GB2468021A

GB2468021A - A Chair Having A Customisable Back Support

Info

Publication number: GB2468021A
Application number: GB201002513A
Authority: GB
Inventors: Colm Campbell
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-02-24
Filing date: 2010-02-15
Publication date: 2010-08-25
Anticipated expiration: 2030-02-15
Also published as: IE86220B1; GB201002513D0; IES20090147A2; GB2468021B; IE20100081A1

Abstract

A chair (1, figure 1) having a back support pad (12) which has a curved surface (12a) which matches elongated S-shaped curve of a specific user's spine. The back support pad comprises a plurality of segments (16) assembled in an abutting relationship, each segment (16) corresponding to a pre-determined portion of the specific user's back. The chair (1) is accompanied with a kit of segments (16) in which for each pre-determined portion of the curved surface of the back support pad, a group of segments (16) is provided corresponding to that pre-determined portion. Each segment (16) of the group varies slightly in size and curvature of the main surface from one another so that by way of trying the different segments of the group a user can determine which segment (16) provides the best support when assembled into the back support pad of the invention.

Description

A CHAIR

The present invention relates to a chair, and in particular to a chair that provides improved support for the user's back.

S

Every spine has its own unique elongated S shape which collapses into a forward C when the person is seated. This creates significant pressure on the intervertebral discs which eventually typically results in pain. Numerous chairs have been developed so far that attempt to provide support for the spine. Still, none of the existing chairs are capable to provide a support which conforms to the unique S shape of each person's spine.

The object of the present invention is to mitigate and obviate the above problems and to provide a chair providing an improved spine support.

Accordingly, the present invention provides a chair comprising; a seat comprising a seat portion and a backrest portion; wherein the backrest portion comprises a back support pad comprising a back support curved surface sized and shaped so as substantially to match an elongated 5-shaped curve of a chair occupier's back, inherent and unique to each individual.

The back support pad ideally comprises a means for adjusting the back support curved surface to match the "5" curvature of an individual's spine.

The present invention also provides a back support pad as herein described for incorporation into a backrest of a chair.

Such an elongated S-shape is unique for every person and is achievable in particular conditions such as a gravity free environment, such as space or in a "zero gravity" position, i.e. a position in which the person's back is substantially horizontal relative the ground and the person's knees are positioned above or at least level with the person's chest. An S-shape is also assumed during walking, but not as ideal as in a "zero gravity" position. The elongated S-shape of the spine comprises three regions, lumbar (lower), thoracic (middle) and cervical (upper). Accordingly, the back support curved surface of the support pad comprises a first convex region corresponding to the lumbar spine region, a second transitional region corresponding to the thoracic spine region and a third concave region corresponding to the cervical spine region.

The referred to above "zero gravity" position minimises the pressure in the intervertebral discs, such as in a gravity-free environment, such as space. In this position a virtually ideal shape of the spine is achieved. This shape is an elongated S-shape that is unique for every person. In the seated position in a regular chair, the spine collapses into a forward C-shape, eventually resulting in pain. The chair of the present invention simultaneously provides for a zero gravity" effect on the spine, i.e. minimises the compressive force of the gravity on the spine, while supporting the spine in the near-ideal elongated S-shape thereby maintaining minimal pressure in the intervertebral disks and minimising the risk of damage and/or injury of the spine. The chair occupier's back is maintained in a near-ideal posture at all times.

In order to achieve as close as possible match between the elongated S-shape that the user's spine assumes in a "zero gravity" condition and the elongated S-shape of the support surface of the back support pad, the elongated S-shape of the latter is preferably determined individually for each user. This determination is preferably carried out using applicant's existing "Spinal System-S" measuring machine, described in European Patent EP0792604, by positioning the individual in the seat of the machine where the persons back assumes the elongated S-shape posture. The person's spine is gently pressed against the backrest surface of the machine which comprises a plurality of movable rods which form a measuring surface. In this way, the contour of the person's spine is impressed on the measuring surface. The measuring surface of the machine is provided with a recording means for recording the measurements necessary to manufacture the back support pad.

