Abstract
A chair includes a base, a support element and a torsion element. The support element is coupled to the base and includes a seat region, a backrest region and a transition region connecting the seat region and the backrest region. The backrest region is reclinable relative to the seat region by way of elastic deformation of the support element. The torsion element is coupled to the base and to the backrest region. The torsion element controls the reclining of the backrest region relative to the seat region. The support element is exclusively connected to the torsion element above a lumbar region, wherein the backrest region can be inclined and/or twisted in relation to the seat region.
Claims
1. A chair comprising: a fixed frame; a support element coupled to the frame, the support element including a seat region forming a seat part, a rear region forming a rear part, and a transition region forming a transition part, the transition part connecting the seat part and the rear part, wherein the rear part is reclinable relative to the seat part by way of elastic deformation of the transition part; and a movement mechanism including a first rocker at least partly controlling movement of the rear part, a second rocker at least partly controlling movement of the seat part, and a basic body connecting the first rocker and the second rocker to the frame, wherein the first rocker is formed by a torsion element having a torsion rod extending in a vertical direction between the seat part and the rear part of the support element, the torsion rod capable of elastic deformation that enables a twisting behavior of the chair, wherein the first rocker is rotatably coupled to the basic body at a first axis of rotation and is rotatably coupled to a rear half of the seat part of the support element at a second axis of rotation, wherein the first rocker is coupled to the rear part of the support element exclusively above a lumbar support, and wherein the second rocker is rotatably coupled to the basic body at a third axis of rotation and is rotatably coupled to a front half of the seat part of the support element at a fourth axis of rotation.
2. The chair of claim 1, wherein the basic body includes a spring mechanism that dampens and restricts rotation of the first rocker and the second rocker.
3. The chair of claim 2, wherein the spring mechanism exclusively influences the inclination behavior of the chair, and wherein the twisting behavior of the chair is exclusively influenced by the torsion element.
4. The chair of claim 1, wherein the support element includes a pair of L-shaped support members.
5. The chair of claim 4, wherein the second rocker is formed by a pair of levers, each of the levers coupled to one of the L-shaped support members.
6. The chair of claim 4, wherein the second rocker further includes a bow connecting the pair of levers.
7. The chair of claim 4, wherein a cover is tensioned between the L-shaped support members, and wherein the support element further includes a spacer rod holding the L-shaped support members at a distance relative to one another, the spacer rod providing additional load bearing capacity to the cover.
8. The chair of claim 4, wherein the first rocker is formed by a torsion element, wherein the torsion element includes a pair of antler-like projections extending upward and outward, each antler-like projection coupled to one of the L-shaped support members on the rear part of the support element at a location above the lumbar support.
9. The chair of claim 1, wherein the rear part is movable between an initial position and an end position, wherein the seat part is movable between an initial position and an end position, and wherein the movement of the rear part is greater than the movement of the seat part.
10. A chair comprising: a fixed frame; a support element coupled to the frame, the support element including a first support member and a second support member, the first support member and the second support member each including a seat region forming a seat part, a rear region forming a rear part, and a transition region forming a transition part, the transition part connecting the seat part and the rear part, wherein the rear part is reclinable relative to the seat part by way of elastic deformation of the transition part; and a movement mechanism including a first rocker having a lumbar support and at least partly controlling movement of the rear part, a second rocker at least partly controlling movement of the seat part, and a basic body connecting the first rocker and the second rocker to the frame, wherein the seat part of the first support member is articulated on the first rocker via a first point of articulation and is articulated on the second rocker via a second point of articulation, wherein the seat part of the second support member is articulated on the first rocker via a third point of articulation and is articulated on the second rocker via a fourth point of articulation, wherein the rear part of the first support member is articulated on the first rocker via a fifth point of articulation that is located above the lumbar support of the first rocker, and wherein the rear part of the second support member is articulated on the first rocker via a sixth point of articulation that is located above the lumbar support of the first rocker.
