CHAIR WITH SEAT TILT MECHANISM

Abstract

A chair, in particular an office chair, has a seat inclination mechanism. A transverse strut of the seat inclination mechanism forms a spring device and this spring device has at least one torsion element. The seat inclination mechanism further has a basic support on which a backrest support and a seat element support are articulated. The transverse strut of the seat inclination mechanism forms a spring device. The transverse strut extends in the chair transverse direction and wherein the spring device has at least one torsion element, in particular a torsion bar spring. The torsion element, together with the basic support and/or the backrest support and/or the seat element support, is formed integrally, in particular in one piece, from plastic.

Claims

1-10. (canceled)

11. A chair, comprising: a seat element; a seat element support; a seat backrest having a backrest support; a seat inclination mechanism; a base frame having a base column on which said seat element and said seat backrest are mounted via said seat inclination mechanism; and said seat inclination mechanism having a joint connection and a basic support connected to said base column and on which said backrest support and said seat element support are articulated, and said seat element and said seat backrest are connected to one another via said joint connection of said seat inclination mechanism, said seat inclination mechanism having a transverse strut forming a spring device, wherein said transverse strut extending in a chair transverse direction and wherein said spring device having at least one torsion element, and wherein said torsion element, together with said basic support and/or said backrest support and/or said seat element support, is formed integrally, from plastic.

12. The chair according to claim 11, wherein: said seat inclination mechanism has a lever; and said at least one torsion element is one of two torsion elements of said spring device, which are integrally attached to said basic support and, with respect to a vertical chair longitudinal center plane, are attached at their respective distal ends to said lever of said seat inclination mechanism.

13. The chair according to claim 12, wherein said torsion elements are attached to said basic support and, together with said backrest support and said basic support, is formed integrally.

14. The chair according to claim 13, wherein: said torsion elements are torsion bar springs; said backrest support, together with said basic support and said torsion bar springs, are formed integrally, from plastic and form levers of said seat inclination mechanism, in such a way that said seat element support is formed from struts, which are articulated on said basic support, and rear rotary joints, which are disposed on said levers and which hold said seat element.

15. The chair according to claim 11, wherein said at least one torsion element, together with said basic support or said seat element support, is formed integrally.

16. The chair according to claim 15, wherein said at least one torsion element is one of two torsion elements being two torsion bar springs; wherein said basic support, together with said torsion bar springs, are formed integrally, from plastic and forms levers of said seat inclination mechanism; further comprising a lower rotary joint; and wherein said backrest support is connected to said basic support via said lower rotary joint.

17. The chair according claim 15, wherein said at least one torsion element is one of two torsion elements being two torsion bar springs; further comprising a lever formed integrally with said torsion bar springs; wherein said seat inclination mechanism has a front rotary joint ; and wherein with respect to a vertical chair longitudinal center plane, said torsion bar springs of said spring device are attached at their respective distal ends to said seat element and are attached, via said lever formed integrally with said torsion bar springs, to said front rotary joint of said seat inclination mechanism on said basic support.

18. The chair according to claim 15, wherein: said seat element support is formed from a frame which forms said transverse strut; said seat inclination mechanism has a front rotary joint; and said at least one torsion element is one of two torsion elements being torsion bar springs having a lever formed integrally therein, wherein with respect to a vertical chair longitudinal center plane, said two torsion bar springs of said spring device are attached at their respective distal ends to said frame and are attached, via said lever formed integrally with said torsion bar springs, to said front rotary joint of said seat inclination mechanism on said basic support.

19. The chair according to claim 18, further comprising a rear rotary joint being formed at a rear end of said frame, and said backrest support is connected to said seat element support via said rear rotary joint, wherein a pivoting movement of said backrest support on said lower rotary joint causes a displacement of said seat element in the chair longitudinal direction relative to said basic support.

20. A chair according to claim 11, wherein: the chair is an office chair; said at least one torsion element is a torsion bar spring; and said torsion element, together with said basic support and/or said backrest support and/or said seat element support, is formed integrally, in one piece.

21. The chair according to claim 12, wherein said two torsion elements of said spring device are torsion bar springs.

22. The chair according to claim 13, wherein said torsion elements are attached to said basic support and, together with said backrest support and said basic support, is formed integrally, in one piece.

23. The chair according to claim 14, wherein said backrest support, together with said basic support and said torsion bar springs, are formed integrally, in one piece.

24. The chair according to claim 16, wherein said basic support, together with said torsion bar springs, are formed integrally, in one piece; and wherein said backrest support is connected to said basic support via said lower rotary joint in such a way that said seat element support is formed from at least one strut, which is articulated on said backrest support, and levers which hold said seat element.

