GB1576407A - Assessment chair - Google Patents

Description

(54) ASSESSMENT CHAIR (71) I, MALCOLM JOHNSTON, a British subject of 46 Ladbroke Square, London W11 3ND, do hereby declare the invention, for which I pray that a patent may be granted to me and the method by which it is to be performed, to be particularly described in and ay the following statement: The present invention relates to an assessment chair for measuring the requirements of an individual and also to a method of constructing a working chair in accordance with the specific dimensional requirements of the user.

There are many people for whom a ready made chair will not provide the support which they require. Invalids in particular have special requirements but there are also many other people, who would ndt be classified as invalids, who have special support requirements and who need a purpose built working chair. By a working chair, is meant a chair for exercising or for everday use by an individual which will meet the specific support requirements of the user.

Building a special chair to meet an individual's requirements is expensive and therefore in many cases not practical. It is therefore an object of the present invention to provide as assessment chair which will enable the requirements of an individual to be measured and recorded. A working chair for everyday use can then be constructed in accordance with the specific dimensional requirements of the user from a range of standardised components to provide a working chair which will give the specific support requirements of the individual.

In accordance with one aspect of the present invention, there is provided an assessment chair for measuring the requirements of an individual, comprising a frame including two upstanding pillars, and chair components including a seat, a backrest and two arm rests, wherein the chair components are each mounted on the upstanding pillars so as to be vertically adjustable along the pillars and are each rotatable about a horizontal axis, and wherein scales are provided on the chair for indicating the vertical and angular position of each of the chair components.

In accordance with a further aspect of the present invention, there is also provided a method of constructing a working chair by measuring the specific dimensional requirements of the user on an adjustable assessment chair as defined above, selecting components including a seat, a backrest and two arm rests from a range of standardised components in accordance with the measured requirements of the user and building the working chair from the selected components, comprising the steps of:: sitting the user in the assessment chair, adjusting the vertical and angular positions of the seat, the backrest and the arm rests of the assessment chair to fit the requirements of the user; taking measurements from the scales of the assessment chair of the vertical and angular positions of each of the seat, backrest and arm rests; selecting components including a seat, a back rest and two arm rests from a range of standardised components in accordance with the measurements so obtained and constructing the working chair from the components so selected.

A preferred form of the present invention will now be described with reference to the accompanying drawings in which: Figure 1 is a side elevation of a measuring chair in accordance with the present invention, Figure 2 is a front elevation of the chair shown in Figure 1, Figure 3 is a plan view of the frame of the chair shown in Figures 1 and 2, Figure 4 is a section through a detail of the frame shown in Figure 3, Figure 5 is a side elevation of the seat of the chair of Figures 1 and 2, Figure 6 is a front elevation of the seat shown in Figure 5, Figure 7 is a plan view partly cut away of the seat shown in Figure 5, Figure 8 is a side elevation of the lower part of the backrest of the seat shown in Figures 1 and 2, Figure 9 is a front elevation of the back shown in Figure 8 Figure 10 is a plan view of the back rest shown in Figure 8, Figure 11 is a section taken on the line XI- XI of a part of the backrest of Figure 9, Figure 12 is a side elevation of one of the arm rests of the seat shown in Figures 1 and 2, Figure 13 is a front elevation of the two arm rests of the seat shown in Figures 1 and 2, Figure 14 is a plan view of Figure 13, Figure 15 is a section taken on the line XV - XV in Figure 14, Figure 16 is a section taken on the line XVI - XVI in Figure 13, Figure 17 is a section taken on the line XVII - XVII of Figure 16, Figure 18 is a plan view partly in section showing a detail of the locking mechanism of the seat assembly of the chair, Figure 19 is a side elevation, partly in sec tion of the locking mechanism shown in Fig ure 18, Figure 20 is an elevation, partly in section showing a detail of the locking mechanism of Figures 18 and 19 and Figure 21 is a section taken on the lineXXI - XXI of Figure 18.

