GB2628150A

GB2628150A - Lateral support assembly for a chair

Info

Publication number: GB2628150A
Application number: GB2303841.7A
Authority: GB
Inventors: Marsh Fred
Original assignee: Accora Ltd
Current assignee: Accora Ltd
Priority date: 2023-03-16
Filing date: 2023-03-16
Publication date: 2024-09-18
Also published as: IE20240125A2; GB202312015D0; AU2024201700A1; GB2628200A

Abstract

An adjustable lateral support for a chair comprising a back plate 12, first and second lateral support members 14 and first and second clamping mechanisms 68 wherein the back plate has first and second laterally extending slots 46, the support members have first and second clamping portions at an angle to each other and an angle adjustment slot extending through them such that the clamps can engage the slots to fix the support members at a chosen position and angle. The back plate 12 may be formed from layers including a support plate 16 and adjustment plate 18 and the clamps may have rods extending through the slots and a cam surface. There may be third clamping portions again at a different angle and the clamping portions may be curved. The support portions may also be padded. The device is designed to help prevent pressure sores.

Description

Lateral Support Assembly for a Chair

FIELD OF THE INVENTION

The present invention relates to lateral supports for chairs, and to chairs including such lateral supports.

BACKGROUND TO THE INVENTION

Some less mobile people, such as the elderly and patients, spend a significant time in bed or in a chair. However, if a person is in bed or in a chair for prolonged periods of time there is a significant risk that they will develop pressure sores. These are wounds that develop over time due to constant pressure and friction against a person's skin. As such, it is important that a chair is comfortable and will not cause or aggravate any pressure sores. For this reason it is desirable to provide a chair that is of the correct size for the person.

In particular, a width of a chair should also be selected to provide the correct level of support, especially if a person's core strength is limited. The width of the seat may 20 ideally be wide enough to be comfortable, but narrow enough to provide some support and to allow a user to use the armrest without stretching.

For these reasons, chairs are typically manufactured in a range of sizes to allow the correct chair to be selected based on the size of the person. This, however, means 25 that a care facility may have to purchase a number of different sizes of chair to be able to select the most appropriate chair for a particular person.

It is also known to provide chairs with additional lateral supports extending from a backrest. These lateral supports encourage a midline siting position to reduce strain on a person's body. They are typically provided when a person requires increased lateral support when in a seated position. It will be appreciated, however, that to be effective these lateral supports must be in the correct position relative to the person.

It is an aim of the present invention to provide a lateral support for a chair that is adjustable to provide the required support for a range of users and that overcomes at least some of the disadvantages of known lateral supports for chairs.

SUMMARY OF THE INVENTION

A first aspect of the invention provides a lateral support assembly for a chair comprising: a back plate having opposite front and rear sides, and first and second elongate lateral adjustment slots extending laterally across the back plate, the first lateral adjustment slot being disposed proximate a first side edge of the back plate and the second lateral adjustment slot being disposed proximate a second side edge of the back plate; a first lateral support member having a support portion, a first clamping portion and a second clamping portion, a plane of the first clamping portion being at a non-zero angle to planes of each of the second clamping portion and the support portion, and the first lateral support member including an elongate angle adjustment slot extending through the first and second clamping portions, the angle adjustment slot of the first lateral support member being aligned with the first lateral adjustment slot of the back plate; a second lateral support member having a support portion, a first clamping portion and a second clamping portion, a plane of the first clamping portion being at a non-zero angle to planes of each of the second clamping portion and the support portion, and the first lateral support member including an elongate angle adjustment slot extending through the first and second clamping portions, the angle adjustment slot of the second lateral support member being aligned with the second lateral adjustment slot of the back plate; a first clamping mechanism engaged with the angle adjustment slot of the first lateral support member and the first lateral adjustment slot; and a second clamping mechanism engaged with the angle adjustment slot of the second lateral support member and the second lateral adjustment slot, -3 -each of the first and second clamping mechanisms being arranged to apply a releasable clamping force to clamp the respective lateral support member against the back plate to secure the lateral support member in a chosen position relative to the back plate, and when a clamping force is not applied to one of the lateral support members, that lateral support member is movable with respect to the back plate to adjust the relative alignment of the corresponding angle adjustment slot and lateral adjustment slot to independently adjust both a lateral position of the lateral support member with respect to the back plate and an angle of the support portion of the lateral support member with respect to the back plate.

