Chair with seat tilt mechanism

Abstract

The invention relates to a chair, in particular an office chair, and a seat tilting mechanism for a chair. The invention proposes that a cross member of a seat tilting mechanism forms a spring device, wherein this spring device has at least one torsion element.

Description

[0001] The invention relates to a chair, in particular an office chair. The invention relates to a chair with a base and a column on which a seat element and a backrest are mounted via a seat tilting mechanism, wherein the seat element and the backrest are connected to each other via a joint connection of the seat tilting mechanism.

[0002] Such a chair is well known and regularly used as an office chair, adjustable to the user in terms of seat height and tilt. The known chair comprises a base with a caster base and a column on which a support structure with a seat and backrest is mounted. The column is height-adjustable, thus allowing the seat height to be adjusted. The seat tilt mechanism is designed so that the backrest can be tilted or inclined vertically. This mechanism includes a spring that pre-tensions the backrest so that it is positioned in a forward end position. When the chair is used by a person, the backrest can be tilted backward against the spring force if the person leans on it. It is also known to move the seat and backrest together via the seat tilt mechanism.Depending on the design of the seat tilting mechanism, the seat element can be tilted together with the backrest or moved lengthwise along the seat surface. The seat tilting mechanism, along with the spring, can be designed as a lever mechanism. The seat element and backrest can consist of a metal or plastic shell or a frame with padding and a cover or upholstery made of a textile fabric.

[0003] A disadvantage of known chairs with a seat tilt mechanism is that, due to the design of the tilt mechanism and its connection to the base, seat, and backrest, they consist of many parts. In particular, the lever mechanism of the seat tilt often comprises numerous levers and springs, which are made of metal to ensure stability. Manufacturing such a chair or seat tilt mechanism therefore requires a large number of parts and a complex assembly process.

[0004] US4236752 describes an armchair with a swivel and tilt mechanism in which a torsion element, rotatably mounted on a base, is screwed to the underside of a seat with an integrated backrest. Since the backrest and seat are rigidly connected and not via a joint, there is no joint connection between these components, so the swivel and tilt mechanism described therein is not suitable as a seat tilting mechanism within the meaning of the invention.

[0005] WO 2017 / 029409 A1 shows a chair suspension system that allows multidimensional movement of the seat relative to a chair base. This is a simple suspension between two components. However, a hinged connection between a seat back and a seat element using a seat tilting mechanism is not provided.

[0006] The invention is based on the objective of creating a chair of the type mentioned in the introduction, which is optimally designed with regard to the aforementioned problem.

[0007] This problem is solved according to the invention by the subject matter of claim 1. Advantageous embodiments of the invention are specified in the dependent claims.

[0008] The invention proposes that a cross member of a seat tilting mechanism of a chair, particularly an office chair, forms a spring device, wherein this spring device includes at least one torsion element. In particular, it is proposed that a cross member be designed as an integral, i.e., integrally integrated into a component of the chair, deformable torsion element. The torsion element not only enables the deformability of the chair component, e.g., a base support, a seat support, or a backrest support, with this deformability advantageously resulting in a functionality of the chair component based solely on this deformability. Furthermore, as an energy storage device, the torsion element also provides a counterforce opposing a functional deformation, e.g., a deflection.

[0009] The invention proposes providing storage elements as integral, deformable components (torsion elements) of the chair mechanism (seat tilt mechanism). In other words, instead of separately manufactured spring elements that need to be mounted into the mechanism assembly, at least one of the chair components already present for the functionality of the seat tilt mechanism, in particular the base support, seat support, and / or backrest support, is to be used as a storage element. Additionally, real pivot points, especially those previously implemented by rotary joints, can be replaced by virtual pivot points. This reduces the number of components required for the seat tilt mechanism and thus the manufacturing and assembly costs for chair mechanisms.By reducing the number of actual pivot points, material stress and wear on bearing-guided axes are minimized, thus reducing the risk of failure and increasing the lifespan of the chair mechanism. Further advantages arise from new construction and design approaches made possible by the integrated design. For example, seat tilt mechanisms can be provided that require significantly less installation space. In particular, much flatter mechanisms can be created.

[0010] Preferably, the torsion elements are deformable due to an application of force or moment to the chair component, in other words, they deform due to their integral design when the chair component is subjected to a specific force or moment. The torsion element according to the invention is thus characterized by the fact that its deformation is directed towards an intended and therefore desired movement of the chair component into which it is integrated.

[0011] Preferably, the torsion elements are made of a plastic material. Since plastic materials have long been used in the manufacture of seating components, particularly office chair components, suitable equipment and facilities for production and assembly are already available. Therefore, no changes are necessary in this respect. In addition to the use of plastic materials, the use of other materials that allow for the provision of an elastically deformable energy storage system is also possible in principle, such as the use of wood.

