GB2323275A

GB2323275A - Chair

Info

Publication number: GB2323275A
Application number: GB9805065A
Authority: GB
Inventors: Graham Andrew Race
Original assignee: MEDICAL ENGINEERING RESOURCE U
Current assignee: MEDICAL ENGINEERING RESOURCE U
Priority date: 1997-03-18
Filing date: 1998-03-11
Publication date: 1998-09-23
Anticipated expiration: 2018-03-11
Also published as: GB9805065D0; GB2323275B; GB9705566D0

Abstract

A therapeutic chair for a physically disabled child comprises a rigid frame formed of two side members (10,11) with cross members (14,18) extending therebetween, and a cushion positioned between the side members with the cross members extending through openings therein. The cushion may be one-piece or separate seat and backrest cushions may be used. Each cushion may also consist of a plurality of cooperating laminar slabs (12,16). The chair is readily dismantled and can be tailored to suit the particular disability of any given child.

Description

IMPROVEMENTS IN CHAIRS This invention relates to chairs.

According to the invention there is provided a chair comprising two side members interconnected by cross members to form a rigid frame, and a cushion of resilient material supported on the cross members and providing the seat of the chair, wherein the cushion is positioned between the side members with the cross members extending through openings in the cushion.

The chair of the invention is of simple construction, and can be very light in weight, although nevertheless of sturdy construction, by use of lightweight components. To this end, the side members of the chair of the invention may be made of thermo-plastics material vacuum-formed in a mould, and the cross members may be made of plastics.

The cross members of the chair of the invention are preferably detachably secured to the side members, whereby the chair may readily be dismantled for cleaning by detaching the side members from the cross members and withdrawing the cross members through the openings in the cushion.

The two side members and the cushion of resilient material may be shaped so that the cushion provides both the seat and a backrest for the chair, or the chair may be provided with two cushions of resilient material, one cushion being positioned between lower portions of the side members and forming the seat of the chair, the cross members connecting the lower portions of the side members extending through openings in said one cushion, and the other cushion being positioned between upper portions of the side members and forming a backrest for the chair, the cross members connecting the upper portions of the side members extending through openings in said other cushion. The upper and lower portions of each side member may be separate components, with the upper portion of each side member pivotally connected to the lower portion thereof, and locking means are operable to lock the upper portion at any desired angular setting relative to the lower portion within the range of movement therebetween, whereby the angular position of the backrest cushion relative to the seat cushion may be adjusted as required.

The length of the cross members and the width of the cushion or cushions are preferably such that the or each cushion is compressed between the side members when the chair is assembled.

The or each cushion may consist of a single block of the resilient material, or the or each cushion may consist of two or more laminar slabs of the resilient material arranged side by side in a laminated formation with the edge surfaces of the laminar slabs co-operating to form at least part of the seating surface of the chair, and each laminar slab having openings for passage of the associated cross members. The laminar slabs may be contoured so that their edge surfaces co-operate to provide the seat and a back rest for the chair.

The openings in the or each cushion when formed from a single block of resilient material, or the openings in the laminar slabs forming the or each cushion, may be slots which are open to the rear or underside of the cushion or laminar slabs, so that the cushion or laminar slabs may be forced rearwards or downwards to force the cross members into the slots. The openings in the or each cushion, or the openings in the laminar slabs, are however preferably apertures.

The cross members may be of circular cross-section and each laminar slab mounted on two or more of the cross members, the laminar slabs having circular apertures through which the cross members extend as a sliding fit. With this construction, the width of the laminar slabs is preferably as narrow as practicable in order to reduce the frictional resistance between the laminar slabs and the cross members to a value which permits easy assembly of the laminar slabs on the cross members.

The resilient material of the or each cushion may be foam plastics or other soft resilient material, so as to provide a high level of comfort without the need to provide additional cushioning for the chair. In a construction in which the or each cushion consists of laminar slabs of resilient material, the slabs can conveniently be cut from a large sheet of the foam plastics material marketed under the trade name PLASTOZOTE ( Registered Trade Mark).

The chair of the invention is particularly suitable for use with children. In a construction in which the cross members are detachably secured to the side members, the overall width of the chair can readily be adjusted by replacing the cross members by other cross members of the length required to provide the desired overall width. It will of course then be necessary to remove or add additional laminar slabs onto the cross members to occupy the space between the side members In this way, the chair of the invention may be adjusted to fit closely between the arms of a conventional arm chair, or between the arms of a seat in a passenger airplane, or to fit closely within the frame of a conventional pushchair for a child, or within the frame of a stand adapted to rest on the floor. The side members of a chair according to the invention which is intended to be used in a pushchair or stand are preferably provided with outwardly projecting lugs adapted to engage the frame of the pushchair or stand and support the chair on the frame.

The invention is particularly applicable to chairs for use with children who are physically disabled.

In the treatment of small children who are physically disabled, it is crucial for the 6 months to 4 years age group, in which the child's physique is supple, to limit the postural deformities which commonly appear when the child learns to sit. It is essential to encourage the development of a lumbar lordosis from the primary spinal curve, and prevent sacral sitting, at an early age..

It is known to provide therapeutic chairs for physically disabled children in which the seat cavity is formed at least partially by pads which are adjusted to positions in which the occupant is supported in a desired seating posture. Such chairs have a rigid frame fitted with numerous mechanisms for adjusting the positions of the pads. The chairs are usually heavy and bulky, it is often difficult to set the pad adjusting mechanisms to obtain the optimum seating posture of a physically disabled child, and the adjusting mechanisms may become loose if the child wriggles or goes into spasm.