In some embodiments the first and second elongate lateral adjustment slots may be separate slots. In other embodiments the first and second elongate lateral adjustment slots may be sections of a single continuous slot. The sections may be 15 contiguous.

The lateral support assembly preferably further comprises means for releasably securing the back plate to a back rest of a chair.

In some embodiments the back plate comprises a support plate and an adjustment plate. A rear surface of the adjustment plate is preferably in contact with a front surface of the support plate. The lateral adjustment slots preferably extend through both the support plate and the adjustment plate.

In preferred embodiments each of the clamping mechanisms comprises a rod that extends through the respective aligned angle adjustment slot and lateral adjustment slot. Each of the clamping mechanisms may comprise a cam surface arranged to apply a force to one of the clamping portions of the respective lateral support member.

In some embodiments the support portion, first clamping portion and second clamping portion of each of the lateral support members are all planar. -4 -

In preferred embodiments the first clamping portion extends from the support portion and the second clamping portion extends from the first clamping portion. The plane of the second clamping portion may be perpendicular to the plane of the support portion.

Each lateral support member may include a third clamping portion, a plane of the third clamping portion being at a non-zero angle to the planes of both the first and second clamping portions.

In some embodiments the first and second clamping portions are pad of a continuously curved clamping portion of each of the lateral support members.

In preferred embodiments, when both of the lateral support members are clamped with the first clamping portion in contact with the back plate, the support portions of the lateral support members are at an angle to each other such that a distance between the support portions increases in a direction away from the back plate. In some embodiments, when both of the lateral support members are clamped with the second clamping portion in contact with the back plate, the support portions of the lateral support members are parallel to each other.

The clamping mechanisms are preferably engaged with the angle adjustment slots and lateral adjustment slots such that each of the angle adjustment slots is constrained to only move along a single axis with respect to the corresponding lateral adjustment slot.

In preferred embodiments a part of a surface of the back plate and a part of a surface of each of the support portions of the lateral support members is covered with a layer of padding.

A second aspect of the invention provides a chair including a lateral support assembly according to the first aspect of the invention, the back plate of the lateral -5 -support assembly being secured to a forward facing surface of a backrest of the chair.

The back plate is preferably releasably secured to the backrest. The back plate may be releasably secured to the backrest by hook and loop material.

Preferred and/or optional features of each aspect and embodiment described above may also be used, alone or in appropriate combination, in the other aspects and embodiments also.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which like reference numerals indicate like features and in which: Figure 1 is a perspective view of a lateral support assembly according to a preferred embodiment of the invention, together with a chair to which the lateral support assembly may be mounted; Figure 2 is a perspective view of the lateral support assembly shown in Figure 1; Figure 3 is a rear perspective cross-sectional view of part of the lateral support assembly of Figure 2; Figure 4 is a perspective view of part of the lateral support assembly of Figure 2; Figure 5 is a top cross-sectional view of the lateral support assembly of Figure 2; Figure 6 is a front perspective cross-sectional view of part of the lateral support assembly of Figure 2; and -6 -Figure 7 is a top view of the lateral support assembly of Figure 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides a lateral support assembly for a chair. The lateral support assembly may provide part of a backrest of a chair in use, and so may also be referred to as a lateral support backrest assembly. The lateral support assembly is adjustable so that in use, a distance and/or angle between lateral support members of the lateral support assembly can be adjusted to suit a user of the chair.

With this arrangement, an internal width of the chair can be adjusted to provide suitable lateral support to the sides of the user's arms and/or body.

In this description, the lateral support assembly is described with reference to a chair to which the lateral support assembly may be mounted. Accordingly, the terms "lateral", "laterally" and related terms refers to a direction extending generally horizontally between lateral sides of the chair in use (e.g. between armrests of the chair). The term "height" and related terms refers to a direction extending generally vertically in use and generally perpendicular to the lateral direction (e.g. towards the top in Figure 1).