[0012] In a particularly preferred embodiment of the invention, the torsion element according to the invention is used to enable a desired movement of a chair component in the first place. In other words, this movement of the chair component would not be possible at all without this element. A seat tilting mechanism according to the invention implemented in this way comprises a number of interacting components whose interaction serves to execute a movement in a specific manner, i.e., allows for the intended mobility and thus functionality of the seat tilting mechanism, and is characterized in that at least one of these components, due to its design with the torsion element according to the invention, is at least partially elastically deformable under load, in particular under the influence of a force or a moment, such that the intended mobility of the device is achieved.It is preferably the deformability of this at least one torsion element alone that enables the intended movement of the mechanism or the chair. Unless otherwise specified, the term "deformable" is always used in the sense of "elastically deformable." In other words, the deformation element changes its shape under the influence of force and returns to its original shape when the force is removed.

[0013] Multi-link linkages, as known from the prior art, can be considered a kinematic chain. Due to the joints of such a linkage, these linkages have degrees of freedom of movement. According to a preferred embodiment of the invention, a multi-link linkage for a seat tilting mechanism of a chair, in particular an office chair, can be provided which, theoretically, no longer has such a degree of freedom when using ideally stiff materials. According to the invention, movement of the linkage is then only made possible by the use of the torsion element, which, when the invention is applied to a seat tilting mechanism, is designed as an integral part of the linkage, in particular as one of the linkages of the linkage or as a part of one of the linkages of the linkage. The kinematic chain thus formed comprises, in addition to a number of real pivot points (i.e.,(one or more real pivot points) at least one virtual pivot point, but preferably several virtual pivot points. The torsion element can be designed such that it consists of a series of virtual pivot points. In other words, it is proposed to replace pivot points and / or coupling elements, the latter completely or partially, by a number, i.e., one or more, component-integrated torsion elements.

[0014] The invention therefore enables the simple and cost-effective production of components and assemblies for seating furniture, particularly chairs, as well as seat tilting mechanisms of any type, which feature a multitude of precisely defined pivot points. The position of these pivot points can be either stationary (i.e., unchanging) or variable. In particular, the position of the pivot points can change even during the movement of the seating furniture or the movement of a component or assembly within the seating furniture. In this way, mechanical devices with highly complex movement characteristics can be manufactured using only a few components. Through a targeted design of the torsion element, the type of deformation of the element can be defined and used to precisely generate a desired movement of a loaded component, especially a component of the seat tilting mechanism or the chair itself.

[0015] With the aid of the torsion element according to the invention, seat tilting mechanisms can be manufactured in a particularly simple manner with a small number of components. The term "seat tilting mechanism" used here also includes chair mechanisms that, in addition to or as an alternative to a tilting movement in the longitudinal direction of the chair, i.e., backwards or forwards, also allow a lateral tilting movement of one or more chair components, i.e., a movement to the right or left.

[0016] According to the invention, the torsion element simultaneously serves as an energy storage element integrated into the mechanical component that provides the torsion element. The torsion element can thus not only define a restoring force for a pivoted mechanical component but also serve to define a pivoting resistance of a mechanical component. Under the influence of a load, the storage element undergoes reversible deformation. The elasticity of the storage element, when subjected to a load, generates a restoring torque, causing it to return to its undeformed original shape as soon as the forces or torques acting upon it cease.

[0017] In particularly preferred embodiments of the invention, the stiffness of the torsion element depends on the direction of action of the force acting on the torsion element. In other words, the deformation element is designed such that it deforms differently depending on the direction of action of the force acting on it. This is preferably achieved by a suitable design of the torsion element.

[0018] By integrating the energy storage device into an existing component of the seat tilting mechanism according to the invention, the number of components (individual parts, assemblies) can be reduced compared to seat tilting mechanisms known from the prior art. This reduces the effort required for parts storage and assembly.

[0019] In the production of the mechanical component containing the torsion element, either a single plastic material is used during the injection molding process, or two or more different plastics are used (multi-component injection molding). Changing the material composition during injection molding is unnecessary if the desired deformation properties of the deformation element can be achieved solely through design.

[0020] The material suitable for manufacturing the torsion element possesses, on the one hand, the necessary stiffness to ensure the required stability and strength of the component. On the other hand, the material is elastic enough to provide the desired deformability during the desired movement.

[0021] The deformation behavior of the torsion element can be modified in its installed state using suitable adjustment mechanisms. These mechanisms can include, for example, mechanically acting mechanisms that completely or partially restrict or block the deformation of a part of the torsion element or the deformation of the entire torsion element. Alternatively, the stiffness of the torsion element can also be selectively altered by temporarily changing a material property of the torsion element.

[0022] When using torsion elements made of plastic, as proposed by the invention, the counterforce to be overcome by the user of the chair when moving the seat tilting mechanism is generated by the plastic material.

[0023] Because integrated torsion elements made of plastic are used instead of steel spring elements or energy storage devices, the weight of the seat tilt mechanism, and therefore the weight of the chair, can be reduced compared to conventional designs. This is particularly advantageous for chairs intended for frequent relocation, as is the case with office chairs. At the same time, recycling such assemblies is simplified, as no material separation is required.