The chair of the present invention can readily be tailored to accommodate various disabilities and encourage the development of symmetrical normal spinal curvatures in the physically disabled, by contouring the laminar slabs to provide a chair of a size and shape in which the intended occupant is in a desired seating posture when confined in the chair with the pelvic and lower spinal regions in contact with the laminar slabs. Alternatively, or in addition, the apertures for reception of the cross members in one or more of the laminar slabs may be substantially larger than the cross sectional dimensions of the associated cross members to permit a degree of freedom of movement of the laminar slabs relative to one another in directions perpendicular to the axes of the cross members, so that the profile of the seating surface may be adjusted to fit the body of an intended occupant of the chair. In this construction it is necessary for the laminar slabs to be compressed between the side members by an amount such that the frictional resistance between the slabs prevents relative movement therebetween under the forces arising in use of the chair.

In one particularly convenient embodiment of the invention, the or each cushion comprises a central laminar slab and two side laminar slabs arranged one on each side of the central slab, each of the side slabs having a width substantially smaller than the width of the associated central slab and a depth substantially greater than the depth of the associated central slab, the arrangement being such that the side slabs of the or each cushion project to the front or above the central slab of the cushion, so that in the assembled chair the upper surface of the seat has a profile with a shallow recess when viewed in vertical section, and the front surface of the backrest has a profile with a shallow recess when viewed in horizontal section. The recessed profiles of the seat and backrest assist in holding a child centrally in the chair.

The chair of the invention can conveniently be provided with a headrest, and with two side supports arranged to engage opposite sides respectively of the trunk of a physically disabled occupant of the chair to hold the occupant in an upright position, the headrest and the side supports being mounted as a sliding fit on one or more of the cross members..

The chair of the invention can also be tailored to control the alignment of the pelvis with the thigh bones and lower spinal regions, and to provide for the abduction of the hips, by adequate separation of the legs, of a physically disabled person. To this end, the edge surfaces of the laminar slabs defining the centre portion of the seat of the chair are preferably contoured to provide an abduction block for separating the thighs of the intended occupant.

The chair of the invention may be provided with an extension unit mounted on the side members of the chair, the extension unit comprising a rigid frame having two opposing side members and cross members secured to and extending between the opposing side members, and a cushion of resilient material supported on the cross members, the cushion being positioned between the side members with the cross members extending through openings in the cushion. The cushion of the extension unit can conveniently comprise laminar slabs of the resilient material, the slabs being arranged side by side in a laminated formation. The extension side members may be arranged so that the edge surfaces of the laminar slabs cooperate to form an extension to the seat of the chair, for example to provide an abduction block for separating the thighs of the intended occupant of the chair, or to form a footrest for the intended occupant of the chair..

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of one construction of a chair according to the invention, Figure 2 is an exploded perspective view of the chair of Figure 1, showing details of the construction, Figure 3 is a perspective view of an assessment chair for determining the profile of the seat and backrest of the chair of Figure 1 best suited to accommodate a physically disabled person in a therapeutically desirable seating posture.

Figure 4 is a perspective view of the chair of Figure 1 provided with side supports, a head rest, and a protective apron, Figure 5 is a perspective view of a seat extension unit having an abduction block, Figure 6 is a perspective view of a footrest extension unit, Figure 7 is a perspective view of a knee block extension unit, Figure 8 is a perspective view of the left hand side member of a modified construction of the chair of Figure 1 mounted on the frame of a pushchair for a child, only the left hand side of the frame of the pushchair and part of the seat of the pushchair being shown, Figure 9 is an exploded perspective view of another construction of chair according to the invention, and Figure 10 is an exploded perspective view of the left hand side member of another modified construction of the chair of the invention.

The chair shown in Figures 1 and 2 comprises a left hand side member 10 as viewed from the front of the chair, a right hand side member 11, a seat cushion 13 consisting of nine narrow laminar slabs 12 of a soft resilient material juxtaposed side by side in a laminated formation between the side members 10, 11 and forming the seat of the chair, the slabs 12 being mounted on three parallel rods 14 detachably secured to and extending horizontally between the side members 10, 11, the rods 14 passing as a close sliding fit through aligned apertures 15 in the slabs 12, a backrest cushion 17 consisting of nine narrow laminar slabs 16 of a soft resilient material juxtaposed side by side in a laminated formation between the side members 10, 11 and forming the backrest of the chair, the slabs 16 being mounted on four parallel rods 18 detachably secured to and extending between the side members 10, 11, the rods 18 passing as a close sliding fit through aligned apertures 19 in the slabs 16, a bottom plate 20 arranged below the slabs 12 and supported on the side members 10, 11, the bottom plate 20 being in contact with the slabs 12, and a backplate 21 arranged behind the slabs 16 and supported on the side members 10, 11, the backplate 21 being in contact with the slabs 16.

The left hand side member 10 is made from a sheet of thermo-plastic material vacuum -formed in a mould to the shape shown in Figures 1 and 2, and comprises a circular boss 25, a seat limb 26 projecting forwardly from the boss 25, a backrest limb 27 projecting upwardly from the boss 25, and a heel 28 projecting rearwardly from the boss 25. The seat limb 26 is shaped to provide a straight channel section 30 extending along the upper edge of the limb 26 with the open side of the channel section 30 facing inwards towards the slabs 12, a straight channel section 31 extending along the lower edge of the limb 26 with the open side of the channel section 31 facing inwards, a straight channel section 32 extending along the centre portion of the limb 26 with the open side of the channel section 32 facing inwards, the base of the channel section 32 being formed with three circular recesses 33 for reception of the adjacent ends of the rods 14 as described hereinafter, and an arcuate reinforcing channel section 34 between the sections 31, 32. The remainder of the seat limb 26 forms a flat wall 35 on the inner side of the limb 26. The backrest limb 27 is shaped to provide a channel section 40 extending along the front edge of the limb 27, around the upper end thereof, and along the rear edge of the limb 27, the channel 40 having the open side thereof facing inwards towards the backrest slabs 16, and three arcuate reinforcing channel sections 41 spaced along the limb 27 to the front of the rear portion of the channel section 40. The remainder of the limb 27 enclosed by the channel section 40 and the arcuate sections 41 consists of a flat wall 44 on the inner side of the limb 27, the centre of the flat wall 44 being formed with four circular recesses 45 for reception of the adjacent ends of the rods 18 as described hereinafter. The boss 25 comprises an annular channel 46 having the open side thereof facing inwards towards the slabs 12, the remainder of the boss surrounded by the annular channel 46 forming a flat wall 47 on the inner side of the boss. The heel 28 comprises a triangular shaped channel 48 having the open side thereof facing inwards, the remainder of the heel surrounded by the channel 48 forming a flat wall 49 on the inner side of the heel.