Figure 1 shows a lateral support assembly 10 according to a first embodiment of the invention, together with a chair 2 with which the lateral support assembly 10 may be used. In use, the lateral support assembly 10 is arranged to be secured to a forwardly facing side of a back 4 of the chair 2. In this way, part of the lateral support assembly 10 provides part of a backrest of the chair 2 in use. The lateral support assembly 10 may be secured to the chair 2 by any suitable securing means (not shown) such as threaded fasteners or hook and loop fasteners. In use, the lateral support assembly 10 is provided with padded or cushioned regions (not shown in Figures 1 to 7) to provide comfort to the user. In Figure 1, an outline of the position on the chair at which the lateral support assembly 10 would be secured is shown by a dotted line.

Referring additionally to Figures 2 to 5, the lateral support assembly 10 comprises a back structure or back plate 12 and lateral support members 14 (in this embodiment a pair of lateral support members 14a, 14b). A lateral position and an angle of each lateral support member 14a, 14b is adjustable with respect to the back plate 12. The back plate 12 in this embodiment comprises a support plate 16, and a clamping plate or adjustment plate 18. It will be appreciated that in other embodiments, the support plate 16 and adjustment plate 18 need not be distinct parts and instead could be provided by a single part so that the back plate 12 is a unitary structure.

In this embodiment, the support plate 16 comprises an elongate plate 16 which extends between a first lateral end 20 and an opposite second lateral end 22 of the support assembly 10. The support plate 16 comprises an elongate middle portion 24 which extends between first and second lateral end portions 26, 28. The first lateral end portion 26 extends between the first lateral end 20 and the middle portion 24. The second lateral end portion 28 extends between the second lateral end 22 and the middle portion 24. In this embodiment, a height of the middle portion 24 (i.e., in a direction generally vertically in use) is less than a height of the lateral end portions 26, 28 where the lateral end portions 26, 28 meet the middle portion 24. In this way, a step is formed between the middle portion 24 and each of the lateral end portions 26, 28. Respective lateral end edges 30, 32 of each lateral end portion 26, 28 disposed furthest from the middle portion have a convex curvature. Accordingly, a lateral end part of each lateral end portion 26, 28 is tapered so that a height of the lateral end portion 26, 28 increases from a respective lateral end 20, 22 towards the middle portion 24. In this way, the support plate 16 is generally dumbbell-shaped from a front or rear side view.

The support plate 16 is arranged to be secured to the forwardly facing side of the backrest of the chair 2. In use, a rear side 34 of the support plate 16 faces the backrest 4 of the chair 2. Accordingly, the securing means may be provided on the rear side 34 of the support plate 16. In preferred embodiments a part of the rear side 34 of the support plate 16 is covered by hook or loop material and a part of the -8 -forward facing surface of the backrest 4 is covered by the other of the hook or loop material. A front side 36 of the support plate 16, opposite the rear side 34, faces forwards in use and thus faces towards the user of the chair 2. It will be appreciated that the rear side 34 of the support plate 16 provides a rear surface of the back plate 12.

As can be seen most clearly in Figure 3, the support plate 16 comprises a pair of elongate guide slots 38a, 38b. A first guide slot 38a extends laterally through the first lateral end portion 26 from proximate the first lateral end 20 into the middle portion 24. A second guide slot 38b extends laterally through the second lateral end portion 28 from proximate the second lateral end 22 into the middle portion 24. In this way, the elongate guide slots 38a, 38b extend generally horizontally in use. Each guide slot 38a, 38b thus provides an elongate opening through the support plate 16. Each guide slot 38a, 38b is arranged to receive part of a respective clamping mechanism (as described further below).