[0024] The torsion element according to the invention can be used in a variety of ways. Although the principle underlying the invention is explained below using the example of seat tilt mechanisms for office chairs, the invention is neither limited to its application in a seat tilt mechanism with the described movement characteristics, nor to the torsion element being part of a specific chair component, for example, the base support. The inventive concept can also be realized using deformable parts of other structural elements or assemblies of chair mechanisms.Furthermore, the inventive concept can be realized with various types of chair mechanisms, in particular with synchronous mechanisms in which the tilting of the backrest occurs with a specific relative movement of the seat and backrest to each other, and with rocking mechanisms in which the tilting of the backrest occurs together with the seat as a single unit of movement. However, a seat tilting mechanism within the meaning of the invention is understood to be any conceivable chair mechanism, including asynchronous mechanisms in which the tilting of the backrest occurs independently of the seat or when the seat is stationary.

[0025] The torsion element according to the invention can be used, in particular, as part of a base support, as part of a seat support, or as part of a backrest support. However, the torsion element can also form the entire base support, seat support, or backrest support. Preferably, in these cases, the torsion element has a minimum number of rigid or substantially rigid areas that form non-deformable connection areas required for the interaction of these assemblies with other assemblies or components.

[0026] In particular, the torsion element according to the invention can form part of a one-piece base support-seat support combination, part of a one-piece base support-backrest support combination, part of a one-piece seat support-backrest support combination or part of a one-piece seat support-base support-backrest support combination.

[0027] The torsion element can also form an entire one-piece base support-seat support combination, an entire one-piece base support-backrest support combination, an entire one-piece seat support-backrest support combination, or an entire one-piece seat support-base support-backrest support combination. Preferably, in these cases, the torsion element has a minimum number of rigid or substantially rigid areas that form non-deformable connection areas required for the interaction of the respective combination with other components or parts.

[0028] When the invention is applied to a chair mechanism, this mechanism need not necessarily be one in which the degree of freedom required for the movement is only provided with the use of the torsion element. The torsion element according to the invention can also be used in traditionally constructed chair mechanisms that employ steel springs or other separate spring elements. In other words, it is possible to combine the use of a torsion element according to the invention with conventional spring arrangements. In such hybrid mechanisms, the combination of separate and integrated energy storage devices offers a wide range of design possibilities, which can be used both to provide ergonomically advantageous movement sequences and to realize particularly compact or low-profile chair mechanisms, as well as to create especially elegant mechanisms.

[0029] According to a first and second embodiment of the invention, a chair, in particular an office chair, is proposed, comprising a base frame with a foot column on which a seat element and a backrest are mounted via a seat tilting mechanism, wherein the seat tilting mechanism comprises a base support connected to the foot column, to which a backrest support and a seat element support are articulated, and the seat element and the backrest are connected to each other via a joint connection of the seat tilting mechanism, wherein a cross member of the seat tilting mechanism forms a spring device, wherein the cross member extends in the transverse direction of the chair and wherein the spring device has at least one torsion bar spring.

[0030] According to the first embodiment, the cross brace is connected to the base support, wherein the backrest support, together with the base support and the torsion spring, is formed integrally, in particular in one piece, from plastic. According to the second embodiment, the base support or the seat element support, together with the torsion spring, is formed integrally, in particular in one piece, from plastic. According to a third embodiment of the invention, the torsion springs, together with the base support and the seat element support and / or together with the backrest support, are formed integrally, in particular in one piece.

[0031] Because the crossbar of the seat tilt mechanism incorporates a spring, a structural component of the seat tilt mechanism can be used to generate a spring force for returning the seat back to its original position. The crossbar, which forms the spring mechanism and is connected to the base support and / or the seat element support and / or the backrest support, makes it possible to significantly reduce the number of parts in the seat tilt mechanism. This makes manufacturing a chair with a common range of functions comparatively simpler and more cost-effective.

[0032] The spring assembly includes at least one torsion bar spring or is itself a torsion bar spring. The torsion bar spring can then be designed particularly simply as a rod-shaped spring or torsion bar. In particular, the crossbar itself can form the torsion bar spring. The one-piece, especially one-piece, design of the torsion bar spring with other chair components made of plastic can be produced very cost-effectively in large quantities, for example, using injection molding or compression molding. Separate assembly of the base support or the seat element support with the torsion bar springs is then no longer necessary.

[0033] It may be provided that the spring device is designed with a preload. For example, the seat tilting mechanism can be mounted to the crossbar in such a way that the crossbar exerts a spring force on the seat back, which always causes the seat back to return to a forward end position when unloaded.

[0034] Preferably, two torsion springs of the spring assembly can be integrally connected to the base support and, with respect to a vertical longitudinal center plane of the chair, connected at their respective distal ends to a lever of the seat tilting mechanism. The cross member connected to the base support can then form two torsion springs, each of which is integrally formed with the base support. The respective proximal ends of the torsion springs can therefore be integrally formed with the base support, and a spring force generated by the torsion springs can be transmitted via a lever at each distal end of the torsion springs. The lever can extend essentially orthogonally relative to a longitudinal axis of the torsion spring or the cross member.