11. The chair of claim 10, wherein the first point of articulation and the third point of articulation are located on a back half of the seat part, and wherein the second point of articulation and the fourth point of articulation are located on a front half of the seat part.
12. The chair of claim 11, wherein a first axis extends through the first point of articulation and the third point of articulation, and wherein a second axis extends through the second point of articulation and the fourth point of articulation.
13. The chair of claim 12, wherein the first axis and the second axis are parallel.
14. The chair of claim 10, wherein the first rocker is formed by a torsion element having a torsion rod extending in a vertical direction between the seat part and the rear part of the support element, the torsion rod capable of elastic deformation that enables a twisting behavior of the chair.
15. The chair of claim 14, wherein the torsion element is X-shaped.
16. The chair of claim 10, wherein the first support member and the second support members are L-shaped.
17. The chair of claim 10, wherein the second rocker is formed by a pair of levers, each of the levers coupled to one of the support members, and wherein the second rocker further includes a bow connecting the pair of levers.
18. The chair of claim 10, wherein a cover is tensioned between the support members, and wherein the support element further includes a spacer rod holding the support members at a distance relative to one another, the spacer rod providing additional load bearing capacity to the cover.
19. A method of constructing a chair including a frame, a support element, and a movement mechanism, the support element having a seat part, a rear part, and a transition part connecting the seat part and the rear part, the movement mechanism having a first rocker, a second rocker, and a basic body, the method comprising: rotatably coupling the first rocker to the basic body, the first rocker including a torsion element having a torsion rod extending in a vertical direction between the seat part and the rear part of the support element, the torsion rod capable of elastic deformation that enables a twisting behavior of the chair; rotatably coupling the second rocker to the basic body; rotatably coupling the first rocker to the support element at a first location and a second location, the first location being on a back half of the seat part, the second location being on the rear part at a position above a lumbar support of the support element; and rotatably coupling the second rocker to the support element at a position on the front half of the seat part.
20. A chair comprising: a fixed frame; a support element coupled to the frame, the support element including a seat region forming a seat part, a rear region forming a rear part, and a transition region forming a transition part, the transition part being located between the seat part and the rear part and connecting the seat part and the rear part, wherein the rear part is reclinable relative to the seat part by way of elastic deformation of the transition part; and a movement mechanism including a first rocker at least partly controlling movement of the rear part, a second rocker at least partly controlling movement of the seat part, and a basic body being located beneath the seat part and connecting the first rocker and the second rocker to the frame, wherein the first rocker is rotatably coupled to the basic body at a first axis of rotation and is rotatably coupled to a rear half of the seat part of the support element at a second axis of rotation, wherein the first rocker is coupled to the rear part of the support element exclusively above a lumbar support, wherein the second rocker is rotatably coupled to the basic body at a third axis of rotation and is rotatably coupled to a front half of the seat part of the support element at a fourth axis of rotation, and wherein the support element includes a pair of L-shaped support members.
Description
(1) In the drawings:
(2) FIGS. 1 and 2: show a side view and a rear view of a first variant of a chair according to the invention;
(3) FIGS. 3 and 4: show a side view and a rear view of a second variant of a chair according to the invention;
(4) FIGS. 5 and 6: show a side view and a rear view of a third variant of a chair according to the invention;
(5) FIGS. 7 and 8: show a side view and a rear view of a fourth variant of a chair according to the invention;
(6) FIGS. 9 and 10: show a side view and a rear view of a fifth variant of a chair according to the invention;
(7) FIGS. 11 and 12: show a side view and a rear view of a sixth variant of a chair according to the invention;
(8) FIGS. 13-15: each show an oblique view of the first, third and fifth variant;
(9) FIG. 16: shows a perspective illustration of the first variant with deconstructed details;
(10) FIGS. 17, 18: show further views of the chair shown in FIG. 16, with the frame removed;
(11) FIGS. 19-21: show modifications of the first variant in two side views and a rear view;
(12) FIGS. 22-24: show modifications of the second variant in two side views and a rear view;
(13) FIGS. 25-27: show modifications of the third variant in two side views and a rear view;
(14) FIGS. 28-30: show modifications of the fourth variant in two side views and a rear view;
(15) FIGS. 31-33: show modifications of the fifth variant in two side views and a rear view, and
(16) FIGS. 34-36: show modifications of the sixth variant in two sides views and a rear view.