In this preferred embodiment, the adjustment plate 18 comprises an elongate generally rectangular plate 18 which extends laterally along the lateral support assembly 10. The adjustment plate 18 is mounted to the front side 36 of the support plate 16. In particular, a rear surface of the adjustment plate 18 is in contact with an area of the front side 36 of the support plate 16. An opposite front surface 40 of the adjustment plate 18 provides a forward facing surface of the back plate 12. In this embodiment the adjustment plate 18 extends between first and second lateral ends, which correspond to the first and second lateral ends 20, 22 of the support assembly 10. Lateral end edges 42, 44 of the adjustment plate 18 (which form short sides of the generally rectangular plate 18) have a convex curvature. The convex end edges 42, 44 of the adjustment plate 18 are aligned with, and match the curvature of, the lateral end edges 30, 32 of the support plate 16.

The adjustment plate 18 comprises a pair of elongate lateral adjustment slots 46a, 46b. A first lateral adjustment slot 46a extends from a middle region 50 of the adjustment plate 18 and towards the first lateral end 20. A second lateral adjustment -9 -slot 46b extends from the middle region 50 towards the second lateral end 22. In this way, the elongate lateral adjustment slots 46a, 46b extend generally horizontally in use. The lateral adjustment slots 46a, 46b are spaced apart so that a central portion of the adjustment plate 18 is without slots. Each lateral adjustment slot 46a, 46b is arranged to receive pad of a respective clamping mechanism. Each lateral adjustment slot 46a, 46b thus provides an elongate opening through the adjustment plate 18. When the lateral support assembly 10 is assembled, the first lateral adjustment slot 46a is aligned with the first guide slot 38a and the second lateral adjustment slot 46b is aligned with the second guide slot 38b. As can be seen most clearly in Figure 3, a width of each lateral adjustment slot 46a, 46b (in a direction generally vertically in use, perpendicular to the length of the slot) is less than the width of each guide slot 38a, 38b.

The lateral support members 14a, 14b are shown most clearly in Figures 2, 4 and 5. For simplicity, Figure 4 shows only a single lateral support member 14a. In particular, Figure 4 shows only the first lateral support member 14a (the second lateral support member 14b is a substantially identical mirror-image replica of the first lateral support member 14a).

Each lateral support member 14a, 14b comprises a support portion 52 and a clamping portion 54. The support portion 52 is arranged to extend generally forwards away from the back 4 of the chair 2 in use. The support portion 52 comprises an elongate plate extending between a proximal end 56 which is closest to the back plate 12 in use and an opposite distal end 58 which is furthest from the back plate 12 in use. The support portion 52 extends between the clamping portion 54 and the distal end 58 of the support portion 52. The clamping portion 54 comprises a generally rectangular plate which extends at an angle to the support portion 52. The clamping portion 54 extends away from the proximal end 56 of the support portion 52. The clamping portion 54 comprises a first portion 60 and a second portion 62. The first portion 60 extends between the proximal end 56 of the support portion 52 and the second portion 62. The second portion 62 extends from an edge of the first portion 60.

A plane of the second portion 62 is substantially perpendicular to a plane of the support portion 52. A plane of the first portion 60 is arranged at an angle to the plane of the support portion 52 and the plane of the second portion 62. Accordingly, the first portion 60 extends between the support portion 52 and the second portion 62 at an angle to both the support portion 52 and the second portion 62. In this embodiment, the support portion 52 and the first and second portions 60, 62 of the clamping portion 54 are provided by portions of a bent or folded plate or sheet. In this way, the first and second portions 60, 62 of the clamping portion 54 are provided on either side of vertical fold line 64 in the clamping portion 54. With this arrangement, each lateral support member 14 has a generally L-shaped profile, with the base of the L' having two segments at an angle to one another, as can be seen in Figure 5.

Each lateral support member 14a, 14b has an outer surface 65 and an inner surface 67.

In use, the clamping portion 54 of each lateral support member 14a, 14b is arranged to be clamped against a front side 40 of the adjustment plate 18, to secure the lateral support member 14a, 14b to the adjustment plate 18 (and thus to the back plate 12), as described further below. With the lateral support member 14a, 14b clamped in this way, the outer surface 65 of a part of the clamping portion 54 is in contact with the front side 40 of the adjustment plate 18 and the support portion 52 extends in a generally forwards direction. Furthermore, with both the lateral support members 14a, 14b secured to the back plate 12, the inner surfaces 67 of the lateral support members 14a, 14b face inwardly towards each other and the opposite outer surfaces 65 of the lateral support members 14a, 14b face outwardly.