The right hand side member 11 is also made from a sheet of thermo-plastics material vacuum-formed in a mould, and is similar to the left hand side member 10 but is a mirror image of the left hand side member. The right hand side member 11, as shown in Figure 2, comprises a circular boss 55, a seat limb 56 projecting forwardly from the boss 55, a backrest limb 57 projecting upwardly from the boss 55, and a heel 58 projecting rearwardly from the boss 55. The seat limb 56 has channel sections 60, 61, 62 similar to the channel sections 30, 31, 32 of the seat limb 26 of the left hand side member, except that the channel sections 60, 61, 62 have the open sides thereof facing in the opposite direction, that is towards the seat slabs 12.

The base of the channel section 62 is formed with three circular recesses 63 for reception of the adjacent ends of the rods 14, and an arcuate reinforcing channel 64 is formed between the channel sections 61, 62. The remainder of the seat limb 56 forms a flat wall 65 on the inner side of the limb 56. The backrest limb 57 has a channel section 68 similar to the channel section 40 of the left hand side member 10, except that the channel section 68 has the open side thereof facing in the opposite direction, that is towards the backrest slabs 16. The backrest limb 57 has three arcuate reinforcing channels 69 similar to the arcuate channels 41 of the left hand side member, and the remainder of the limb 57 enclosed by the channel sections 68, 69 consists of a flat wall 70 on the inner side of the limb 57, the centre of the flat wall 70 being formed with four circular recesses 71 for reception of the adjacent ends of the rods 18. The circular boss of the right hand side member 11 has an annular channel 72 similar to that of the annular channel 46 of the left hand side member 10, except that the annular channel 72 has the open side thereof facing in the opposite direction, that is towards the seat slabs 12, and the remainder of the boss surrounded by the annular channel 72 forms a flat wall 73 on the inner side of the boss. The heel 58 of the right hand side member has a triangular shaped channel similar to that of the triangular shaped channel 48 of the left hand side member 10, except that the open side of the channel faces in the opposite direction, that is inwardly.

The rods 14, 18 are made of plastics material, but may be made of aluminium or any other suitable lightweight material.

The seat slabs 12 and the backrest slabs 16 are made of foam -plastics material marketed under the trade name PLASTOZOTE (Registered Trade Mark) but may be made of any other suitable material. The slabs can conveniently be cut from a large sheet of the foam plastics, and are juxtaposed side by side to form the cushions 13 and 17 providing the seat and backrest respectively of the chair. The seat slabs are of the same shape and size, and each has a flat bottom surface 78, a contoured top surface 79, a further top surface 80 which is flat and to the rear of the contoured surface 79, and a flat rear end surface 81. The backrest slabs are also of the same size and shape, and each has a flat rear surface 82, a contoured front surface 83 and a flat bottom surface 84 of the same shape and dimensions as the flat top surfaces 80 on the seat slabs.

The chair of Figures 1 and 2 may be assembled by inserting the rods 14, 18 into the recesses 33, 45 respectively in the left hand side member 10 and securing the rods to the side member 10 by screws 86 passing through apertures in the end walls of the recesses 33, 45 and screwed into bores in the adjacent ends of the rods. The seat laminar slabs 12 are then mounted on the rods 14 with the rods passing through the apertures 15 in the slabs 12, and the backrest laminar slabs 16 are mounted on the rods 18 with the rods passing through the apertures 19 in the slabs 16. The left hand edge of the bottom plate 20 is engaged in the channel 31 along the bottom edge of the seat limb 26, and the left hand edge of the back plate 21 is engaged in the channel 40 along the rear edge of the backrest limb 17. The right hand side member 11 is then engaged against the laminar slabs 12, 16 with the ends ofthe rods 14, 18 engaged in the recesses 63, 71 respectively in the right hand side member 11, the right hand edge of the bottom plate 20 engaged in the channel 61 along the bottom of the seat limb 56, and the right hand edge of the back plate 21 engaged in the channel 68 along the rear edge of the backrest limb 57. The right hand side member is then secured to the rods 14, 18 by screws 86 passing through apertures in the end walls of the recesses 63, 71 and screwed into bores in the adjacent ends of the rods.

The rods 14, 18 are of a length such that, when the components of the chair are assembled as described above, the seat slabs 12 are compressed between the flat walls 35, 65 on the seat limbs 26, 56 and between the flat walls 47, 73 on the circular bosses 27, 55 of the two side members 10,. 11, and the backrest slabs 16 are compressed between the flat walls 44, 70 on the backrest limbs 27, 56 of the two side members 10, 11.

In the chair of Figures 1 and 2, the side members 10, 11 are interconnected by the parallel rods 14, 18 to form a rigid frame, and the laminar slabs 12, 16 forming the seat cushion 13 and backrest cushion 17 are freely mounted on the rods 14, 18 and sandwiched between the side members. The chair can easily be dismantled into its separate components for convenience in travelling or for cleaning by removing the screws 86 and withdrawing the slabs 12, 16 from the rods. The screws may, if desired, be replaced by wing nuts mounted on screwthreaded stub shafts on the ends of the rods to facilitate dismantling of the chair without the use of tools.