(17) In FIG. 1 a first variant of a chair 1 is shown in side view. The chair 1 comprises a permanent support element 2, a movement mechanism 3 and a frame 4. The support element 2 comprises a seat region 5, a rear region 6 and a transition region 7. In this case, the seat region 5 forms a seat part 8, the rear region 6 a rear part 9 and the transition region 7 a transition part 10 of the support element 2. The movement mechanism 3 comprises a torsion element 11 and two front levers 12 and 13, the second front lever 12 being concealed by the first front lever 12 in the view of FIG. 1. The torsion element 11 is configured as a first rocker 14, which is connected about a rotational axis 15 in the manner of a rotary joint to the seat part 8 and about a rotational axis 16 in the manner of a rotary joint to the frame 4. The two front levers 12, 13 are configured as a second rocker 38 as a single component. Furthermore, the torsion element 11 is connected at two fastening points 17 and 18 to the rear part 9. Viewed in the y-direction, the fastening points 17 and 18 are located above a lumbar support 19 of the rear part 9 in an upper half 20 of the rear part 9. A central part M11 of the torsion element 11 is configured as a torsion rod 21, which extends in a vertical plane of symmetry 22 of the chair 1. The plane of symmetry 22 is also denoted as the xy-plane, and is located perpendicular to the drawing plane of FIG. 2, which shows the chair 1 from the direction of an arrow II provided in FIG. 1. The frame 4 is configured as a fixed frame. According to a variant, not shown, it is provided to design the frame 4 as a swivel frame with rollers in order to use the chair, for example, as an office chair. Between the support element 2 and the frame 3, a schematically shown resilient element 23 is arranged which holds the support element 2 in the resting position R1 shown in FIG. 1, and partially compensates for the loading of the support element 2 by a person seated on the support element 2, and permits a limited alteration of the position of the support element 2 relative to the frame 3 with correspondingly high loads. The above-described movement mechanism 3 is designed so that the inclination of the seat part and the inclination of the rear part are dependent on one another and the inclination of the rear part 9 between an initial position 9-1 shown in FIG. 1 and an end position 9-2 indicated by dashed lines, increases to a greater extent than the inclination of the seat part 8 between an initial position 8-1 shown in FIG. 1 and an end position 8-2 indicated by dashed lines. A relative movement which takes place between the seat part 8 and the rear part 9, when said parts are moved from their initial positions 8-1 and 9-1 into their end positions 8-2 and 9-2, is compensated by a deformation of the transition part 10, so that in spite of the permanent support element 2 a so-called synchronous mechanism 24 is produced in the chair 1. The torsional properties of the torsion element 11 come to bear when the person seated on the chair 1 does not lean centrally against the rear part 9 in the region of the plane of symmetry 22, but loads the rear part laterally, for example at a loading point 25. Such a loading of the support element 2 leads to a deformation of the support element 2, namely to torsion between the seat part 8 and the rear part 9. This torsion of the support element 2 is limited by the torsion element 11 and, in particular, the torsion rod 21, as said torsion rod creates a counter force, which is introduced via the fastening points 17 and 18 into the rear part 9, to this end the torsion element 11 being supported on the basic frame 4. Such a limited torsion of the support element 2 is possible, irrespective of the inclination of the rear part 9 of the support element 2, in any inclined position between the initial position 9-1 and the end position 9-2. The torsion rod 21 extends in the y-direction upwards beyond the lumbar support 19. The support element of the first variant shown in FIGS. 1 and 2, comprises two curved, L-shaped support members 26 and 27 and a cover 28 which is tensioned between the support members 26 and 27. The torsion element 11 and the levers 12 and 13 of the movement mechanism 3 in each case act on the support members 26 and/or 27. In the extension of the torsion rod 21, the torsion element 11 is configured as a pair of antler-like projections 29, which divide the torsion rod 21 towards the upper free ends 26a and 27a of the support members 26 and/or 27.