As shown most clearly in Figure 4, the clamping portion 54 comprises an elongate angle adjustment slot 66 which extends laterally in and across the first and second portions 60, 62. In use, the angle adjustment slot 66 extends generally horizontally and is aligned with a respective lateral adjustment slot 46a, 46b of the adjustment plate 18. The angle adjustment slot 66 is sized to receive part of a clamping mechanism in use.

Referring again to Figures 2 and 3, the lateral support members 14a, 14b are arranged to be releasably secured to the back plate 12. A lateral position and angle of each lateral support member 14a, 14b is adjustable with respect to the back plate 12. Each lateral support member 14a, 14b is secured to the back plate 12 by a respective clamping mechanism 68a, 68b. In this embodiment, a first clamping mechanism 68a is arranged to clamp the first lateral support member 14a to the back plate 12 and a second clamping mechanism 68b is arranged to clamp the second lateral support member 14b to the back plate 12. In this embodiment, each clamping mechanism 68a, 68b comprises a lever cam clamping mechanism. The clamping mechanisms 68a, 68b are releasable to allow the position and angle of the lateral support members 14a, 14b to be adjusted, as described further below.

Each of the first and second clamping mechanisms 68a, 68b comprises a cam lever 70, a retaining member 72 and an elongate rod 74 which extends between the cam lever 70 and the retaining member 72. The cam lever 70 has a head 76 comprising a pair of spaced apart cams 78, and a lever arm 80 which extends away from the head 76. A pin 82 is pivotally mounted in the head 76 between the cams 78. The cam lever 70 is arranged to be pivotally mounted to the rod 74 by the pin 82. In particular, a threaded bore 84 extends transversely through the pin 82 and is arranged to engage with a threaded first end part 86 of the rod 74. An opposite second end part 88 of the rod 74 is secured to the retaining member 72. In use, pivoting of the cam lever 70 with respect to the rod 74 acts to reduce a distance between a surface of the cams 78 and the retaining member 72, such that objects can be clamped between the head 76 and the retaining member 72. For clarity, parts of the first clamping mechanism 68a for clamping the first lateral support member 14a are not shown in Figures 3, 5 and 6. It will be appreciated that the first clamping mechanism 68a is substantially the same as the second clamping mechanism 68b.

Figures 3 and 6 show most clearly the second clamping mechanism 68b. In use, the rod 74 is arranged to extend through the angle adjustment slot 66 in the respective clamping portion 54, through the second lateral adjustment slot 46b and into the second guide slot 38b. In the guide slot 38b, the first end part 86 of the rod 74 is secured to the retaining member 72. The retaining member 72 is arranged to retain the end part 86 of the rod 74 in the guide slot 38b. A width of the retaining member 72 is larger than a width of the second adjustment slot 46b so that the retaining member 72 cannot pass through the adjustment slot 46b. The retaining member 72 is shaped so as to slide in the guide slot 38b but so that it cannot rotate in the guide slot 38b. In this embodiment the retaining member 72 has a stadium-shaped cross-sectional profile (only partly shown in Figure 3), having flat side surfaces which engage with sides of the guide slot 38b to prevent rotation of the retaining member 72 in the guide slot 38b. The retaining member 72 also comprises a reduced width portion 90 which is sized to extend into and slide in the adjustment slot 46b. The rod 74 is fixed to the retaining member 72 so that it cannot rotate with respect to the retaining member 72.

Each clamping mechanism 68a, 68b is arranged to clamp the clamping portion 54 of each lateral support member 14a, 14b against the adjustment plate 18. Each cam lever 70 is pivotable between a clamping position (as shown in Figures 1 to 6) and an open position (as can be seen in Figure 7). In the clamping position, the cams 78 are urged against the clamping portion 54 of a respective lateral support member 14, thus urging the clamping portion 54 against the adjustment plate 18. In this clamping position, the cam lever 70 pulls on the rod 74, which in turn urges the retaining member 72 against the rear side of the adjustment plate. In this way, the clamping portion 54 is clamped against the adjustment plate 18 between the cams 78 and the retaining member 72, so as to fix a position of the respective lateral support member 14a or 14b with respect to the adjustment plate 18. In the open position, little or no clamping force is applied to each clamping portion 54 by its respective cam lever 70, so a position of each lateral support member 14a, 14b with respect to the adjustment plate 18 can be adjusted.