On the basis of the spine contour measurement, a back support pad comprising the correctly shaped back support curved surface is manufactured. Thus, the back support pad of each reclining chair of the invention matches substantially the elongated 5-shaped curve of a specific individual.

Ideally, the back support pad comprises means for fine adjustment or tailoring of the back support surface so that it matches precisely the elongated S-shaped curve of the individual. For this purpose, the back support pad comprises a plurality of segments assembled in an abutting relationship, each segment comprising a body comprising a main surface, the main surface corresponding to a pre-determined portion of the back support surface of the pad, the main surfaces of a each pair of adjacent abutting segments being complementary to each other such that when the segments of the back support pad are assembled, the main surfaces of the segments form the back support surface of the pad.

In order to enable the user to carry out fine adjustments to the back support surface to match accurately the user's spine unique elongated S-shape, a kit is provided in which for each pre-determined portion of the back support surface, a group of segments is provided corresponding to that pre-determined portion, each segment of the group varying slightly in size and curvature of the main surface from one another, such that a user can by way of trying the different segments of the group determine which segment provides the best support when assembled into the back support pad of the invention. A means of identification, such as a mark or text, is preferably provided on each segment indicating to which pre-determined portion of the back support surface the segment belongs, and a means indicating the size of each segment is also provided.

Preferably, each segment of the back support pad corresponds to a pre- determined portion of the back support surface which in turn corresponds to a pre-determined portion of a person's back. The pre-determined portion of a person's back is preferably selected from lumbar (lower), thoracic (middle) and cervical (upper) regions of the back. ideally, each or some of the pie-determined portions of the back support surface are subdivided into two or more sub-areas and a corresponding segment is provided for each of the sub-areas.

According to an advantageous embodiment, the number of the segments in each group, and the variations in their size (e.g. thickness) and curvature of the main surface are determined based on an initiai data of person's height and weight. The initial data is correlated with data of an empirical database compiled by the applicant by measuring about ten thousand spines, the database containing the size variations and number of segments in each group which have to be provided for a particular combination of height and weight of a user.

In use, in order to carry out fine adjustment, the user seats in the chair of the invention in the upright position. The user then arches the lumbar (lower) zone of the spine forward making sure that the thoracic (middle) zone is kept in contact with the backrest portion of the chair. It has been determined during a research carried out by the applicant carried out during a considerable period of time (over 25 years) that most users are able to realize when their spine is in the ideal elongated S-shape. The user then estimates the distance between the backrest surface and the spine by for example placing a hand in the lumen between the backrest and the lumbar zone. On the basis of the estimated distance, a segment is then selected from the relevant group whose thickness is the closest to the estimated distance. Alternatively, the segment is selected by placing the various segments from the group in the lumen and judging which segment provides the most comfortable support. Once the suitable segment has been selected, the user then proceeds to select a segment from another group, and so on until all the segments necessary to assemble the back support pad have been selected. The assembled in the required correct order and orientation to define the back support pad and the back support pad is then fastened to the backrest portion of the chair.

A suitable fastening means apparent to those skilled in the art for securing the back support pad to the backrest portion is provided, such as e.g. VeIcroTM fasteners, harness, zip etc. In one modification, each segment may be provided with a fastening means.

Conveniently, the back support pad preferably comprises an outer cover, preferably made from a pliable material, the outer cover defining an inner space for receiving the segments forming the back support pad, and an access opening into the inner space for receiving the segments therethrough. The cover is suitably sized and shaped to receive all the segments assembled in the required correct order and orientation to define the back support pad. In use, when the selected segments are located inside the cover in the required correct order and orientation, the cover is substantially taut around the assembled segments so that the segments remain substantially immovable relative each other inside the cover. In one modification, one or more flaps are provided for covering the access opening, the flaps being preferably securable in the closed position via a suitable means such as, e.g. a zip or snaps, to prevent the segments from becoming dislodged. The outer cover is then attached to the backrest support.

