GB2436930A

GB2436930A - Elevation chair

Info

Publication number: GB2436930A
Application number: GB0702547A
Authority: GB
Inventors: Roy Targonski
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-02-09
Filing date: 2007-02-09
Publication date: 2007-10-10
Also published as: GB0702547D0; GB0602572D0

Abstract

An elevation chair 1 comprised a seat 32 upon which, in use, a person is seatable and a drive device 4 to which the seat is operably connected, the drive device being operable to raise and lower the seat. The seat comprises at least one seat extension 33, 34 movable between a relatively extended position (Fig. 1), for increasing the load bearing surface area of the seat, and a relatively stowed position (Fig. 5). The seat extension may pivot or slide relative to the seat, and may include a fixing plate 36 through which a bolt B may extend to fix the position of the seat extension at two or more angular positions relative to the seat. The elevation chair may further comprise a substantially vertical post 22. Also disclosed are an elevation chair comprising a base having extended and stowed conditions, an elevation chair weighing less than 50kg and comprising a drive device located at least in part within a post, and an elevation chair being at least partially x-ray transparent and comprising a drive device located at least in part within a post.

Description

2436930

i

ELEVATION

The present invention relates generally to an elevation device. More specifically, but not exclusively, this invention relates to an elevation chair for lifting a person thereon.

10 Conventional elevation devices for lifting people generally comprise a hoist arrangement with chains and a sling. Such devices may be cumbersome in situations where there is insufficient space for manoeuvring. Moreover, these arrangements may be uncomfortable and/or undignified for the person.

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15 In order to overcome the aforementioned problems, elevation chairs have been developed which assist individuals to be manoeuvred from a floor level lying or partially seated position to an upright seated or standing position.

For example, GB 2296429 discloses an elevation chair having an inflatable seat and 20 comprising back and base portions hinged together and made of thin elongate bars. The person is manoeuvred onto the collapsed chair and the back portion of the chair is pivoted about the base portion thereby to urge the person into a partially seated position. The seat is then inflated to elevate the person to a fully seated position. This arrangement requires a separate compressed air supply, which may be 25 inconvenient and cumbersome in use.

EP 1275363 discloses an elevation chair having a frame and a seat which is raised or lowered relative to the frame by a drive mechanism. As the seat is elevated, a further mechanism causes it to incline forward, thereby manoeuvring the person into 30 a standing position. The arrangement disclosed in this document requires the person

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to be manoeuvred into a partially seated position before elevation can occur. This elevation chair design may also be cumbersome to transport due to its expansive base, heavy frame and two drive mechanisms. This elevation chair is currently marketed by Williams Rehab Equip Limited and is advertised as having an overall 5 weight of 64kg.

Consequently, there exists a need for an improved elevation device which addresses the aforementioned issues.

10 It is a non-exclusive object of the invention to provide an improved elevation device which facilitates manoeuvring a person from a lying or seated condition on a substrate to an elevated and seated or standing position.

It is another non-exclusive object of the invention to provide an improved elevation 15 device which facilitates elevating a person from a substrate to a raised surface.

It is a further, non-exclusive object of the invention to provide an elevation device which is robust, durable and reliable.

20 It is yet a further, non-exclusive object of the invention to provide an elevation device which is lightweight and portable.

It is yet a further, non-exclusive object of the invention to provide an elevation device which may be used for supporting a person undergoing x-ray procedures.

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One aspect of the invention provides an elevation chair comprising a seat upon which, in use, a person is seatabie and drive means, the seat being operably connected to the drive means, the drive means being operable to raise and lower the

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seat, wherein the seat comprises a seat extension which is movable between a relatively extended position for increasing the load bearing surface area of the seat and a relatively stowed position.

5 Preferably, the seat extension extends from a first edge of the seat.

Optionally, the elevation chair further comprises a further seat extension, which may extend from a second edge of the seat. Preferably, the seat extensions extend from opposing edges of the seat.

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Preferably, the, each or one seat extension is pivotable relative to the seat.