Advantageously, in the present invention, a lateral position of the lateral support members 14a, 14b is adjustable so that a distance between the lateral support members 14a, 14b can be adjusted to suit a particular user of the chair 2. To adjust the position of one of the lateral support members, the cam lever 70 is moved to the open position. Figure 7 shows the cam lever 70 of the second clamping mechanism 68b in the open position. In this position, the cams 78 do not exert a force on the clamping portion 54 and a gap is present between the cams 78 and the clamping portion 54. In this example, the second lateral support member 14b can then be slid laterally by sliding the rod 74 and retaining member 72 in the adjustment slot 46b and guide slot 38b respectively. In this way, each lateral support member 14a, 14b can be moved laterally inward (i.e. towards the middle region 50 of the adjustment plate) or laterally outward (i.e. towards the nearest lateral end 20, 22 of the support assembly 10). Accordingly, a distance between the lateral support portions 14a, 14b can be adjusted. Opposite ends of each of the adjustment slots 46a, 46b therefore define a minimum and maximum width or distance between the lateral support members 14a, 14b.

The present invention also has the advantage that an angle of each lateral support portion 14a, 14b with respect to the back plate 12 can be adjusted. The angle of each lateral support member 14a, 14b can be adjusted independently of a lateral position of the lateral support member 14a, 14b. Also, since the angle of each lateral support member 14a, 14b can be adjusted independently, the angle of one of the lateral support members 14a, 14b can be adjusted with respect to the angle of the other of the lateral support members 14a, 14b.

Referring in particular to Figures 2 and 5, the angle of a lateral support member 14a, 14b can be adjusted by using the clamping mechanism 68a, 68b to clamp either the first portion 60 or the second portion 62 of the clamping portion 54 against the clamping plate 18. Because the first and second portions 60, 62 are arranged at an angle to one another (i.e. they extend in different planes), and at different angles to the plane of the support portion 52, an angle of the support portion 52 with respect to the adjustment plate 18 can be adjusted. In this embodiment, the angle of each lateral support member 14a, 14b can be adjusted to a first angle or a second angle.

For example, and as shown in Figures 2, 5 and 7 the first lateral support portion 14a (towards the left in Figures 2, 5 and 7) is shown at the first angle, with the first portion 60 of the clamping portion 54 clamped against the adjustment plate 18. Since the plane of the first portion 60 extends at an obtuse angle to the plane of the support portion 52, the support portion 52 thus extends away from the adjustment plate at an angle which deviates from normal to a plane of the adjustment plate 18. In particular, the support portion 52 of the first lateral support member 14a extends in a direction laterally outwards and away from the adjustment plate 18. In use therefore, in this configuration, the first lateral support portion 14a extends in a direction forwards from the back 4 of the chair 2 and laterally away from the user.

In this illustrated example, the second lateral support portion (towards the right in Figures 2, 5 and 7) is shown at the second angle, with the second portion 62 of the clamping portion 54 in contact with the adjustment plate 18. Since the plane of the second portion 62 extends perpendicular to the plane of the support portion 52, the support portion 52 thus extends away from the adjustment plate normal (perpendicular) to the plane of the adjustment plate 18. In use therefore, in this configuration, the second lateral support portion 14b extends in a direction forwards from and generally perpendicular to the back 4 of the chair 2.

With both of the lateral support members 14a, 14b adjusted so that the second portion 62 of the clamping portion 54 is in contact with the adjustment plate 18, the support portions 52 of the lateral support members 14a, 14b are generally parallel to each other. With both of the lateral support members 14a, 14b adjusted so that the first portion 60 of the clamping portion 54 is in contact with the adjustment plate 18, the support portions 52 of the lateral support members 14a, 14b are at an angle to each other such that a distance between the support portions 52 increases in a forwards direction away from the back 4 of the chair 2.