In one modification, a means for fastening the adjacent abutting segments of the pad to each other is provided in order to secure the segments in the assembled position.

In a most preferred arrangement, each segment comprises an elongate body having a pair of long sides and a pair of short sides. On assembly, the elongate segments are disposed in sequence in the direction along a longitudinal axis of the back support pad corresponding to the user's spine, with the long sides of adjacent elongate segments being disposed transverse to the longitudinal axis of the back support pad and abutting each other, such that the main surfaces of a pair of adjacent elongate segments complement each other such that in an assembled state the main surfaces of the elongate segments form the support surface of the back support pad.

The chair of the present invention is suitable in many applications, including, but not in any way limited thereto, home, office and car seats.

In one embodiment, the chair is a reclining chair. Ideally, the chair is of a so called zero gravity" type. In one embodiment, the reclining chair comprises: a frame; wherein the seat comprises a leg support portion; wherein the seat is connected to the frame via a pivot means to tilt with respect to the frame between upright and reclined positions; wherein the backrest portion is connected to the seat portion such that the seat portion and the backrest are disposed at an angle with respect to each other; wherein the chair further comprises an actuation means for pivoting the seat about the pivot means; a stop means for fixing the seat with respect to the frame in a selected position; wherein the angle between the seat portion and the backrest and the angular position of the seat with respect to the frame in the reclined position are selected such that in the reclined position, a chair occupier's knees are positioned on the leg support portion higher, or at least level with, the users chest, relative to the ground.

The above position is known as a "zero gravity" position, in which the compressive effect of gravity acting along the person's spine is minimised. The zero gravity position has been found beneficial for a number of medical conditions, However, whilst minimising the compressive effect of gravity, such a position creates the risk of causing even more back pain or even injury due to the resulting restricted mobility of a user assuming such a position. Back support is often inadequate and spine damage or injury is possible when the person for example attempts to move in the chair, such as e.g. return from a horizontal into an upright position, bending the spine forward as far as possible, fully extending the arms, grasping the armrests and pulling the body upright. This creates considerable pressure and resultant damage in the intervertebral discs. Such a risk remains even during mere raising of the backrest of the chair from a horizontal to an upright position. The provision of the back support pad as described above in the reclining chair of the invention makes it easier for the chair occupier to get in and out of the chair and to make movements while occupying the chair.

The backrest portion and the seat portion are preferably secured to each other so that the backrest portion and the seat portion tilt as a unit. Preferably, the angle required to be maintained between the seat portion and the backrest portion during the upright mode or the reclined mode is between 90 and 135 degrees. A releasable lock means is preferably provided between the seat portion and the backrest portion in order to adjust the angle therebetween.

Conveniently, the actuation means is electrically controlled and comprises a hand held control unit which can be either remote or attached to the actuation means. The actuation means is preferably a low-voltage (e.g. 24V) actuation means. In one embodiment the actuation means comprises a ram arrangement mounted between the frame and the backrest portion of the chair. The actuation means is preferably adapted to function as the stop means.

In one modification, the seat, the backrest and the leg support portions are manufactured from tubular steel, preferably 22mm diameter.

Preferably, the pivot means is connected to the frame via at least a pair of ball bearings thereby providing for smooth and noiseless actuation of the seat.

The seat, the backrest, the back support pad of the chair and, if applicable, the frame and the leg support portion, are preferably supplied disassembled and, therefore are suitable for flat packaging. A fastening means is provided on each of the above components adapted for quick and easy assembly of the chair of the invention.

The invention will now be described with reference to the accompanying drawings which show by way of example only one embodiment of a chair according to the invention.

In the drawings: Figure 1 is a side elevation of a reclining chair of the invention in a reclined, "zero gravity mode"; Figure 2 is a front elevation of the chair of Figure 1 in an upright position; Figure 3 is a perspective rear view of the back support pad arrangement of the chair of Figures 1 and 2; and Figure 4 is a side elevation of a prior art spine measuring machine.