25. The chair according claim 16, further comprising a lever formed integrally with said torsion bar springs; wherein said seat inclination mechanism has a front rotary joint; and wherein with respect to the vertical chair longitudinal center plane, said torsion bar springs of said spring device are attached at their respective distal ends to said seat element and are attached, via said lever formed integrally with said torsion bar springs, to said front rotary joint of said seat inclination mechanism on said basic support, in such a way that said distal ends of said torsion bar springs are screwed to or integrally formed on said seat element.

26. A seat inclination mechanism for a chair, the seat inclination mechanism comprising: a backrest support; a seat element support; a basic support on which said backrest support and said seat element support are articulated; and a transverse strut of the seat inclination mechanism forming a spring device, said transverse strut extending in a chair transverse direction and said spring device having at least one torsion element, and said torsion element, together with said basic support and/or said backrest support and/or said seat element support, is formed integrally, from plastic.

27. The seat inclination mechanism according to claim 26, wherein said a least one torsion element is a torsion bar spring, and said torsion element, together with said basic support and/or said backrest support and/or said seat element support, is formed integrally, in one piece.

Description

[0057] Exemplary embodiments of a chair according to the invention are illustrated in schematically simplified form in the drawing and are explained in more detail in the following description. In the drawing:

[0058] FIG. 1 shows a seat inclination mechanism (prior art),

[0059] FIG. 2 shows a side view of a chair according to the invention (first embodiment),

[0060] FIG. 3 shows a further side view of the chair from FIG. 2,

[0061] FIG. 4 shows a perspective exploded illustration of the chair from FIG. 2,

[0062] FIG. 5 shows an embodiment of a basic support in a perspective view,

[0063] FIG. 6 shows a further perspective view of the basic support from FIG. 5,

[0064] FIG. 7 shows a development of the basic support from FIG. 5 in a perspective view,

[0065] FIG. 8 shows a further perspective view of the basic support from FIG. 7,

[0066] FIG. 9 shows a perspective exploded illustration of the basic support from FIG. 7,

[0067] FIG. 10 shows a further development of the basic support from FIG. 5 in a perspective view,

[0068] FIG. 11 shows a sectional illustration of the basic support from FIG. 10,

[0069] FIG. 12 shows a perspective exploded illustration of a further development of the basic support from FIG. 7,

[0070] FIG. 13 shows a side view of a chair according to the invention (second embodiment),

[0071] FIG. 14 shows a further side view of the chair from FIG. 13,

[0072] FIG. 15 shows a perspective exploded illustration of the chair from FIG. 13,

[0073] FIG. 16 shows a partial sectional view of the chair from FIG. 15,

[0074] FIG. 17 shows a side view of a further chair according to the invention,

[0075] FIG. 18 shows a further side view of the chair from FIG. 17,

[0076] FIG. 19 shows a bottom view of the chair from FIG. 17,

[0077] FIG. 20 shows a perspective exploded illustration of the chair from FIG. 17,

[0078] FIG. 21 shows a further perspective view of the crossmember from FIG. 20,

[0079] FIG. 22 shows a side view of a further chair according to the invention,

[0080] FIG. 23 shows a further side view of the chair from FIG. 22,

[0081] FIG. 24 shows a bottom view of the chair from FIG. 22,

[0082] FIG. 25 shows a perspective exploded illustration of the chair from FIG. 22,

[0083] FIG. 26 shows a bottom view of a frame from FIG. 25.

[0084] FIG. 1 shows the prior art. FIGS. 2 to 12 show a first embodiment and variants thereof, and FIGS. 13 to 26 show a second embodiment and variants thereof.

[0085] All the figures show the invention not true to scale, here merely schematically and only with its essential constituent parts. The same reference signs correspond here to elements having an identical or comparable function.

[0086] At the front or front here means that a structural part is arranged at the front in the chair longitudinal direction or refers to a component extending in the direction of the front seat edge or pointing in this direction, whereas at the rear or rear means that a structural part is arranged at the rear in the chair longitudinal direction or refers to a component which extends in the direction of the backrest or of the backrest support or of the rear seat edge or points in this direction. The expressions at the top or upper or higher and at the bottom or lower or deeper relate to the intended use state of the office chair or of the office chair mechanism.