(18) In FIG. 13, the chair 1 is additionally shown in an oblique view obliquely from the rear. It can be seen in this view how the two levers 12 and 13 form the second rocker 38 by means of a bow 37 connecting said levers. The movement mechanism 3 therefore essentially comprises the first rocker 14, the second rocker 38 and a basic body 41. Like the first rocker 14, the second rocker 38 has a rotational axis 39 and a rotational axis 40, on four rotational axes 15, 16 and 39, 40 all the movement mechanism 3 running parallel to one another. The first rocker 14 is not only articulated in the region of the rotational axis 15 on the support element 2 but is also connected to the latter by means of the support members 26, 27 thereof at the fastening points 17, 18. A free rotatability of the rockers 14, about the rotational axes 16, 40 is damped and restricted by a spring mechanism 42 which is incorporated into the basic body 41.
(19) In FIGS. 3 and 4, a second variant of a chair 30 is shown in side view and rear view. Relative to this second variant, reference is initially made to the description of the first variant shown in FIGS. 1 and 2. Accordingly, similar components are denoted by the reference numerals used in FIGS. 1 and 2. In contrast to the first variant, the movement mechanism 3 essentially comprises just one torsion element 11 which is rigidly fastened between the seat part 8 of the support element 2 and the frame 4. This torsion element 11 comprises, in the same manner as the torsion element of the first variant, a torsion rod 21 which is divided in the manner of a pair of antler-like projections 29, and is fastened to the free ends 26a and 27a of the support members 26 and 27. In addition to its torsional properties, the torsion element 11 is still configured to be flexible and, as a result, cushions the rear part 9 of the support element 2 between the initial position 9-1 and the end position 9-2, to this end the transition region 7 of the support element 2 being elastically deformed. The movement mechanism also comprises a bearing element 48 with which the two support members 26, 27 are held at a predefined distance from one another.
(20) FIGS. 5 and 6 show a third variant of a chair 31. Relative to this third variant, reference is initially made to the description of the first variant shown in FIGS. 1 and 2. Accordingly, similar components are denoted by the reference numerals used in FIGS. 1 and 2. In contrast to the first variant, the support element 2 in the third variant has no support members and no cover but a curved, L-shaped seat shell 32 which is molded, for example, from plastics material. The seat shell 32 is elastically deformable, in particular, in its transition region 7. Analogous to FIG. 13, FIG. 14 shows an oblique view of the chair 31 shown in FIGS. 5 and 6. Accordingly, reference is made here to the description of FIG. 13. The first rocker 14 is configured comparably to the first rocker of the first variant and is connected to the support element 2 at two points of articulation, but the points of articulation 17, 18 lie on the seat shell 32 instead of on support members.
(21) FIGS. 7 and 8 show a fourth variant of a chair 33. Relative to this fourth variant, reference is initially made to the description of the first variant shown in FIGS. 1 and 2. Accordingly, similar components are denoted by the reference numerals used in FIGS. 1 and 2. In contrast to the first variant, the support element 2 in the fourth variant has no support members and no cover but a curved, L-shaped seat shell 32, which is molded, for example, from plastics material. The seat shell 32 is elastically deformable, in particular, in its transition region 7. Moreover, the movement mechanism 3 of the fourth variant comprises, in contrast to the movement mechanism of the first variant, only one torsion element 11 which is rigidly fastened between the seat part 8 of the support element 2 and the frame 4. This torsion element 11 comprises, in a similar manner to the torsion element of the first variant, a torsion rod 21 which is split in the manner of a pair of antler-like projections 29 and is fastened to the free ends 26a and 27a of the support members 26 and 27. In addition to its torsional properties, the torsion element 11 is still configured to be flexible and, as a result, cushions the rear part 9 of the support element 2 between the initial position 9-1 and the end position 9-2, to this end the transition region 7 of the support element 2 being elastically deformed.