Referring to Figures 1 to 3, a reclining chair in accordance with the invention is indicated generally by reference numeral 1. It will be appreciated that the reclining chair described below represents a specific embodiment of the chair of the invention, whereas the chair in accordance with the invention is not limited to only reclining chairs and includes home chairs, office chairs, car seats and other types of chairs known to a person skilled in the art. The reclining chair 1 comprises a frame 2 which incorporates armrests 2a a seat 3 comprising a seat portion 4, a leg support portion 5 and a backrest portion 6.

The backrest portion 6 and the seat portion 4 are preferably secured to each other so that the backrest portion and the seat portion tilt as a unit. The angle required to be maintained between the seat portion 4 and the backrest portion 6 is between 90 and 135 degrees. A releasable lock means (not shown) may be provided between the seat portion and the backrest portion in order to adjust the angle therebetween. The seat 3 is connected to the frame 2 via a pivot 7 to tilt with respect to the frame 2 between an upright 8 and a reclined 9 positions.

A low-voltage (about 24V) electrically operated actuator 10 having a ram 11 is mounted between the frame 2 at one end 20 and the backrest portion 6 of the chair 1 at the other end 21 (see Figure 2) for pivoting the seat 3 about the pivot 7 and thereby tilting the chair 1 as required by the user. The actuator 10 preferably comprises a hand held control unit (not shown) which can be either remote or attached to the actuator 10 via a cable. The actuator 10 is also adapted to function as a stop means for fixing the seat 3 with respect to the frame 3 in a selected position.

As shown in Figure 1, in use, the angle between the seat portion 4 and the backrest portion 6 and the angular position of the seat 3 with respect to the frame 2 in the reclined position 9 are selected such that in the reclined position 9, a chair occupier's knees are positioned on the leg support portion 5 higher, or at least level with, the user's chest, relative to the ground.

The backrest portion 6 comprises a back support pad 12 comprising a back support curved surface 1 2a sized and shaped so as substantially to match an elongated S-shaped curve of a chair occupier's back. This elongated S-shaped curve of the back results from a minimal possible compressive force acting on the chair occupier's spine. The minimal possible force, in turn, is achieved in the reclined position 9 of the chair 1. This reclined position is generally known as a "zero gravity" position because it minimises the pressure in the intervertebral discs, such as in a gravity-free environment, such as space. In this position a virtually ideal shape of the spine is achieved automatically as soon as the person assumes the zero gravity position. This shape is an elongated S-shape that is unique for every person. In the seated position in a regular chair, the spine collapses into a forward C-shape, eventually resulting in pain. The reclining chair 1 simultaneously provides for a "zero gravity" effect on the spine, i.e. minimises the compressive force of the gravity on the spine in the reclined position 9 of the chair 1, while supporting the spine in the elongated S-shape. In this manner, minimal pressure in the intervertebral disks is maintained and the risk of damage and/or injury of the spine is minimised.

Furthermore, the chair occupier's back is maintained in a near-ideal posture not only in the fully reclined, "zero gravity" position 9 but also in the upright position 8 and in any intermediate position 15. Also, the provision of the above described back support makes it easier for the chair occupier to get in and out of the chair 1 and to make movements while occupying the chair 1.

It will be appreciated that the use of the back support pad 12 is not limited to the use in a reclining chair only, and that the back support pad of the invention can be incorporated into almost any type of chair including home, office and car seats.

In order to achieve as close as possible match between the elongated S-shape that the user's spine assumes in a "zero gravity" condition and the elongated S-shape of the support surface 12a of the back support pad 12, the elongated S-shape of the back support pad 12 is preferably determined individually for each user. This determination is preferably carried out using applicant's existing "Spinal System-S' measuring machine (see Figure 4), subject of a European patent EP0792604, by positioning the individual in the seat of the machine in which seat the persons back assumes the elongated S-shape posture. The person's spine is then gently pressed against the backrest surface of the machine which comprises a plurality of movable rods which form a measuring surface, thereby matching the measuring surface with the contour of the person's spine. The measuring surface of the machine is provided with a recording means for recording the measurements necessary to manufacture the back support pad.