[0087] In order to illustrate the pivoting principle, FIG. 1 depicts in highly simplified form a seat inclination mechanism generally known from the prior art. This is a synchronous mechanism 139 in which the three main components of the mechanism, namely basic support 1, seat element support 3 and backrest support 4, are coupled to one another via rotary joints, with the result that a pivoting movement of the backrest support 4 in the pivoting direction 7, as seen in the chair longitudinal direction 146, induces toward the rear a synchronous following movement of the seat element support 3, whereas the basic support 1 remains positionally fixed and immovable. The mechanism is mounted by its basic support 1 on a base column 2 which stands on the floor by way of a chair cross. The backrest support 4, forms with its articulation to the basic support 1 on the one hand and to the rear region of the seat element support 3 or of the seat shell or of the seat frame on the other hand, a rear coupling element 140 integrated into the backrest support 4, whereas a separate front coupling element 141 connects the basic support 1 to the front region of the seat element support 3 or of the seat shell or of the seat frame. In this way there are provided four rotary points, realized by four rotary joints, wherein each rotary joint is assigned a transverse axle. These are the first rotary joint 142 for connecting the basic support 1 to the rear coupling element 140, the second rotary joint 143 for connecting the rear coupling element 140 to the seat element support 3, the third rotary joint 144 for connecting the basic support 1 to the front coupling element 141, and the fourth rotary joint 145 for connecting the front coupling element 141 to the seat element support 3.

[0088] According to the invention, it is then possible in principle for all the actual rotary points realized by rotary joints 142, 143, 144, 145 to be replaced by virtual rotary points which are provided by one or more torsion elements according to the invention.

[0089] The transverse axis according to the invention, which has the spring device, of the seat inclination mechanism can serve for forming any desired rotary joints of the seat inclination mechanism. Thus, for example, a front, upper transverse axle serving to form the rotary joint 145 can have the spring device according to the invention. Alternatively or additionally, a front, lower transverse axle serving to form the rotary joint 144 can have the spring device according to the invention. Alternatively or additionally, a rear, upper transverse axle serving to form the rotary joint 143 can have the spring device according to the invention. Alternatively or additionally, a rear, lower transverse axle serving to form the rotary joint 142 can have the spring device according to the invention.

[0090] The invention is not restricted to the use of a single transverse axle according to the invention in a seat inclination mechanism. Thus, a seat inclination mechanism can have a plurality of such transverse axles with spring devices. It is for possible for example for transverse axles according to the invention all to form front rotary joints, as seen in the chair longitudinal direction, of a seat inclination mechanism and/or transverse axles according to the invention can all form rear rotary joints, as seen in the chair longitudinal direction, of a seat inclination mechanism. Likewise, it is possible for transverse axles according to the invention all to form lower rotary joints, which are assigned to the basic support, of a seat inclination mechanism and/or transverse axles according to the invention can all form upper rotary joints, which are assigned to the seat element support, of a seat inclination mechanism. A formation of the rotary joints by the transverse axles according to the invention in a cross-over arrangement is also possible (for example formation of the rotary joints bottom front and top rear). Possible in principle are any desired arrangements of the transverse axles according to the invention for forming an individual rotary joint, a plurality of selected rotary joints or all rotary joints of the seat inclination mechanism.

[0091] Each of the transverse axles according to the invention comprises a spring device having at least one torsion element, in particular a torsion bar spring. Transverse axles can be provided here which are formed essentially completely from a single torsion element. However, transverse axles can also be provided which have a plurality of torsion elements. Here, these torsion elements can be arranged behind one another along the longitudinal direction of the transverse axle. In this case, the torsion elements can also be spaced apart from one another. For example, the torsion elements of a transverse axle can be formed as axle portions which are connected to one another via axle portions with relatively low twistability or via rigid axle portions. Embodiments are also conceivable in which the transverse axle has a plurality of torsion elements arranged parallel to one another in the axle longitudinal direction.

[0092] The application of the transverse axles according to the invention is also not restricted to seat inclination mechanisms having four-joint coupling. The use in seat inclination mechanisms with another coupling geometry is also possible. Likewise possible is the application of one or more transverse axles according to the invention in seat inclination mechanisms in which use can also be made of deformation elements which run in the chair longitudinal direction and which deform, in particular bend, as a result of tensile or compressive loading.

[0093] A first embodiment of the invention will be described below. Here, the rotary joint 142 shown in FIG. 1 is replaced with the aid of a transverse strut according to the invention by a virtual rotary point.

