CN210008754U

CN210008754U - Leaning self-adaptive adjustable backrest mechanism and seat with same

Info

Publication number: CN210008754U
Application number: CN201821705854.XU
Authority: CN
Inventors: 彭汉强
Original assignee: Zhejiang Yueqiang Furniture Technology Co Ltd
Current assignee: Zhejiang Yueqiang Furniture Technology Co Ltd
Priority date: 2018-10-22
Filing date: 2018-10-22
Publication date: 2020-02-04
Anticipated expiration: 2028-10-22

Abstract

A leaning self-adaptive adjustable backrest mechanism and a seat with the same are provided, wherein the backrest mechanism comprises a backrest supporting part and an elastic seat back part connected with the backrest supporting part, and further comprises a first magnetic adjusting assembly and a second magnetic adjusting assembly, the first magnetic adjusting assembly is connected with the backrest supporting part and/or the elastic seat back part, the second magnetic adjusting assembly is connected with the elastic seat back part, and the first magnetic adjusting assembly and the second magnetic adjusting assembly are arranged at intervals in the front and back; the first magnetic adjustment assembly comprises a first magnet, the second magnetic adjustment assembly comprises a second magnet which is magnetically repulsive to the first magnet, and the repulsive surfaces of the first magnet and the second magnet are oppositely arranged. The utility model discloses utilize magnet repulsion to support human back buffering, can give good support feedback along with back pressure, can further satisfy different people's dependence custom simultaneously by the interval between the initiative adjustment magnet, overall structure intensity is high to utilize magnet itself and the design of partition intentionally, produce the magnetotherapy effect to whole human back, be worth using widely.

Description

Leaning self-adaptive adjustable backrest mechanism and seat with same

Technical Field

The utility model relates to a seat design technical field specifically is a lean on self-adaptation adjustable backrest mechanism and take seat of this backrest mechanism.

Background

A seat is a common seating device with a backrest and armrests, and is frequently used in daily life situations such as at home and at work. In modern life, particularly in the case of working at desk, the comfort of the seat is a significant factor in the physical health or working efficiency of the person. The conventional chair has a simple structure, particularly a backrest structure, which generally only has a design for supporting a soft or elastic back and is dedicated to comfort, and further has a backrest chair with an elastic backrest, which is disclosed in a patent document with the application number of CN200320118286.0, and comprises a stool surface, stool legs fixedly connected below the stool surface, and a backrest surface arranged above the back side of the stool surface, and is characterized in that the backrest surface is separated from the stool surface and the stool legs, a spring sheet is arranged between the stool surface and the backrest surface, and two ends of the spring sheet are respectively fixedly connected to the stool surface and the backrest surface.

Disclosure of Invention

One of the technical purposes of the utility model is to provide an adjustable back mechanism of dependence self-adaptation solves the simple and crude, the poor problem of dependence travelling comfort of traditional seat back structure, and its concrete technical scheme is as follows: a leaning self-adaptive adjustable backrest mechanism comprises a backrest supporting part and an elastic chair back part connected with the backrest supporting part, and further comprises a first magnetic adjusting assembly and a second magnetic adjusting assembly, wherein the first magnetic adjusting assembly is connected to the backrest supporting part and/or the elastic chair back part, the second magnetic adjusting assembly is connected to the elastic chair back part, and the first magnetic adjusting assembly and the second magnetic adjusting assembly are arranged at intervals in the front and back; the first magnetic adjustment assembly comprises a first magnet, the second magnetic adjustment assembly comprises a second magnet which is magnetically repulsive to the first magnet, and the repulsive surfaces of the first magnet and the second magnet are oppositely arranged.

Preferably, the first magnetic adjustment assembly and the second magnetic adjustment assembly are respectively provided with one or more magnet subareas taking the surface of the elastic chair back as a maximum reference area; the first magnet is disposed in the magnet partition of the first magnetic adjustment assembly, and the second magnet is disposed in the magnet partition of the second magnetic adjustment assembly.

Preferably, the first magnetic adjustment assembly and the second magnetic adjustment assembly are respectively provided with an upper magnet partition, a middle magnet partition and a lower magnet partition from top to bottom; the first magnet is disposed in the upper, middle and lower magnet partitions of the first magnetic adjustment assembly, and the second magnet is disposed in the upper, middle and lower magnet partitions of the second magnetic adjustment assembly.