In the drawings, a measuring chair is indi cated generally at 10. The chair 10 comprises a frame assembly 11, a seat assembly 12, an arm rest assembly 13 and a back rest assem bly 14.

The frame assembly 11 comprises three U-shaped frame elements 15, 16 and 17.

Each of the frame elements comprises two parallel legs 18,19,20,21 and 22, respec- tively joined by web portions 24, 25 and 26.

The web portions 24, 25 and 26 are attached together, as shown in Figure 4 by two con- nector assemblies 27 and 28 respectively.

Each web portion is provided with a connec tor sleeve 29, 30 and 31 respectively, each of which is brazed to the frame element. A threaded pin 32 is passed through the con nector sleeves 30 and 31 and threadedly engaged with the connector sleeve 29 to attach the three frame elements together.

Frame elements 15 and 16 are positioned horizontally so as to form a floor standing support for the frame assembly and the legs 22 and 23 of the frame element 17 extend upwardly at an angle of 22.5 to the vertical to form support pillars for the seat assembly, the back assembly and the arm rest assembly.

The ends of the legs of the frame elements are closed by suitable natural or synthetic rubber or plastics caps 33 and the legs 18 and 19 of the frame element 15, which project forwardly of the chair 10 incorporate extension members 34 which are telescopically extensible from the legs 18 and 19 respectively and lockable in a manner which is not shown in the drawings.

Each of the support pillars 22 and 23 is formed with a row of apertures 36 in its back face for incremental adjustment of the position of the seat, back and arm rest assemblies. The front surface of the pillar 22 has a scale 37 enabling the vertical position of each of the assemblies mounted on the support pillars to be quickly and easily read and recorded.

The seat assembly 12 comprises a substantially flat seat 40 which is supported on and attached to two similar slide assemblies 41 and 42. As the slide assemblies 41 and 42 are similar, only the slide assembly 41 will be described in detail. The slide assembly 41 comprises two similar, channel section slide rails 43 and 44 which are arranged back to back and which are attached to the underside of the seat 40. The slide rails 43 and 44 slide on blocks 45 and 46 respectively which are attached to side brackets 47 and 48. The side brackets 47 and 48 are rigidly mounted on a seat assembly cross-bar 49.

The cross-bar 49 carries sleeves 50 and 51 at its opposite ends which are mounted for sliding adjustment on the support columns 22 and 23. A locking assembly 53 is provided adjacent each sleeve 51 and 52 which enables the cross-bar 49 to be vertically and rotationally adjusted and locked in position.

The locking mechanism 53 is shown in detail in Figures 18 to 21 and will be described more fully below. Each locking mechanism 53 is protected by a plastics cover 54.

The seat 40 is formed with two elongate slots 55 and 56 adjacent the back edge of the seat to provide a hand grip on the seat. The lever 57 is pivotally mounted on a pin 58 so that movement of a knob 59 on one end of the lever in the direction of the arrow 'a' causes movement of the opposite end 60 of the lever in the direction of arrow 'b'.

Attached to the end 60 of the lever 57 is a wire 61 which is anchored at its opposite end by a clamp 62 to the underside of the seat.

The wire 61 passes through a link 63 which is attached to a pin 64. The pin 64 is biassed inwardly and passes through the side bracket 48, through the adjacent slide block 46 and locates in one of a series of apertures (not shown) which are formed in the web of the slide rail 44. Manual depression of the knob 59 in the direction of the arrow 'a' causes the wire 61 to lift the pin 64 out of engagement with the aperture in the slide rail and frees the slide rail and seat for movement relative to the slide, blocks 45 and 46 and cross-bar 49. The spacing of the slide assemblies 41 and 42 and the positioning of the slots 55 and 56 in the seat is such that the knobs 59 and the two slide assemblies can be depressed simultaneously with the thumb of each hand so as to provide a quick and easy method of releasing the slide assemblies for movement of the seat.

