Chair and method for operating a chair

Abstract

The invention relates to a chair (1) which comprises a base frame (2), a seat element (3), a back element (4), a spring mechanism (5), and an adjusting device (6). The spring mechanism (5) comprises a leaf spring (9) which is clamped into the base frame (2) on one side and a support (10) which can be moved under the leaf spring (9) on a track (12) formed on the base frame (2). The back element (4) is hinged to the base frame (2) by means of a rocker (22), and the rocker (22) is supported on the leaf spring (9), the seat element (3) and the base frame (2) being either hingedly connected via a rear coupling device (27), the rocker (22), and a front coupling device (26) in such a way that a five-member coupling joint with five pivot points is formed or being hingedly connected via the rocker (22) and a front coupling device (26) in such a way that a four-member coupling joint with four pivot points is formed, a person sitting in an upright sitting position on the chair generating, as a result of the person's weight, a thrust force acting forwards in the x direction.

Description

[0001] Chair and operating procedures for a chair

[0002] The invention relates to a chair according to the preamble of claim 1 or 18 or 19 and an operating method according to the preamble of claim 25.

[0003] Modern chairs increasingly demand that a person sitting upright be able to easily adjust the chair's return force. However, with such chairs, this easy adjustment is immediately lost if the return force is activated even by a slight backward tilt.

[0004] The invention is based on the objective of developing a chair or an operating method in which a restoring force of the chair is not only easily adjustable when the chair is loaded by an upright sitting person, but also remains easily adjustable while the upright sitting person is already leaning back slightly, whereby the leaning back nevertheless takes place against a restoring force from the beginning.

[0005] This problem is solved by the characterizing features of claims 1, 18, 19, and 25, respectively, starting from the features of the preamble. Advantageous and expedient embodiments are specified in the respective dependent claims.

[0006] The core of the invention is to ensure, through a combination of three measures, both a weight-independent, smooth adjustability, which is also present when a seated person tilts back slightly, and to provide an immediate action of a restoring force when tilting back, which is initially weight-dependent and then adjustment-dependent.

[0007] Weight-independent, smooth adjustability for an upright sitting person is essentially achieved by the upright sitting person causing the chair to assume a rest position, whereby the seat element is moved against a stop by means of a thrust force generated by the weight of the upright sitting person.

[0008] Maintaining a smooth, weight-independent adjustability when a person leans slightly backward is achieved primarily by generating a restoring force. This is accomplished by the person having to pivot the seat element back against the backrest coupled to the seat element, using their own weight to swing it back past a top dead center. Accordingly, a restoring force dependent on the person's weight is initially applied, without the need for a spring element to generate the force.

[0009] The generation of the adjustment-dependent restoring force only occurs from the moment the seat element reaches its top dead center and then lowers again as a result of further tilting backwards, since the back element connected to it then rests on a free end of a preset leaf spring by means of its rocker arm and thereby experiences an increasing counterforce with the degree of deformation of the leaf spring.

[0010] Thus, the possibility of easily adjusting the restoring force is only lost during the second step, when moving from a starting position to a subsequent position. Simultaneously, during the second step, the leaf spring is clamped in such a way that it develops the desired force in the subsequent position. Nevertheless, even in the second step, a restoring force is present when the person leans slightly backward, generated by their weight. In the third step, the restoring force of the leaf spring is then immediately available, corresponding to the selected adjustment position for the support.

[0011] This shows:

[0012] Figure 1a: a schematic side view of a first embodiment of a chair according to the invention, which is unloaded by a person in a starting position (A);

[0013] Figure 1b: a schematic side view of a second embodiment of a chair according to the invention, which is unloaded by a person in a starting position (A);

[0014] Figure 2a: a schematic side view of the chair shown in Figure 1b, wherein it is in the starting position (A) and is loaded by a light person and wherein a spring mechanism of the chair is set for a light person; Figure 2b: a schematic side view of the chair shown in Figure 2a, wherein it is in a final position (C) and is loaded by the light person and wherein the spring mechanism of the chair is set for the light person;

[0015] Figure 3a: a schematic side view of the chair shown in Figure 1b, in which it is in the starting position (A) and is loaded by a heavy person and in which a spring mechanism of the chair is set to a heavy person;

[0016] Figure 3b: a schematic side view of the chair shown in Figure 3a, in the end position (C) and loaded by the heavy person, and in the spring mechanism of the chair being adjusted to the heavy person;

[0017] Figure 4: in idealized form a perspective view of the first version of the chair shown in Figure 1a;

[0018] Figures 5a, 5b; in analogy to Figures 2a, 2b a third embodiment of a chair according to the invention, wherein the actuating element causes a non-linear displacement of the support;

[0019] Figure 5c: an enlarged detail view of Figure 5a;

[0020] Figure 5d: in perspective view an enlarged detail view of Figure 5c;

[0021] Figure 5e: the representation of Figure 5c with the support surface adjusted

[0022] Figure 5f: in perspective view an enlarged detail view of Figure 5e;

[0023] Figure 5g: a modification of the third design variant in analogy to Figure 5e in a detailed view;

[0024] Figures 6a, 6b; by analogy to Figures 2a, 2b, a fourth embodiment of a chair according to the invention, wherein the actuating element is designed as a rotary actuator; Figures 7a, 7b: by analogy to Figures 5a, 5b, a fifth embodiment of a chair according to the invention, wherein the chair comprises a third coupling device;

[0025] Figures 8a to 11b: a sixth, seventh, eighth and ninth variant of the chair, in which a kind of four-part coupling element is used.

[0026] Figure 1a shows a schematic side view of a chair 1 according to the invention. The chair 1 is shown in a starting position A, in which it is unloaded by a person. The chair 1 comprises a base frame 2, a seat element 3, a back element 4, a spring mechanism 5, and an adjustment device 6.

[0027] The spring mechanism 5 comprises a leaf spring 9 clamped at one end into the base frame 2 and a support 10. The leaf spring 9 is clamped in a bearing 11 formed on the base frame 2. The support 10 can be moved forward in the direction of arrow x and backward in the direction of arrow x' on a track 12 formed on the base frame 2 by means of the adjusting device 6. The direction of arrow x is in the line of sight of a person sitting upright on the chair 1.

[0028] The adjusting device 6 comprises an actuator 13 and a transmission element 14, wherein the support 10 and the actuator 13 are connected to each other by the transmission element 14, which is designed as a Bowden cable 15, such that the support 10 can be moved to different positions on the roadway 12 by means of a slide 16a of the actuator 13. In Figure 1, the support 10 is shown in a central position MP10. The Bowden cable 15 is designed to transmit tensile and compressive forces.

[0029] The back element 4 and the seat element 3 are connected to form a shell 19 by means of two connecting elements 17, 18. The connecting elements 17, 18 are designed as elastically deformable connecting webs 20, 21 formed laterally to the seat element 3.

[0030] The shell 19 is articulated to the base frame 2 in the area of ​​the back element 4 by means of a rocker arm 22. The rocker arm 22 is pivotally connected to the support unit 7 of the base frame 2 about a lower pivot bearing 23 with a pivot axis 23-1. In the side view of Figure 1, the right connecting element 17 obscures the left connecting element 18, and the right connecting web 20 obscures the left connecting web 21. The base frame 2 comprises a support unit 7 and a foot frame 8. A vertical axis H1 of the chair 1 is defined by a longitudinal axis L8 of its support column 8a.