Preferably, the first magnetic adjustment assembly further comprises a flexible magnetic-carrying bracket connected to the top end of the chair back support part and/or the elastic chair back, and the flexible magnetic-carrying bracket is provided with a first magnetic-carrying mounting seat for mounting the first magnet.

Preferably, the upper end of the flexible magnetic support is fixedly connected to the top end of the chair back support part and/or the elastic chair back part, and the lower end is free.

Preferably, the flexible magnetic carrier bracket is further connected with a bracket front-rear pushing part for pushing the free lower end of the flexible magnetic carrier bracket.

Preferably, the front and rear pushing part of the bracket comprises a vertical positioning sliding seat movably connected to the chair back supporting part and a butt joint connected to the vertical positioning sliding seat and abutted against the lower end of the toughness magnetic carrying bracket, and the connecting surface of the vertical positioning sliding seat and the chair back supporting part is inclined.

Preferably, the front and rear pushing part of the bracket comprises a vertical positioning sliding seat movably connected to the chair back supporting part and a butt joint connected to the vertical positioning sliding seat and movably connected to the lower end of the toughness magnetic carrying bracket, and the connection surface of the butt joint and the lower end of the toughness magnetic carrying bracket is inclined.

Preferably, the ductile magnetic bearing bracket is provided with a horizontal through inclined long hole; the front and rear pushing part of the support comprises a vertical positioning sliding seat movably connected with the chair back supporting part and a butt joint connected with the vertical positioning sliding seat, and the butt joint is provided with a butt joint end penetrating through the horizontal through inclined long hole.

Preferably, the chair back supporting part is provided with a vertical limiting slideway; and the vertical positioning sliding seat is provided with a limiting sliding block connected with the vertical limiting slide way.

Preferably, the chair back supporting part is provided with a clamping groove; and the vertical positioning sliding seat is provided with a clamping bulge which is clamped and locked with the clamping groove or separated by force.

Preferably, a holding handle is further arranged on the vertical positioning sliding seat.

Preferably, the second magnetic adjustment assembly further comprises a second magnet-carrying mounting seat attached to the flexible seat back portion for mounting the second magnet.

Preferably, the elastic chair back part comprises an outer frame body and a latticed backrest framework connected in the outer frame body; the chair back support portion comprises a support rod frame; the outer frame body is fixedly connected with the support rod frame.

Preferably, an upper end of the outer frame is connected and fixed to an upper end of the support rod frame, and/or a lower end of the outer frame is connected and fixed to a lower end of the support rod frame.

Another technical object of the utility model is to provide a seat of adjustable back mechanism of self-adaptation is leaned on in area solves the simple and crude, the poor problem of leaning on travelling comfort of traditional seat back structure, and its concrete technical scheme is as follows: a seat with reclining self-adapting function, comprising a reclining self-adapting adjustable backrest mechanism as described above. Namely, on the traditional chair, the leaning self-adaptive adjustable backrest mechanism is applied, and the leaning self-adaptive adjustable backrest mechanism and the chair seat are provided with corresponding butt joint parts.

The technical advantages of the utility model reside in that the seat overall structure of leaning on adjustable back mechanism of self-adaptation and this back mechanism is compact and uncomplicated, convenient to use, utilize magnet repulsion to cushion the support to human back, can give good support feedback along with back pressure, interval that simultaneously can the initiative between the regulation magnet further satisfies different people's dependence custom, overall structure intensity is high, and utilize magnet itself and the design of the partition of carelessness, produce the magnetotherapy effect to the whole back of the whole body, further reached and promoted user experience, do benefit to the purpose of human health, be worth using widely.

Drawings

Fig. 1 is a schematic structural view of an embodiment of the backrest mechanism of the present invention;

fig. 2 is a schematic structural view of an embodiment of the backrest mechanism of the present invention;

fig. 3 is a schematic partial structural view of an embodiment of the backrest mechanism of the present invention;

fig. 4 is a schematic structural diagram of a seat with a leaning self-adapting function according to the present invention;

the names of the parts corresponding to the numbers in the figure are respectively: a 1-a first magnet, a 11-a tough magnetic carrying bracket, a 111-a horizontal through inclined long hole, a 112-a clamping groove, a 12-a first magnetic carrying mounting seat, a 13-a vertical positioning sliding seat, a 131-a holding handle, a 14-a butt joint, a 2-a second magnet, a 21-a second magnetic carrying mounting seat, a 3-an outer frame body, a 31-a latticed backrest framework and a 4-a support rod frame.