[0035] According to the first embodiment, the backrest support, together with the base support and the torsion bar springs, can be formed integrally, particularly in one piece, from plastic and form the levers of the seat tilting mechanism. For example, the backrest support can be designed as a frame, at the lower end of which the base support is molded for connection to the base column. The crossbar is then formed by a lower, vertical rod of the frame. The parallel rods or legs of the frame connected to the crossbar then each form the lever of the seat tilting mechanism. A further frame for receiving a backrest cushion or upholstery can be arranged or integrated into the frame. Tilting of the frame due to the weight of a person then causes torsion of the crossbar, since it is rigidly connected to the base support and the base column.

[0036] The seat element support can be formed from struts articulated to the base support and rear pivot joints arranged on the levers, which can hold the seat element. The struts can also be integrally formed with the plastic base support and extend towards a front edge of the seat element. The seat element can thus be easily supported at the front by the struts and at the rear by the pivot joints. The pivot joints can, for example, be formed by a recess in a frame of the backrest support into which axles molded onto the seat element are inserted. Alternatively, the axles can be molded onto the frame and inserted into recesses in the seat element.

[0037] Furthermore, at least one front pivot joint, slidable in an elongated slot, can be formed between the struts and the seat element, whereby pivoting the backrest support on the torsion springs can cause a displacement of the seat element in the longitudinal direction of the chair relative to the base support. The elongated slot or the front pivot joint can be formed at the distal ends of the struts, with a corresponding pivot joint, axis, or elongated slot being formed on the seat element. The pivot joint or axis can then be moved and pivoted in the elongated slot, so that when the backrest pivots, the seat element is moved along the longitudinal direction of the chair with the backrest.

[0038] The spring assembly can include an adjustment device for setting the spring constant of the torsion bar springs, wherein the adjustment device can be formed from support elements that are displaceable in the longitudinal direction of the groove. The support elements can increase the profile cross-section of the respective torsion bar spring, and thus its section modulus, in sections. For example, the support elements can be inserted into the groove and displaced along the groove, so that a comparatively lower spring stiffness can be achieved when the support elements are displaced towards the base column, and a comparatively higher spring stiffness can be achieved when the support elements are displaced towards a distal end of the torsion bar springs.

[0039] The support elements can each be designed as a threaded stud with an internal profile, the opposing threads of which can engage transverse grooves formed in the groove. The support elements can be designed to be displaceable along the longitudinal direction of the groove by means of a rotation of an actuating shaft of the adjusting device inserted in the internal profile. The threaded studs can then be pushed onto the actuating shaft, whereby a rotation of the actuating shaft, for example by means of a hand-operated crank, causes the threaded studs to move relative to or away from each other, depending on the direction of rotation, due to the opposing threads. Preferably, the internal profile is designed to correspond to a cross-section of the actuating shaft. The transverse grooves, which can run orthogonally to the groove, can be easily formed by machining or forming.Moving the threaded pins by rotating the actuating shaft also results in an adjustment of the spring constant.

[0040] According to the invention, the first embodiment proposes a seat tilting mechanism for a chair, in particular an office chair, comprising a base support connectable to a base column of the chair, wherein two torsion springs of the seat tilting mechanism are integrally connected to the base support and, with respect to a vertical longitudinal center plane of the chair, are connected at their respective distal ends to a lever of the seat tilting mechanism, wherein a backrest support of the chair, together with the base support and the torsion springs, is formed integrally, in particular in one piece, from plastic and forms the levers of the seat tilting mechanism, wherein a seat element support of the chair is formed from struts articulated to the base support and rear pivot joints arranged on the levers, which hold the seat element, wherein at least one front pivot joint, slidable in an elongated hole, is formed between the struts and the seat element.wherein a pivoting of the backrest support on the torsion bar springs causes a displacement of the seat element in the longitudinal direction of the chair relative to the base support.

[0041] Furthermore, according to the invention, an adjustment device for a chair, in particular an office chair, is proposed, wherein the adjustment device serves to adjust a spring constant of torsion springs of a seat tilting mechanism of the chair, wherein the torsion springs are formed from a rod-shaped profile section with a groove extending at least partially in a longitudinal direction of the profile section, wherein the adjustment device is formed from support elements that are longitudinally displaceable in the groove, wherein the support elements are each formed as a threaded pin with an inner profile whose opposing threads engage transverse grooves formed in the groove, wherein the support elements are displaceable in the longitudinal direction of the groove by means of a rotation of an actuating shaft of the adjustment device inserted in the inner profile.The advantages of the adjustment device are described in the description of advantages of the chair according to the invention. Further advantageous embodiments of an adjustment device are described in the feature descriptions of claims 1 to 10.