[0031] The description of the first embodiment shown in Figure 1a also applies to the second embodiment II of a chair 1 according to the invention, shown in Figure 1b. In contrast to the first embodiment I, in the second embodiment II, the rocker arm 22 is pivotally connected to the back element 4 near the connecting elements 17, 18 by means of upper pivot bearings 24, 25. In the side view of Figure 1b, the right pivot bearing 24 obscures the left pivot bearing 25. The pivot bearings 24, 25 reduce the resistance with which the shell 5, via the connecting elements 17, 18, counteracts deformation when a seated person leans back against the back element 4.

[0032] Figures 2a to 3b also show the second embodiment of the chair 1 according to the invention. In contrast to the detailed representations in Figures 2a to 3b, the base frame 2 is shown in Figure 1b with all its components.

[0033] Figure 2a shows the chair 1, as shown in Figure 1b, again without the base. Reference is made to the description of Figure 1b, where, unlike in Figure 1b, the support 10 in Figure 2a is in a "light" position LP10 and the chair 1 is loaded by a light, upright person P1.

[0034] Figure 4 shows an idealized perspective view of the first version I of chair 1 as depicted in Figure 1a.

[0035] Figures 5a to 5g show a third version III of chair 1, and figures 6a and 6b show a fourth version IV of chair 1. Figures 7a and 7b show a fifth version V of chair 1. The following explanations regarding the second version II also apply to versions I, III, and IV.

[0036] In all four embodiments I to IV, the seat element 3 – as shown, for example, in Figure 2a – is connected to the support unit 7 of the base frame 2 by means of a front coupling device 26 and to the rocker arm 22 by means of a rear coupling device I, such that when the seat element 3 is loaded with the weight GP1 of an upright seated person P1 – viewed in the illustrated side view – the shell 19 experiences a forward thrust force S1 in the x-direction. This thrust force S1 is caused by the fact that the front coupling device 26 has an upper pivot axis 26-1, which is offset in the x-direction relative to a lower pivot axis 26-2, and that the rear coupling device 27 has an upper pivot axis 27-1, which is offset in the x-direction relative to a lower pivot axis 27-2.Accordingly, the seat element 3, as a result of the weight force GP1 of the light person P1 acting upon it, tends to move forward in the direction of arrow x and downward in the direction of arrow y', guided by the coupling devices 26, 27, in the direction of a floor 101 on which the chair 1 stands.

[0037] The base frame 2 includes a stop 28 on its support unit 7, which blocks such movement when the seat element 3 rests against this stop 28 with a nose 29. Accordingly, the seat element 3 is prevented from sinking further forward. Alternatively, the forward sinking can also be blocked by corresponding stops via one or both of the coupling devices.

[0038] Both when the seat element 3 is unloaded (see Figure 1b) and when the seat element 3 is loaded with the weight GP1 of the upright person P1 (see Figure 2a), a clearance 30 exists between the support 10 and the leaf spring 9. This clearance 30 is designed such that the support 10 can slide freely on the track 12 without contacting an underside 9b of the leaf spring 9. This clearance 30 is also present when the seat element 3 of the chair 1 is loaded – as shown in Figure 3a – by a heavy person P2 sitting upright with a weight GP2. This clearance 30 is fundamentally independent of the position of the support 10. In Figure 3a, the support 10 is in a "heavy" position SP10.

[0039] The support 10 can be moved on the track 12 between the front end position LP10 and the rear end position SP10 by means of the adjusting device 6. Version variants I to V show partially differently designed adjusting devices. Reference is made to the respective descriptions in this regard.

[0040] The course of the track 12 is adapted to the bending curve of the leaf spring 9, which it assumes when the seat element 3 is loaded, if at all, by a person sitting upright and rests against the stop 28. This ensures, over the entire adjustment range of the support 10, that the support 10, in all positions it can move into, has a clearance 30 from the underside 9b of the leaf spring 9 and is therefore easily adjustable.

[0041] The free space 30 between the support 10 and the leaf spring 9 is closed by the rocker arm 22, which increasingly rests on the leaf spring 9, when the seat element 3 is raised to an upper dead center 31 determined by the coupling devices 26, 27 by the seated person P1 tilting backwards against the back element 4 (compare, for example, figures 2a and 2b).

[0042] The top dead center 31 of the seat element 3 is schematically indicated in Figure 2a. In a superimposed representation, the front section of the seat element 3 is shown with dashed lines in a position it assumes when the front coupling device 26 with its arms 26a, 26b is vertical. This position is designated as subsequent position B in Figures 2a and 2b. This position B of the arms 26a, 26b, which are superimposed in the side view, is also indicated with dashed lines in Figure 2a. Similarly, the upper section of the back element 4 is shown with dashed lines in a position it assumes when the seat element 3 is at its top dead center 31. Naturally, the rear coupling device 27 with its arms 27a, 27b is then also in a position between those shown in Figures 2a and 2b.

[0043] At the top dead center 31, the swing arm 22, and thus the back element 4 and the seat element 3 connected to it, as well as during further tilting back, experiences a support force F determined by the adjustment position LP10 of the support 10.

[0044] Figure 2a shows chair 1 in a starting position A. Figure 2a also indicates the subsequent position B of chair 1 with dashed lines. Figure 2b then shows a final position C of chair 1, and positions A and B are indicated by dashed sections of the backrest element 4.

[0045] Figure 2b shows in particular how person P1, sitting upright on chair 1, experiences a first restoring force R1 from the back element 4 when leaning back in the direction of arrow x' against the back element 4, which is in the initial position A, until the back element 4 is in the subsequent position B. This first restoring force R1 is generated by the weight force GP1 of person P1 acting on the seat element 3. The first restoring force R1 is thus a restoring force generated by person P1's own weight and is therefore also a restoring force adapted to that weight, since it is directly dependent on it. As soon as the seat element 3 is in the aforementioned dead center 31, the first restoring force R1 ceases. In this position of chair 1, or rather...The seat element 3 then already exerts a second restoring force R2 to support a further backward movement of person P1 against the back element 4, since the leaf spring 9 in this position of the chair 1 or the seat element 3 has already rested on the support 10 and thus exerts its effect against the rocker 22 and thus the back element 4.

[0046] The person P1, seated on chair 1, experiences a second restoring force R2 in the subsequent position B of the backrest element 4, in all intermediate positions between position B and final position C, and in final position C when further leaning back against the backrest element 4. This second restoring force R2 increases as the person approaches final position C. The second restoring force R2 is generated by the leaf spring 9. To generate the second restoring force R2, the backrest element 4 is supported by a counter bearing 32 formed on the rocker arm 22 on a top surface 9a of the leaf spring 9 at a free end 33 of the leaf spring 9. The leaf spring 9, clamped in the bearing 11, is supported on the support 10 with its underside 9b. Accordingly, the second restoring force R2 is influenced by the position of the support 10 on the track 10.