To adjust the angle of one of the lateral support members 14a, 14b, the respective clamping mechanism 68a, 68b is released by moving the cam lever 70 to the open position. The relative position of the clamping portion 54 with respect to the clamping mechanism 68a, 68b can then be adjusted by moving the support member 14a, 14b laterally with respect to the clamping mechanism 68a, 68b, allowing the rod 74 to slide in the angle adjustment slot 66. In this way, the respective clamping mechanism 68a, 68b can be arranged to act on either the first portion 60 or the second portion 62 of the clamping portion 54. Accordingly, the clamping mechanism 688, 68b may be arranged to clamp the first portion 60 against the adjustment plate 18 (for securing a lateral support member 14a, 14b at the first angle), or the clamping mechanism 68a, 68b may be arranged to clamp the second portion 62 against the adjustment plate 18 (for securing a lateral support member 14a, 14b at the second angle). With this arrangement, the angle of the lateral support portions 14a, 14b can be adjusted with respect to the backrest 4 of the chair 2 in use, to suit the user.

It will be appreciated that in other embodiments, each clamping portion may comprise more than two angled portions. For example, each clamping portion may comprise a third portion having a plane arranged at an angle to the plane of the first and second portions, to allow the angle of a lateral support member to be adjusted to a third angle with respect to the adjustment plate, different to the first and second angles. In some embodiments, the clamping portions may comprise curved plates, so that an angle of each lateral support portion is continuously adjustable over a range of angles. It will also be appreciated that in other embodiments, other clamping mechanisms may be used. For example, substantially any suitable mechanism for clamping a clamping portion to the adjustment plate could be used.

It will be appreciated that, in embodiments in which the back plate 12 is not provided by distinct parts such as a support plate and an adjustment plate, the guide slots and lateral adjustment slots may be formed in a single component. In particular, the guide slot and lateral adjustment slot may be provided by a single lateral adjustment slot having a rebate edge in the rear surface of the back plate to provide a shoulder or retaining surface on which the retaining member of the clamping mechanism is seated. In embodiments in which the back plate 12 does include a distinct support plate and adjustment plate, the support plate and adjustment plate may advantageously be made of different materials. For example, the support plate may be made of wood and the adjustment plate may be made of metal. This may allow the overall weight of the back plate to be minimised whilst retaining the required stiffness, and providing a tough surface against which the lateral support members are clamped.

In other embodiments the clamping mechanism may be of any suitable configuration to be able to selectively apply a clamping force to the lateral support member. The clamping mechanism may, for example, include a threaded rod and nut, the nut being moveable along the threaded rod to apply a force to the lateral support member. In other embodiments the clamping mechanism may include a sloped or wedge surface that may be moved with respect to the lateral support member to apply more of less clamping force to a part of the lateral support member.

In the preceding description the first and second lateral adjustment slots have been described as discrete, separate slots. It will be appreciated that in some embodiments the first and second lateral adjustment slots may be sections of one continuous slot. In particular the first and second lateral adjustment slots may be respective first and second end sections of a single elongate slot. In some embodiments the first and second lateral adjustment slots may be contiguous.

As described above, in use, one or more surfaces of the lateral support assembly 10 may be covered with suitable padding. Padding may be disposed over one or more of the front side 36 of the back plate 16, the front side 40 of the adjustment plate 18, inner surfaces 67 of the lateral support members 14a, 14b and outer surfaces 65 of the lateral support members 14a, 14b.

Other modifications and variations not explicitly disclosed above may also be contemplated without departing from the scope of the invention as defined in the 30 appended claims.