The chair of Figures 1 and 2 is very suitable for use by a small child. The chair can conveniently be placed directly on a floor or on a carpet. There is no danger of the chair tilting backwards since the weight of a child sitting in the chair is to the front of the heels 28, 58 on the chair. The chair is light in weight and can easily be placed on the seat of a conventional arm chair with the backrest strapped to the backrest of the arm chair. The chair of Figures 1 and 2 may be provided with straps for holding the child in the chair. For this purpose the backplate 21 is provided with two slots (not shown) spaced one on each side of the backplate..

A strap is threaded rearwardly between the two backrest slabs 16 at the front of a first of the slots, through the first slot, across the backplate 21, through the second slot, and then between the two adjacent slabs 16 to the front of the chair.

In the chair of Figures 1 and 2, the rods 14, 18 are a close sliding fit in the apertures 15, 19 in the laminar slabs. The apertures 15, 19 may however be substantially larger than the cross sectional dimensions of the rods 14, 18 to provide some freedom of movement of the laminar slabs in directions perpendicular to the axes of the rods. Upon assembly of the chair, the laminar slabs may then be adjusted relative one one another in directions perpendicular to the rods to provide a profile for the seat or backrest which conforms more closely to the body of an occupant. In this construction it is however necessary for the laminar slabs to be compressed between the side members by a force such that the frictional resistance between adjacent slabs is sufficient to prevent relative movement between the slabs during use of the chair.

When the chair of Figures 1 and 2 is to be used with physically disabled children, the laminar slabs 12, 16 are preferably contoured for each child to provide a seat and backrest designed to hold the child in a therapeutically desirable posture when seated in the chair, for example a posture which would encourage the development of a lumbar lordosis from the primary spinal curve. An assessment chair for determining the best profile for the slabs 12, 16 for each particular child is shown in Figure 3.

The assessment chair of Figure 3 comprises a base plate 90, two legs 91, 92 mounted on the base plate and supporting a horizontal pivot pin 93 therebetween, a cantilever beam 94 pivotally mounted at one end on the pivot pin 93, and an upright beam 95 pivotally mounted at its lower end on the pivot pin 93. The beam 94 is supported by a strut 96 formed by a metal bar bent into a U-shape with the free ends of the arms bent inwards to form two co-axial stub axles (not shown) pivotally mounted in aligned bores in opposite sides of the beam 94, and the cross piece 97 of the U-shaped strut 96 abutting a selected one of several rails 98 spaced along the base plate below the beam 94. The beam 94 may therefore be adjusted to different angular settings about the pivot pin 93 and located in that angular setting by engagement of the strut with the appropriate rail 98. The beam 95 is supported by a strut 100 formed by a metal bar bent into a U-shape with the free ends of the arms bent inwards to form two co-axial stub axles (not shown) pivotally mounted in aligned bores in opposite sides of the beam 95, and the cross piece 101 of the U-shaped strut 100 abutting a selected one of several rails 102 spaced along the base plate in the pivotal plane of the beam 95. The beam 95 may therefore be adjusted to different angular settings about the pivot pin 93 and located in that angular setting by engagement of the strut 100 with the appropriate rail 102. The cantilever beam 94 supports six horizontal cylindrical bars 105 spaced parallel to one another along the beam 94 and forming the seat ofthe assessment chair. Each of the bars 105 is mounted on the upper end of an upright spindle 106 slidably mounted in an aperture in the beam 94. The beam 94 is formed in two longitudinal sections secured together side by side, the apertures for the spindles 106 being formed by opposing recesses in the mating faces of the two sections of the beam. Each spindle 106 is secured in position on the beam 94 by a locking pin 107 screwed into a bore in the beam 94 and engaging in a groove 108 in the spindle. The height of each cylindrical bar 105 may therefore be individually adjusted by unscrewing the associated locking pin 107, raising or lowering the associated spindle 106 as desired, and screwing the pin 107 back into its locked position. The upright beam 95 supports ten horizontal cylindrical bars 109 spaced parallel to one another along the beam 95 and forming the backrest of the assessment chair. Each of the bars 109 is supported on one end of a spindle 110 slidably mounted in an aperture in the beam 95. The beam 95 is formed in two longitudinal sections secured together side by side, the apertures for the spindles 110 being formed by opposing recesses in the mating faces of the two sections of the beam. Each spindle 110 is secured in position on the beam 95 by a locking pin 111 screwed into a bore in the beam 95 and engaging in a groove 112 in the spindle. The position of each cylindrical bar 109 may therefore be individually adjusted forwards or rearwards by unscrewing the associated locking pin ill, moving the associated spindle 110 as desired, and screwing the pin 111 back into its locked position.

The assessment chair of Figure 3 would normally be used by medical personnel in determining the best profile for the slabs 12, 16 of the chair of Figures 1 and 2. In use, the child is seated in the assessment chair and the positions of the cylindrical bars 105, 109 adjusted as described above, that is by selecting the angular setting of the beams 94, 95 about the pivot pin 93 and selecting the spacing of each of the bars 105, 109 from its associated beam 94, 95, to provide a profile for the seat and backrest which is appropriate for that child. The assessment chair is then used as a template in the cutting of the seat slabs 12 and the backrest slabs 16 from a sheet of foam plastics material to provide the slabs with shapes which result in the chair of Figures 1 and 2 having a profile for the seat and backrest similar to that of the seat and backrest of the assessment chair.

Figure 4 shows the chair of Figures 1 and 2 adapted for use with physically disabled children by the provision of two side supports 115, 116, a headrest 117 and a protective apron 118. The side supports 1 115, 116 are arranged to engage opposite sides of the trunk of a child and hold the trunk in an upright position, and the headrest is arranged to keep the head of a child in an upright position..