[0047] In the starting position A, the leaf spring 9 is spaced away from the support 10, and on the way to the subsequent position B, the leaf spring 9 increasingly approaches the support 10 and then lies against the support 10 in the subsequent position B.

[0048] The above description applies analogously to figures 3a and 3b. In contrast to figures 2a and 2b, here the chair 1 is shown being used by the aforementioned heavy person P2.

[0049] In chair 1, which features a seat element 3 whose orientation is synchronized by the tilt of the back element 4, the track 12, the support 10, the leaf spring 9, and the counter bearing 32 are positioned spatially relative to each other by tilting the back element 4 from a starting position A to a subsequent position B in such a way that the spring mechanism 5 only exerts its supporting force in the subsequent position B and thereafter, namely until it reaches a final position C following the subsequent position B. This allows the support to be easily adjusted in the starting position and up to just before the subsequent position, as it is not yet clamped between its track 12 and the leaf spring 9. The operation of chair 1 proceeds as follows; see in particular Figures 2a to 3b:

[0050] In the starting position A, in which the chair 1 is unloaded or is only loaded by the person P1 sitting upright on the seat element 3 of the chair 1, the support 10 arranged at a distance below the leaf spring 9 is placed in a desired adjustment position, namely e.g. in the "light" position LP10 or in the "heavy" position SP10 or an intermediate position MP10.

[0051] If the back element 4 of the chair 1 is tilted back from the starting position A to the subsequent position B by the seated person P1, the leaf spring 9 is acted upon in such a way that it is placed on the support 10 and that the seat element 3 is lifted against the weight force GP1 of the person P1 to the dead center 31, so that a first restoring force R1 acting between the starting position A and the subsequent position B is generated by the weight force GP1 of the person P1.

[0052] If the back element 4 of the chair 1 is tilted back from the subsequent position B to the final position C by the seated person P1 by further tilting back, the restoring force R2 is generated by the leaf spring 9 in the subsequent position B, in all intermediate positions between the subsequent position B and the final position C and in the final position C.

[0053] The reference symbol starting position A denotes both one of the positions of the back element 4, as well as the positions of all other components of the chair 1 that they assume when the back element 4 is in starting position A.

[0054] The reference symbol "sequence position B" refers both to one of the positions of the back element 4, and to the positions of all other components of the chair 1 that these assume when the back element 4 is in the sequence position B.

[0055] The reference symbol Endposition C denotes both one of the positions of the back element 4, as well as the positions of all other components of the chair 1 that they assume when the back element 4 is in the end position C.

[0056] In the second embodiment II shown in Figures 1b to 3b, the rocker arm 22 and the back element 4 are connected by the right upper pivot bearing 24, and the rocker arm 22 and the back element 4 are connected by the left upper pivot bearing 25. The pivot bearings 24, 25 are each formed at the free ends of lateral arms 22a, 22b of the Y-shaped rocker arm 22.

[0057] As already explained above, Figure 4 shows an idealized perspective view of the first embodiment I of the chair 1, as depicted in Figure 1a. Except for details concerning the design of the adjustment device 6, the connection of the rocker arm 22 to the shell 19, the design of the leaf spring 9 and the counter bearing 32, and the design of the rear coupling device, Figure 4 is also schematically representative of the second to fifth embodiments II to V.

[0058] In Figure 4, the upholstery 3a of the seat element 3 and the upholstery 4a of the back element 4 are each only partially shown in order to make the construction of the chair 1 more easily recognizable.

[0059] In the perspective view of Figure 4, the two arms 26a, 26b of the front coupling device 26 are clearly visible. The rear coupling device TI, which connects the seat element 3 to the swing arm 22, is also visible here.

[0060] Figure 4 clearly shows how the back element 4 is supported by the Y-shaped arm 22. The Y-shaped arm 22 comprises a central arm 22c, to which it is pivotally connected with the base frame 2. The Y-shaped arm 22 also includes two lateral arms 22a and 22b, which connect to a frame 4b of the back element 4.

[0061] In the first embodiment variant I (see Figures 1 a and 4) the side arms 22a and 22b of the swing arm 22 are firmly connected to the frame 4b of the back element.

[0062] In the second embodiment variant II (see figures 1b to 3b), in the third embodiment variant III (see figures 5a to 5g) and in the fourth embodiment variant IV (see figures 6a, 6b) the side arms 22a and 22b are connected to the frame 4b of the back element 4 via the upper pivot bearings 24, 25.

[0063] As shown in Figure 4, the back element 4 and the seat element 3 are directly connected only via the two connecting elements 17 and 18. The connecting elements 17 and 18 are integrally formed with the frame 4b of the back element 4 and are torsionally rigidly connected to a frame 3b of the seat element 3. According to a modification, the connecting elements can also be integrally formed with the frame of the seat element, so that the frame of the seat element, the connecting elements, and the frame of the back element form a single component. Additionally, with regard to the first embodiment, it could also be provided that the rocker arm is formed on this component.

[0064] In the embodiments I to IV of chair 1 shown in the figures, the back element 4 and the seat element 3 are connected by the right connecting element 17 and the left connecting element 18. Each of the two connecting elements 17, 18 acts as an elastically deformable tension rod when the person P1, P2 sitting upright on the chair 1 leans back against the back element 4. The elastic deformability of the connecting elements can be selected by material choice and / or cross-sectional design and / or structural design such that an angle o increases by up to 10°. The angle o is measured in a perpendicular longitudinal mid-plane of the chair 1, in which the vertical axis H1 runs, between the upholstery 3a of the seat element 3 and the upholstery 4a of the back element 4 (see Figure 1a). The structural design of the connecting elements can be, for example, a grid structure or a honeycomb structure.

[0065] The front coupling device 26 comprises – as shown in the four embodiment variants I to IV – a first arm 26a and a second arm 26b. According to an embodiment variant not shown, the two arms can also be formed by a central arm.

[0066] In the first embodiment (see Figures 1a and 4), the rear coupling device 27 comprises a central arm 27c.

[0067] In the second to fifth version variants ll-V, the rear coupling device 27 comprises a first arm 27a and a second arm 27b.

[0068] In all five embodiments I to V, the lower pivot axis 27-2 of the rear coupling device 27 is positioned between the lower pivot bearing 23 and the counter bearing 32, with which the rocker arm 22 rests on the leaf spring 9. This ensures a compact design of the chair 1. In the third embodiment III (see Figures 5a to 5g) of the chair 1, the actuating element 13 of the adjusting device 6 comprises a mechanical, logarithmic rotary actuator 16b. When actuated, this actuator acts on the support 10 via the transmission means 14 in such a way that the ratio between the rotation angle of the logarithmic rotary actuator 16b and the displacement of the support 10 caused by the changed position of the logarithmic rotary actuator 16b changes over a total adjustment range V.

[0069] The following description of the logarithmic rotary actuator 16b is based primarily on Figures 5c and 5e, which show enlarged detail views of Figures 5a and 5b, and on Figures 5d and 5f, which show the adjusting device 6 depicted in Figures 5d and 5f in enlarged and perspective views. Figure 5d shows the adjusting device 6 in a first stop position A1, in which the support 10 is in the "light" position LP10 (see Figure 5c). Figure 5f shows the adjusting device 6 in a second stop position A2, in which the support 10 is in the "heavy" position SP10 (see Figure 5e).