Detailed Description

The invention will be further explained by means of specific embodiments with reference to the drawings, in which:

referring to fig. 1, the leaning self-adaptive adjustable backrest mechanism comprises a backrest support part and an elastic backrest part connected with the backrest support part, and further comprises a first magnetic adjustment assembly and a second magnetic adjustment assembly, wherein the first magnetic adjustment assembly is connected with the elastic backrest part (the backrest support part can also be used as a connecting part on which the first magnetic adjustment assembly depends according to requirements), the second magnetic adjustment assembly is connected with the elastic backrest part, and the first magnetic adjustment assembly and the second magnetic adjustment assembly are arranged at a front-back interval; the first magnetic adjustment assembly includes a first magnet a1, the second magnetic adjustment assembly includes a second magnet a2 magnetically repulsive to the first magnet a1, and the opposing faces of the first magnet a1 and the second magnet a2 are disposed opposite to each other.

Referring to fig. 2 again, the elastic chair back comprises an outer frame body a3 and a latticed backrest framework a31 connected in the outer frame body a3, the latticed backrest framework a31 can be designed into a plurality of rows of hexagonal grid groups, the grid groups can be connected with each other through transverse ribs, polygonal grids are formed among the grid groups, the same side grid group is connected with the outer frame body a3 through the transverse ribs, polygonal grids are also formed between the side grid group and the outer frame body a3, the whole latticed backrest framework a31 is made of a tough material, and an adaptive curved surface which is wrapped from two sides to the middle and is attached to and supports the back of a human body is formed, and the chair backs are also common in the market at present, so that the strength and comfort of the attached support are ensured while the material is saved; the back support portion includes a support bar frame a 4; the outer frame a3 is fixed to the support rod frame a4, the upper end of the support rod frame a4 can be designed with an upper connection leg, the lower end can be designed with a lower connection leg, the connection legs have various forms, such as a forked connection leg, or a new plate-shaped connection leg matching the upper and lower sides of the outer frame a3, so long as the connection legs can be well matched with the shape of the outer frame a3 and can complete support with good strength. Specifically, the upper end of the outer frame body a3 is fixedly connected with the upper end of the support rod frame a4, and optionally, the lower end of the outer frame body a3 is fixedly connected with the lower end of the support rod frame a4, so that the outer frame body a3 and the support rod frame a4 are connected into a whole, stress is shared, and strength is improved. Referring to fig. 4 again, for the whole of a seat support and back, the chair foot has been saved, the lower extreme of back of the chair supporting part is connected with butt joint portion, can both see the signal in fig. 1~4, can be a structure of buckling, also have corresponding butt joint portion on the seat support of traditional chair, but both rigid couplings are in the same place, or wherein butt joint portion sets up horizontal axis pole, set up the shaft hole in another butt joint portion, realize the function that can further adjust the angle of the back of the chair with articulated mode, then corresponding spacing portion structure that sets up (for example simpler all sets up assorted bayonet socket on two butt joint portions, insert the kelly in the bayonet socket and carry on spacingly), such rigid coupling or articulated mode can all realize with prior art, belong to comparatively common and comparatively traditional connected mode in the design of chair, and do not use this as the limit.

The first magnetic adjusting assembly further comprises a flexible magnetic carrying bracket a11 connected to the chair back support part, and a first magnetic carrying mounting seat a12 for mounting a first magnet a1 is arranged on the flexible magnetic carrying bracket a 11. The upper end of the first magnetic adjusting assembly is fixedly connected with the upper end of the latticed backrest framework a4, and the lower end of the first magnetic adjusting assembly is free, so that the lower end of the first magnetic adjusting assembly can be finely adjusted in the front-back direction, the distance between the first magnet a1 and the second magnet a2 is finally changed, and the repulsive force between the first magnet a1 and the second magnet a2 is adjusted. The first magnetic adjustment assembly is also actually a flexible magnetic-carrying bracket a11 in the figure, generally located between the back support and the flexible back portion, but it is not excluded to design it as a bifurcated bracket, but located between the back support and the flexible back portion, such as on both sides of the back support even on the back support rear side, which is not illustrated but is a completely feasible solution.