[0094] FIGS. 2 to 4 illustrate a chair 232 according to the invention which comprises a base column 233 with a roller cross (not shown in more detail), a seat inclination mechanism 234, a seat element 235, a seat backrest 236, and a basic support 237 connected to the base column 233. A transverse strut 238 of the seat inclination mechanism 234 forms torsion bar springs 239. In particular, an essentially frame-shaped backrest support 240 of the seat backrest 236, together with the basic support 237 and the torsion bar springs 239, is formed integrally, in particular in one piece, from plastic. Parallel legs 241 of the backrest support 240 form levers 242 of the seat inclination mechanism 234, said levers being integrally formed on the torsion bar springs 239. Furthermore, struts 243 which hold the seat element 235 are integrally formed on the basic support 237. In a seat shell 244 of the seat element 235 there are formed oblong holes 245 into each of which an axle 246 of the strut 243 is movably inserted. The oblong hole 245 and the axle 246 form a front rotary joint 248. Moreover, a rear rotary joint 247 is formed between in each case a leg 241 or lever 242 and the seat shell 244. An inclination of the seat backrest 236 toward the rear, as illustrated in FIG. 7, produces, in addition to the tilting of the seat backrest 236, a displacement of the seat element 235 toward the rear, wherein the axle 246 is also displaced in the oblong hole 245. The torsion bar springs 239 are in each case formed with an oblong hole 249 which runs in the longitudinal direction of the torsion bar spring 239. Overall, the chair 232 is essentially formed from the backrest support 240, which is integrally formed with the basic support 237 consisting of plastic, and the seat shell 244.

[0095] FIGS. 5 and 6 show a schematic illustration of an embodiment of a basic support 250 which consists of plastic and which has a spring device 251 with torsion bar springs 252. The torsion bar springs 253 are formed by a transverse strut 253 having a continuous oblong hole 254, wherein in each case a pivotable lever 256 is integrally formed at distal ends 255 of the torsion bar springs 252. Furthermore, a flange 257 on the transverse strut 253 for connection to a base column (not shown in more detail here) of a chair is formed in the basic support 250. As can be seen from FIG. 6, the levers 226 can be inclined by an angle , thereby generating a spring force and a deformation of the torsion bar springs 252.

[0096] FIGS. 7 to 9 show a basic support 258 which, by contrast with the basic support from FIG. 5, has a setting device 259. The setting device 259 comprises threaded pins 260 which can be rotated with an actuating shaft 261 via a crank 262 and are displaceable on the actuating shaft 261 in a longitudinal direction. The threaded pins 260 engage in transverse oblong holes 263 which are formed in an oblong hole 264 in torsion bar springs 265 of a transverse strut 266. Depending on the displacement of the threaded pins 260, a resistance torque of the torsion bar springs 265 can be changed, with the result that a spring constant or the torsion bar springs 265 can be set to be harder or softer.

[0097] FIGS. 10 and 11 show a basic support 267 which, by contrast with the basic support from FIG. 9, has further torsion bar springs 268 made of spring steel. The further torsion bar springs 268 are inserted into an oblong hole 269 and fastened to the basic support 267 in a rotationally fixed manner. The arrangement of the further torsion bar springs 268 on the basic support 267 allows a spring constant of the thus formed torsion bar springs 270 to be substantially influenced.

[0098] FIG. 12 shows a basic support 271 which combines the basic supports described in relation to FIGS. 7 to 10.

[0099] With respect to the first embodiment of the invention that is described in conjunction with FIGS. 2 to 12, the solution according to the invention is distinguished in particular by the fact that what is concerned is a chair 232, in particular an office chair, which comprises a base frame with a base column 233 on which a seat element 235 and a seat backrest 236 are mounted via a seat inclination mechanism 234, wherein the seat inclination mechanism comprises a basic support 237, 250, 258, 267, 271 which is connected to the base column and to which a backrest support 240 and a seat element support are articulated, and the seat element and the seat backrest are connected to one another via a joint connection 221 of the seat inclination mechanism, wherein a transverse strut 238, 253, 266 of the seat inclination mechanism forms a spring device 251, wherein the transverse strut extends in the chair transverse direction 100 and is attached to the basic support, wherein the spring device has at least one torsion bar spring 239, 252, 265, 270, wherein the backrest support, together with the basic support and the torsion bar spring, is formed integrally, in particular in one piece, from plastic.

[0100] This chair is advantageously characterized in that the spring device 251 is formed with preloading.

[0101] This chair is advantageously characterized in that two torsion bar springs 239, 252, 265, 270 of the spring device 251 are integrally attached to the basic support 237, 250, 258, 267, 271 and, with respect to a vertical chair longitudinal center plane, are attached at their respective distal ends 255 to a lever 242, 256 of the seat inclination mechanism 234.

[0102] This chair is advantageously characterized in that the backrest support 240, together with the basic support 237, 250, 258, 267, 271 and the torsion bar springs 239, 252, 265, 270, is formed integrally, in particular in one piece, from plastic and forms the levers 242, 256 of the seat inclination mechanism 234.