On the basis of the spine contour measurement, a back support pad 12 comprising the correctly shaped support curved surface 12a is manufactured. Thus, the back support surface 12a of each reclining chair of the invention matches substantially the elongated 5-shaped spine curve of a specific individual.

As shown in Figure 3, the back support pad 12 comprises means for fine adjustment or tailoring of the back support surface 12a so that it matches precisely the elongated 5-shaped curve of the individual when occupying the chair 1 of the invention. For this purpose, the back support pad 12 comprises a plurality of elongate segments 16 having a pair of long sides 16a and a pair of short sides 16b a main surface 17 corresponding to a pre-determined portion of the back support surface 12a of the pad 12. On assembly, the elongate segments 16 are disposed in sequence in the direction along a longitudinal axis 18 of the back support pad 12 that corresponds to the user's spine, with the long sides 16a of adjacent elongate segments 16 being disposed transverse the longitudinal axis of the back support pad and abutting each other. The correct assembly and orientation of the elongate segments 16 results in that the main surfaces 17 of a pair of adjacent elongate segments 16 complement each other such that in an assembled state the main surfaces 17 of the elongate segments 17 form the back support surface 12a of the back support pad 12.

In order to enable the user to carry out fine adjustments to the back support surface 12a, a kit is provided in which for each pre-determined portion of the back support surface 12a, a group of segments 17 is provided corresponding to that pre-determined portion. Each pre-determined portion of the support surface 1 2a in turn corresponds to a pre-determined portion of a persons back. The segments 17 of the group vary slightly in size and curvature of the main surface 17 from each other, such that a user can by way of trying the different segments 17 of the group determine which segment 17 provides the best support when assembled into the back support pad 12. An identification mark 18 is provided on each segment 17 indicating to which pre-determined portion of the back support surface 12a the segment 17 belongs, and a mark (not shown) indicating the size of each segment 17 is also provided.

In the presently embodiment, the pre-determined portions of a person's back are a lumbar (lower), thoracic (middle) and cervical (upper) regions of the back. These pre-determined portions are subdivided into two sub-areas and a corresponding segment 17 (Cl, C2, Ti, T2, LI, L2) is provided for each of the sub-areas.

The number of the segments 17 in each group, and the variations in their size (e.g. thickness) and curvature of the main surface i7a are determined based on an initial data relating to the individual's height and weight. The initial data is correlated with an empirical database compiled by the applicant by measuring about ten thousand spines, the database containing the size variations and number of segments 17 in each group which have to be provided for a particular combination of height and weight.

In use, in order to carry out fine adjustment, the user seats in the chair 1 of the invention fixed in the upright position 8. The user then arches the lumbar (lower) zone of the spine forward making sure that the thoracic (middle) zone is kept in contact with the backrest portion 6 of the chair I. It has been determined during a research carried out by the applicant carried out during a considerable period of time (over 25 years) that most users are able to realize when their spine is in the ideal S-shape. The user then estimates the distance between the backrest portion 6 surface and the spine by for example placing a hand in the lumen between the backrest portion 6 and the lumbar zone. On the basis of the estimated distance, a segment 17 is then selected from the lumbar group of segments 17 whose thickness is the closest to the estimated distance. Alternatively, the segment 17 may be selected by placing the various segments 17 from the group in the lumen and judging which segmentl7 provides the most comfortable support. The user then proceeds to select a second segment 17 from the same group in order to form the pre-determined portion of the support surface 12a from two sub-areas. Once the suitable segments 17 have been selected from the lumbar group, the user then proceeds to select a segment 17 from the next group, i.e. the thoracic group, and so on until all the segments necessary to assemble the back support pad 12 pad have been selected.