[0070] The mechanical, logarithmic rotary control 16b is designed such that the adjustment range per rotation angle decreases from the "light" position LP10 of the support 10 towards the "heavy" position SP10 of the support 10, and conversely, the adjustment range per rotation angle increases from the "heavy" position SP10 of the support 10 towards the "light" position LP10 of the support 10. This allows for rapid achievement of increased effectiveness of the leaf spring 9 with minimal effort. Furthermore, the logarithmic rotary control 16b permits fine adjustment of the leaf spring 9's effectiveness when high support is required.

[0071] In the third embodiment of chair 1, the transmission means 14 is designed in particular as a Bowden cable 15. A first end 14a of the transmission means 14 is guided over a first winding surface WF1 of the logarithmic rotary actuator 16b. A second end 14b of the transmission means 14 is guided in the opposite direction to the first end 14a over a second winding surface WF2 of the logarithmic rotary actuator 16b.

[0072] The first winding surface WF1 and the second winding surface WF2 each have a spiral or eccentric shape with respect to a rotation axis R16b of the logarithmic rotary actuator 16b and are arranged in a mirror image of each other with respect to the rotation axis R16b.The support 10 is adjusted by means of the logarithmic rotary actuator 16b of the actuator 13 such that, when the logarithmic rotary actuator 16b (see Figure 5d) is turned clockwise R about the axis of rotation R16b, a tensile side Z14 of the transmission means 14 is wound up more slowly than an slack side L14 of the transmission means 14 is unwound, and when the logarithmic rotary actuator 16b (see Figure 5f) is turned counterclockwise L about the axis of rotation R16b, the tensile side Z14 of the transmission means 14 is wound up more slowly than the slack side L14 of the transmission means 14 is unwound.

[0073] The Bowden cable 15 is designed as a continuous Bowden cable, which is divided approximately halfway along its length for simplified assembly, but is connected via the support 10.

[0074] By turning R to the right of the logarithmic rotary control 16b (see figures 5c and 5d) the support 10 can be pulled from the first stop position A16b-1 by the pull string Z14 in the direction of the "heavy" position SP10.

[0075] By turning L to the left of the logarithmic rotary control 16b (see figures 5e and 5f) the support 10 can be pulled from the second stop position A16b-2 by the pull string Z14 in the direction of the "light" position LP10.

[0076] Depending on the direction of rotation in which the logarithmic rotary actuator 16b is actuated, the tension side Z14 and the slack side L14 in the Bowden cable 15 alternate between the ends 14a, 14b of the transmission means 14.

[0077] The two winding surfaces WF1 and WF2 are connected in such a way that they are always rotated together, whether the winding is clockwise or counterclockwise.

[0078] Figure 5g shows a modification of the adjusting device shown in Figures 5a to 5g. In this modification, the transmission means 14 is deflected via a rotatable roller R14.

[0079] In the fourth embodiment IV shown in Figures 6a and 6b, the actuator 13 is designed as a simple rotary actuator 16c, which always generates the same travel distance of the support 10 for each angle of rotation. In all embodiments I to V of the chair 1, the rocker arm 22 (see Figure 5e) rests with a counter-contact element 40 on a contact element 41 of the leaf spring 9. The counter-contact element 40 is formed in each case by the counter bearing 32. Due to a relative movement between the rocker arm 22, which rotates about the lower pivot bearing 23 when tilting backward, and the leaf spring 9, which deflects further due to the increasing load, the counter bearing 32, which forms the counter-contact element 40, moves on the contact element 41 of the leaf spring 9 in the direction of the free end 33 of the leaf spring 9.

[0080] According to the third and fourth embodiments III and IV of chair 1, the counter-contact element 40 is designed as a projection 42 formed by the counter bearing 32, and the contact element 41 is formed by a wedge-shaped body 43. The counter-contact element 40 and the contact element 41 interact in such a way that when a person sitting upright leans backward—due to a relative displacement between the rocker arm 22 and the leaf spring 9—the counter-contact element 40, which moves relative to the contact element 41, increases the distance between a top surface 9a of the leaf spring 9 and the counter-contact element 40 of the rocker arm 22 from a first distance A1 in the initial position A to a second distance A2 in the final position C (compare Figures 5a and 5b).This ensures that the leaf spring 9 generates a restoring force that increases with the increasing distance between the upper surface 9a of the leaf spring 9 and the counter-contact element 41 of the rocker arm 22.

[0081] According to a modification of the third and fourth embodiments III and IV (not shown), it is also possible to form both the counter-contact element and the contact element with a wedge-shaped body, or to form the counter-contact element with a wedge-shaped body and the contact element as a projection. A wedge-shaped design of the contact element and the counter-contact element makes it possible to increase the distance between the upper surface of the leaf spring and the counter-contact element of the rocker arm to a greater extent.

[0082] In the third, fourth, and fifth embodiments III, IV, and V of chair 1, the wedge-shaped contact element 41 is designed in multiple stages. The wedge-shaped body has a profile that includes a first plateau PL1, on which the counter bearing 32 rests when the back element 4 of chair 1 is in the starting position A. The profile also includes a second plateau PL2, on which the counter bearing 32 rests when the back element 4 of chair 1 is in the end position C. See Figures 5a and 5b. When the back element 4 moves from the starting position A to the end position C, the counter bearing 32 moves along the profile from the first plateau PL1 via a slope S to the second plateau PL2. The slope S is positioned such that the counter bearing 32 has already overcome the slope S by the time it reaches the subsequent position B.Accordingly, an increased restoring force of the leaf spring 9 on the rocker arm 22 is generated right from the beginning of a backward tilting motion. A contact element can also be designed with at least three stages.

[0083] With regard to the aforementioned modifications, a shaping of the counter-contact element or of the contact element and the counter-contact element can also be provided in at least two stages.

[0084] In the third, fourth and fifth design variants III, IV, V of the chair 1, the contact element 41 of the leaf spring 9 is arranged at the free end 33 of the leaf spring 9.

[0085] Adjustment of the support by means of a logarithmic rotary actuator can be provided in all described embodiments. Furthermore, all embodiments can incorporate a contact element and a counter-contact element as shown in Figure 5e.

[0086] In design variants I to IV, the back element 4 and the seat element 3 are connected to form a shell 19 by means of the connecting elements 17, 18, as mentioned above. Similarly, the seat element 3 and the back element 4 are connected to each other via the connecting elements 17, 18 and via the rear coupling device 27 and the rocker arm 22.

[0087] For the sake of clarity, the illustration of the stop mechanism has been omitted in the third and fourth versions. Naturally, in all versions, the stop mechanism is implemented in the design shown in the first and second versions, or in another suitable design.

[0088] Figures 7a and 7b show, in particular by analogy to Figures 5a and 5b, the fifth embodiment V of the chair 1 according to the invention, wherein, in contrast to embodiments I to IV, the chair 1 comprises a third coupling device 44. In embodiments I to V, the base frame 2, the seat element 3, the rocker arm 22, the front coupling device 26, and the rear coupling device 27 together form a type of five-joint coupling joint K5. The coupling joint K5 has five pivot points K5-1 to K5-5.

