

Preferably, the pelvic harness is secured to the sacral pad by means of a pair of couplings whose position can be varied.

Preferably, the pelvic harness is width adjustable.

Preferably, the pelvic harness is shaped and dimensioned to provide a anatomic fit with the iliac crests.

Preferably, the pelvic harness is releasably anchored to the base.

Preferably, the chair comprises a pair of foot rests articulated with respect to the base.

Preferably, each foot rest is connected to a respective one of the thigh support members.

Preferably, each thigh support member comprises a pair of upstanding thigh restraints. According to a second aspect of the invention there is provided a chair for a physically disabled person comprising a seat base and a backrest, wherein the angular position of the backrest is adjustable relative to the base about a substantially horizontal transverse axis which passes, in use, at least approximately through the ischial tuberosity at the base of the pelvis of a person sitting in the chair.

According to a third aspect of the invention there is provided a chair for a physically disabled person comprising a seat base; a backrest; and a pair of thigh and buttock support members slidably and rotatably mounted side-by-side on the base for independent depth adjustment relative to the base and rotation relative to the base about an upright axis.

In the present context the depth dimension is the distance back from the front edge of the base, and a transverse axis is an axis substantially normal to the front to rear centreline of the base.

As used herein, the term "chair" is intended to mean a stand alone item having a dedicated support structure such as conventional legs or the like. Additionally a "chair" may be an insert or the like intended to be interfaced with an existing chair or other support, for example a high-low base, powered and non-powered wheelchairs and strollers.

Brief description of the drawings

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG l is a perspective view of a chair according to the present invention.

FIG 2 is a side view of the chair of FIG 1.

FIG 3 is a plan view of the chair of FIG 1, omitting the backrest. FIG 4 is a perspective view of the chair of FIG 1 omitting the seat cushions.

FIG 5 is a plan view of the chair of FIG 4, omitting the pelvic harness.

FIG 6 is a rear perspective view of the chair of FIG 5 omitting the various cushions.

Detailed description of the drawings

It will be appreciated that although FIGS 4, 5 and 6 show a slightly different aesthetic design of chair than FIGS 1 to 3, functionally they are the same and will be considered the same chair for the purposes of the present specification.

Referring to the drawings, a chair for a disabled person comprises a rigid base 10 having a three-part seat cushion comprising a pair of side-by-side front cushions 12 A and a rear cushion 12B. The base 10 is preferably moulded from a plastic material, although any other suitable arrangement may be employed. The front seat cushions 12A are mounted upon the forward ends of respective thigh and buttock support plates 50 which are slidably and rotatably adjustable relative to the base 10, as will be described below. The rear seat cushion 12B extends in common across the rear ends of the plates 50 behind the cushions 12A. Adjustable footrest supports 11 extend downwardly from the fronts of the support plates 50 respectively, and terminate in footrests 52. The seat base 10 may be mounted on legs (not shown) or other means for supporting the base 10 at a suitable height above the ground. It will be appreciated that the particular arrangement of cushions described above may be varied without affecting the overall functionality of the chair.

The rear seat cushion 12B is contoured to define a depression 14 to accommodate the buttocks and a transverse ridge 16 for engaging the gluteal crease of a person sitting in the chair. The depression 14 cradles the buttocks and with the addition of the ridge 16 at the gluteal crease helps prevent the pelvis from sliding forward into a sacral seated posture. The forward end of each support plate 50 has a pair of upstanding thigh restraints on its opposite edges, in the form of wings 54, to ensure that a user's thigh remains centred on the plate 50. The chair includes a cushioned backrest 18 (the cushioning has been omitted on FIGs 4 and 6) mounted on a rigid frame for rotation about a horizontal transverse axis X-X defined by pivot points 20 on each side of the base 10. The frame includes a broad, generally U-shaped bracket 22 whose opposite free ends are pivoted at the points 20, and two arms 24 extending rigidly upwards from the centre of the bracket 22, the backrest 18 being mounted on the arms 24. This arrangement allows the angular position of the backrest 18 to be adjusted relative to the base 10, the backrest being maintained at any selected angle by telescopically adjustable bracing struts 26. The sides 23 of the bracket 22 are telescopically adjustable to allow adjustment of the depth of the backrest 18 relative to the front of the base 10.

The chair also includes a pad 28 for supporting the sacral and lower lumbar region of a person sitting in the chair. The sacral pad 28 is mounted on two arms 30 which are pivoted to the arms 24 at respective pivot points defined by a pair of bolts 32. The pivot points (bolts) 32 define a horizontal transverse axis Y-Y which is substantially parallel to the axis X-X defined by the pivot points 20 and, for any given position of the backrest 18, allow the angular position of the sacral pad 28 to be adjusted relative to the base 10 by rotation about such axis. The depth of the sacral pad 28, i.e. its distance back from the front edge of the base 10, and its height above the base, can also be adjusted by sliding the bolts 32 in slots 33 in the arms 24 and 30.