A scale 65 is provided on the upper surface of the seat 40 and adjacent a side edge of the seat. The scale 65 enables the position of the seat in relation to the cross-bar 49 to be quickly and easily read and recorded. Preferably, the cross-bar 49 is provided with a spot or arrow to indicate the exact position of the seat.

Each of the sleeves 50 and 51 is provided with a handle 66, having a knob at one end to make the handle easy to grasp. The handle 66 is shown in detail in Figure 20. A pin 67 is mounted slidably in a recess in the handle 66 so as to project into the bore of the sleeve.

The pin 67 is normally biassed into the sleeve by a spring 68 and can be withdrawn against the action of the spring by a manually movable knob 69 which projects outwardly of the handle 66. The pin 67 normally located in one of the apertures 35 or 36 on the support column to lock the seat assembly in position.

In order to move the seat assembly the handles 66 are grasped, the knobs 69 are withdrawn with the thumb of each hand and the seat assembly can then be moved up or down on the support pillars 22 and 23. When the seat assembly is in the desired position, the knobs 69 are released and the pins 67 locate in the nearest holes in the support columns.

The back assembly 14 which is shown in detail in Figures 8 to 11 comprises a plurality of back rest'unites 70, 71, 72 each of which comprises a back panel 73 attached to two tubular supports 74 and 75. The width of the back rest assembly may be varied by using any combination of the narrow panels 73 and the wide back rest panels 73a. The tubular supports 74, 75 of each back rest unit have spigots 76 projecting outwardly from their bottom ends, which spigots locate in the upper end of the tubular supports enabling the back to be built up, as shown in Figure 11 by a plurality of back rest units.

The tubular supports 74 and 75 of the bottom back rest unit 73 are rigidly attached, by brazing or any other suitable means to a back rest cross-bar 77 so that the back rest, comprising the back rest units 70, 71, 72 extends upwardly from the cross-bar 77. The bottom backrest unit 73 is attached to the cross-bar 77 in such a way that the back rest normally extends upwardly approximately vertically from the cross-bar 77. Tubular sleeves 78 and 79 are attached to the ends of the cross-bar 77. The sleeves 78 and 79 are mounted on the support pillars 22 and 23 similarly to the sleeves of the seat cross-bar 49 and each sleeve is provided with a handle 66 and similar in all respects to the handles 66 on the seat assembly. Each sleeve is also provided with a locking mechanism 53 which is covered by a cover 54.

The arm rest assembly 1 3 which is shown in Figures 12 to 17 comprises two arm units 80 and 81 which are similar and which are mounted for horizontal sliding adjustment along and angular rotation with an arm rest cross-bar 82. As the arm rest units 80 and 81 are similar, only the arm rest unit 80 will be described in detail. The arm rest unit 80 comprises a T-section arm rest 83 which is rigidly attached to a pair of channel section slide rails 84 and 85. The slide rails 84 and 85 are arranged back to back against the stem of the T-section arm rest 83 and slide on fixed slide bars 86 and 87 respectively. The slide bars are rigidly attached to side brackets 88 and 89 respectively which are in turn rigidly attached to a sleeve 90.

The arm rest 83 and rails 84, 85 can be slidably moved relative to the slide bars 86 and 87 and can be locked in position by a pin 91 having a knob 92 at its outer end. The pin 91 extends through an aperture 93 in the outer side brackeh 89, through a bore in the slide bar 87 and into one of a series of apertures 94 formed in the web of the slide rail 83. The pin 91 is normally urged towards the web of the slide rail 83 by a compression spring 95 and can be manually withdrawn against the bias of the spring and out of engagement with the aperture 94.