[0042] According to the second advantageous embodiment, the base support, together with the torsion springs, can be formed integrally, particularly in one piece, from plastic and form the levers of the seat tilting mechanism. The base support can, for example, extend towards a front edge of the seat element, with the torsion springs being integrally formed at a front end of the base support. Simultaneously, the levers of the seat tilting mechanism can be integrally formed on the crossbar or the torsion springs essentially orthogonally to a longitudinal axis. This also makes it possible to connect the levers directly to the seat element and to transmit a restoring force from the pivot joints to the movement of the seat back via the seat element.

[0043] The backrest support can be connected to the base frame via a lower pivot joint. For example, the backrest support can be designed as a frame that may be fitted with a backrest cushion or a fabric covering. The frame can be pivotally attached directly to the base frame or via a connecting section molded onto the frame. This pivoting connection can be easily implemented via the lower pivot joint, thus allowing the backrest support or seat back to swivel.

[0044] Furthermore, the seat element support can be formed from at least one strut articulated to the backrest support and the levers that hold the seat element. The strut can also be formed integrally with the backrest support, particularly as a single piece, and serve to connect it to the seat element. The strut can be connected to the seat element at its rear and support it. Optionally, several struts can be integrally formed with the backrest support and connected to the seat element. The levers can also be directly connected to the seat element, so that the seat element rests directly on the levers at its front.

[0045] A rear pivot joint can be formed between the strut and the seat element, and the levers can each be connected to the seat element via a front pivot joint. Pivoting the backrest support at the lower pivot joint can cause the seat element to shift longitudinally relative to the base support. Thus, pivoting the backrest support at the lower pivot joint can cause the seat element to shift longitudinally due to its connection to the rear pivot joint or the strut. The levers connected to the seat element via the front pivot joint are then moved by the longitudinal shift of the seat element, causing torsion of the torsion bar springs and thereby generating a spring force or restoring force.

[0046] Two torsion bar springs of the spring device can be connected to the seat element at their respective distal ends with respect to a vertical longitudinal plane of the chair and connected to a front pivot joint of the seat tilting mechanism on the base support via a lever integrally formed with the torsion bar springs.

[0047] The distal ends of the torsion bar springs can be screwed to the seat element or molded onto it.

[0048] A rear pivot joint can be formed between the seat element support and the seat element, and the lever can be connected to the base support via the front pivot joint, whereby pivoting the backrest support at the lower pivot joint can cause a displacement of the seat element in the longitudinal direction of the chair relative to the base support.

[0049] The seat element support can be formed from a frame that forms the crossbar, wherein two torsion bar springs of the spring device can be attached to the frame at their respective distal ends with respect to a vertical longitudinal plane of the chair and can be connected to a front pivot joint of the seat tilting mechanism on the base support via a lever integrally formed with the torsion bar springs.

[0050] A rear pivot joint can be formed at a rear end of the frame, and the backrest support can be connected to the seat element support via the rear pivot joint, whereby pivoting the backrest support at the lower pivot joint can cause a displacement of the seat element in the longitudinal direction of the chair relative to the base support.

[0051] According to the invention, the second embodiment proposes a seat tilting mechanism for a chair, in particular an office chair, comprising a base support connectable to a base column of the chair, an extension of a backrest support of the chair articulated to the base support, and a seat element support, wherein two torsion springs are integrally connected to the base support or the seat element support and, with respect to a vertical longitudinal center plane of the chair, are connected at their respective distal ends to a lever of the seat tilting mechanism or to the seat element support, wherein the extension is connected to the base support via a lower pivot joint, wherein the seat element support is formed from at least the extension and the lever that holds the seat element, wherein a rear pivot joint is formed between the extension and the seat element, and the lever is connected to the seat element or the seat element support via a front pivot joint.wherein a pivoting of the backrest support with the extension at the lower pivot joint causes a displacement of the seat element in the longitudinal direction of the chair relative to the base support.

[0052] According to further embodiments of the invention, the torsion elements, in particular in the form of torsion bar springs, can be formed integrally, in particular in one piece, together with the base support and the seat element support and / or together with the backrest support and the seat element support and / or together with the base support and the backrest support. In other words, the torsion elements are integrally connected to the base support and / or integrally to the seat element support and / or integrally to the backrest support.

[0053] Advantageously, the seat tilting mechanism has a plurality of crossbars formed in one piece, in particular in one piece, so that the number of actual pivot joints and required components can be reduced even further.

[0054] According to the invention, a seat tilting mechanism for a chair, in particular an office chair, is provided, comprising a base support to which a backrest support and a seat element support are articulated, characterized in that a cross member of the seat tilting mechanism forms a spring device, wherein the cross member extends in the transverse direction of the chair and wherein the spring device has at least one torsion element, in particular a torsion bar spring, and wherein the torsion element together with the base support or the backrest support or the seat element support is formed integrally, in particular in one piece, from plastic.This does not preclude the seat tilting mechanism from comprising several crossbars with spring devices, whereby the torsion elements of these spring devices, depending on the arrangement of the crossbars on various components of the chair mechanism, may also be formed in one piece, in particular in one piece, with the base support and / or with the seat element support and / or with the backrest support.