Preferably, and as seen in FIG 3, the arms 30 are pivoted to the rear of the sacral pad 28 to allow the arms 30 to be adjusted to different depths relative to the arms 24. This allows the lateral edges of the pad 28 to be adjusted to different depths, effectively allowing rotation of the pad about an axis normal to the axis Y-Y.

The sacral pad 28 can be secured at any selected depth, height and angular position by tightening the bolts 32 at the pivot points. The ability to independently adjust the sacral pad 28 in respect of height, depth and angular position allows the pad 28 to accommodate pelvic position and anterior posterior tilt. Referring in particular to FIG 6, each of the arms 30 is preferably provided as a number of interleaved plates, although any other suitable configuration may be employed. A resiliently flexible lumbar support member 34 is fixed at its lower end to, and extends upwardly from, the sacral pad 28. As seen in FIG 2, the upper end of the lumbar support member 34 is slidably captured by the cushioned backrest 18 (the upper end of the member 34 is shown free of the backrest in FIGS 1, 4 and 6). In use, as the sacral pad 28 is angle adjusted the flexible support member 34 adjusts and distributes the load over the lumbar area. In this way the combination of the sacral pad 28 and lumbar support member 34 can assist a child into a more extended posture, where they have the desired lower spinal curve and improved upper trunk position. Equally, where a child is presenting with a Lumbar Lordosis, the sacral pad 28 and lumbar support member 34 will help bring them back into a more neutral position. Where the Kyphosis or Lumbar Lordosis is fixed, the sacral pad 28 and support member 34, being flexible, is designed to accommodate this by conforming to the child's shape to maintain a comfortable position.

The chair further includes a pair of wing-like couplings 36, each extending forwardly from a respective lateral end of the sacral pad 28. The couplings 36 are preferably resiliently flexible or laterally displaceable to accommodate growth and pelvic medial alignment. Each coupling 36 is preferably formed as an L-shaped leg such as to project laterally and then forwardly from the sacral pad 28. Each coupling 36 is slidable into and out of the sacral pad 28, and may be fixed in any desired position by means of a bolt or other suitable fastener.

A padded pelvic harness 38 is attached to the couplings 36 of the sacral pad 28 so that the pelvic harness will follow the angular, height and depth adjustments made to the sacral pad 28. The harness 38 is preferably secured to the couplings 36 using conventional buckle type connections, although any other suitable fastener may be employed. The harness 38 can be width-adjusted with a buckle 40 at the front so that the harness pads on either side of the buckle 40 fit correctly over the iliac crests (the bony prominence at the front of the pelvis). Two additional straps 42 anchor the harness 38 to the base 10, to prevent the harness 38 and sacral pad 28 from riding up should the user thrust their pelvis forward. The lengths of the straps 42 may be adjusted to provide the correct fit, and to allow for growth of a child. The rotational axis of the backrest 18, as defined by the pivot points 20, is located sufficiently below and forwardly of the backrest 18 that it passes at least approximately through the ischial tuberosity at the base of the pelvis of a person sitting in the chair. Thus when a user is seated and the backrest 18 is reclined the user does not rotate about the ball and socket joint at the head of femur and the pelvis acetabulum, but on the ischial tuberosity at the base of the pelvis. This means that the gluteal ridge 16, pelvic harness 38 and lumbar support member 34 are always in the correct anatomic position when the backrest 18 is reclined, ensuring that this region is appropriately supported.

The sacral pad 28, lumbar support member 34 and pelvic harness 38 have been combined into one dynamic assembly to position the pelvis in an optimal neutral position for improved postural support and to maximise functional ability. As indicted by the four inwardly pointing arrows in FIG 2, the pelvis is captured by opposing forces through the sacral pad 28, the contoured seat cushion 12B at the back of the buttocks, the gluteal ridge 16 at the gluteal crease and the pelvic harness 38 which locates over the iliac crests of the pelvis. This four point pelvic positioning encourages a child to sit with their pelvis in a more horizontal position, correcting flexible obliquity.

To ensure the pelvis is always parallel to the backrest 18 and where the user cannot be brought back into midline, it is necessary to accommodate a wind sweeping of the legs. Thus, and referring in particular to FIGS 3 to 5, each thigh and buttock support plate 50 has a pair of slots 56A, 56B which are engaged by respective pins 58A, 58B carried by the base 10. These allow each support plate 50 to be individually adjusted for depth relative to the base 10, the pins 58A, 58B sliding along the slots 56A, 56B respectively. Furthermore, although the pin 58A is fixed relative to the base 10, the pin 58B can slide along a curved slot 60 in the base 10, cantered on the pin 58 A. This allows each support plate 50 to be rotated about a substantially vertical axis, in particular so that the inner edge of either support 50 may rotate past the front to rear centreline C-C of the base 10 In this way each support plate 50 may be rotated into a position overlying the centreline C-C. Since the footrests 52 are fitted to the lower ends of the supports 1 1 , and the latter are connected to the front edges of the support plates 50, the footrests 52 will adjust with the plates 50. Accordingly, the support plates 50 can be adjusted individually to accommodate varying degrees of abduction or adduction in each leg, and the rotation of the plates 50 allows angular adjustment relative to the plane of the backrest 18. Since the footrests 52 also adjust with the under leg supports 50 the foot position is always maintained inline with the upper legs. The left leg and right leg supports 1 1 are locked in desired depth and angle by means of a mechanical fixing to the seat base. While the footrests 52 are designed to follow the leg supports 50 as they pivot laterally, the footrests 52 are preferably adapted to stay in position as the leg support 50 move forwardly. This is to allow the foot positioning to be behind the line of the knee increasingly as the child grows.