The sleeve 90 is mounted on the cross-bar 82 for sliding engagement relative to the cross-bar but is keyed to the cross-bar so that it rotates with the cross-bar. The sleeve 90 is formed with an aperture 96 through which a pin 97 projects. The outer end of the pin 97 is provided with a knob 98 and the inner end of the pin projects through a slot 99 formed in the cross-bar 82. The slot 99 is formed with a plurality Qf arcuate recesses 100. A tab 101 having a stepped flange 102 is attached to the sleeve 90 so that the flange 102 overlies the end of the pin 97. The flange 102 is fomed with an aperture 103 and the end of the pin 97 locates in the aperture 103. The pin 97 is also formed with a shoulder 104 of a diameter such that it will locate as a close fit in the recesses 100 in the cross-bar 82.A spring 105 normally urges the pin 97 radially outwardly so that the shoulder 104 locates within one of the recesses 100 to lock the sleeve 90 in position against sliding movement, relative to the cross-bar 82. In order to move the sleeve lengthwise relative to the cross-bar 82, the knob 98 is pushed radially inwardly so that the spring 105 is compressed and the shoulder 104 is moved radially inwardly out of engagement with the recess 100 in the cross-bar. The sleeve 90 can then be moved the full length of the slot 99 in the cross-bar 82 and can be locked in any one of the positions determined by the location of the recesses 100.

Tubular sleeves 106 and 107 are provided at the ends of the cross-bar 82 to enable the cross-bar 82 to be slidably and lockably mounted on the support pillars 22 and 23.

Each sleeve 106 and 107 is provided with a handle 66 and an associated locking mechanism 53 protected by a cover 54.

Each arm 80 and 81 is provided on its upper surface with a scale 108 which enables the extent to which each arm projects forwardly from the cross-bar 82 to be read and recorded. A scale 109 is also provided on the front face of the back rest panel 73a from which the lateral position of each arm can also be read and recorded.

The locking mechanism 53 which is provided at each end of the cross-bar of the seat assembly, arm rest assembly and back assembly to control the position and locking of the assemblies on the support columns 22 and 23 will now be described in greater detail with reference in particular to Figures 18 to 21. The mechanism comprises an end plate 110 which is brazed or otherwise attached to an end of the cross-bar for instance, the cross-bar 49, as shown in Figures 18 and 19.

The end plate 110 is formed with a circular aperture 111 and two diametrically opposite slots 112 and 113. The end plate 110 is also formed with a second circular aperture 114.

The sleeve 51 is mounted on the cross-bar 49 with the aid of a part circular back plate 115 which is brazed or otherwise attached to the sleeve 51. The back plate carries a lug 116 and spaced from the lug 1 16 is a fixed pin 117 which is mounted on the sleeve 51. The lug 116 carries a projecting spigot 118 which extends into the aperture 111 in the end plate 110 and serves as the pivot for rotation of the cross-bar relative to the sleeve. The spigot 118 also carries two projecting pins 119 and 120 which are locatable through the slots 112 and 113 in the end plate 110 so as to retain the spigot 118 in position through the aperture 111 once the cross-bar has been rotated to move the pins 119 and 120 out of registry with the slots 112 and 113.

Mounted for rotation on the pin 117 is a quadrant plate 121 which is formed with a slot 122 and a plurality of apertures 123 which are arranged on an arc centred on the pivot pin 117 and coincident with the axis of the cross-bar 49. Rotatably mounted through the aperture 114 in the end plate 110 is a connecting pin 125 which has an end formed with flats 126 and which locates in the slot 122 in the quadrant 121.

Located within the cross-bar 49 and extending through the spigot 118 is a pin 130. The pin 130 is connected to a wire 131 which in turn is connected to a resiliently loaded pin 132. The pin 132 extends transversely through the wall of the cross-bar 49 approximately at the centre of the cross-bar and terminates in a knob 133. A similar arrangement is provided for the locking mechanism 53a at the opposite end of the cross-bar 49 and the two wires, 131 and 13 lea are linked by a spring 134 which normally urges each wire 131 and 131a outwardly so as to urge the pin 130 through the spigot 118 and against the quadrant 121. As the pin 130 is located on the axis of the cross-bar 49, it is in register with the apertures 123 in the quadrant and will normally locate in one of the apertures thereby locking the cross-bar 49 against rotation relative to the sleeve 51.