[0103] This chair is advantageously characterized in that the seat element support is formed from struts 243 which are articulated to the basic support 237, 250, 258, 267, 271, and rear rotary joints 247 which are arranged on the levers 242, 256 and which hold the seat element 235.

[0104] This chair is advantageously characterized in that at least one front rotary joint 248 which is displaceable in an oblong hole 245 is formed between the struts 243 and the seat element 235, wherein a pivoting movement of the backrest support 240 on the torsion bar springs 239, 252, 265, 270 causes a displacement of the seat element 235 in the chair longitudinal direction relative to the basic support 237, 250, 258, 267, 271.

[0105] This chair is advantageously characterized in that the torsion bar spring 239, 252, 265, 270 is formed from a bar-shaped profile portion having an oblong hole 249, 254, 264, 269 which runs at least in certain portions in a longitudinal direction of the profile portion.

[0106] This chair is advantageously characterized in that the spring device has a setting device 259 for setting a spring constant of the torsion bar springs 265, 270, wherein the setting device is formed from support elements which are displaceable in the longitudinal direction in the oblong hole 264, 269.

[0107] This chair is advantageously characterized in that the support elements are formed in each case as a threaded pin 260 with an inner profile whose oppositely arranged threads engage in transverse oblong holes 263 formed in the oblong hole 264, 269, wherein the support elements are displaceable in the longitudinal direction of the oblong hole by means of a rotation of an actuating shaft 261, which is inserted in the inner profile, of the setting device 259.

[0108] This chair is advantageously characterized in that the spring device has for each torsion bar spring 270 a further torsion bar spring 268 made of spring steel, wherein the further torsion bar spring is inserted into the oblong hole 269 and is in each case fastened in a rotationally fixed manner at its proximal end to the basic support 267, 271 and at its distal end to the lever of the seat inclination mechanism.

[0109] With respect to the embodiment of the invention that is described in conjunction with FIGS. 2 to 12, the solution according to the invention is distinguished in particular by the fact that what is concerned is a seat inclination mechanism 234 for a chair 232, in particular an office chair, which comprises a basic support 237, 250, 258, 267, 271 which can be connected to a base column 233 of the chair, wherein two torsion bar springs 239, 252, 265, 270 of the seat inclination mechanism are integrally attached to the basic support and, with respect to a vertical chair longitudinal center plane, are attached at their respective distal ends 255 to a lever 242, 256 of the seat inclination mechanism, wherein a backrest support 240 of the chair, together with the basic support and the torsion bar springs, is formed integrally, in particular in one piece, from plastic and forms the levers of the seat inclination mechanism, wherein a seat element support of the chair is formed from struts 243, which are articulated on the basic support, and rear rotary joints 247 which are arranged on the levers and which hold the seat element 235, wherein at least one front rotary joint 248 which is displaceable in an oblong hole 245 is formed between the struts and the seat element, wherein a pivoting movement of the backrest support on the torsion bar springs 239, 252, 265, 270 causes a displacement of the seat element in the chair longitudinal direction relative to the basic support 237, 250, 258, 267, 271.

[0110] With respect to the embodiment of the invention that is described in conjunction with FIGS. 2 to 12, the solution according to the invention is distinguished in particular by the fact that what is concerned is a setting device 259 for a chair 232, in particular an office chair, wherein the setting device serves for setting a spring constant of torsion bar springs 265, 270 of a seat inclination mechanism of the chair, wherein the torsion bar springs are formed from a bar-shaped profile portion having an oblong hole 264, 269 which runs at least in certain portions in a longitudinal direction of the profile portion, wherein the setting device is formed from support elements which are displaceable in the longitudinal direction in the oblong hole, wherein the support elements are formed in each case as a threaded pin 260 with an inner profile whose oppositely arranged threads engage in transverse oblong holes 263 formed in the oblong hole, wherein the support elements are displaceable in the longitudinal direction of the oblong hole by means of a rotation of an actuating shaft 261, which is inserted in the inner profile, of the setting device 259.

[0111] A second embodiment of the invention will be described below. Here, the rotary joint 145 shown in FIG. 1 is replaced with the aid of a transverse strut according to the invention by a virtual rotary point.

[0112] FIGS. 13 to 16 schematically illustrate a chair 10 according to the invention which is formed as an office chair and which consequently can be adjusted in terms of its seat height, its seat depth and its inclination behavior.

[0113] The chair 10 comprises a base column (not shown in further detail) which is designed to be telescopable and at whose lower end there is arranged a roller cross formed in a customary manner.