The side support 115 is mounted on one of the rods 18 and comprises a plate 120 having an aperture (not shown) through which the rod 18 passes as a close sliding fit, the plate 120 being positioned between two of the backrest slabs 16 on the left hand side of the chair and projecting forwardly in front of the backrest, and a slab 121 of foam plastics material glued to the inside surface of the front end portion of the plate 120 with the rear end of the slab abutting the adjacent backrest slab 16. The plate 120 is made of thermo-plastics material vacuumformed in a mould to provide a peripheral rim 122 on the inside surface of the plate. The rim 122 engages the periphery of the slab as a close fit. A length of VELCRO webbing 123 (VELCRO is a Registered Trade Mark) extends through aligned slots in the plate 120 and slab 121 adjacent the front ends thereof, for use in strapping a physically disabled occupant into the chair.

The side support 116 is similar to the side support 115 and is mounted on the same rod 18. The support 116 comprises a plate 125 positioned between two of the backrest slabs 16 on the right hand side of the chair, and a slab 126 of foam plastics material glued to the inside surface of the front end portion of the plate 120 with the rear end portion of the slab abutting the adjacent backrest slab. The inside surface of the plate 125 has a rim 127 which engages the periphery of the slab 126 as a close fit. A length of VELCRO webbing 123 (VELCRO is a Registered Trade Mark) extends through aligned slots in the plate 125 and slab 126 adjacent the front ends thereof.

The headrest 117 is mounted on the two uppermost rods 18 in the frame of the chair and comprises a rigid frame consisting of two upright side plates 130, only one of which is shown in Figure 4, and a rod (not shown) detachably secured to and sufficient to provide side support for the head of an occupant in the chair, and the upper end portion of each side plate has a forwardly projecting lug 133 which reinforces the adjacent slabs 131. The lower end portion of the left hand side plate 130, as viewed from the front of the headrest, is positioned between two of the backrest slabs 16 on the left hand side of the chair, and the lower end portion of the right hand side plate 130 is positioned between two of the backrest slabs 16 on the right hand side of the chair, the lower end portions of the two side plates 130 being each formed with two apertures through which the two uppermost rods 18 pass as a close sliding fit.

The apron 118 comprises a sheet of washable waterproof material, for example plastics sheeting, of a size to cover the seat and backrest of the chair, the apron having slots 135, 136 for enabling the apron to fit around the side supports 115, 116. The ends of the apron are fitted with lengths of VELCRO webbing 123 (VELCRO is a Registered Trade Mark) for use in securing the apron to the chair.

The seat extension unit shown in Figure 5 comprises a rigid frame consisting of two parallel side members 135, 136 and two parallel rods (not shown) extending between the side members and detachably secured thereto by screws 86 which project through apertures in the side members and engage in threaded bores in the ends of the rods. The seat extension unit also comprises a cushion consisting of nine narrow laminar slabs 138 of resilient material juxtaposed side by side in a laminated formation between the side members 135, 136, each of the slabs 138 having two apertures through which the two rods interconnecting the side members 135, 136 extend as a close sliding fit. The three slabs 138 at the centre of the laminated formation of slabs project above the upper surfaces of the other slabs 138 to form an abduction block 139. The side member 135 is made from a sheet of thermo-plastics material vacuum-formed in a mould to the shape shown in Figure 5 and comprises a channel section 140 extending along the upper edge of the side member 135, around the front edge thereof, and along the lower edge of the side member 135, and a channel section 141 extending along the centre of the rear portion of the side member, the two channel sections 140, 141 having the open sides thereof facing inwards towards the opposite side member 136. The remainder of the side member 135 enclosed by the channel sections consists of a flat wall 142 on the inner side of the side members and cylindrical recesses for reception of the ends of the rods interconnecting the side members 135, 136. The side member 136 is similar in construction to the side member 135 but is a mirror image thereof, and comprises a channel section 145 extending along the upper edge of the side member 136, around the front edge thereof, and along the lower edge of the side member 135, and a channel section 146 extending along the centre of the the rear portion of the side member, the two channel sections 145, 146 having the open sides therof facing inwards towards the opposite side member 135. The remainder of the side member 136 enclosed by the channel sections consists of a flat wall 147 on the inner side of the side members and cylindrical recesses for reception of the end of the rods interconnecting the two side members. The rods interconnecting the two side members 135, 136 are of a length such that the slabs 138 are compressed between the flat walls 142, 147 of the side members 135, 136. The side member 135 is dimensioned so that the channel section 140 on the upper and lower edges of the side member 135 are a close sliding fit on the channel sections 30, 31 respectively on the seat limb 26 of the chair of Figures 1 and 2, and the side member 136 is dimensioned so that the channel section 145 on the upper and lower edges of the side members 136 are a close sliding fit on the channel sections 60, 61 respectively on the seat limb 56 of the chair of Figures 1 and 2.

In use, the seat extension unit is mounted on the chair of Figures 1 and 2 with the side members 135, 136 engaged as a telescopic fit on the seat limbs 26, 56 of the chair. The seat extension unit is adjusted to any desired position within the range of the telescopic movement and then located in position by drilling holes through the walls of the seat limbs of the chair and the side members of the seat extension unit and inserting pins through the aligned holes.

The upper surfaces of the slabs 138 on either side of the abduction block 139 are then approximately level with the upper surfaces of the seat slabs 12 on the chair, and the legs of an occupant in the chair are separated by the abduction block 139.