[0089] The first pivot point K5-1 is formed between the base frame 2 and the front coupling device 26 and is defined by a pivot axis 26-2 of the front coupling device 26.

[0090] The second pivot point K5-2 is formed between the front coupling device 26 and the seat element 3 and is defined by an upper pivot axis 26-1 of the front coupling device 26.

[0091] The third pivot point K5-3 is formed between the seat element 3 and the rear coupling device 27 and is defined by an upper pivot axis 27-1 of the rear coupling device 27.

[0092] The fourth pivot point K5-4 is formed between the rear coupling device 27 and the swing arm 22 and is defined by a lower pivot axis l- of the rear coupling device 27.

[0093] The fifth pivot point K4-5 is formed between the rocker arm 22 and the base frame 2 and is defined by a lower pivot axis 22-1 of the rocker arm 22.

[0094] In embodiments I to V – see in particular Figures 7a and 7b – the chair 1 is designed such that an angle β5 between a front straight line G1 and a rear straight line G2 increases by at least 5° and preferably at least 10° when leaning back from the starting position A to the end position C. Here, the rear straight line G2 connects the rear pivot point K5-3 of the seat element 3 and the rear pivot point K5-5 of the base frame 2, and the front straight line G1 connects the front pivot point K5-2 of the seat element 3 and the front pivot point K5-1 of the base frame 2.

[0095] As can be seen from Figures 2a and 3b, which exemplify embodiment variants I to V, a person P1; P2 sitting upright on chair 1 generates a forward thrust force S1 acting in the x-direction on the seat element 3 through their weight GP1; GP2. Here, chair 1 is in a starting position A when person P1, P2 is in an upright sitting position.To generate the thrust, the five-joint coupling joint K5 is designed such that a front straight line G1, which passes through the front pivot point K5-1 of the base frame 2 and the front pivot point K5-2 of the seat element 3, is inclined forwards in the direction of arrow x to a front seat edge 3c of the seat element 3 by a first angle Ä1-K5 relative to a vertical axis H1 of the chair 1, that a rear straight line G2, which passes through the rear pivot point K5-5 of the base frame 2 and the rear pivot point K5-3 of the seat element 3, is inclined away from the front seat edge 3c of the seat element 3 by a second angle A2-K5 relative to the vertical axis H1 of the chair 1, and that the front angle Ä1-K5 is greater than the rear angle Ä2-K5.

[0096] To absorb the generated thrust force S1, the base frame 2 includes the stop 28, against which the seat element 3 rests under such a load.

[0097] A contact area 45, in which the rocker arm 22 and the leaf spring 9 touch in the starting position A of the chair 1 (see figure 7a), in an end position C of the chair 1 (see figure 7b) and all positions in between, lies outside a pentagonal polygon P5 formed by the five pivot points K5-1 to K5-5 of the five-part coupling device K5.

[0098] In embodiment V (Figures 7a, 7b), the rocker arm 22 and the seat element 3 are connected to the third coupling device 44 in addition to the rear coupling device I. Here, the rear coupling device 27 and the third coupling device 44 interact with the rocker arm 22 and the seat element 3 in the manner of a further coupling joint KV. The third coupling device 44 reduces the load on a lower area 47 of the rocker arm 22. The third coupling device 44 is arranged between the backrest element 4 and the rear coupling device TI. A counter bearing 32 of the rocker arm 22, with which it rests on the leaf spring 9, is positioned between the rear coupling device 26 and the third coupling device 44.

[0099] The rocker arm 22 is rigidly designed in the lower section 47 and in an upper section 48 adjoining the lower section 48. The back element 4 can, for example, be elastically deformable from the dashed line onwards, so that it reacts to a person leaning back by means of elastic deformation. Figures 8a to 11b show a sixth embodiment VI, a seventh embodiment VII, an eighth embodiment VIII, and a ninth embodiment IX of a chair 1 according to the invention. In all these embodiments VI to IX, a base frame 2, a seat element 3, a rocker arm 22, and a front coupling device 26 together form a type of four-part coupling joint K4.

[0100] In embodiments VI to IX, the chair 1 also includes a backrest element 4, a spring mechanism 5, and an adjustment device 6. The adjustment device 6 is shown symbolically only in the seventh embodiment, VII, and only in Figure 9a. The adjustment device 6 can be designed according to the adjustment devices shown for embodiments I to V. The spring mechanism 5 comprises a leaf spring 9 clamped at one end in the base frame 2 and a support 10 movable under the leaf spring 9 on a track 12 formed on the base frame 2. The backrest element 4 is articulated to the base frame 2 by means of the rocker arm 22, and the rocker arm 22 is supported on the leaf spring 9. The coupling joint K4 has four pivot points, K4-1 to K4-4.

[0101] The chairs 1 of versions VI to IX all include a base frame as shown in Figure 1a for the first version. The base frame can be designed with or without casters.

[0102] Figures 9a to 9b show examples of the following versions: VI, VIII and IX:

[0103] The first pivot point K4-1 is formed between the base frame 2 and the front coupling device 26 and is defined by a pivot axis 26-2 of the front coupling device 26.

[0104] The second pivot point K4-2 is formed between the front coupling device 26 and the seat element 3 and is defined by an upper pivot axis 26-1 of the front coupling device 26.

[0105] The third pivot point K4-3 is formed between the seat element 3 and the rocker arm 22 and is defined by an upper pivot axis 22-2 of the rocker arm 22. The fourth pivot point K4-4 is formed between the rocker arm 22 and the base frame 2 and is defined by a lower pivot axis 22-1 of the rocker arm 22.

[0106] The coupling device 26 is formed analogously to the first embodiment variant I (see figure 4) by two levers which connect the base frame 2 and seat element 4.

[0107] A person P1 sitting in an upright position on the chair 1, in which the chair 1 is in a starting position A (see figure 9a), generates a forward thrust force S1 acting in the x-direction through their weight force GP1 on the seat element 3.To generate the thrust force S1, the four-part coupling joint K4 is designed such that a front straight line G3, which passes through the front pivot point K4-1 of the base frame 2 and the front pivot point K4-2 of the seat element 3, is inclined forward to a front seat edge 3c of the seat element 3 by a first angle X1-K4 relative to a vertical axis H1 of the chair 1, that a rear straight line G4, which passes through the rear pivot point K4-4 of the base frame 2 and the rear pivot point K4-3 of the seat element 3, is inclined backward away from the front seat edge 3c of the seat element 3 in the direction of arrow x' relative to the vertical axis H1 of the chair 1 by a second angle X2-K4, and that the front angle Ä1-K4 is greater than the rear angle Ä2-K4.

[0108] According to the limiting special case shown in Figure 8a, the second angle can also be close to 0°.

[0109] To absorb the generated thrust force S1, the base frame 2 includes a stop 28 against which the seat element 3 rests under such a load.