In addition, when a child presents with tight hamstrings, placing them in a seated position with their knees at 90° can easily disturb their pelvic tilt encouraging them to "sacral sit". For this reason the footrests 52 can be adjusted in height relative to the base 10. Furthermore, the angle of the footrests 52 can be adjusted, for example by pivoting the footrests 52, in order to accommodate both plantarflexion and dorsilflexion.

The chair may be provided with removable armrests (not shown) locatable on either side of the base 10, preferably at a position forward of the pivot points 20. The armrests (not shown) are preferably height and angle adjustable.

It will therefore be appreciated that the chair of the present invention provides a large number of adjustments in order to accommodate a range of physical disabilities. In addition to accommodating fixed deformity, the chair is adapted to correct flexible deformity, and so replace or supplement the therapist's hands by holding the pelvis in the desired position as closely as possible. The chair of the invention is adapted to accommodate growth of the user, and may be configured according to the current activity of the user. In particular, the growth adjustments are designed such as to ensure that the gluteal ridge 16, sacral pad 28 and pelvic harness 38 are always in the correct position. Thus the bracket 22 is adjustable rearwardly and hingedly from the pivot points 20, which correspond substantially in position with the gluteal ridge 16. In addition, the support plates 50 are displacable forwardly, in order to increase the length thereof to accommodate growth, from directly in front of the gluteal crease 16, as is clear from FIG 3. Thus throughout all the available adjustments, the gluteal ridge 16 and rear cushion 12B, defining the hollow 14, remain fixed in position as a datum.

Claims

1. A chair for a physically disabled person comprising a seat base; a backrest; and a pad for supporting the sacral region of a person sitting in the chair, the position of the sacral pad being adjustable relative to the base.

2. A chair according to claim 1 in which the height, depth and angular position of the sacral pad about a substantially horizontal transverse axis are independently adjustable relative to the base.

3. A chair according to claim 2 in which lateral edges of the sacral pad can be adjusted to different depths.

4. A chair according to any preceding claim comprising a resiliently flexible lumber support member fixed at its lower end to, and extending upwardly from, the sacral pad.

5. A chair according to claim 4 in which an upper end of the lumbar support member is slidably captured by the backrest.

6. A chair according to any preceding claim in which the base comprises a transverse ridge for engaging, in use, the gluteal crease of a person sitting in the chair.

7. A chair according to any preceding claim comprising a pair of thigh support members slidably and rotatably mounted side-by-side on the base for independent depth adjustment relative to the base and rotation relative to the base about an upright axis.

8. A chair according to claim 7 in which each thigh support is capable of rotation relative to the base such as to overly a front to rear centreline of the base.

9. A chair according to any preceding claim in which the substantially horizontal transverse axis passes, in use, at least approximately through a position corresponding to the ischial tuberosity at the base of the pelvis of a person sitting in the chair.

10. A chair according to any preceding claim comprising a pelvic harness releasably secured to the sacral pad.

1 1. A chair according to claim 10 in which the pelvic harness is secured to the sacral pad by means of a pair of couplings whose position can be varied.

12. A chair according to claim 1 1 in which the pelvic harness is width adjustable.

13. A chair according to any of claims 9 to 12 in which the pelvic harness is shaped and dimensioned to provide an anatomic fit with the iliac crests.

14. A chair according to any of claims 9 to 13 in which the pelvic harness is releasably anchored to the base.

15. A chair according to any preceding claim comprising a pair of foot rests articulated with respect to the base.

16. A chair according to claim 15, when dependent on any of claims 7 to 14, in which each foot rest is connected to a respective one of the thigh support members.

17. A chair according to any of claims 7 to 16 in which each thigh support member comprises a pair of upstanding thigh restraints.

18. A chair for a physically disabled person comprising a seat base and a backrest, wherein the angular position of the backrest is adjustable relative to the base about a substantially horizontal transverse axis which passes, in use, at least approximately through the ischial tuberosity at the base of the pelvis of a person sitting in the chair.

19. A chair for a physically disabled person comprising a seat base; a backrest; and a pair of thigh and buttock support members slidably and rotatably mounted side- by-side on the base for independent depth adjustment relative to the base and rotation relative to the base about an upright axis.