The footrest extension unit shown in Figure 6 comprises a rigid frame consisting of two similar side members 150, 151 of a cranked configuration lying one in each of two parallel planes and in opposing relation, the side member 150 having a vertical portion 152, an upper horizontal portion 153 projecting rearwardly from the upper end of the vertical portion 152, and a lower horizontal portion 154 projecting forwardly from the lower end of the vertical portion 152, the side member 151 having a vertical portion 155, an upper horizontal portion 156 projecting rearwardly from the top of the vertical portion 155, and a lower horizontal portion (not shown, but similar in construction to the lower horizontal portion 154 of the side member 150) projecting horizontally forwards from the lower end ofthe vertical portion 155, and two parallel rods (not shown) extending between the lower horizontal portions and detachably secured thereto by screws 86 which project through apertures in the lower horizontal portions and engage in threaded bores in the ends of the rods. The footrest extension unit also comprises a cushion consisting of nine narrow laminar slabs 158 of resilient material juxtaposed side by side in a laminated formation between the lower horizontal portions of the two side members 150, 151, each of the slabs 158 having two apertures through which the two rods interconnecting the lower horizontal portions extend as a close sliding fit.

The side member 150 is made of thermo-plastics material vacuum-formed in a mould to the shape shown in Figure 6. The junction between the vertical portion and the upper horizontal portion comprises an annular channel 160 having the open side thereof facing inwards towards the other side member 151 and a circular wall 161 on the inner side of the side member 151.

The junction between the vertical portion and the lower horizontal portion comprises an annular channel 162 having the open side thereof facing inwards, and a circular wall 163 on the inner side of the side member.. The vertical portion 152 comprises two parallel channel sections 164, 165 having the open sides thereof facing inwards towards the other side member, and a flat wall 166 between the two channel sections 164, 165. The upper horizontal portion 153 has a cross section similar to that of the rear end of the side member 135 of the seat extension unit of Figure 5, and the lower horizontal portion 154 has a cross section similar to the front end portion of the side member 135 of the seat extension unit. The side member 151 is similar in construction to the side member 150 but is a mirror image thereof. The rods interconnecting the two lower horizontal portions of the two side members are of a length such that the slabs 158 are compressed between the the two lower horizontal portions. The side members 150, 151 are dimensioned so that the upper horizontal portions 153, 156 are a telescopic fit on the seat limbs 26, 56 in the manner already described in the fitting of the seat extension unit to the chair.

The knee block extension unit shown in Figure 7 comprises two parallel side members 180, 181 interconnected at the front ends thereof by a cross member 182, and a block of foam plastics material 183 extending between the side members 180,181 and to the rear of the cross member 182. The rear face of the block 183 is formed with two spaced apart semi-cylindrical recesses 184. The side members 180, 181 have cross sections similar to those of the rear end portions of the side members 135, 136 of the seat extension unit of Figure 5 and are a telescopic fit on the seat limbs 26, 56 of the chair. In use, the knee block extension unit is mounted on the seat limbs of the chair in a position in which the knees of the occupant of the chair are held in the recesses 184 in the block 183.

The pushchair of Figure 8 comprises two side frames 188 (only one of which is shown) and a length of canvas 189 extending between the side frames and forming the seat and backrest of the chair. Each side frame comprises a side member 191, a front leg 192 telescopically connected to the side member 191, and a rear leg 193. The bottom of the front leg is fitted with a wheel 194 and the upper end of the side member 191 is shaped to form a handle 195. The bottom of the rear leg 193 is fitted with a wheel 196 and the upper end ofthe rear leg is connected to a block 197 mounted on the side member 191. A side rail 198 for the seat of the pushchair is connected to the lower end portion of the side member 191 and a side rail 199 for the backrest is also connected to the side member 191, the adjacent side edge ofthe length of canvas 189 being wrapped around and secured to the rails 198, 199.

The chair according to the invention and fitted in the pushchair of Figure 8 has a construction similar to that of the chair of Figures 1 and 2, except that each seat limb is provided with a side lug 200 adjacent the front end thereof, each backrest limb is provided with an upper side lug 201 and a lower side lug 202, the lower portion of each circular boss at the junction of the two limbs is formed as a semi-cylindrical trunnion 203, and the heels on the two side members are omitted. The lugs 200, 201, 202 and the trunnions 203 project laterally outwards beyond the sides of the remainder of the chair. The chair of the invention is made to a size such that, when it is fitted in the pushchair, the side lugs 200 rest on the seat side rails 198, the upper side lugs 201 engage the backrest side rails 199, the lower side lugs 202 engage against the rear surfaces of the rear legs, and the trunnions 203 rest on the seat side rails 198 and the backrest side rails 199.

The chair shown in Figure 8 can conveniently be mounted on an open framework of any suitable construction designed to stand on the floor and having two V-shaped brackets one on each side of the framework for reception of the lugs 201 on opposite sides of the chair, and a cross bar adapted to support the seat of the chair when the lugs 201 are engaged in the Vshaped brackets.

The chair shown in an exploded perspective view in Figure 9 comprises a left hand side member 10, a right hand side member 11, parallel rods 14, 18, a bottom plate 20, and a backplate 21 identical to the corresponding components of the chair of Figure 2 described above, and like parts are denoted by like reference numerals in Figures 2 and 9. However, the seat and backrest of the chair of Figure 9 are formed by a cushion consisting of a wide central laminar slab 210 and two relatively narrow side laminar slabs 211 disposed one on each side of the central laminar slab 210, the three laminar slabs being juxtaposed side by side in a laminated formation between the side members, 10, 11. Each of the laminar slabs is made of a soft resilient foam plastics material. The central slab 210 is of L-shaped construction, one limb 212 of which forms part of the seat of the chair and the other limb 213 of which forms part of the backrest of the chair. Similarly each side slab 211 is of L-shaped construction, one limb 214 of which forms part of the seat of the chair and the other limb 215 of which forms part of the backrest of the chair. The seat limb 214 of each side slab 211 is formed with three apertures 220 through which the rods 14 pass as a sliding fit, and the backrest limb 215 of each side slab 211 is formed with four apertures 221 through which the rods 18 pass as a sliding fit.