Optionally, the elevation chair further comprises fixing means for fixing the angular position of the, each or one seat extension relative to the seat. The fixing means 15 may comprise a fixing member and a fastener for securing the, each or one seat extension to the fixing member. Preferably, the fixing means is adapted to fix the position of the, each or one seat extension at two or more angular positions relative to the seat.

The, each or one seat extension may be slideable relative to the seat.

The, each or one seat extension may also comprise a primary and a secondary seat extension. Preferably, the secondary seat extension is moveable between an extended position and a stowed position relative to the primary seat extension. More preferably, the secondary seat extension is foldable or slidable relative to the primary seat extension.

Optionally, the elevation chair comprises a substantially vertical post.

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Preferably, the seat is moveable between an extended position and a stowed position relative to the post. Preferably, the seat is foldable relative to the post.

5 The elevation chair may further comprise a back portion, wherein the seat is foldable relative to the back portion.

Optionally, the elevation chair further comprises a base portion to which the post is secured. Preferably, the base portion comprises a cross member and at least one 10 leg member. More preferably, the at least one leg member is hinged to the cross member.

According to a further optional feature of the invention, the drive means is located, at least in part, within the post.

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Preferably, the drive means comprises a linear actuator. More preferably, the drive means comprises a prime mover and a ball screw assembly, the ball screw assembly being driveable by the prime mover.

The elevation chair may further comprise at least one wheel for moving the elevation chair on a substrate.

Preferably, the elevation chair further comprises an adjustable handle for manoeuvring the elevation chair.

Optionally, the elevation chair is at least partially x-ray transparent, to allow at least some x-ray radiation impinging thereon to pass therethrough. Preferably, the seat and seat extension are at least partially x-ray transparent.

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Preferably, the elevation chair weighs less than 50kg. More preferably, the elevation chair weighs less than 30kg. More preferably, the elevation chair weighs less than 20kg.

The drive means may be powered by a standalone power source, for example a battery.

A second aspect of the invention provides a collapsible elevation chair comprising a seat upon which, in use, a person is seatabie and a base, wherein the base has an extended condition for use and a stowed condition.

A third aspect of the invention provides an elevation chair comprising a seat upon which, in use, a person is seatabie, a post and drive means located, at least in part, within the post, the seat being operably connected to the drive means, the drive means being operable to raise and lower the seat relative to the post, the elevation chair weighing less than 50kg.

Preferably, the elevation chair weighs less than 30kg. More preferably, the elevation chair weighs less than 20kg.

A fourth aspect of the invention provides an elevation chair comprising a seat upon which, in use, a person is seatabie, a post and drive means located, at least in part, within the post, the seat being operably connected to the drive means, the drive means being operable to raise and lower the seat relative to the post, the elevation chair being at least partially x-ray transparent, to allow at least some x-ray radiation impinging thereon to pass therethrough.

Preferably, the seat and seat extension are at least partially x-ray transparent.

In order that the invention may be well understood, it will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a perspective view of an elevation chair of the invention with both seat extensions in a fully extended and horizontal position;

Figure 2 is a perspective view of the elevation chair of Figure 1 with one seat extension in a horizontal position and the other seat extension in a substantially vertical position;

Figure 3 is a perspective view of the elevation chair in the condition shown in Figure 2 with the chair in a fully lowered condition;

Figure 4 is a front view of the elevation chair in the condition shown in Figure 3 showing the outline of a user;

Figure 5 is a perspective view of the elevation chair of Figure 1 in a fully collapsed condition;

Figure 6 is a partial side view of the elevation chair of Figure 1 shown with an optional seat belt;

Figure 7 is a partial side view of a further embodiment of the elevation chair showing an alternative engaging means between the back portion and the seat;

Figure 8 is a partial front view of an alternative embodiment of the elevation chair in a fully lowered position showing the seat extensions in a stowed condition;

Figure 9 is a side view of a further embodiment of the elevation chair of the invention with a frame made up of T-cross sectional members;

Figure 10 is a cross-sectional view along line A-A of Figure 9; and

Figure 11 is a perspective view of a further embodiment of the elevation chair of the invention with seat extensions that are slideably retractable.

As shown in Figure 1, the elevation chair 1 includes a frame 2, a chair 3, a drive box 4 and manoeuvring handles 5.