The second magnetic adjustment assembly is attached to the latticed back frame a 4. The second magnetic adjustment assembly also includes a second magnetic-carrying mount a21 attached to the flexible seat back portion for mounting a second magnet a 2. The back of the elastic chair can be designed with a preset mounting position for the second magnetic adjusting component at the beginning of the design, for example, the second magnetic mounting seat a21 is directly designed at several positions determined on the latticed backrest framework a4, or after the latticed backrest framework a4 completes the prototype, the later design is carried out.

The lower end of the toughness magnet carrying bracket is also connected with a bracket front and back pushing part which has at least two pushing modes, one of the pushing modes mentioned in the technical scheme comprises a bracket front and back pushing part and a bracket back and forth pushing part, wherein the bracket front and back pushing part comprises a vertical positioning sliding seat a13 movably connected to a chair back supporting part and an abutting joint a14 connected to the vertical positioning sliding seat a13 and abutted against the lower end of the toughness magnet carrying bracket a11, and the connecting surface of the vertical positioning sliding seat a13 and the chair back supporting part is inclined, namely the vertical positioning sliding seat a13 can relatively obliquely rise or fall on the chair back supporting part, the abutted abutting joint a14 is utilized to push the lower end of the toughness magnet carrying bracket a11 in different ranges, so that the toughness magnet carrying bracket a11 can have position change of transverse forward tilting or retraction;

referring to fig. 2 and 3 again, another one mentioned in the technical solution is that the forward and backward pushing portion of the bracket includes a vertical positioning slide a13 movably connected to the chair back support portion and an abutting joint a14 connected to the vertical positioning slide a13 and movably connected to the lower end of the flexible magnetic carrier a11, the connecting surface between the abutting joint a14 and the lower end of the flexible magnetic carrier a11 is inclined, that is, the abutting joint a14 directly drives the flexible magnetic carrier a11 to tilt forward or backward, where the manner of inclining the connecting surface between the abutting joint a14 and the flexible magnetic carrier a11 is simpler and more convenient to implement, that is, an inclined groove section or an inclined hole section is provided on the flexible magnetic carrier a11, a horizontally through inclined long hole a111 is provided on the flexible magnetic carrier a11 in the drawing, and the horizontally through inclined long hole a111 in the drawing is inclined from the lower portion to the upper right portion or inclined from the lower portion to the upper portion; the bracket front-back pushing part comprises a vertical positioning sliding seat a13 movably connected to the chair back supporting part and a butt joint a14 connected to a vertical positioning sliding seat a13, a butt joint section penetrating through a horizontal through inclined long hole a111 is arranged on the butt joint a14, the vertical positioning sliding seat a13 moves upwards or downwards in the operation process, and the butt joint section moves in the horizontal through inclined long hole a 111. Since the upper end of the flexible magnetic carrier a11 is fixed and the lower end is free, the flexible magnetic carrier a11 moves forwards or backwards along with the movement of the docking rod, so that the distance between the first magnet a1 and the second magnet a2 changes, and the repulsive force changes accordingly, that is, the flexible magnetic carrier a11 can be adjusted to meet different people or different leaning comfort requirements. The other means for realizing the front and back pushing part of the bracket can be realized by a pushing mode such as an air cylinder, a screw rod and the like, and can also be realized by a simpler electric structure.

The design of the chair back support part is matched, a vertical limiting slideway is arranged on the chair back support part, and a limiting slide block connected with the vertical limiting slideway is arranged on the vertical positioning slide seat a 13; the chair back supporting part is provided with a clamping groove a112, the vertical positioning sliding seat a13 is provided with a clamping protrusion which is clamped and locked with the clamping groove a112 or separated by force, and the vertical positioning sliding seat a13 is also provided with a holding handle a 131. The vertical limiting slide way limits the movement of the whole vertical positioning slide seat a13 to prevent deviation, the clamping groove a112 and the clamping protrusion complete locking action mutually, the vertical positioning slide seat a13 is fixed when moving to a designated position, the fixing means that under small external force, the clamping groove a112 and the clamping protrusion are not easy to loosen and separate, namely, the force applied during normal leaning is not enough to loosen the vertical positioning slide seat a13, and the clamping groove a112 and the clamping protrusion can be separated from each other by large external force, namely, a person forcibly moves the vertical positioning slide seat a13, in order to increase reasonable stress condition and stability between locking and separation, the clamping groove a112 can be deepened to a proper depth, the clamping protrusion can also be correspondingly protruded to a proper position, in addition, the clamping groove a112 and the surface of the clamping protrusion can be polished and polished to a certain extent, it can be determined through many practices, for example, the engaging groove a112 can be a circular groove, and an edge leading-out section for the engaging protrusion to enter or exit can also be provided on the engaging groove a112, for example, another guiding groove along the action direction of the engaging protrusion is provided on the edge portion on the circular groove, and the engaging protrusion can be a sphere.