The back support pad 12 comprises an outer cover 25, made form a pliable material, the outer cover 25 defining an inner space (not indicated by a numeral) for receiving the segments 17, and an access opening 26 into the inner space for receiving the segments 17 therethrough. The cover 25 is suitably sized and shaped to receive all the segments 17 assembled in the required correct order and orientation to define the back support pad 12. In use, when the selected segments 17 are located inside the cover 25 in the required correct order and orientation, the cover 25 is substantially taut around the assembled segments 17 so that the segments 17 remain substantially immovable relative each other inside the cover 25. A pair of flaps 28 are provided for closing the access opening 26. The flaps are securable in the closed position via a zip 29 to prevent the segments from becoming dislodged. When, the selected segments 17 are disposed inside the outer cover 25 in the correct order and orientation, the outer cover 25 is attached to the backrest support 6. A fastening means for securing the back support pad 12 to the backrest portion is provided in the form of VeIcroTM fasteners (not shown). Due to the provision of the fasteners, the outer cover 25 may remain attached to the backrest portion 6 during the selection of the segments 17, and the selected segments 17 can be inserted one by one after each selection. The user simply needs to pull the outer cover 25 away from the backrest portion 6, insert the segment 17 and re-position the outer cover 25.

In the presently described embodiment, the seat portion 4, the backrest portion 6 and the leg support portion 5 are manufactured from tubular steel, preferably 22mm diameter.

The frame 2, the seat 3 and the back support pad 12 of the chair 1 are supplied disassembled and arranged in a flat packaging and a fastening means (not shown) is provided on each of the above components adapted for quick and easy assembly of the chair 1.

As shown in Figure 2, the pivot 7 is connected to the frame 2 via ball bearings 2 for smooth and noiseless actuation of the seat 3.

It will be appreciated by those skilled in the art that variations and modification can be made without departing from the scope of the invention as defined in the appended claims.