The locking mechanism operates in the following manner. If it is desired to rotate the cross-bar 49 and thereby adjust the angle of the seat assembly 12, the two knobs 133 and 133a are grasped manually and squeezed together. This has the effect of withdrawing the pins 130 and 130a inwardly and away from the quadrants 121. Withdrawal of the pin 130 from an aperture 123 in the quadrant 121 enables the end plate 110 and the crossbar 49 to pivot about the spigot 118. Rotation of the cross-bar 49, through the connection between the pin 125 in the slot 122 in the quadrant, causes rotation of the quadrant about the pin 117.When the seat assembly 12 is adjusted to the correct new angular position, the knobs 133 and 133a are released thereby allowing the pin 130 of each locking mechanism 53 and 53a to move outwardly under the action of the spring 134 and into register and engagement with an aperture 123 in the quadrant 121. This again locks the cross-bar 49 in its new position against any further relative rotation.

The outer face of each cover plate 54 on the pillar 22 is provided with a scale 135 and the adjacent cross-bar or sleeve such as 49 is provided with an arrow or other mark which enables the angular position of each crossbar to be read and recorded.

The method of measuring the requirements of an individual with the air of the assessment chair 10 and then constructing a working chair for the individual will now be described in detail.

The person for whom an individual working chair is required is first seated in the assessment chair 10. The various movable components of the assessment chair 10 are then adjusted to achieve the position which best suits the individual requirements of the person sitting in the chair. Specifically the following adjustments can be made: 1. The height of the seat assembly 12 can be adjusted by grasping the handles 66 of the seat assembly, withdrawing the locking pins 67 and sliding the whole seat assembly 12 up or down the support columns 22 and 23 to the correct position. If the person being measured is relatively light, it might be possible to adjust the position of the seat while the person is sitting in the chair.Normally however it will be necessary for the person to get up from the chair in order to adjust the position of the seat and this may have to be done several times before the correct position is found.

2. The angular position of the seat 40 can be adjusted by grasping and squeezing the pair of knobs 133 and 133a to release the cross-bar 49 and-allow rotation of the crossbar 49 relative to the support columns 22 and 23.

3. The extent to which the seat 40 projects from the support columns 22 and 23 can be adjusted by moving the two knobs 59 inwardly and sliding the seat into the required positon.

4. The height of the backrest assembly 14 can be adjusted in a similar manner to the seat assembly.

5. The angular position of the backrest assembly can be adjusted in the same manner as the angular position of the seat assembly.

6. The height of the arm rest assembly can be adjusted in the same manner as the seat assembly.

7. The angular position of the arm rest assembly can be adjusted in the same manner as the angular position of the seat assembly.

8. The spacing between the two arm rests can be adjusted by pressing one or both of the knobs 98 inwardly and sliding the arm rest and its associated sleeve 90 inwardly or outwardly relative to the cross-bar 82 to achieve the required spacing and positioning of each arm rest assembly.

9. The extent to which each arm rest projects forwardly relative to the backrest assembly can be adjusted by pulling the pin 92 of each arm rest outwardly and sliding the arm rest into its required position. When all of the required adjustments have been made, the position of each component is read from the scales 37, 65, 108,109 and 135. From these readings, standardised components for the construction of a working chair can be selected and a working chair built from the standardised components which will meet the specific requirements of the individual.

It is envisaged that the frame of the working chair will be made from a plurality of standard length frame members which will be built up in accordance with the readings to provide a chair frame of the correct length, width and depth. Further chair components, such as the seat, arms and back rest will then be attached to the frame in the correct position and at the correct angles. In this way, a working chair is built from selected components which will fit the specific support requirements of the individual.

It will be noted that the back rest assembly 14 is provided with some relatively wide back panels and some narrower back panels. This enables the arm rests to be brought inwardly towards one another so that they are located within the dimensions of the wider panels. It will also be appreciated that the construction of the back rest assembly enables the back rest to be built up by standard modules to any required height.