The frame 2 is fabricated using tubular members made of aluminium with a substantially rectangular cross-section. The frame 2 includes a base portion 21 and a post portion 22. The base portion 21 includes three legs 23 and a cross beam 24. A wheel 28 is mounted to each end of the cross beam 24 and is rotatable about an axis corresponding to the longitudinal centre of the cross beam 24. A castor comprising a wheel 25 is connected to the terminal end of each leg 23, the castor being rotatable relative to the terminal end of the leg to allow movement of the elevation chair 1 on a substrate in any direction.

Each leg 23 is connected to the cross beam 24 by a hinge 26. When the legs 23 are in their extended position, as shown in Figure 1, each leg 23 is substantially perpendicular to the cross beam 24. A first leg 23 is hinged to the cross beam 24 such that it extends from the centre thereof in a first direction. The second and third

legs 23 are hinged to the cross beam 24 such that they extend from the ends thereof in a second direction which is opposite the first direction.

The front facing surface of the post portion 22 has a slot 27 along its length. The post portion 22 is fixedly connected to the cross beam 24 and extends from the centre thereof in a third direction substantially perpendicular to both the cross beam 24 and the legs 23. Each end of the cross beam 24 includes a brake lever 29 attached thereto which actuates a brake mechanism (not shown) thereby to prevent rotation of the relevant wheel 28.

The chair 3 includes a back portion 31, a seat 32 and two seat extensions 33a, 34a and 34b,34b. Each seat extension 33a, 34a and 33b, 34b include one primary seat extension 33a, 33b and one secondary seat extension 34a, 34b. The back portion 31 includes two fixing plates 36a, 36b secured thereto.

The back portion 31 is made of moulded plastics material, is substantially rectangular in plan and is shaped to conform to or approximate the shape of a user's back. The back portion 31 has a seat support portion 31a which extends from the lower edge thereof and is substantially perpendicular thereto (see Figures 6 and 7). Each fixing plate 36a, 36b is made of steel, has two straight edges which are substantially perpendicular to each other and an arcuate edge which intersects both of the straight edges. Two through holes are formed in each fixing plate 36a, 36b near the corners formed by the arcuate edge and each of the straight edges.

One of the straight edges of a first fixing plate 36a is secured to a first side edge of the back portion 31, with the second straight edge of the first fixing plate 36a lowermost the first plate 36a extending from the first side edge in a direction substantially parallel to the back portion 31. One of the straight edges of a second

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fixing plate 36b is secured to a second side edge of the back portion 31, with the second straight edge of the second fixing plate 36b lowermost, the second fixing plate 36b extending from the second side edge in a direction substantially perpendicular to the back portion 31.

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The seat 32, the primary seat extensions 33a, 33b and the secondary seat extension 34a, 34b are all made of moulded plastics material, are substantially rectangular in plan and are shaped to conform generically to a user.

10 Each of the primary seat extensions 33a, 33b comprises a flange 37a, 37b protruding from the top surface thereof and adjacent the back edge thereof. Each flange 37a, 37b is made of moulded plastics material and houses a steel insert having a threaded bore therethrough (not shown).

15 The seat 32 is connected to the back portion 31 by a main hinge 35, which is marginally offset from its back edge (see Figure 6). The primary seat extensions 33a, 33b are connected to the sides of the seat 32 by respective hinges 38a, 38b. Each of the secondary seat extensions 34a, 34b is connected to a respective primary seat extension 33a, 33b by a hinge 39a, 39b along the edge of the primary extension 20 33a, 33b opposite the edge thereof connected to the seat 32.

The aforementioned hinges 35, 38a, 38b, 39a, 39b are piano hinges which extend the length of the aforementioned abutting edges between the back portion 31, the seat 32, the primary seat extensions 33a, 33b and the secondary seat extensions 25 34a, 34b. The hinges 39a, 39b which connect the secondary seat extensions 34a, 34b to the primary seat extensions 33a, 33b are mounted and secured to the abutting edges such that the secondary seat extensions are only free to pivot toward the top

surface of the relevant primary seat extension 33a, 33b from the fully extended condition shown in Figure 1.