(22) FIGS. 9 and 10 show a fifth variant of a chair 34. Relative to this fifth variant, reference is initially made to the description of the first variant shown in FIGS. 1 and 2. Accordingly, similar components are denoted by the reference numerals used in FIGS. 1 and 2. In contrast to the first variant, the support element 2 in the fifth variant has no support members and no cover but a curved, L-shaped seat shell 32 which is molded, for example, from plastics material. The seat shell 32 is elastically deformable, in particular, in its transition region 7. Moreover, the seat shell 32 is not attached via a pair of antler-like projections of the torsion element 11 but is centrally fastened in the region of the plane of symmetry 22 to an extension 35 of the torsion rod 21. Analogously to FIG. 13 and to FIG. 14, FIG. 15 shows an oblique view of the chair 34 shown in FIGS. 9 and 10. Accordingly, reference is made here to the description of FIGS. 13 and 14. In a departure from the first rocker of the first and third variant, the first rocker 14 does not fork in the manner of a pair of antler-like projections but rather merely has a central point of articulation 18 in which the first rocker 14 is connected to the seat shell 32 of the chair 34.
(23) FIGS. 11 and 12 show a sixth variant of a chair 36. Relative to this sixth variant, reference is initially made to the description of the first variant shown in FIGS. 1 and 2. Accordingly, similar components are denoted by the reference numerals used in FIGS. 1 and 2. In contrast to the first variant, the support element 2 in the sixth variant comprises no support members and no cover but a curved, L-shaped seat shell which is molded, for example, from plastics material. The seat shell 32 is elastically deformable, in particular, in its transition region 7. Moreover, the movement mechanism 3 of the sixth variant, in contrast to the movement mechanism of the first variant, comprises just one torsion element 11 which is fastened rigidly between the seat part 8 of the support element 2 and the frame 4. The seat shell 32 is not attached via a pair of antler-like projections of the torsion element but is centrally fastened in the region of the plane of symmetry 22 to an extension 35 of the torsion rod 21. In addition to its torsional properties, the torsion element 11 is still configured to be flexible, and as a result cushions the rear part 9 of the support element 2 between the initial position 9-1 and the end position 9-2, to this end the transition region 7 of the support element 2 being elastically deformed.
(24) With reference to the schematic illustrations of FIGS. 1, 2 and 13, FIG. 16 illustrates the chair 1 described as the first variant together with structural details, the frame 4 being shown without rollers provided. A cover 28 is also only indicated as a hatched surface in order to obtain clarity. In addition to the support members 26, 27 and the cover 28, the support element 2 also comprises two spacer rods 43, 44 illustrated schematically. The spacer rods 43, 44 hold the two support members 26, 27 at a defined distance a43, a44 at the free ends 26a, 26b and 27a, 27b thereof (see FIG. 18) and thus ensure a high load-bearing capacity of the cover 28. A high load-bearing capacity of the cover 28 is furthermore ensured by the articulation of the support members 26, 27 on the movement mechanism 3. In the seat region 5, the support member 26 is articulated on the first rocker 14 via a first point of articulation A and on the second rocker via a second point of articulation B, which is concealed. In the seat region 5, the support member 27 is articulated on the first rocker 14 via a first point of articulation C and on the second rocker 38 via a second point of articulation D. Furthermore, the fastening points 17, 18, at which the forking torsion element 11 merges into the support members 26, 27, form two further points of articulation E and F. By means of such a four-point bearing of the seat region 5, during dynamic sitting torsion of the seat region 5 or rolling of the seat region 5 about a roll axis WA, which lies in the plane of symmetry 22 and extends in the x direction (see FIG. 2), is reliably avoided and it is ensured that the rear part 9 twists in relation to the seat region 5 with corresponding loading by the seated person. By means of an approximately X-shaped geometry of the torsion element 11 and of the first rocker 14, the movement mechanism 3 confers a high degree of stability on the chair 1 while simultaneously permitting a torsion-like twisting between the upper half 20 of the rear part 9 and the seat