The seat limb 212 of the central slab 210 is also provided with three apertures 222 through which the rods 14 pass, and the backrest limb 213 of the central slab 210 is provided with four apertures 224 through which the rods 18 pass in the assembled chair. The limbs 214, 215 of each side slab have a depth substantially greater than the depth of the limbs 212, 213 of the central slab, so that the upper edges of the seat limbs 214 of the side slabs project above the seat limb 212 of the central slab, and the front edges of the backrest limbs 215 of the side slabs project to the front of the backrest limb 213 of the central slab, so that in the assembled chair the upper surface of the seat has a profile with a shallow recess when viewed in vertical section, and the front surface of the backrest has a profile with a shallow recess when viewed in horizontal section. In addition, the apertures 222,224 in the central laminar slab are substantially larger than the apertures 220, 221 in the side laminar slabs so as to permit some freedom of movement of the central slab relative to the side slabs in directions perpendicular to the axes of the rods 14, 18 during assembly of the chair, and thereby permit a small degree of adjustment of the depth of the shallow recesses in the surfaces of the seat and backrest. The recessed profiles of the seat and backrest assist in holding a child centrally in the chair.

Figure 10 shows an exploded perspective view of the left hand side member 230 of a modified construction of the chair of Figures 1 and 2 in which the angle between the backrest and the seat is adjustable. This modified construction comprises a right hand side member (not shown) which is a mirror image of the left hand side member 230, cross members extending between the side members, and two cushions formed of laminar slabs between the side members, the cross members and laminar slabs being similar to those shown in Figures 1 and 2. The side member 230 of Figure 10 comprises a seat member 231 and a separate backrest member 232, each of the members 231 and 232 being made from a sheet of thermo-plastic material vacuum-formed in a mould. The seat member 231 comprises a circular boss 233 and a seat limb 234 projecting forwardly from the boss 233. The circular boss 233 comprises an annular channel 235 having the open side thereof facing inwards towards the laminar slabs, the remainder of the boss surrounded by the channel 235 forming a flat wall 236 on the inner side of the boss. The wall 236 has an aperture 237 offset from the radial centre of the wall. The seat limb 234 is identical to the seat limb 26 of Figures 1 and 2 and like parts are denoted by like reference numerals. The backrest member 232 comprises a circular boss 240 and a backrest limb 241 projecting upwardly from the boss 240. The circular boss 240 comprises an annular channel 242 having the open side thereof facing inwards towards the laminar slabs, the remainder of the boss surrounded by the cylinder 242 forming a flat wall 243. The radially outer wall of the annular channel 242 has an axial length greater than that of the radially inner wall thereof. The annular channel 242 is of a size to be a close rotational fit within the annular channel 235 in the seat member with the wall 243 on the backrest member engaged flat against the wall 236 on the seat member., and the flat wall 243 is formed with an arcuate slot 244 arranged to register with the aperture 237 in the wall 236 of the seat member when the channel 242 is engaged in the channel 235. A screw 245 with a knurled head 246 extends through the aperture 237, the arcuate slot 244, and a washer 247, and is fitted with a screwthreaded nut 248, the screw and nut being operable to clamp the wall 236 on the seat member against the wall 243 on the backrest member, and thereby lock the backrest to the seat. In this modified construction of the chair of Figures 1 and 2, the angle between the backrest and the seat may be varied as desired by slackening the screws 246 by hand, angular moving both the backrest members simultaneously together with the associated cross members and cushion relative to the seat members to the desired angular setting within the range permitted by movement of the screws 245 within their respective arcuate slots 244, and then tightening the screws 246. The rear ends of the laminar slabs forming the seat cushion and the bottom ends of the laminar slabs forming the backrest cushion must of course be shaped to permit angular movment of the backrest members 232 relative to the seat members 231.

Claims

CLAIMS:

1. A chair comprising two side members interconnected by cross members to form a rigid frame, and a cushion of resilient material supported on the cross members and providing the seat of the chair, wherein the cushion is positioned between the side members with the cross members extending through openings in the cushion.

2 A chair as claimed in claim 1, wherein the cross members are detachably secured to the side members, whereby the chair may readily be dismantled by detaching the the side members from the cross members and withdrawing the cross members through the openings in the cushion.

3. A chair as claimed in claim 1 or 2, wherein the two side members and the cushion are shaped so that the cushion provides both the seat and a backrest for the chair.

4. A chair as claimed in claim 1 or 2 and provided with two cushions of resilient material, one cushion being positioned between lower portions of the side members and forming the seat of the chair, the cross members connecting the lower portions of the side members extending through openings in said one cushion, and the other cushion being positioned between upper portions of the side members and forming a backrest for the chair, the cross members connecting the upper portions of the side members extending through openings in said other cushion.

5. A chair as claimed in claim 4, wherein the upper and lower portions of each side member are separate components, with the upper portion of each side member pivotally connected to the lower portion thereof, and locking means are operable to lock the upper portion of each side member at any desired angular setting relative to the lower portion thereof within the range of angular movement therebetween, whereby the angular position of the backrest cushion relative to the seat cushion may be adjusted as required.

6. A chair as claimed in claim 1 or 2 and provided with two cushions of resilient material, one cushion forming the seat of the chair and the other cushion forming a backrest, wherein each side member comprises a seat limb, a backrest limb pivotable relative to the seat limb, and means for locking the backrest limb at any desired angular setting relative to the seat limb within the range of movement therebetween, the seat limbs of the two side members being interconnected by at least two of said cross members extending through openings in the cushion forming the seat, and the backrest limbs of the two side members being interconnected by at least two of said cross members extending through openings in the cushion forming the backrest, whereby the angular position of the backrest cushion relative to the seat cushion may be adjusted as required..

7. A chair as claimed in any of claims 1 - 6, wherein the components of the chair are so dimensioned that the or each cushion is compressed between the side members in the assembled chair.