Each of the primary seat extensions 33a, 33b is secured to the respective fixing plate 36a, 36b by a bolt B which passes through one of the holes in the fixing plate 36a, 36b and into the threaded bore of the flange 37a, 37b. The angular position of the primary and secondary seat extensions 33a, 33b, 34, 34b is thereby fixed relative to the seat 32.

The angular positions of the seat extensions 33a, 34a and 33b, 34b relative to the seat 32 are independently adjustable. As shown in Figure 2, one of the seat extensions 33a, 34a may be fixed at a first angle substantially perpendicular to the seat 32, while the other seat extension 33b, 34b may be fixed at a second angle substantially parallel to the seat 32.

Alternatively, or additionally, one of the seat extensions 33b, 34b may be lowered to a substantially vertical position, without being secured to the fixed plate 36b.

The drive mechanism (not shown) is a linear actuator including an electric motor housed in the drive box 4 which drives a ball screw assembly (not shown) contained within the post portion 22 of the frame. The chair 3 is operably attached to the drive mechanism (not shown) by a securing member 6 (see Figure 6). The securing member 6 is fixed to the rear surface of the back portion 31, passes through the slot 27 in the post portion 22 of the frame 2 wherein it is connected to the driving mechanism (not shown) contained therein. The drive mechanism induces linear motion of the securing member 6 relative to the frame 2 along the length of the post portion 22.

Referring now to Figure 3, the chair 3 may be lowered to a position adjacent the base portion 21 of the frame 2. The width of the seat 32 is narrower than the space between the legs 23, thereby to allow the seat 32 to be lowered substantially adjacent the substrate. The primary seat extensions 33a, 33b each comprise a recess which provides space for the legs 23 to be located therein.

With the chair 3 in the lowered condition, the user may be moved on to the chair in a lying (not shown) or partially seated (Figure 4) position.

In use, the chair is preferably in the lowered condition with both seat extensions 33a, 34a and 33b, 34b in a horizontal position and adjacent the user. Both brake levers 29 are depressed to actuate the brakes. The user is then assisted onto the chair 3 and into lying position (not shown). The chair 3 may then be raised to a predetermined height, for example, corresponding to the length of the lower part of the user's legs.

The seat extension 33a, 34a adjacent the user's upper body is then released from the relevant fixing plate 36a by removing the relevant bolt B. The seat extension 33a, 34a is then pivoted about the relevant hinge 38a to the angular position in which the upper hole in the relevant fixing plate 36a is aligned with the threaded hole in the relevant flange 37a. The bolt B is then passed through the hole in the fixing plate 36a and secured in the flange 37a, thereby to secure the angular position of the seat extension 33a 34a and support the user in a partially seated position.

The seat extension 33b, 34b adjacent the user's legs is then released from the relevant fixing plate 36b by removing the relevant bolt B. The seat extension 33b, 34b is then pivoted about the relevant hinge 38b to a substantially vertical position such that the user is in a fully seated position.

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The user may then be rotated through 90 degrees about the seat such that his or her back is adjacent the back portion 31 of the chair 3. The user may then be assisted to a standing position from the seated position, for example, by continuing to raise the 5 seat as he or she disembarks if required.

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It should be appreciated that circumstances will dictate the time a user is kept in a lying or partially seated position prior to raising the chair 3. Also, the circumstances may require an alternative method or sequence to that described above. For 10 example, the raising of the seat extension 33a, 34a adjacent the user's upper body to a substantially perpendicular position may be done whilst the chair is in a lowered condition. Alternatively, the person may already be in a partially seated position and so one of the seat extensions 33a, 34a may be in the substantially perpendicular position prior to transferring the user onto the chair as shown in Figures 2 to 4.

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Moreover, the elevation chair may simply be used as an elevation seat for assisting a person sat on the floor to a standing position without the use of the seat extensions. The secondary seat extensions 34a, 34b may be folded about their respective hinges 39a, 39b and adjacent their respective primary seat extension 33a, 33b with the 20 primary seat extensions 33a, 33b both fixed in a substantially vertical position thereby to provide additional support for the user.