part 5, the torsion being made possible by elastic deformation of the torsion element 11, the support members 26, 27 and the cover 28. The torsion takes place in particular in the region of the lumbar support 19 and of the transition part 10. By means of the rotatable articulation of the first rocker 14 on the basic body 41 of the movement mechanism 3, with corresponding loading by the seated person the torsion element 11 permits the torsion-like twisting to be combined with the inclination movement of the rear part 9, which movement is indicated in FIG. 2 by the positions 9-1 and 9-2. The seat part 8 is connected in the front half 8a thereof, which is located close to the spacer element 44, to the second rocker 38 and in the rear half 8b thereof, which adjoins the front half 8a at the spacer element 43, to the first rocker 14. By this means, the support members 26, 27 are guided on the basic body 41 by two parallelogram guides P1 and P2 which are arranged in a mirror-inverted manner with respect to the plane of symmetry 22, the parallelogram guides P1, P2 being substantially formed by the two rockers 14 and 38 and operating synchronously.
(25) In FIGS. 17 and 18 the chair 1 is shown perspectively in views from below, the frame, the spacer rods, the cover and the spring mechanism having been omitted from view. Two installation spaces 45, 46 for the spring mechanism (not illustrated) can be seen in the basic body 41. However, the spring mechanism (not illustrated) exclusively influences the inclination behavior of the chair 1. The torsional behavior of the chair 1 is influenced only by the torsion element 11 rather than the spring mechanism. It can be fully seen in FIG. 17 how the seat part 8 is suspended on the movement mechanism 3 by means of a four-point bearing 47 via the points of articulation A to D. Furthermore, it can be seen how the rear part 9, which is shown only with the support members 26, 27 and without the cover and spacer rod, is suspended on the movement mechanism 3 by means of a two-point bearing 49 via the points of articulation E and F.
(26) FIG. 18 once again denotes the four parallel rotational axes 15, 16, 39 and 40 and the four free ends 26a, 26b and 27a, 27b of the two support members 26, 27.
(27) With regard to FIGS. 16 to 18, reference is also made to the description of FIGS. 1, 2 and 13 with some of the reference numerals mentioned there also being noted in FIGS. 16 to 18.
(28) A combining of the inclination movement and torsional movement is possible if the first rocker 14 is of X-shaped configuration or upside down y-shaped configuration, as shown in the fifth and sixth variant.
(29) FIGS. 19 to 36 illustrate modifications of the six variants illustrated in FIGS. 1 to 12, in two side views and one rear view in each case. With regard to the basic construction and the basic functioning of the modifications shown in FIGS. 19 to 36, reference is correspondingly made to the description of FIGS. 1, 2 and 3, 4 and 4, 5 and 5, 6 and 7, 8 and 9, 10 and 11, 12. In contrast to the chairs shown in FIGS. 1 to 12, in all six chairs shown in FIGS. 19 to 36, 1a (see FIGS. 19 to 21), 30a (see FIGS. 22 to 24), 31a (see FIGS. 25 to 27), 33a (see FIGS. 28 to 30), 34a (see FIGS. 31 to 33) and 36a (see FIGS. 34 to 36), the rear part 9 is a first buckling device 50 (illustrated symbolically), and the torsion element 11 is a second symbolically illustrated buckling device 51, a lower section 52 of the rear part 9, which section adjoins the transition part 10, and an upper section 53 of the rear part 9, which section adjoins the lower section 52, being pivotably connected by the first buckling device 50. In this case, the first buckling device 50 is arranged below a region of articulation 54, in which the torsion element 11 is connected to the rear part 9. The second buckling device 51 formed in the torsion element 11 comprises a lower section 55 of the torsion element 11, which section is connected to a basic body 41 of the movement mechanism 3, and an upper section 56 of the torsion element 11, which section is connected to the rear element 9 in the region of articulation 54, the two sections 55, 56 being connected pivotably by the second buckling device 51. In the region of articulation 54, the upper section 53 of the rear part 9 and the upper section 56 of the torsion element 11 are connected to one another. The second buckling device 51 and therefore also the first buckling device 50 are formed above the lumbar support 19 of the chair 1a, 30a, 31a, 33a, 34a and 36a. In this case, the second buckling device 51 is arranged below the first buckling device 50.