[0110] A contact area 45, in which the rocker arm 22 and the leaf spring 9 touch in the starting position A of the chair 1 (see figure 8a), in an end position C of the chair 1 (see figure 9b) and all positions in between, lies outside a square polygon P4 formed by the four pivot points K4-1 to K4-4 of the four-part coupling device K4.

[0111] Possibly an insert for 9b

[0112] In versions VI to VIII, the back element 4 and the seat element 3 are connected to each other only via the rocker arm 22. The back element 4 is integrally formed with the rocker arm 22, and the rocker arm 22 is pivotally connected to the base frame 2 and the seat element 3.

[0113] In version IX, the back element 4 and the seat element 3 are connected to each other via the rocker arm 22 and a central connecting element 46. Here, the back element 4 is integrally formed with the rocker arm 22, and the rocker arm 22 is pivotally connected to the base frame 2 and the seat element 3. The back element 4 and the seat element 3 are joined to form a shell 19 by means of the central connecting element 42.

[0114] In versions VI to IX, the front coupling device 26 is directly connected to the base frame 2 and is pivotable relative to it about the lower pivot axis 26-2. A type of rear coupling device is formed by the swing arm 22. Here, the swing arm 22 is pivotable relative to the base frame 2 about the lower pivot axis 22-1. The front coupling device 26 is directly connected to the seat element 3 and is pivotable relative to it about the upper pivot axis 26a. The swing arm 22 is directly connected to the seat element 3 and is pivotable relative to it about an upper pivot axis 22-2.

[0115] Figures a and 8b (version VI) show an exemplary design of chair 1 in which an angle β4 between the line G3 and the line G4 decreases by about 3° when leaning back from the starting position A to the end position C.

[0116] Figures 9a and 9b (version VII) show an exemplary design of chair 1 in which an angle β4 between the line G3 and the line G4 increases by about 3° when leaning back from the starting position A to the end position C.

[0117] For the sake of clarity, the illustration of the stop mechanism has been omitted in versions VI, VIII, and XI. Naturally, in these versions, the stop mechanism is designed according to the construction shown in version VII, or in another suitable design.

[0118] The chair 1, in all its design variants I to IX, operates according to a method in which, in a starting position A, in which the chair 1 is unloaded or only loaded by a person P1 or P2 sitting upright on the seat element 3 of the chair 1, a support 10 arranged with a clearance 30 under a leaf spring 9 is moved into a desired setting position LP10; MP10; SP10 is set, in which the back element 4 of the chair 1 is tilted back from the starting position A to a subsequent position B by the seated person P1 or P2, whereby the back element acts on the leaf spring 9 via the rocker arm 22, which is connected to the back element 4 and the base frame 2, such that the rocker arm 22 is placed on the support 10 and that the seat element 3 is lifted by the back element 4 or the rocker arm 22 against the weight force of the person P1 or P2 to a dead center 31,so that a first restoring force R1 acting between the initial position A and the subsequent position B is generated by the weight of the person, whereby the back element 4 of the chair 1 is tilted back by the seated person P1 or P2 from the subsequent position B to an end position C in such a way that a second restoring force R2 is generated in the subsequent position B, in all intermediate positions between the subsequent position B and the end position C and in the end position C by the leaf spring 9.

[0119] Regarding design variants V and VI to XI, with respect to the adjustment and setting of the support 10 and the behavior of the chair when leaning back, reference is made to the explanations for design variants I to IV, which are to be made analogously.

[0120] In embodiments V to IX, the leaf spring 9 comprises a contact element 40, which is formed by a wedge-shaped body 43 and on which the rocker arm 22 is supported by a counter bearing 32. Reference is made to the description of the third embodiment III.

[0121] Reference symbol list

[0122] 1 chair

[0123] 2 Base frame

[0124] 3 seating elements

[0125] 3a Covering of 3

[0126] 3b Frame of 3

[0127] 3c front seat edge

[0128] 4 back element

[0129] 4a Covering of 4

[0130] 4b Frame of 4

[0131] 5 spring mechanism

[0132] 6 Adjustment device

[0133] 7 carrying unit of 2

[0134] 8 foot frame of 2

[0135] 9 leaf spring

[0136] 9a Top side of 9

[0137] 9b Underside of 9

[0138] 10 supports

[0139] 11 warehouses

[0140] 12 lanes for 10

[0141] 13 Actuator of 6

[0142] 14 means of transmission of 6

[0143] 14a first end of 14

[0144] 14b second end of 14

[0145] 15 Bowden cables from 6

[0146] 16a Slide of 13

[0147] 16b mechanical, logarithmic rotary actuator of 13

[0148] 16c rotary switch of 13

[0149] 17, 18 Connecting element

[0150] 19 bowls

[0151] 20, 21 Connecting bridge

[0152] 22 Swingarm

[0153] 22a right lateral arm of 22

[0154] 22b left lateral arm of 22

[0155] 22c Central arm of 22

[0156] 22-1 upper pivot axis between 22 and 3 22-2 lower pivot axis between 22 and 2

[0157] 23 under the swivel bearing of 22

[0158] 23-1 Swivel axis of 23

[0159] 24, 25 upper pivot bearings of 22

[0160] 26 front coupling device

[0161] 26a, 26b Arm of 26

[0162] 26-1 upper pivot axis of 26 with 3

[0163] 26-2 lower pivot axis of 26 with 7

[0164] 27 rear coupling device

[0165] 27a, 27b Arm of 27

[0166] 27c central arm

[0167] 27-1 upper pivot axis of 27 with 3

[0168] 27-2 lower pivot axis of 27 with 22

[0169] 28 stops for 3

[0170] 29 Nose on 3

[0171] 30 Free space between 10 and 9

[0172] 31 Dead center of 3

[0173] 32 counter bearings at 22

[0174] 33 free end of 9

[0175] 40 Counter contact element at 22

[0176] 41 contact element of 9

[0177] 42 lead over 22

[0178] 43 wedge-shaped body formed by 41

[0179] 44 third coupling device

[0180] 45 Contact area of ​​22 and 9

[0181] 46 central connecting elements

[0182] 47 lower range of 22

[0183] 48 upper range of 22

[0184] 101 Floor

[0185] I first version variant

[0186] II second version variant

[0187] III third version variant

[0188] VI fourth execution variant A starting position (of 4)

[0189] B Subsequent position (of 4)

[0190] C End position (of 4)

[0191] A1 Distance between 9a and 40 in starting position A

[0192] A2 Distance between 9a and 40 in the final position

[0193] A16b-1 first stop position of 6

[0194] A16b-2 second stop position of 6

[0195] F Support force

[0196] G1 front straight (version variants I to V)

[0197] G2 rear straight (version variants I to V)

[0198] G3 front straight (version variants VI to IX)

[0199] G4 rear straight (version variants VI to IX)