[0055] All embodiments share the common feature that the torsion bar spring(s) can be formed from a rod-shaped profile section with a groove running at least partially along one longitudinal direction of the profile section. The groove can, in principle, also be designed as a continuous elongated slot on the cross member. The essential aspect is that a cross-section of the profile section is such that a section modulus suitable for generating a spring force is created. The torsion bar spring can then be readily elastically deformed and cost-effectively manufactured from, for example, plastic. A desired spring constant of the torsion bar spring can then be achieved by appropriately shaping the groove.

[0056] The spring assembly can include an additional torsion bar spring made of spring steel. This additional torsion bar spring can be inserted into the groove and fixed at its proximal end to the base support, seat element support, or backrest support, and at its distal end to the lever of the seat tilting mechanism. The spring constant of the torsion bar spring can be easily adjusted using this additional spring steel spring. For example, it is then possible to adapt a chair to different weight classes of users. The additional torsion bar spring can be made of spring steel wire, with both the proximal and distal ends being bent. Two bores can be provided in the groove to accommodate the proximal and distal ends, respectively. The additional torsion bar spring can then be easily fixed by inserting it into the bores at the proximal and distal ends.The additional torsion bar spring can also be fixed to the bores with its proximal and distal ends in such a way that a preload is formed on the additional torsion bar spring.

[0057] The advantages of the seat tilting mechanism according to the embodiments are described in the description of advantages of the chair according to the invention. Further advantageous embodiments of a seat tilting mechanism are described in the features of the claims.

[0058] Further advantages and advantageous embodiments of the objects according to the invention can be found in the description, the drawing and the claims.

[0059] Exemplary embodiments of a chair according to the invention are shown schematically simplified in the drawing and are explained in more detail in the following description. It shows: Fig. 1 a seat tilting mechanism (prior art), Fig. 2 a side view of a chair according to the invention (first embodiment), Fig. 3 another side view of the chair made of Fig. 2 , Fig. 4 a perspective exploded view of the chair made of Fig. 2 Fig. 5 shows an embodiment of a base support in a perspective view, Fig. 6 shows another perspective view of the base support made of Fig. 5 , Fig. 7 a further development of the basic carrier from Fig. 5 in a perspective view, Fig. 8 another perspective view of the base support made of Fig. 7 , Fig. 9 a perspective exploded view of the base support made of Fig. 7 , Fig. 10 a further development of the basic carrier from Fig. 5 in a perspective view, Fig. 11 a sectional view of the base support made of Fig. 10 , Fig. 12 a perspective exploded view of a further development of the basic support made of Fig. 7 Fig. 13 a side view of a chair according to the invention (second embodiment), Fig. 14 another side view of the chair made of Fig. 13 , Fig. 15 a perspective exploded view of the chair made of Fig. 13 , Fig. 16 a partial sectional view of the chair made of Fig. 15 Fig. 17 shows a side view of another chair according to the invention, Fig. 18 shows another side view of the chair made of Fig. 17 , Fig. 19 a bottom view of the chair made of Fig. 17 , Fig.20 a perspective exploded view of the chair made of Fig. 17 , Fig. 21 another perspective view of the crossbeam made of Fig. 20 Fig. 22 a side view of another chair according to the invention, Fig. 23 another side view of the chair made of Fig. 22 , Fig. 24 a bottom view of the chair made of Fig. 22 , Fig. 25 a perspective exploded view of the chair made of Fig. 22 , Fig. 26 a bottom view of a frame made of Fig. 25 .

[0060] The Fig. 1 demonstrates the state of the art. Fig. 2 bis 12 show a first embodiment and its variants, which Fig. 13 bis 26 show a second embodiment and its variants.

[0061] All figures do not show the invention to scale, only schematically and with its essential components. Identical reference numerals correspond to elements with the same or comparable function.

[0062] "Front" or "frontal" means that a component is located at the front along the length of the chair, or refers to a component extending towards or pointing in the direction of the front edge of the seat, while "rear" or "backal" means that a component is located at the rear along the length of the chair, or refers to a component extending towards or pointing in the direction of the backrest, back support, or rear edge of the seat. The terms "top" or "upper" or "higher" and "bottom" or "lower" or "lower" refer to the intended state of use of the office chair or its mechanism.

[0063] In Fig. 1 To illustrate the swivel principle, a seat tilting mechanism generally known from the prior art is shown in a highly simplified form. This is a synchronous mechanism 139 in which the three main components of the mechanism, namely base support 1, seat element support 3, and backrest support 4, are coupled to each other via pivot joints, so that a swiveling movement of the backrest support 4 in the direction of swivel 7, viewed from the rear in the longitudinal direction 146 of the chair, induces a synchronous subsequent movement of the seat element support 3, while the base support 1 remains stationary and immobile. The mechanism is mounted with its base support 1 on a base column 2, which rests on the floor with a chair base. The backrest support 4, with its pivot point to the base support 1 on the one hand and the rear area of ​​the seat element support 3 on the other, forms theOn the one hand, the seat shell or seat frame has a rear coupling element 140 integrated into the backrest support 4, while a separate front coupling element 141 connects the base support 1 to the front area of ​​the seat element support 3, or the seat shell or seat frame. In this way, four pivot points are created, realized by four rotary joints, each with a transverse axis. These are the first rotary joint 142 for connecting the base 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 base 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.