(30) The first buckling device 50 is preferably configured as a bending zone B50 which permits a type of buckling formation between the lower section 52 and the upper section 53 of the rear part 9 depending on in which position the chair 1a, 30a, 31a, 33a, 34a or 36a is in. In a resting position R1, as shown in FIGS. 19, 22, 25, 28, 31 and 34, the lower section 52 and the upper section 53 of the rear part 9 have a first angle of aperture -R1 with respect to one another, the angle of aperture -R1 lying in the plane of symmetry 22, which has already been described for the individual variants, and being measured between a surface 52a of the lower section 52 in contact with a seated person and a surface 53a of the upper section 53 in contact with a seated person. The resting position R1 is taken up by the chair 1a, 30a, 31a, 33a, 34a or 36a when said chair is unloaded or when a person sits on the chair in such a manner than the person exerts only a small pressure, if any at all, on the rear element 9 of said chair. In a reclined position R2, as shown in FIGS. 20, 23, 26, 29, 32 and 35, the lower section 52 and the upper section 53 of the rear part 9 have a second angle of aperture -R2 with respect to one another, the angle of aperture -R2 likewise lying in the plane of symmetry 22 mentioned. During the transition from the position R1 into the position R2, the two interacting buckling devices 50 and 51 of the rear part 9 and of the torsion element 11 cause a reduction in the angle of aperture from the value -R1 to the value -R2. The position which the two sections 52, 53 of the rear part 9 take up with respect to each other therefore changes in the manner of an easily closing flap. The upper section 53 of the rear part 9 moves forwards relative to the lower section 52 of the rear part 9 in the arrow direction x. That is to say, the upper section 53 of the rear part 9 moves relative to the lower section 52 of the rear part 9 during the inclination movement, which the chair 1a, 30a, 31a, 33a, 34a or 36a executes when a person seated on the chair 1a, 30a, 31a, 33a, 34a, or 36a leans back against the rear part 9, and in the process buckles forwards. Said movement, which is opposed to the inclination movement, which is directed in the arrow directions x and y, stabilizes the neck and the head of the person seated on the chair 1a, 30a, 31a, 33a, 34a or 36a, depending on the shaping and the size of the upper section 53 of the rear part 9, and makes it possible for the person, in an ergonomically desirable manner, to maintain a viewing axis, which has been adopted in the position seated upright, during the reclining and in the reclined position, since the upper section 53 of the rear part 9, against the surface 53a of which the head of the person seated on the chair bears, inclines to a smaller extent between the position R1 and the position R1 than the lower section 52 of the rear part 9, against the surface 52a of which the upper body of the person seated on the chair leans. In this case, the second buckling device 51 is arranged below the first buckling device 50 in both positions R1 and R2 of the chair 1a, 30a, 31a, 33a, 34a or 36a.