[0114] On the base column there are arranged a seat inclination mechanism 11, a seat element 12 and a seat backrest 13 of the chair 10. The seat inclination mechanism 11 comprises a basic support 14 which is connected to the base column and on which a backrest support 15 and a seat element support 16 are articulated. The seat element 12 is formed from a seat shell 17 having a seat pad 18, and the seat backrest 13 is formed from a backrest shell 19 having a backrest pad 20.

[0115] The seat element 12 is connected to the seat backrest 13 via a joint connection 21. The seat inclination mechanism 11 comprises two torsion bar springs 22 which are formed from a transverse strut 23. The torsion bar springs 22 are integrally formed on the basic support 14 and have levers 25 at outer, distal ends 24, said levers being attached to the seat shell 17 via a front rotary joint 26. Furthermore, a lower rotary joint 27 is formed on the basic support 14, via which rotary joint an extension 28 of the seat backrest 13 pivotably supports the seat backrest toward the rear, as illustrated in FIG. 14.

[0116] Furthermore, a strut 29 is integrally formed on the seat backrest 13 or on the extension 29 and is connected to the seat shell 17 via a rear rotary joint 30. As can be seen from FIG. 14, a rearwardly inclined seat backrest 13 on the lower rotary joint 27 leads to a displacement of the seat element 12, wherein the torsion bar springs 22 are twisted. The transverse strut 23, which forms the torsion bar springs 22, is formed with a slot 31 which runs in the longitudinal direction of the transverse strut 23 and which facilitates torsion of the transverse strut 23 or of the torsion bar springs 22. The chair 10 is essentially formed from the basic support 14, which is formed integrally, in particular in one piece, from plastic, the backrest support 15 and the seat shell 17 or the seat element support 16.

[0117] FIGS. 17 to 21 illustrate a chair 32 according to the invention which comprises a base column 33 with a roller cross (not shown in further detail), a seat inclination mechanism 34, a seat element 35, a seat backrest 36 and a basic support 37 which is connected to the base column 33. Here, too, a transverse strut 38 of the seat inclination mechanism 34 forms torsion bar springs 39.

[0118] Here, too, a transverse strut 38 of the seat inclination mechanism 34 forms torsion springs 39. Distal ends 40 of the torsion bar spring 39 are in each case screwed to the seat element 35 by means of screws (not shown in further detail here). A lever 41 is formed integrally, in particular in one piece, centrally on the torsion bar springs 39 or the transverse strut 38. The lever 41 is connected to the basic support 37 via a front rotary joint 42. Also formed on the basic support 37 is a lower rotary joint 43 together with an extension 44 of the seat backrest 36. Moreover, a rear rotary joint 45 together with the seat element 35 is formed on the extension 44. As can be seen in FIG. 18, a rearward inclination of the seat backrest 36 then causes a displacement of the seat element 35 in the chair longitudinal direction relative to the basic support 37. In the embodiment of the chair 32 as shown here, the extension of the seat backrest 36 is formed independently of a backrest support 46. Furthermore, a continuous oblong hole is formed in the transverse strut 38.

[0119] FIGS. 22 to 26 show a chair 48 in which, by contrast with the chair from FIGS. 17 to 21, a seat element support 49 is formed from a frame 50. The frame 50 forms a transverse strut 51 with the torsion bar springs 52. The frame 50 is in particular formed integrally, in particular in one piece, from plastic together with the torsion bar springs 52 and a lever 53, which is here integrally formed on the torsion bar springs 52. A seat element 54 is placed on and fastened to the frame 50.

[0120] With respect to the embodiment of the invention that is described in conjunction with FIGS. 13 to 26, the solution according to the invention is distinguished in particular by the fact that what is concerned is a chair 10, 32, 48, in particular an office chair, which comprises a base frame with a base column 33 on which a seat element 12, 35, 54 and a seat backrest 13, 36 are mounted via a seat inclination mechanism 11, 34, wherein the seat inclination mechanism comprises a basic support 14, 37 which is connected to the base column and on which a backrest support 15, 46 and a seat element support 16, 49 are articulated, and the seat element and the seat backrest are connected to one another via a joint connection 21 of the seat inclination mechanism, wherein a transverse strut 23, 38, 51 of the seat inclination mechanism forms a spring device, wherein the transverse strut extends in the chair transverse direction 100, wherein the spring device has at least one torsion bar spring 22, 39, 52, wherein the basic support or the seat element support, together with the torsion bar spring, is formed integrally, in particular in one piece, from plastic.

[0121] This chair is advantageously characterized in that the spring device is formed with preloading.

[0122] This chair is advantageously characterized in that two torsion bar springs 22 of the spring device are integrally formed on the basic support 14 and, with respect to a vertical chair longitudinal center plane, are attached at their respective distal ends 24 to a lever 25 of the seat inclination mechanism 11.