8. A chair as claimed in any of claims 1 - 7, wherein the or each cushion comprises laminar slabs of the resilient material arranged side by side in a laminated formation with the edge surfaces of the slabs co-operating to form at least part of the seating surface of the chair, each laminar slab having openings for passage of the associated cross members.

9. A chair as claimed in claim 8 as appendant to claim 3, wherein the laminar slabs are contoured so that their edge surfaces co-operate to provide the seat and a backrest for the chair.

10. A chair as claimed in claim 8 or 9, wherein the laminar slabs are provided with apertures and the cross members are a sliding fit in said apertures.

11. A chair as claimed in claim 8 or 9, as appendant to claim 7, wherein at least some of the laminar slabs are provided with apertures of a size to permit freedom of movement of such slabs, relative to cross members extending through the apertures, in directions transverse to the axes of the cross members during assembly of the chair, to permit adjustment of the profile of the seating surface of the chair.

12. A chair as claimed in claim 8, wherein the or each cushion comprises a central laminar slab and two side laminar slabs arranged one on each side of the central slab, each of the side slabs having a width substantially smaller than the width of the associated central slab and a depth substantially greater than the depth of the associated central slab, the arrangement being such that the side slabs of the or each cushion project to the front or above the central slab of the cushion.

13. A chair as claimed in claim 12, wherein the side slabs have apertures which receive the associated cross members as a close sliding fit, and the central slab of the or each cushion has large apertures for the associated cross members so as to permit freedom of movement of the central slab relative to the cross members in directions transverse to the axes of the cross members during assembly of the chair, to permit adjustment of the profile of the seating surface of the chair.

14. A chair as claimed in any of the preceding claims, wherein the or each cushion is made of a soft resilient foam plastics material.

15. A chair as claimed in any of claims 1 - 14, wherein a bottom plate is arranged below the cushion or part thereof forming the seat of the chair, the bottom plate being detachably mounted on the side members and in contact with the cushion.

16. A chair as claimed in any of claims 1 - 15, wherein a backplate is arranged behind the cushion or part thereof forming a backrest of the chair, the backplate being detachably mounted on the side members and in contact with the cushion.

17. A chair as claimed in claim 15 or 16, wherein the side members are formed with inwardly facing channels and the side edges of the or each of the bottom plate and backplate are engaged in an opposing pair of said channels.

18. A chair as claimed in any of claims 8 - 13 and provided with side supports arranged to engage opposite sides of the trunk of an occupant in the chair and hold the trunk in an upright position, wherein the side supports are mounted on one or more of the cross members and each comprises a plate positioned between an adjacent two of the laminar slabs forming the backrest and projecting forwardly to the front of the backrest.

19. A chair as claimed in any of claims 8 - 13 and provided with a headrest arranged to hold the head of an occupant in the chair in an upright position, wherein the headrest is supported on two side plates mounted on one or more of the cross members, each side plate being positioned between an adjacent two ofthe laminar slabs forming the backrest and projecting upwardly above the backrest.

20. A chair as claimed in any of the preceding claims, wherein the side members are made of thermo-plastic material vacuum-formed in a mould.

21. A chair as claimed in claim 20, wherein each side member comprises a boss, a seat limb projecting forwardly from the boss, a backrest limb projecting upwardly from the boss, and a heel projecting rearwardly from the boss.

22. A chair as claimed in claim 20 or 21, wherein the ends of the cross members are engaged as a close fit in recesses in the side members, the cross members being secured to the side members by screw-threaded means extending through apertures in the bases of the recesses.

23. A chair as claimed in any of claims 8, 9 or 10, and tailored to accommodate a physically disabled child in a therapeutically desirable seating posture, wherein the edge surfaces of the laminar slabs are contoured to define a seat cavity of a size and shape to receive the pelvic and lower spinal regions of the intended occupant as a close fit therein when the intended occupant is in the desired seating posture.

24. A chair as claimed in claim 18, 19 or 23, wherein the edge surfaces of the laminar slabs defining the centre portion of the chair are contoured to provide an abduction block for separating the thighs of the intended occupant.

25. A chair as claimed in any of the preceding claims and provided with an extension unit mounted on the side members of the chair, the extension unit comprising a rigid frame having two opposing side members and cross members secured to and extending between the opposing side members, and a cushion of resilient material supported on the cross members, the cushion being positioned between the side members with the cross members extending through openings in the cushion, the cushion of the extension unit forming an extension to the seat of the chair..

26. A chair as claimed in any of claims 1 - 24 and provided with an extension unit mounted on the side members of the chair, the extension unit comprising two opposing side members of cranked configuration, each having an upper portion, a central portion, and a lower portion, and cross members secured to and extending between the lower portions of the opposing side members, and a cushion of resilient material mounted on the cross members, the cushion being positioned between the lower portions of the side members and the cross members extending through openings in the cushion, the cushion of the extension unit forming a foot rest for an occupant in the chair.

27. A chair as claimed in claim 25 or 26 in which the cushion of the extension unit comprises a plurality of laminar slabs of the resilient material, the slabs being arranged side by side in a laminated formation between the side members of the extension unit with the cross members extending through openings in the laminar slabs.

28. A chair as claimed in claim 27 as appendant to claim 25, wherein the laminar slabs at the centre of the extension unit project above the remaining slabs of the extension unit and form an abduction block for separating the thighs of an occupant in the chair.

29. A chair as claimed in any of claims 25 - 28, wherein the side members of the extension unit are mounted as a telescopic fit on the side members of the chair.

30. A chair as claimed in any of the preceding claims and mounted on a pushchair having a seat of flexible strip material supported on a frame, wherein the side members of the chair have outwardly projecting lugs which engage the frame of the pushchair and support the chair on the framework.

31. A chair as claimed in any of the preceding claims and substantially as hereinbefore described with reference to any of the accompanying drawings.