Alternatively, the seat extensions may be kept in a horizontal position and the elevation chair 1 may be used to transfer the person from the floor directly onto a 25 bed.

The use of chair members made from moulded plastics material results in the majority of the chair being x-ray invisible. The present invention may therefore be

used for supporting a person undergoing x-ray procedures, which would preclude the need to transfer the user to a further supporting substrate.

After use, the chair 3 is preferably returned to the lowered condition and collapsed for transportation and/or storage. The adjustable handle 5 and wheels 25, 28 facilitate manoeuvring and transporting the elevation chair.

In order to collapse the elevation chair 1, the secondary seat extension 34a, 34b are folded about their respective hinge 39a, 39b to a position adjacent the top surface of their respective primary seat extension 33a, 33b. The primary seat extensions 33a, 33b are then folded about their respective hinges 38a, 38b such that the bottom surface of one of a first secondary seat extensions 34b is adjacent the top surface of the seat 32 and the bottom surface of the second secondary seat extension 34a is adjacent the bottom surface of the first primary seat extension 33b. The seat 31 is then folded about the main hinge 35 such that the bottom of the second primary seat extension 33a is adjacent the front surface of the back portion 31 of the chair 3.

Finally, the three legs 23 are folded about their respective hinges 26 so that the chair is in a fully collapsed condition as shown in Figure 5. The elevation chair may then be stored, for example in a cupboard or automobile.

Although the post portion 22 is substantially vertical, it is angled back slightly to retain the chair in a collapsed condition as well as providing a more comfortable seated position for the user when the chair 3 is erected.

Prior to use, the collapsed elevation chair 1 may be carried to the requisite place and erected in situ if space constraints so require. This is facilitated by the lightweight design of the frame. However, if there is sufficient space, the legs 23 are preferably

unfolded prior to wheeling the elevation chair into position. In order to erect the chair, the method described above may be employed in reverse order.

A seatbelt may be secured to the back portion 31, as shown in Figure 6, to provide additional support for the user when the user is in a seated position. The seatbelt may also be used to secure the chair 3 in its collapsed condition.

Moreover, the seat 32 may be connected to the back portion 31 by a releasable hinge arrangement as shown in Figure 7. The releasable hinge arrangement includes a modified seat support portion 310a, a bar 350, two hinge members 320, a hinge slot 352, a hinge lock 351 and a hinge latch 321.

The width of the seat support portion 310a is substantially narrower than the width of the back portion 31, contrary to the embodiments described above. The hinge 350 is a bar of aluminium. The hinge members 320 are arcuate extensions extending outward and downward from the sides of the back edge of the seat support portion 310a. The hinge slot 352 is a recess in the bottom surface of the seat support portion 310a near the back thereof and shaped to correspond to a portion of the bar 350. The hinge lock 351 is an arcuate extension extending outward and downward from the front edge of the seat support portion 310a to form a further recess shaped to correspond to a portion of the bar 350. The hinge latch 321 is an arcuate member which depends from the bottom surface of the seat 32 and is hingedly connected thereto.

The two hinge members 320 straddle the seat support portion 310a. Each end of the bar 350 is secured to one of the hinge members 320.

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In an erected condition, the bar 350 engages the hinge slot 352 and the hinge latch 321 engages the hinge lock 351 thereby securing the seat 32 relative to the back portion 31.

5 In order to collapse the seat 32 relative to the back portion, the hinge latch 321 is pivoted away from the hinge lock 351 and the seat 32 is pivoted toward the back portion 31 thereby releasing the bar 350 from the hinge slot 352. The seat 32 is then slid along the seat support portion 310a until it engages the hinge lock 351. The seat 32 is then pivoted toward the back portion 31 until the seat extension about the back 10 portion 31 as shown in Figure 7.