[0200] GP1 Weight force of P1

[0201] GP2 Weight force of P2

[0202] H1 Vertical axis of 1

[0203] K4 four-joint coupling

[0204] K4-1 -K4-4 Pivot point of K4

[0205] K5 five-joint coupling joint

[0206] K5-1 -K5-5 Pivot point of K5

[0207] KV further (third) coupling joint

[0208] Left turn

[0209] L14 space of 14

[0210] LP10 "Light" position of 10

[0211] MP10 middle position of 10

[0212] P1 light person

[0213] P2 heavy person

[0214] P4 square polygon

[0215] P5 pentagonal polygon

[0216] PL1 first plateau of 41

[0217] PL2 second plateau of 41

[0218] R Right turn

[0219] R14 roll

[0220] R16b Rotation axis of 16b

[0221] S slope of 41

[0222] S1 Thrust force generated by GP1

[0223] SP10 "Heavy" position of 10 V Total adjustment range of 10

[0224] WF1 first winding surface of 16b

[0225] WF2 second winding surface of 16b

[0226] Z14 Traction line of 14 x, x' direction y 1 Direction o Angle between 3a and 4a ß4 Angle between L3 and L4 ß5 Angle between L1 and L2

[0227] A1 -K5 first angle (version variants I to V)

[0228] A2-K5 second angle (version variants I to V) A1-K4 first angle (version variants VI to IX)

[0229] A2-K4 second angle (version variants VI to IX)

Claims

Claims 1. Chair (1) comprising a base frame (2), a seat element (3), a back element (4), a spring mechanism (5) and an adjustment device (6), wherein the spring mechanism (5) comprises a leaf spring (9) clamped on one side into the base frame (2) and a support (10) movable under the leaf spring (9) on a track (12) formed on the base frame (2), wherein the back element (4) is articulated to the base frame (2) by means of a rocker arm (22) and the rocker arm (22) is supported on the leaf spring (9), wherein the seat element (3) and the base frame (2) are either articulated via a rear coupling device (27), the rocker arm (22) and a front coupling device (26) such that a type of five-jointed coupling joint (K5) with five pivot points (K5-1 to K5-5) is formed, or articulated via the rocker arm (22) and a front coupling device (26) are connected,that a type of four-joint coupling joint (K4) with four pivot points (K4-1 to K4-4) is formed, wherein a person (PI; P2) sitting in an upright position on the chair generates a forward thrust force (S1) acting in the x-direction on the seat element (3) through their weight force (GP1; GP2), wherein the four-joint coupling joint (K4) or the five-joint coupling joint (K5) is designed such that a front straight line (G1; G3), which passes through the front pivot point (K4-1; K5-1) of the base frame (2) and the front pivot point (K4-2; K5-2) of the seat element (3), is inclined forward relative to a vertical axis (H1) of the chair (1) by a first angle (A1-K4; A1-K5) to a front seat edge (3c) of the seat element (3), that a rear straight line (G2; G4) which passes through the rear pivot point (K4-4; K5-5) of the base frame (2) and the rear pivot point (K4-3; K5-3) of the seat element (3),the chair (1) is inclined at a second angle (A2-K4; A2-K5) away from the front edge (3c) of the seat element (3) relative to the vertical axis (H1) of the chair (1), and that the first angle (A1-K4; A1-K5) is greater than the second angle (A2-K4; A2-K5), and wherein the base frame (2) includes a stop (28) by which the generated thrust force (S1) is absorbed. - ZI - 1. Chair (1 ) according to one of the preceding claims, characterized in that a contact area (41 ) in which the rocker arm (22) and the leaf spring (9) touch in a starting position (A) of the chair (1 ), in an end position (C) of the chair (1 ) and in all positions in between, lies either outside a pentagonal polygon (P5) formed by the five pivot points (K5-1 - K5-5) of the five-member coupling device (K5) or outside a quadrilateral polygon (P4) formed by the four pivot points (K4-1 - K4-4) of the four-member coupling device (K4).

3. Chair (1 ) according to one of the preceding claims, characterized in that the adjusting device (6) comprises an actuating element (13) and a transmission means (14) and that the support (10) and the actuating element (13) are connected by the transmission means (14).

4. Chair (1) according to one of the preceding claims, characterized in that, when the seat element (3) is unloaded and when the seat element (3) is loaded with the weight force (GP1; GP2) of the upright sitting person (P1; P2), a clearance (30) is provided between the support (10) and the leaf spring (9), which is designed such that the support (10) is slidable on the roadway (12) without contact with an underside (9b) of the leaf spring (9).

5. Chair (1) according to one of the preceding claims, characterized in that the free space (30) between the support (10) and the leaf spring (9) is closed by the rocker arm (22) which increasingly rests on the leaf spring (9) when the seat element (3) has been raised to an upper dead center (31) determined by the coupling devices (26, 27) by the seated person (P1; P2) tilting backwards against the back element (4), so that the rocker arm (22) experiences a support force (F) determined by an adjustment position (LP10; MP10; SP10) of the support (10) in the corresponding position and also during further tilting backwards.

6. Chair (1 ) according to claim 1 , characterized in that the back element (4) rests on the free end (33) of the leaf spring (9) by means of the rocker arm (22), wherein the back element (4) increasingly supports itself on the leaf spring (9) when the seated person (P1 ; P2) leans slightly backward until a dead point (31 ) of the seat element (3) is reached, bending the leaf spring (9) in such a way that it rests on the support (10) when the dead point (31 ) is reached.

7. Chair according to at least one of the preceding claims, characterized in that the rocker arm (22) comprises a counter bearing (32) and rests with the counter bearing (32) on a top side (9a) of the leaf spring (9) at a free end (33) of the leaf spring (9).

8. Chair according to at least one of the preceding claims, characterized in that the support (10) is movable on the roadway (12) between a front end position (LP10) and a rear end position (SP10) by means of the adjusting device (6).

9. Chair according to at least one of the preceding claims, characterized in that the back element (4) and the seat element (3) are connected to form a shell (19) by means of a connecting element (42) or by means of at least two connecting elements (17, 18).

10. Chair according to at least one of the preceding claims, characterized in that the front coupling device (26) is directly connected to the base frame (2) and is pivotable relative to it about a lower pivot axis (26-2), and the front coupling device (26) is directly connected to the seat element (3) and is pivotable relative to it about an upper pivot axis (26a), and that either the rear coupling device (27) is indirectly connected to the base frame (2) via the rocker arm (22), and for this purpose the rear coupling device (26) is pivotable relative to the rocker arm (22) about a lower pivot axis (27-2) and is pivotable relative to the seat element (3) about an upper pivot bearing (27-1), and the rocker arm (22) is pivotable relative to the base frame (2) about a lower pivot axis (23-1).or the swing arm (22) is directly connected to the seat element (3) and is pivotable relative to the seat element (3) about an upper pivot axis (22-1) and relative to the base frame (2) about a lower pivot axis (22-2).

11. Chair according to claim 10, characterized in that the seat element (3) is connected to the rocker arm (22) by means of a third coupling device (44), wherein the third coupling device (44) is arranged between the back element (4) and the rear coupling device (27) and wherein the counter bearing (32) of the rocker arm (22) is positioned between the rear coupling device (26) and the third coupling device (40).

12. Chair according to at least one of the preceding claims, characterized in that the front coupling device (26) comprises a central arm (26c) or a first arm (26a) and a second arm (26b) and that the rear coupling device (27) comprises a central arm (27c) or a first arm (27a) and a second arm (27b).