(31) The second buckling device 51 is preferably likewise configured as a bending zone B51 which permits a type of buckling formation between the lower section 55 and the upper section 56 of the torsion rod 11. Where the buckling formation is controlled by the movement mechanism 3, the part thereof is the buckling device 51. In a resting position R1, as shown in FIGS. 19, 22, 25, 28, 31 and 34, the lower section 55 and the upper section 56 of the torsion rod 11 have a first angle of aperture -R1 with respect to one another, the angle of aperture -R1 lying and being measured in the plane of symmetry 22, which has already been described for the individual variants. In a reclined position R2, as shown in FIGS. 20, 23, 26, 29, 32 and 35, the lower section 55 and the upper section 56 of the torsion element 11 have a second angle of aperture -R2 with respect to one another, the angle of aperture -R2 likewise being measured in the plane of symmetry 22. Owing to the fact that the upper section 56 buckles forwards in the x direction during the change from the position R1 into the position R2, the value of the angle of aperture is reduced from -R1 to -R2. The upper section 56 of the torsion element 11 therefore moves forwards relative to the lower section 55 of the torsion element 11 when a person seated on the chair 1a, 30a, 31a, 33a, 34a, or 36a leans back. The two buckling devices 50 and 51 therefore operate synchronously as a consequence of the connection of the upper sections 53 and 56 thereof in the region of articulation 54and therefore a closing movement of the movement mechanism 3, to which the buckling device 51 and the upper section 56 of the torsion element 11 belong, is transmitted to the rear part 9 of the support element 2. Correspondingly, upon departing from the position R2 into the position R1, an opening movement of the lower and of the upper sections 55, 56 of the movement mechanism 3 takes place again and therefore, as a consequence of the coupling, an opening movement of the lower section 52 and of the upper section 53 of the rear part 9 also takes place again.
(32) It is provided for the first buckling device 50 to arrange the latter approximately level with the uppermost thoracic vertebra of a person seated in the chair 1a, 30a, 31a, 33a, 34a or 36a in order optimally to support the neck and head of said person in a reclined seating position. Correspondingly, the rear part in the modifications shown in FIGS. 19 to 36 is dimensioned such that the upper section 53 of the rear part 9 lies level with a neck region or a neck and head region of a person seated on the chair.
(33) In the modifications, which are shown in FIGS. 19 to 21 and 22 to 24, of the first and second variants, the first buckling device 50 is technically formed in the two support members 26, 27 by respective bending zones B50, configured as an elastic region, or alternatively by respective joint elements. The cover 28 follows the movement predetermined by the support members 26, 27 without additional adaptation.
(34) In the modifications, which are shown in FIGS. 25 to 27, 28 to 30, 31 to 33 and 34 to 36, of the third to sixth variants, the first buckling device 50 is incorporated into the seat shell 32 forming the support element 2, and extends in a horizontal alignment over the rear part 9. The first buckling device 50 is formed by a bending zone B50, which is configured as an elastic region, or alternatively by a joint element.
(35) In the modifications, which are shown in FIGS. 19 to 21, 22 to 24, 25 to 27 and 28 to 30, of the first to fourth variants, the second buckling device 51 is formed in the torsion element 11, or in the first rocker 14 which forms the torsion element 11, below the pair of antler-like projections 29, into which the torsion rod 21 forks in order to merge in the region of articulation 54 into the support members 26, 27. The second buckling device 51 is formed by a bending zone B51, which is configured as an elastic region, or alternatively as a joint element. The pair of antler-like projections 29 forms the upper section 56 of the torsion element 11. The pair of antler-like projections 29 is connected in particular in a planar manner to the support members 26, 37.
(36) In the modifications, which are shown in FIGS. 31 to 33 and 34 to 36, of the fifth and sixth variants, the second buckling device 51 is formed in the torsion element 11, or in the first rocker 14 which forms the torsion element 11, below the central region of articulation 54, in which the rocker 14 is articulated on the seat shell 32. The second buckling device 51 is formed by a bending zone B51, which is configured as an elastic region, or alternatively by a joint element.
(37) The invention is not limited to the exemplary embodiments shown or described. On the contrary, it comprises developments of the invention which lie within the scope of the protected claims.