Furthermore, an alternative embodiment of the fixing plate arrangement can be seen in Figure 8, wherein the fixing plate and back portion 310 are integrated. This arrangement is advantageous as a result of its simplicity, however, the material used 15 must be sufficiently strong to support the forces exerted on the fixing plate portions of the back portion 310. The holes in the back portion comprise slots to provide some degree of adjustability in the angle at which the seat extensions 330a, 340a and 330b, 340b. This embodiment also includes an additional, lower hole on each side of the back portion. These additional holes may be used to secure the seat extensions 20 330a, 331a, 340a and 330b, 340b at an intermediate angle between a horizontal and

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...• downward vertical positions when the chair 3 is at least partially raised.

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**" The embodiment of Figure 8 also includes a variation in the design of the seat

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extensions. One of the primary seat extensions includes a first member 330a and a "*••• 25 second member 331a connected by a hinge 334a. The arrangement includes seat extension locks 332a, 333a and 342a, 343a and 342b, 343b to secure the abutting surfaces. Each lock includes a hole 332a, 342a, 342b and a flange 333a, 343a, 343b having a threaded hole therein. In order to secure the abutting surfaces, a bolt

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is passed through the hole 332a, 342a, 342b and fastened to the flange 333a, 343a, 343b with the surfaces in abutment.

A further embodiment is shown in Figures 9 and 10, wherein the leg members 230 5 have a T-shaped cross-section.

A basic embodiment of the invention is shown in Figure 11, wherein the seat extensions 133a, 133b with handles H are slideably retractable. The leg members 123a, 123b are fixed relative to the cross member 124. This embodiment includes 10 arm rests 108 pivotably attached to the back portion 131. The handle 105 is fixed to the post portion 122 of the frame 102. The drive motor 104 is mounted to the top of the post portion 122 of the frame 102.

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Whilst the drive means described herein includes a ball screw drive and electric 15 motor, it should be appreciated that any suitable drive means may be used. For example, the ball screw drive may be replaced by a trapezoidal ACME or other lead screw driver or any suitable linear actuator. The electric motor may be replaced with any suitable prime mover including a manually operated prime mover such as a crank mechanism. Alternatively, the drive means may comprise a hydraulically or 20 pneumatically actuated means.

Moreover, whilst the frame is preferably made of aluminium for cost-effectiveness, it is envisaged that titanium or other suitable light weight, high strength material or alloy may be used.

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Although the seat extensions are pivotable about the seat in a perpendicular direction, which provides both the foldability of the seat extensions as well as their angular adjustment relative to the seat, alternative arrangements are envisaged. For

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example, the seat extensions may be pivotable about the seat in a perpendicular direction for angular adjustment and pivotable in a planar direction for stowing.

Furthermore, the fixing means for fixing the angular position disclosed herein may be 5 replaced by any suitable configuration. For example, the fixing plate 36a, 36b may comprise four or more holes or a single arcuate slot to allow for continuous adjustment. The bolt B may be replaced by a resiliently urged pin secured to the fixing plate 36a, 36b, wherein the flanges 37a, 37b comprise a plurality of holes for engaging the resiliently urged pin. Alternatively, a resiliently urged pin may be 10 secured to the flanges 37a, 37b for engaging holes in the fixing plate 36a, 36b. Alternatively or additionally, the fixing means may comprise a support member attachable to and extending from the lower surface of the seat to support the seat extension.

15 Furthermore, whilst the seat 32, back portion 31, 310, seat extensions 33a, 34a, 330a, 331a, 340a, 33b, 34b, 330b and 340b in the embodiment described herein are made of moulded plastics material, they may be made of any suitable material. Preferably, the material should be lightweight in order to minimise the weight of the elevation chair. However, any suitable material may be used without departing from 20 the scope of the invention.

Claims

18 CLAIMS

An elevation chair comprising a seat upon which, in use, a person is seatabie and drive means, the seat being operably connected to the drive means, the drive means being operable to raise and lower the seat, wherein the seat comprises a seat extension which is movable between a relatively extended position for increasing the load bearing surface area of the seat and a relatively stowed position.

An elevation chair as claimed in Claim 1, wherein the seat extension extends from a first edge of the seat.

An elevation chair as claimed in Claim 1 or Claim 2, further comprising a further seat extension

An elevation chair as claimed in Claim 3, wherein the further seat extension extends from a second edge of the seat.