13. Chair according to at least one of the preceding claims, characterized in that the rocker arm (22) is Y-shaped and comprises a central arm (22c), a right lateral arm (22a) and a left lateral arm (22b), wherein the central arm (22c) is pivotally connected to the base frame (2).

14. Chair according to at least one of the preceding claims, characterized in that the rocker arm (22) is pivotably connected to the support unit (7) of the base frame (2) about a lower pivot bearing (23).

15. Chair according to at least one of the preceding claims, characterized in that the lower pivot axis (27-2) of the rear coupling device (27) is positioned between the lower pivot bearing (23) and the counter bearing (32).

16. Chair according to at least one of the preceding claims, characterized in that, in a chair which is designed with the five-joint coupling joint (K5), an angle (ß5) between the front straight line (G1 ) and the rear straight line (G2) increases by a maximum of 6° when leaning back from the starting position (A) to the end position (C).

17. Chair according to at least one of the preceding claims 1 to 15, characterized in that, in a chair which is designed with the four-part coupling joint (K4), an angle (ß4) between the front straight line (G3) and the rear straight line (G2) increases or decreases by a maximum of 6° when leaning back from the starting position (A) to the end position (C).

18. Chair (1), in particular according to at least one of the preceding claims and in particular with an alignment of the seat element (3) synchronized by the inclination of the back element (4), characterized in that that a person (P1; P2) sitting upright on the chair (1) experiences a first restoring force (R1) from the back element (4) when leaning back against the back element (4) which is in a starting position (A) until the back element (4) is in a subsequent position (B), wherein the first restoring force (R1) is generated by a weight force (GP1; GP2) of the person (P1; P2) acting on the seat element (4), that the person (P1; P2) sitting on the chair (1)P2) in the subsequent position (B) of the back element (4) and all intermediate positions between the subsequent position (B) and an end position (C), and in the end position (C) during further reclining of the back element (4), an increasing second restoring force (R2) is experienced, wherein the second restoring force (R2) is generated by a leaf spring (9), wherein the back element (4) is supported by a counter bearing (32) on a free end (33) of the leaf spring (9) to generate the second restoring force (R2), and the leaf spring (9), which is clamped in a bearing (1 1 ), is supported on a support (10) such that the leaf spring (9) is spaced away from the support (10) in the initial position (A), and that the leaf spring (9) increasingly approaches the support (10) on its way to the subsequent position (B) such that it rests on the support (10) in the subsequent position (B). (10) is attached.; 19. Chair (1), in particular according to at least one of the preceding claims and in particular with an alignment of the seat element (3) synchronized by the inclination of the back element (4), wherein the chair (1) comprises a spring mechanism (5), wherein the spring mechanism (5) comprises a leaf spring (9) and a support (10), wherein the chair (1) comprises a counter bearing (32) associated with the back element (4) for cooperating with the leaf spring (10) and a track (12) for the support (10), characterized in that the track (12), the support (10), the leaf spring (9) and the counter bearing (32) are spatially positioned relative to each other by tilting the back element (4) from an initial position (A) to a subsequent position (B) such that the spring mechanism (5) only exerts its support force in the subsequent position (B) and thereafter, namely until an end position (C) following the subsequent position (B).

20. Chair according to at least one of the preceding claims, characterized in that the actuating element (13) of the adjusting device (6) comprises a mechanical, logarithmic rotary actuator (16b), wherein the logarithmic rotary actuator (16b) The support (10) is moved by means of the transmission means (14) such that the ratio between a rotation angle of the logarithmic rotary actuator (16b) and a displacement path of the support (10) caused by the changed position of the logarithmic rotary actuator (16b) changes over a total adjustment range (V).

21. Chair according to claim 20, characterized in that the transmission means (14) is in particular designed as a Bowden cable (15) and that a first end (14a) of the transmission means (14) is guided over a first winding surface (WF1) of the logarithmic rotary actuator (16b), that a second end (14b) of the transmission means (14) is guided in the opposite direction to the first end (14a) over a second winding surface (WF2) of the rotary actuator (16b), that the first winding surface (WF1) and the second winding surface (WF2) each have a spiral or eccentric shape with respect to an axis of rotation (R16b) of the logarithmic rotary actuator (16b) and are arranged in a mirror-image fashion with respect to the axis of rotation (R16b), so that when the logarithmic rotary actuator (16b) is rotated clockwise, one pull strand (Z14) of the transmission means (14) is wound up more slowly.as a slack side (L14) of the transmission means (14) is unwound, and so that when the logarithmic rotary control (16b) is turned counterclockwise, the tension side (Z14) of the transmission means (14) is wound up more slowly than the slack side (L14) of the transmission means (14) is unwound.

22. Chair according to at least one of the preceding claims, characterized in that the rocker arm (22) rests on a contact element (41) of the leaf spring (9) with a counter-contact element (40), wherein the counter-contact element (40) and the contact element (41) are each formed by a wedge-shaped body, or wherein the counter-contact element is formed by a wedge-shaped body and the contact element is designed as a projection, or wherein the counter-contact element is designed as a projection and the contact element is formed by a wedge-shaped body, wherein the counter-contact element (40) and the contact element (41) interact in such a way that when a person sitting upright leans backward—due to a relative displacement between the rocker arm (22) and the Leaf spring (9) - by means of the counter contact element (40) which moves relative to the contact element (41) a distance (A1 , A2) between a top surface (9a) of the leaf spring (9) and the counter contact element (40) of the rocker arm (22) is increased.

23. Chair according to claim 22, characterized in that the ramp-shaped counter-contact element (41) and / or the ramp-shaped contact element is / are designed in multiple stages.

24. Chair according to claims 22 and 23, characterized in that the contact element (41 ) of the leaf spring (9) is arranged at a free end (33) of the leaf spring (9).

25. Operating method for a chair (1) wherein the chair (1) comprises a base frame (2), a seat element (3), a back element (4), a rocker arm (22), a spring mechanism (5) and an adjustment device (6) and is designed in particular according to at least one of the preceding claims, characterized in that in an initial position (A) in which the chair (1) is unloaded or is loaded only by a person (P1; P2) sitting upright on the seat element (3) of the chair (1), a support (10) arranged with a clearance (30) under a leaf spring (9) is placed in a desired adjustment position (LP10; MP10; SP10), and that the back element (4) of the chair (1) is adjusted by the seated person (P1;P2) is tilted back from the starting position (A) to a subsequent position (B), such that the back element acts on the leaf spring (9) via the rocker arm (22), which is connected to the back element (4) and the base frame (2), in such a way that the rocker arm (22) is placed on the support (10) and that the seat element (3) is lifted by the back element (4) or the rocker arm (22) against the weight force (GP1; GP2) of the person (P1; P2) to a dead center (31), so that a first restoring force (R1) acting between the starting position (A) and the subsequent position (B) is generated by the weight force of the person, so that the back element (4) of the chair (1) is lifted by the seated person (P1;P2) is tilted back from the subsequent position (B) to an end position (C) by further tilting, whereby a second restoring force (R2) is generated in the subsequent position (B), in all intermediate positions between the subsequent position (B) and the end position (C) and in the end position (C) by the leaf spring (9).;

Images