[0064] According to the invention, in principle all real pivot points realized by rotary joints 142, 143, 144, 145 can now be replaced by virtual pivot points provided by one or more torsion elements according to the invention.

[0065] The transverse axis of the seat tilting mechanism according to the invention, which includes the spring device, can serve to form any number of pivot joints of the seat tilting mechanism. For example, a front, upper transverse axis serving to form the pivot joint 145 can include the spring device according to the invention. Alternatively or additionally, a front, lower transverse axis serving to form the pivot joint 144 can include the spring device according to the invention. Alternatively or additionally, a rear, upper transverse axis serving to form the pivot joint 143 can include the spring device according to the invention. Alternatively or additionally, a rear, lower transverse axis serving to form the pivot joint 142 can include the spring device according to the invention.

[0066] The invention is not limited to the use of a single transverse axis according to the invention in a seat tilting mechanism. A seat tilting mechanism can thus have several such transverse axes with spring devices. For example, transverse axes according to the invention can form all the front pivot joints of a seat tilting mechanism when viewed in the longitudinal direction of the chair, and / or transverse axes according to the invention can form all the rear pivot joints of a seat tilting mechanism when viewed in the longitudinal direction of the chair. Likewise, transverse axes according to the invention can form all the lower pivot joints of a seat tilting mechanism associated with the base support, and / or transverse axes according to the invention can form all the upper pivot joints of a seat tilting mechanism associated with the seat element support. It is also possible to configure the pivot joints "crosswise" using the transverse axes according to the invention (e.g., pivot joints at the front bottom and rear top).In principle, any arrangement of the transverse axes according to the invention is possible for forming a single pivot joint, several selected pivot joints or all pivot joints of the seat tilting mechanism.

[0067] Each of the transverse axes according to the invention comprises a spring device with at least one torsion element, in particular a torsion bar spring. Transverse axes can be provided that are essentially formed entirely from a single torsion element. However, transverse axes can also be provided that have several torsion elements. These torsion elements can be arranged one behind the other along the longitudinal direction of the transverse axis. In this case, the torsion elements can also be spaced apart from one another. For example, the torsion elements of a transverse axis can be designed as axis sections that are connected to one another via axis sections with lower torsional flexibility or via rigid axis sections. It is also conceivable in which the transverse axis has several torsion elements arranged parallel to one another in the longitudinal direction of the axis.

[0068] The application of the transverse axes according to the invention is not limited to seat tilting mechanisms with four-bar linkages. Use in seat tilting mechanisms with a different linkage geometry is also possible. Furthermore, one or more transverse axes according to the invention can be used in seat tilting mechanisms that also employ deformation elements extending in the longitudinal direction of the chair, which deform, in particular bend, due to tensile or compressive stress.

[0069] A first embodiment of the invention is described below. This involves the in Fig. 1 The pivot joint 142 shown is replaced by a virtual pivot point using a cross brace according to the invention.

[0070] In the Fig. 2 bis 4 A chair 232 according to the invention is shown, comprising a base column 233 with a roller cross (not shown in detail), a seat tilting mechanism 234, a seat element 235, a seat back 236, and a base support 237 connected to the base column 233. A cross member 238 of the seat tilting mechanism 234 forms torsion springs 239. In particular, a substantially frame-shaped backrest support 240 of the seat back 236, together with the base support 237 and the torsion 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 tilting mechanism 234, which are integrally formed on the torsion springs 239. Furthermore, struts 243 are integrally formed on the base support 237, which hold the seat element 235. In a seat shell 244 of the seat element 235, elongated holes 245 are formed, into each of which an axle 246 of the strut 243 is movably inserted. The elongated hole 245 and the axle 246 form a front pivot joint 248.Furthermore, a rear pivot joint 247 is formed between each leg 241 or lever 242 and the seat shell 244. A backward tilting of the seat back 236, as shown in . Fig. 7 As shown, in addition to tilting the seat back 236, the seat element 235 is displaced backwards, whereby the axis 246 is also displaced in the elongated hole 245. The torsion bar springs 239 are each designed with a groove 249 extending longitudinally along the torsion bar spring 239. Overall, the chair 232 is essentially formed from the backrest support 240, which is integrally formed with the plastic base support 237, and the seat shell 244.