It is envisaged that a foot support may be attached to each leg 18 and 19 of the front frame element 15 but these have not been shown for simplicity. It is also envisaged that many other support members and support straps may be attached to the frame or to the chair components and readings taken of the position of each of these additional support members for incorporation in the working chair. These other supporting elements are particularly necessary for an invalid. In particular it is envisaged that attachment means will be provided for a groin pommel, groin straps, thigh supports, chest supports and chest straps. The position of these support elements will be incrementally adjustable and scales will be provided for readily reading the position of each support element on the frame.

In order to facilitate adjustment of the movable components of the chair 10, the internal surfaces of the sleeves attached to the ends of the cross-bars and the internal surfaces of the sleeves 90 and 91 are preferably lined with a low-friction material such as PTFE.

WHAT I CLAIM IS: 1. A assessment chair for measuring the requirements of an individual comprising a frame including two upstanding pillars and chair components including a seat, a back rest and two arm rests, wherein the chair components are each mounted on the upstanding pillars so as to be vertically adjustable along the pillars and are each rotatable about a horizontal axis and wherein scales are provided on the chair for indicating the vertical and angular position of each of the chair components.

2. An assessment chair as claimed in claim 1, wherein each of the chair components is incrementally adjustable vertically and angularly and lockable in each of a plurality of positions.

3. An assessment chair as claimed in claim 1 or claim 2 wherein each of the chair components is mounted on a cross-bar which is slidably mounted on the pillars and rotatable about its own axis.

4. An assessment chair as claimed in claim 3, wherein each cross-bar is associated with a locking mechanism.

5. An assessment chair as claimed in claim 4, wherein the locking mechanism comprises a first element rotatable with the cross-bar, a second element rotatable relative to the cross-bar about an axis offset from

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (15)

**WARNING** start of CLMS field may overlap end of DESC **. measured is relatively light, it might be possible to adjust the position of the seat while the person is sitting in the chair. Normally however it will be necessary for the person to get up from the chair in order to adjust the position of the seat and this may have to be done several times before the correct position is found. 2. The angular position of the seat 40 can be adjusted by grasping and squeezing the pair of knobs 133 and 133a to release the cross-bar 49 and-allow rotation of the crossbar 49 relative to the support columns 22 and 23. 3. The extent to which the seat 40 projects from the support columns 22 and 23 can be adjusted by moving the two knobs 59 inwardly and sliding the seat into the required positon. 4. The height of the backrest assembly 14 can be adjusted in a similar manner to the seat assembly. 5. The angular position of the backrest assembly can be adjusted in the same manner as the angular position of the seat assembly. 6. The height of the arm rest assembly can be adjusted in the same manner as the seat assembly. 7. The angular position of the arm rest assembly can be adjusted in the same manner as the angular position of the seat assembly. 8. The spacing between the two arm rests can be adjusted by pressing one or both of the knobs 98 inwardly and sliding the arm rest and its associated sleeve 90 inwardly or outwardly relative to the cross-bar 82 to achieve the required spacing and positioning of each arm rest assembly. 9. The extent to which each arm rest projects forwardly relative to the backrest assembly can be adjusted by pulling the pin 92 of each arm rest outwardly and sliding the arm rest into its required position. When all of the required adjustments have been made, the position of each component is read from the scales 37, 65, 108,109 and 135. From these readings, standardised components for the construction of a working chair can be selected and a working chair built from the standardised components which will meet the specific requirements of the individual. It is envisaged that the frame of the working chair will be made from a plurality of standard length frame members which will be built up in accordance with the readings to provide a chair frame of the correct length, width and depth. Further chair components, such as the seat, arms and back rest will then be attached to the frame in the correct position and at the correct angles. In this way, a working chair is built from selected components which will fit the specific support requirements of the individual. It will be noted that the back rest assembly 14 is provided with some relatively wide back panels and some narrower back panels. This enables the arm rests to be brought inwardly towards one another so that they are located within the dimensions of the wider panels. It will also be appreciated that the construction of the back rest assembly enables the back rest to be built up by standard modules to any required height. It is envisaged that a foot support may be attached to each leg 18 and 19 of the front frame element 15 but these have not been shown for simplicity. It is also envisaged that many other support members and support straps may be attached to the frame or to the chair components and readings taken of the position of each of these additional support members for incorporation in the working chair. These other supporting elements are particularly necessary for an invalid. In particular it is envisaged that attachment means will be provided for a groin pommel, groin straps, thigh supports, chest supports and chest straps. The position of these support elements will be incrementally adjustable and scales will be provided for readily reading the position of each support element on the frame. In order to facilitate adjustment of the movable components of the chair 10, the internal surfaces of the sleeves attached to the ends of the cross-bars and the internal surfaces of the sleeves 90 and 91 are preferably lined with a low-friction material such as PTFE. WHAT I CLAIM IS:

1. A assessment chair for measuring the requirements of an individual comprising a frame including two upstanding pillars and chair components including a seat, a back rest and two arm rests, wherein the chair components are each mounted on the upstanding pillars so as to be vertically adjustable along the pillars and are each rotatable about a horizontal axis and wherein scales are provided on the chair for indicating the vertical and angular position of each of the chair components.

2. An assessment chair as claimed in claim 1, wherein each of the chair components is incrementally adjustable vertically and angularly and lockable in each of a plurality of positions.

3. An assessment chair as claimed in claim 1 or claim 2 wherein each of the chair components is mounted on a cross-bar which is slidably mounted on the pillars and rotatable about its own axis.

4. An assessment chair as claimed in claim 3, wherein each cross-bar is associated with a locking mechanism.

5. An assessment chair as claimed in claim 4, wherein the locking mechanism comprises a first element rotatable with the cross-bar, a second element rotatable relative to the cross-bar about an axis offset from

the axis of the cross-bar in response to rotation of the cross-bar and a locking member associated with the cross-bar and adapted to lock the second element against rotation thereby locking the cross-bar.

6. An assessment chair as claimed in claim 5, wherein the locking member comprise a pin which is reciprocable on the axis of the cross-bar and normally biassed into engagement with the second element.

7. An assessment chair as claimed in claim 5 or claim 6 wherein a pin acts as a pivot for the cross-bar.

8. An assessment chair as claimed in any of claims 5 to 7, wherein the second element comprises a quadrant plate formed with a plurality of apertures arranged on an arc coincident with the axis of the cross-bar.

9. An assessment chair as claimed in claim 8, wherein the quadrant plate is keyed to the cross-bar for rotation therewith.

10. An assessment chair as claimed in any of claims 3 to 9, wherein a scale is provided for each cross-bar for indicating the angular position of the cross-bar.

11. An assessment chair as claimed in any of claims 3 to 10, wherein the seat is horizontally movable relative to a seat cross-bar and a scale is provided for indicating the position of the seat relative to the cross-bar.

12. An assessment chair as claimed in any of claims 3 to 11 wherein the arm rests are slidably mounted on an arm cross-bar so as to be individually movable horizontally relative to the arm cross-bar and scales are provided for indicating the position of each arm rest relative to the arm cross-bar.

13. A method of constructing a working chair by measuring the specific dimensional requirements of the user on an adjustable assessment chair as claimed in any of the preceding claims, selecting components including a seat, backrest and two arm rests from a range of standardised components in accordance with the measured requirements of the user and building the working chair from the selected components, comprising the steps of: : sitting the user in the assessment chair; adjusting the vertical and angular positions of the seat, the backrest and the arm rests of the assessment chair to fit the requirements of the user; taking measurements from the scales on the assessment chair of the vertical and angular positions of each of the seat, backrest and arm rests; selecting components including a seat, a backrest and two arm rests from a range of standardised components in accordance with the measurements so obtained and constructing the working chair from the components iso selected.

14. An assessment chair substantially as described herein with reference to the accompanying drawings.

15. A method of constructing a working chair as claimed in claim 13 and substantially as described herein.