[0123] This chair is advantageously characterized in that the basic support 14, together with the torsion bar springs 22, is formed integrally, in particular in one piece, from plastic and forms the levers 25 of the seat inclination mechanism 11.

[0124] This chair is advantageously characterized in that the backrest support 15 is connected to the basic support 14 via a lower rotary joint 27.

[0125] This chair is advantageously characterized in that the seat element support 16 is formed from at least one strut 29, which is articulated on the backrest support 15, and the levers 25 which hold the seat element 12.

[0126] This chair is advantageously characterized in that a rear rotary joint 30 is formed between the strut 29 and the seat element 12, and the levers 25 are connected to the seat element via in each case a front rotary joint 26, wherein a pivoting movement of the backrest support 15 on the lower rotary joint 27 causes a displacement of the seat element in the chair longitudinal direction relative to the basic support 14.

[0127] In a further embodiment, the above-described chair can advantageously be characterized in that, with respect to a vertical chair longitudinal center plane, two torsion bar springs 39 of the spring device are attached at their respective distal ends 40 to the seat element 35 and are attached, via a lever 41, which is formed integrally with the torsion bar springs, to a front rotary joint 42 of the seat inclination mechanism on the basic support 37. In this case, this chair is also advantageously characterized in that the distal ends 40 of the torsion bar springs 39 are screwed to or integrally formed on the seat element 35 and/or this chair is characterized in that a rear rotary joint 45 is formed between the seat element support and the seat element 35, and the lever 41 is connected to the basic support 37 via the front rotary joint 42, wherein a pivoting movement of the backrest support 46 on the lower rotary joint 43 causes a displacement of the seat element in the chair longitudinal direction relative to the basic support.

[0128] In a further embodiment, the above-described chair can advantageously be characterized in that the seat element support 49 is formed from a frame 50 which forms the transverse strut 51, wherein, with respect to a vertical chair longitudinal center plane, two torsion bar springs 52 of the spring device are attached at their respective distal ends to the frame and are attached, via a lever 53, which is integrally formed with the torsion bar springs, to a front rotary joint 42 of the seat inclination mechanism on the basic support 37. In this case, this chair is advantageously also characterized in that a rear rotary joint 45 is formed at a rear end of the frame 50, and the backrest support 46 is connected to the seat element support 49 via the rear rotary joint, wherein a pivoting movement of the backrest support on the lower rotary joint 43 causes a displacement of the seat element 54 in the chair longitudinal direction relative to the basic support 37.

[0129] In a further embodiment, the above-described chair can advantageously be characterized in that the torsion bar spring 22 is formed from a bar-shaped profile portion having an oblong hole 31 which runs at least in certain portions in a longitudinal direction of the profile portion. In this case, this chair is advantageously also characterized in that the spring device has for each torsion bar spring a further torsion bar spring made of spring steel, wherein the further torsion bar spring is inserted into the oblong hole and is in each case fastened in a rotationally fixed manner at its proximal end to the basic support or the seat element support and at its distal end to the lever of the seat inclination mechanism.

[0130] With respect to the embodiment of the invention as described in conjunction with FIGS. 13 to 26, the solution according to the invention is distinguished in particular by the fact that what is concerned is a seat inclination mechanism 11, 34 for a chair 10, 32, 48, in particular an office chair, said mechanism comprising a basic support 14, 37, which can be connected to a base column 33 of the chair, an extension 28, 44, which is articulated on the basic support, of a backrest support 15, 46 of the chair, and a seat element support 16, 49, wherein two torsion bar springs 22, 39, 52 are integrally attached to the basic support or the seat element support and, with respect to a vertical chair longitudinal center plane, are attached at their respective distal ends 24, 40 to a lever 25 of the seat inclination mechanism or to the seat element support, wherein the extension is connected to the basic support via a lower rotary joint 27, 43, wherein the seat element support is formed from at least the extension and the lever, which holds the seat element, wherein a rear rotary joint 30, 45 is formed between the extension and the seat element, and the lever is connected to the seat element or the seat element support via in each case a front rotary joint 26, 42, wherein a pivoting movement of the backrest support with the extension on the lower rotary joint causes a displacement of the seat element in the chair longitudinal direction relative to the basic support.