Claims

CLAIMS: 1, A chair comprising a seat comprising a seat portion and a backrest portion; wherein the backrest portion comprises a back support pad comprising a back support curved surface sized and shaped substantially to match an elongated S-shaped curve of a specific user's spine.
2. A chair as claimed in Claim 1, wherein the back support pad comprises a means for adjusting the back support curved surface to match the "S' curvature of the specific user's spine.
3. A chair as claimed in Claim 1 or Claim 2, wherein the back support curved surface of the back support pad comprises a first convex region corresponding to lumbar spine region, a second transitional region corresponding to thoracic spine region and a third concave region corresponding to cervical spine region.
4. A chair as claimed in any preceding claim, wherein the back support pad comprises means for fine adjustment or tailoring of the back support surface so that it matches precisely the elongated S-shaped curve of the individual.
5. A chair as claimed in Claim 4, wherein the back support pad comprises a plurality of segments assembled in an abutting relationship, each segment comprising a body comprising a main surface, the main surface corresponding to a pre-determined portion of the back support surface of the pad, the main surfaces of a each pair of adjacent abutting segments being complementary to each other such that when the segments of the back support pad are assembled, the main surfaces of the segments form the back support surface of the pad.
6. A chair as claimed in Claim 5, wherein a means of identification is provided on each segment indicating to which pre-determined portion of the back support surface the segment belongs.
7. A chair as claimed in Claim 5 or Claim 6, wherein a means indicating the size of each segment is also provided.
8. A chair as claimed in any one of Claims 5 to 7, wherein each segment of the back support pad corresponds to a pre-determined portion of the back support surface which in turn corresponds to a pre-determined portion of a person's back.
9. A chair as claimed in Claim 8, wherein the pre-determined portion of a person's back is preferably selected from lumbar, thoracic and cervical regions of the back.
10. A chair as claimed in any one of Claims 5 to 9, wherein one or more of the pre-determined portions of the back support surface is subdivided into two or more sub-areas and a corresponding segment is provided for each of the sub-areas.
11. A chair as claimed in any one of Claims 5 to 10, wherein each segment comprises an elongate body having a pair of long sides and a pair of short sides, wherein in an assembled mode the elongate segments are disposed in sequence in the direction along a longitudinal axis of the back support pad corresponding to the user's spine, with the long sides of adjacent elongate segments being disposed transverse to the longitudinal axis of the back support pad and abutting each other, such that the main surfaces of a pair of adjacent elongate segments complement each other such that in an assembled state the main surfaces of the elongate segments form the support surface of the back support pad.
12. A chair as claimed in any one of Claims 5 to 11, wherein the back support pad comprises an outer cover, the outer cover defining an inner space for receiving the segments forming the back support pad, and an access opening into the inner space for receiving the segments therethrough.
13. A chair as claimed in Claim 12, wherein the outer cover is made from a pliable material.
14. A chair as claimed in Claim 12 or Claim 13, wherein the outer cover is configured so that when the segments are located inside the cover in the required correct order and orientation, the cover is substantially taut around the assembled segments so that the segments remain substantially immovable relative each other inside the cover.
15. A chair as claimed in any one of Claims 12 to 14, wherein one or more flaps are provided for covering the access opening.
16. A chair as claimed in any one of Claims 5 to 15, wherein a means for fastening the adjacent abutting segments of the pad to each other is provided in order to secure the segments in the assembled position.
17. A chair as claimed in any preceding claim, wherein a fastening means for securing the back support pad to the backrest portion is provided.
18. A chair as claimed in any preceding claim, wherein the chair is a reclining chair!
19. A chair as claimed in Claim 18, wherein the chair comprises a frame; wherein the seat comprises a leg support portion; wherein the seat is connected to the frame via a pivot means so as to tilt with respect to the frame between upright and reclined positions; wherein the backrest portion is connected to the seat portion such that the seat portion and the backrest are disposed at an angle with respect to each other; wherein the chair further comprises an actuation means for pivoting the seat about the pivot means; a stop means for fixing the seat with respect to the frame in a selected position; wherein the angle between the seat portion and the backrest and the angular position of the seat with respect to the frame in the reclined position are selected such that in the reclined position, a chair occupier's knees are positioned on the leg support portion higher, or at least level with, the user's chest, relative to the ground.
20. A chair as claimed in Claim 19, wherein the backrest portion and the seat portion are secured to each other so that the backrest portion and the seat portion tilt as a unit.
21. A chair as claimed in Claim 19 or Claim 20, wherein the angle between the seat portion and the backrest portion during the upright mode or the reclined mode is between 90 and 135 degrees.
22. A chair as claimed in any one of Claims 19 to 21, wherein a releasable lock means is provided between the seat portion and the backrest portion for adjusting the angle therebetween.
23. A chair as claimed in any one of Claims 19 to 22, wherein the actuation means is electrically controlled and comprises a hand held control unit which is either remote or attached to the actuation means.
24. A chair as claimed in any one of Claims 19 to 23, wherein the actuation means is a low-voltage (e.g. 24V) actuation means.
25. A chair as claimed in any one of Claims 19 to 24, wherein the actuation means comprises a ram arrangement mounted between the frame and the backrest portion of the chair.