An elevation chair as claimed in Claim 4, wherein the seat extensions extend from opposing edges of the seat.

An elevation chair as claimed in any preceding Claim, wherein the, each or one seat extension is pivotable relative to the seat.

An elevation chair as claimed in Claim 6, wherein the elevation chair further comprises fixing means for fixing the angular position of the, each or one seat extension relative to the seat.

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8. An elevation chair as claimed in Claim 7, wherein said fixing means comprises a fixing member and a fastener for securing the, each or one seat extension to the fixing member.

5 9. An elevation chair as claimed in Claim 7 or Claim 8, wherein the fixing means is adapted to fix the position of the seat extension at two or more angular positions relative to the seat.

10. An elevation chair as claimed in any preceding Claim, wherein the, each or 10 one seat extension is slideable relative to the seat.

11. An elevation chair as claimed in any preceding Claim, wherein the, each or one seat extension comprises a primary and a secondary seat extension.

15 12. An elevation chair as claimed in Claim 11, wherein the secondary seat extension is moveable between an extended position and a stowed position relative to the primary seat extension.

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13. An elevation chair as claimed in Claim 11 or Claim 12, wherein the secondary 20 seat extension is foldable or slidable relative to the primary seat extension.

14. An elevation chair as claimed in any preceding Claim, further comprising a substantially vertical post.

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15.

An elevation chair as claimed in Claim 14, wherein the seat is moveable between an extended position and a stowed position relative to the post.

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An elevation chair as claimed in Claim 14 or Claim 15, wherein the seat is foldable relative to the post.

An elevation chair as claimed in any preceding Claim, further comprising a back portion, wherein the seat is foldable relative to the back portion.

An elevation chair as claimed in any one of Claims 14 to 17, further comprising a base portion to which the post is secured.

An elevation chair as claimed in Claim 18, wherein the base portion comprises a cross member and at least one leg member.

An elevation chair as claimed in Claim 19, wherein the at least one leg member is hinged to the cross member.

An elevation chair as claimed in any one of Claims 14 to 17, wherein the drive means is located, at least in part, within the post.

An elevation chair as claimed in any preceding Claim, wherein the drive means comprises a linear actuator.

An elevation chair as claimed in any preceding Claim, wherein the drive means comprises a prime mover and a ball screw assembly, the ball screw assembly being driveable by the prime mover.

An elevation chair as claimed in any preceding Claim, further comprising at least one wheel for moving the elevation chair on a substrate.

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An elevation chair as claimed in any preceding Claim, further comprising an adjustable handle for manoeuvring the elevation chair.

An elevation chair as claimed in any preceding Claim, the elevation chair is at least partially x-ray transparent, to allow at least some x-ray radiation impinging thereon to pass therethrough.

An elevation chair as claimed in Claim 26, wherein the seat and seat extension are at least partially x-ray transparent.

An elevation chair as claimed in any preceding Claim, wherein the elevation chair weighs less than 50kg.

An elevation chair as claimed in any preceding Claim, wherein the drive means is powered by a standalone power source

An elevation chair as claimed in Claim 29, wherein the standalone power source comprises a battery.

A collapsible elevation chair comprising a seat upon which, in use, a person is seatabie and a base, the base having an extended condition for use and a stowed condition.

An elevation chair comprising a seat upon which, in use, a person is seatabie, a post and drive means located, at least in part, within the post, the seat being operably connected to the drive means, the drive means being operable to raise and lower the seat relative to the post, the elevation chair weighing less than 50kg.

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33. An elevation chair as claimed in Claim 34, wherein the elevation chair weighs less than 30kg.

5 34. An elevation chair as claimed in any preceding Claim, wherein the elevation chair weighs less than 20kg.

35. An elevation chair comprising a seat upon which, in use, a person is seatabie, a post and drive means located, at least in part, within the post, the seat 10 being operably connected to the drive means, the drive means being operable to raise and lower the seat relative to the post, the elevation chair being at least partially x-ray transparent, to allow at least some x-ray radiation impinging thereon to pass therethrough.

15 36. An elevation chair as claimed in Claim 35, wherein the seat and seat extension are at least partially x-ray transparent.

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