The first magnetic adjustment assembly and the second magnetic adjustment assembly are respectively provided with one or more magnet subareas which take the surface of the elastic chair back as the maximum reference area, and generally, the first magnetic adjustment assembly and the second magnetic adjustment assembly can be respectively provided with one integral magnet subarea which is as large as the surface of the elastic chair back from top to bottom; two magnet sections may be disposed up and down in the first magnetic adjustment assembly and the second magnetic adjustment assembly, respectively, the first magnet a1 may be disposed in the magnet section of the first magnetic adjustment assembly, and the second magnet a2 may be disposed in the magnet section of the second magnetic adjustment assembly. The two magnet sections may be equally arranged on the upper and lower sides or on the left and right sides. The repulsion force generated by the magnet can keep relative balance on the whole chair back surface when a person leans against, namely the support for the human body reaches the balance on the whole chair back surface.

Preferably, the first and second magnetic adjustment assemblies are each provided with an upper magnet section, a middle magnet section and a lower magnet section from top to bottom, the first magnet a1 is provided in the upper, middle and lower magnet sections of the first magnetic adjustment assembly, and the second magnet a2 is provided in the upper, middle and lower magnet sections of the second magnetic adjustment assembly. The upper magnet partition, the middle magnet partition and the lower magnet partition respectively correspond to the upper region, the middle region and the lower region of the back of a human body, namely the region near the shoulders, the region near the waist and the back region between the two regions, the back is supported more comfortably and uniformly by fewer and more proper magnet partitions, the magnet cost is relatively saved, the back can not bear counter force too much and widely, the back is supported by aiming at the upper part, the middle part and the lower part of the back, the stress is sufficient and proper, the design of the first magnetic adjustment assembly and the second magnetic adjustment assembly ensures that the whole backrest mechanism can carry out follow-up and adaptive support feedback on different people when the people lean on the back or under different leaning postures and forces, and the people can obtain good comfortable experience by matching with structures such as a back cushion; meanwhile, the magnet can carry out magnetic therapy on a sedentary human body due to the characteristics of the magnet, the back part is a reflecting area of five internal organs and six internal organs, magnet partitions can be additionally arranged or the positions of the first magnet a1 and the second magnet a2 are set in a targeted manner, the magnetic therapy massage is mainly carried out on a shoulder neck area, a heart-lung area, a liver-gallbladder area, a spleen-stomach area, a kidney-bladder area and an Baliao area, the back supporting effect is further improved, and the specific arrangement of the magnet partitions, the number of the magnets and the positions can meet different requirements through customization. In the illustrated embodiment, the magnets are selected to be round blocks, the first magnet a1 is arranged on the first magnet carrying mounting seat a12 of the flexible magnet carrying bracket a11, the second magnet a2 is connected to the second magnet carrying mounting seat a21 of the latticed backrest skeleton a31, and two support blocks which are bilaterally symmetrical are selected from the upper magnet section, the middle magnet section and the lower magnet section respectively to arrange the magnets.

Claims

1. The utility model provides a lean on self-adaptation adjustable backrest mechanism, including back of the chair supporting part and with the elasticity back of the chair portion that back of the chair supporting part is connected, its characterized in that: the chair back support part is connected with the chair back support part, the elastic chair back part is connected with the chair back support part, the first magnetic adjusting assembly is connected with the chair back support part, and the second magnetic adjusting assembly is connected with the elastic chair back part; the first magnetic adjustment assembly comprises a first magnet (a 1), the second magnetic adjustment assembly comprises a second magnet (a 2) magnetically repulsive to the first magnet (a 1), and the first magnet (a 1) is disposed opposite to a repulsive face of the second magnet (a 2).