Claims

CLAIMS1. A lateral support assembly for a chair comprising: a back plate having opposite front and rear sides, and first and second elongate lateral adjustment slots extending laterally across the back plate, the first lateral adjustment slot being disposed proximate a first side edge of the back plate and the second lateral adjustment slot being disposed proximate a second side edge of the back plate; a first lateral support member having a support portion, a first clamping portion and a second clamping portion, a plane of the first clamping portion being at a non-zero angle to planes of each of the second clamping portion and the support portion, and the first lateral support member including an elongate angle adjustment slot extending through the first and second clamping portions, the angle adjustment slot of the first lateral support member being aligned with the first lateral adjustment slot of the back plate; a second lateral support member having a support portion, a first clamping portion and a second clamping portion, a plane of the first clamping portion being at a non-zero angle to planes of each of the second clamping portion and the support portion, and the first lateral support member including an elongate angle adjustment slot extending through the first and second clamping portions, the angle adjustment slot of the second lateral support member being aligned with the second lateral adjustment slot of the back plate; a first clamping mechanism engaged with the angle adjustment slot of the first lateral support member and the first lateral adjustment slot; and a second clamping mechanism engaged with the angle adjustment slot of the second lateral support member and the second lateral adjustment slot, each of the first and second clamping mechanisms being arranged to apply a releasable clamping force to clamp the respective lateral support member against the back plate to secure the lateral support member in a chosen position relative to 30 the back plate, and when a clamping force is not applied to one of the lateral support members, that lateral support member is movable with respect to the back plate to adjust the relative alignment of the corresponding angle adjustment slot and lateral adjustment slot to independently adjust both a lateral position of the lateral support member with respect to the back plate and an angle of the support portion of the lateral support member with respect to the back plate.
2. A lateral support assembly according to Claim 1, wherein each of the first and second elongate lateral adjustment slots are sections of a single continuous slot.
3. A lateral support assembly according to Claim 1 or Claim 2, further comprising means for releasably securing the back plate to a back rest of a chair.
4. A lateral support assembly according to any one of Claims 1 to 3, in which the back plate comprises a support plate and an adjustment plate, a rear surface of the adjustment plate being in contact with a front surface of the support plate and the lateral adjustment slots extending through both the support plate and the adjustment plate.
5. A lateral support assembly according to any one of Claims 1 to 4, in which each of the clamping mechanisms comprises a rod that extends through the respective aligned angle adjustment slot and lateral adjustment slot.
6. A lateral support assembly according to Claim 5, in which each of the clamping mechanisms comprises a cam surface arranged to apply a force to one of the clamping portions of the respective lateral support member.
7. A lateral support assembly according to any one of Claims 1 to 6, in which the support portion, first clamping portion and second clamping portion of each of the lateral support members are all planar.
8. A lateral support assembly according to any one of Claims 1 to 7, in which the first clamping portion extends from the support portion and the second clamping portion extends from the first clamping portion.
9. A lateral support assembly according to Claim 8, in which the plane of the second clamping portion is perpendicular to the plane of the support portion.
10. A lateral support assembly according to any one of Claims 1 to 9, in which each lateral support member includes a third clamping portion, a plane of the third clamping portion being at a non-zero angle to the planes of both the first and second clamping portions.
11. A lateral support assembly according to any one of Claims 1 to 10, in which the first and second clamping portions are part of a continuously curved clamping portion of each of the lateral support members.
12. A lateral support assembly according to any one of Claims 1 to 11, wherein when both of the lateral support members are clamped with the first clamping portion in contact with the back plate, the support portions of the lateral support members are at an angle to each other such that a distance between the support portions increases in a direction away from the back plate.
13. A lateral support assembly according to Claim 12, wherein when both of the lateral support members are clamped with the second clamping portion in contact with the back plate, the support portions of the lateral support members are parallel to each other.
14. A lateral support assembly according to any one of Claims 1 to 13, in which the clamping mechanisms are engaged with the angle adjustment slots and lateral adjustment slots such that each of the angle adjustment slots is constrained to only move along a single axis with respect to the corresponding lateral adjustment slot.
15. A lateral support assembly according to any one of Claims 1 to 14, in which a part of a surface of the back plate and a part of a surface of each of the support portions of the lateral support members is covered with a layer of padding.
-20 - 16. A chair including a lateral support assembly according to any one of Claims 1 to 15, the back plate of the lateral support assembly being secured to a forward facing surface of a backrest of the chair.
17. A chair according to Claim 16, in which the back plate is releasably secured to the backrest.
18. A chair according to Claim 17, in which the back plate is releasably secured to the backrest by hook and loop material.