[0131] What applies to all embodiments is that a seat element support in the broader sense is to be understood to mean a part which supports or holds the seat element. If the seat element consists, on the one hand, of a seat frame or a seat shell or the like and, on the other hand, of a pad, a cover or the like, in preferred embodiments a seat element support then also comprises, in the narrower sense, the seat frame or the seat shell, since these parts also exert a supporting or holding function for the actual seat surface. The seat element support is always articulated on the basic support. According to the basic construction illustrated in FIG. 1, the term seat element support can for example comprise the seat frame 3 and/or the front coupling element 141. In the case of the chair 232, as illustrated in FIGS. 2 to 4, the seat shell 244 and/or the front rotary joint 248 serve/serves for example as seat element support. In the case of the chairs 10, 32 as shown in FIGS. 13 to 26, the seat element supports 16, 49 are provided, for example. It is also possible there for the seat shell 17 or the seat frame 50 to serve as seat element support.

[0132] The positions of the rotary points relative to one another and relative to other construction elements of the mechanism, these positions being stated in conjunction with the above-described exemplary embodiments of individual seat inclination mechanisms, are to be understood merely as examples of concrete advantageous variants of the invention. The invention can also be applied to seat inclination mechanisms which have a different arrangement of the rotary points.

[0133] All design and functional features, properties and advantages explained for an exemplary embodiment of the invention in connection with transverse struts having spring devices can also be applied to the other exemplary embodiments.

[0134] All the features presented in the description, in the following claims and the drawing may be essential to the invention both individually and in any desired combination with one another.

LIST OF REFERENCE SIGNS

[0135] 1 Basic support

[0136] 2 Base column

[0137] 3 Seat element support, seat frame

[0138] 4 Backrest support

[0139] 7 Pivoting direction

[0140] 10 Chair

[0141] 11 Seat inclination mechanism

[0142] 12 Seat element

[0143] 13 Seat backrest

[0144] 14 Basic support

[0145] 15 Backrest support

[0146] 16 Seat element support

[0147] 17 Seat shell

[0148] 18 Seat pad

[0149] 19 Backrest shell

[0150] 20 Backrest pad

[0151] 21 Joint connection

[0152] 22 Torsion bar spring

[0153] 23 Transverse strut

[0154] 24 Distal end

[0155] 25 Lever

[0156] 26 Front rotary joint

[0157] 27 Rear rotary joint

[0158] 28 Extension

[0159] 29 Strut

[0160] 30 Rear rotary joint

[0161] 31 Oblong hole

[0162] 32 Chair

[0163] 33 Base column

[0164] 34 Seat inclination mechanism

[0165] 35 Seat element

[0166] 36 Seat backrest

[0167] 37 Basic support

[0168] 38 Transverse strut

[0169] 39 Torsion bar spring

[0170] 40 Distal end

[0171] 41 Lever

[0172] 42 Front rotary joint

[0173] 43 Lower rotary joint

[0174] 44 Extension

[0175] 45 Rear rotary joint

[0176] 46 Backrest support

[0177] 47 Oblong hole

[0178] 48 Chair

[0179] 49 Seat element support

[0180] 50 Frame

[0181] 51 Transverse strut

[0182] 52 Torsion bar spring

[0183] 53 Lever

[0184] 54 Seat element

[0185] 100 Chair transverse direction

[0186] 139 Synchronous mechanism

[0187] 140 Rear coupling element

[0188] 141 Seat element support, front coupling element

[0189] 142 First rotary joint

[0190] 143 Second rotary joint

[0191] 144 Third rotary joint

[0192] 145 Fourth rotary joint

[0193] 146 Chair longitudinal direction

[0194] 232 Chair

[0195] 233 Base column

[0196] 234 Seat inclination mechanism

[0197] 235 Seat element

[0198] 236 Seat backrest

[0199] 237 Basic support

[0200] 238 Transverse strut

[0201] 239 Torsion bar spring

[0202] 240 Backrest support

[0203] 241 Leg

[0204] 242 Lever

[0205] 243 Strut

[0206] 244 Seat shell

[0207] 245 Oblong hole

[0208] 246 Axle

[0209] 247 Rear rotary joint

[0210] 248 Front rotary joint

[0211] 249 Oblong hole

[0212] 250 Basic support

[0213] 251 Spring device

[0214] 252 Torsion bar spring

[0215] 253 Transverse strut

[0216] 254 Oblong hole

[0217] 255 Distal end

[0218] 256 Lever

[0219] 257 Flange

[0220] 258 Basic support

[0221] 259 Setting device

[0222] 260 Threaded pin

[0223] 261 Actuating shaft

[0224] 262 Crank

[0225] 263 Transverse oblong hole

[0226] 264 Oblong hole

[0227] 265 Torsion bar spring

[0228] 266 Transverse strut

[0229] 267 Basic support

[0230] 268 Further torsion bar spring

[0231] 269 Oblong hole

[0232] 270 Torsion bar spring

[0233] 271 Basic support