2. A reclining adaptive adjustable backrest mechanism according to claim 1, wherein: the first magnetic adjustment assembly and the second magnetic adjustment assembly are respectively provided with one or more magnet subareas taking the surface of the elastic chair back as a maximum reference area; the first magnet (a 1) is disposed in the magnet sub-section of the first magnetic adjustment assembly and the second magnet (a 2) is disposed in the magnet sub-section of the second magnetic adjustment assembly.

3. A reclining adaptive adjustable backrest mechanism according to claim 2, wherein: the first magnetic adjustment assembly and the second magnetic adjustment assembly are respectively provided with an upper magnet partition, a middle magnet partition and a lower magnet partition from top to bottom.

4. A reclining adaptive adjustable backrest mechanism according to claim 1, wherein: the first magnetic adjusting assembly further comprises a flexible magnetic carrying bracket (a 11) connected to the top end of the chair back supporting part and/or the elastic chair back part, and a first magnetic carrying mounting seat (a 12) used for mounting the first magnet (a 1) is arranged on the flexible magnetic carrying bracket (a 11).

5. A reclining adaptive adjustable backrest mechanism according to claim 4, wherein: the upper end of the flexible magnetic carrying bracket (a 11) is fixedly connected with the top end of the chair back supporting part and/or the elastic chair back part, and the lower end is free.

6. A reclining adaptive adjustable backrest mechanism according to claim 5, wherein: the flexible magnetic carrier bracket (a 11) is also connected with a bracket front and back pushing part for pushing the free lower end of the flexible magnetic carrier bracket.

7. A reclining adaptive adjustable backrest mechanism according to claim 6, wherein: the front and back pushing part of the bracket comprises a vertical positioning sliding seat (a 13) movably connected to the chair back supporting part and a butt joint (a 14) connected to the vertical positioning sliding seat (a 13) and abutted to the lower end of the toughness magnetic carrying bracket (a 11), and the vertical positioning sliding seat (a 13) and the connecting surface of the chair back supporting part are inclined.

8. A reclining adaptive adjustable backrest mechanism according to claim 6, wherein: the front and rear pushing part of the bracket comprises a vertical positioning sliding seat (a 13) movably connected to a chair back supporting part and a butt joint (a 14) movably connected to the vertical positioning sliding seat (a 13) and the lower end of a toughness-loaded magnetic bracket (a 11), wherein the butt joint (a 14) and the connecting surface of the lower end of the toughness-loaded magnetic bracket (a 11) are inclined.

9. A reclining adaptive adjustable backrest mechanism according to claim 7 or 8, wherein: a vertical limiting slideway is arranged on the chair back supporting part; and the vertical positioning sliding seat (a 13) is provided with a limiting sliding block connected with the vertical limiting sliding way.

10. A reclining adaptive adjustable backrest mechanism according to claim 7 or 8, wherein: the chair back supporting part is provided with a clamping groove (a 112); and the vertical positioning sliding seat (a 13) is provided with a clamping protrusion which is clamped and locked with the clamping groove (a 112) or separated by force.

11. A reclining adaptive adjustable backrest mechanism according to claim 7 or 8, wherein: and a holding handle (a 131) is also arranged on the vertical positioning sliding seat (a 13).

12. A reclining adaptive adjustable backrest mechanism according to claim 1, wherein: the second magnetic adjustment assembly further comprises a second magnetic-carrying mount (a 21) attached to the flexible seat back portion for mounting the second magnet (a 2).

13. A reclining adaptive adjustable backrest mechanism according to claim 1, wherein: the elastic chair back part comprises an outer frame body (a 3) and a latticed backrest framework (a 31) connected in the outer frame body (a 3); the seat back support portion includes a support bar frame (a 4); the outer frame body (a 3) is fixedly connected with the support rod frame (a 4).

14. A reclining adaptive adjustable backrest mechanism according to claim 13, wherein: the upper end of the outer frame body (a 3) is fixedly connected with the upper end of the support rod frame (a 4), and/or the lower end of the outer frame body (a 3) is fixedly connected with the lower end of the support rod frame (a 4).

15. The utility model provides a seat that self-adaptation adjustable back mechanism is leaned on in area which characterized in that: comprising the reclining self-adapting adjustable backrest mechanism according to any one of claims 1 to 14.