26. A chair as claimed in any one of Claims 19 to 25, wherein the actuation means is adapted to function as the stop means.
27. A chair as claimed in any one of Claims 19 to 26, wherein the seat, the backrest and the leg support portions are manufactured from tubular steel.
28. A chair as claimed in Claim 27, wherein the tubular steel has a diameter of 22mm.
29. A chair as claimed in any one of Claims 19 to 28, wherein the pivot means is connected to the frame via at least a pair of ball bearings.
30. A chair as claimed in any one of Claims 19 to 29, wherein the backrest, the back support pad of the chair, the frame and the leg support portion are configured so as render them suitable for flat packaging.
31. A chair as claimed in any one of Claims 19 to 30, wherein a fastening means is provided on the backrest, the back support pad of the chair, the frame and the leg support portion adapted for quick and easy assembly of the chair of the invention.
32. A chair as claimed in Claim 5, wherein the means for fine adjustment or tailoring of the back support surface comprises a kit in which for each pre-determined portion of the back support surface, a group of segments is provided corresponding to that pre-determined portion, each segment of the group varying slightly in size and curvature of the main surface from one another so that a user can determine which segment provides the best support when assembled into the back support pad of the invention by way of trying the different segments of the group.
33. A back support pad comprising a back support curved surface sized and shaped substantially to match an elongated S-shaped curve of a specific user's spine for incorporation into a backrest of a chair.
34, A back support pad as claimed in Claim 33, wherein the back support pad comprises a means for adjusting the back support curved surface to match the "5" curvature of the specific user's spine.
35. A back support pad as claimed in Claim 32 or Claim 34, wherein the back support curved surface of the support pad comprises a first convex region corresponding to lumbar spine region, a second transitional region corresponding to thoracic spine region and a third concave region corresponding to cervical spine region.
36. A back support pad as claimed in any preceding claim, wherein the back support pad comprises means for fine adjustment or tailoring of the back support surface so that it matches precisely the elongated S-shaped curve of the specific user's spine.
37. A back support pad as claimed in Claim 36, wherein the back support pad comprises a plurality of segments assembled in an abutting relationship, each segment comprising a body comprising a main surface, the main surface corresponding to a pre-determined portion of the back support surface of the pad, the main surfaces of a each pair of adjacent abutting segments being complementary to each other such that when the segments of the back support pad are assembled, the main surfaces of the segments form the back support surface of the pad.
38. A back support pad as claimed in Claim 37, the means for fine adjustment or tailoring of the back support surface comprises a kit in which for each pre-determined portion of the back support surface, a group of segments is provided corresponding to that pre-determined portion, each segment of the group varying slightly in size and curvature of the main surface from one another so that a user can determine which segment provides the best support when assembled into the back support pad of the invention by way of trying the different segments of the group.
39. A method of manufacturing a chair of Claim 32 comprising the step of determining the number of the segments in each group, and the variations in their size (e.g. thickness) and curvature of the main surface using an initial data of person's height and weight.
40. A method as claimed in Claim 39, comprising the step of correlating the initial data with data of an empirical database compiled upon measuring about ten thousand spines, the database containing the size variations and number of segments in each group which have to be provided for a particular combination of height and weight of a user.
41. A method of assembling a chair of Claim 32 comprising the steps of seating the user in the chair of in the upright position, whereby the user arches the lumbar zone of the spine forward while the thoracic zone is kept in contact with the backrest portion of the chair in order to assume the ideal elongated S-shape; estimating the distance between the backrest surface and the spine; based on the estimation, selecting a segment from the r&evant group whose thickness is the closest to the estimated distance; selecting a segment from another group, and so on until all the segments necessary to assemble the back support pad have been selected.
42. A method of Claim 41 comprising the step of fastening the segments assembled in the required correct order and orientation to define the back support pad and fastening the back support pad to the backrest portion of the chair.
43. A method of manufacturing a back support pad of Claim 38 comprising the step of determining the number of the segments in each group, and the variations in their size (e.g. thickness) and curvature of the main surface using an initial data of person's height and weight.
44. A method as claimed in Claim 43, comprising the step of correlating the initial data with data of an empirical database compiled upon measuring about ten thousand spines, the database containing the size variations and number of segments in each group which have to be provided for a particular combination of height and weight of a user.
45. A chair substantially in accordance with any of the embodiments as herein described with reference to and/or as shown in the accompanying drawings.
46. A back support pad substantially in accordance with any of the embodiments as herein described with reference to and/or as shown in the accompanying drawings.
47. A method of manufacturing a chair substantially as herein described with reference to the accompanying drawings.
48. A method of manufacturing a back support pad substantially as herein described with reference to the accompanying drawings.
49. A method of assembling a chair substantially as herein described with reference to the accompanying drawings.