[0071] The Fig. 5 and 6Figure 1 shows a schematic representation of an embodiment of a base support 250 made of plastic, which has a spring device 251 with torsion bar springs 252. The torsion bar springs 253 are formed by a cross member 253 with a continuous groove 254, wherein a pivotable lever 256 is formed at each distal end 255 of the torsion bar springs 252. Furthermore, a flange 257 is formed on the cross member 253 in the base support 250 for connection to a chair leg (not shown in detail here). As can be seen from the Fig. 6 As can be seen, the levers 226 can be inclined by an angle α, which causes the formation of a spring force and a deformation of the torsion bar springs 252.

[0072] The Fig. 7 bis 9 show a base support 258, which differs from the base support made of Fig. 5 The device 259 includes an adjusting device 259. The adjusting device 259 comprises threaded pins 260, which are rotatable via a crank 262 on an actuating shaft 261 and are longitudinally displaceable on the actuating shaft 261. The threaded pins 260 engage in transverse grooves 263, which are formed in a groove 264 in torsion springs 265 of a cross member 266. Depending on the displacement of the threaded pins 260, the resistance torque of the torsion springs 265 can be changed, so that a spring constant or the torsion springs 265 can be adjusted to be stiffer or softer.

[0073] The Fig. 10 and 11 show a base support 267, which, unlike the base support made of Fig. 9 The torsion bar springs 268 made of spring steel are further incorporated. These further torsion bar springs 268 are inserted into a groove 269 and are rotationally fixed to the base support 267. The arrangement of the further torsion bar springs 268 on the base support 267 allows for a significant influence on the spring constant of the torsion bar springs 270 thus formed.

[0074] The Fig. 12 shows a base support 271, which is attached to the Fig. 7 bis 10 described base carrier combined.

[0075] Regarding the issues related to the Fig. 2 bis 12 The first embodiment of the invention described above is characterized in particular by the fact that it is a chair 232, in particular an office chair, comprising a base frame with a foot column 233, on which a seat element 235 and a seat back 236 are mounted via a seat tilting mechanism 234, wherein the seat tilting mechanism comprises a base support 237, 250, 258, 267, 271 connected to the foot column, to which a backrest support 240 and a seat element support are articulated, and the seat element and the seat back are connected to each other via a joint connection 221 of the seat tilting mechanism, characterized in that a cross member 238, 253, 266 of the seat tilting mechanism forms a spring device 251, wherein the cross member extends in the transverse direction 100 of the chair and is connected to the base support, wherein the spring device comprises at least one torsion bar spring 239, 252, 265,270, wherein the backrest support, together with the base support and the torsion bar spring, is formed in one piece, in particular in one piece, from plastic.

[0076] Advantageously, this chair is characterized by the fact that the spring device 251 is designed with a preload.

[0077] Advantageously, this chair is characterized in that two torsion bar springs 239, 252, 265, 270 of the spring device 251 are integrally connected to the base support 237, 250, 258, 267, 271 and are connected at their respective distal ends 255 to a lever 242, 256 of the seat tilting mechanism 234 with respect to a vertical longitudinal plane of the chair.

[0078] Advantageously, this chair is characterized in that the backrest support 240 together with the base support 237, 250, 258, 267, 271 and the torsion bar springs 239, 252, 265, 270 is formed in one piece, in particular in one piece, from plastic and forms the levers 242, 256 of the seat tilting mechanism 234.

[0079] Advantageously, this chair is characterized in that the seat element support is formed from struts 243 articulated to the base support 237, 250, 258, 267, 271 and rear pivot joints 247 arranged on the levers 242, 256, which hold the seat element 235.

[0080] Advantageously, this chair is characterized in that at least one front pivot joint 248, which is slidable in an elongated hole 245, is formed between the struts 243 and the seat element 235, wherein a pivoting of the backrest support 240 on the torsion bar springs 239, 252, 265, 270 causes a displacement of the seat element 235 in the longitudinal direction of the chair relative to the base support 237, 250, 258, 267, 271.

[0081] Advantageously, this chair is characterized in that the torsion spring 239, 252, 265, 270 is formed from a rod-shaped profile section with a groove 249, 254, 264, 269 extending at least partially in a longitudinal direction of the profile section.

[0082] Advantageously, this chair is characterized in that the spring device has an adjusting device 259 for adjusting a spring constant of the torsion bar springs 265, 270, wherein the adjusting device is formed from support elements which are displaceable in the longitudinal direction in the groove 264, 269.

[0083] Advantageously, this chair is characterized in that the support elements are each designed as a threaded pin 260 with an internal profile whose opposing threads engage in the transverse grooves 263 formed in the groove 264, 269, wherein the support elements can be displaced in the longitudinal direction of the groove by means of a rotation of an actuating shaft 261 of the adjusting device 259 inserted in the internal profile.

[0084] Advantageously, this chair is characterized in that the spring device has a further torsion spring 268 made of spring steel for each torsion spring 270, wherein the further torsion spring is inserted into the groove 269 and is fixed in a rotationally fixed manner at its proximal end to the base support 267, 271 and at its distal end to the lever of the seat tilting mechanism.

[0085] Regarding the issues related to the Fig. 2 bis 12 The described embodiment of the invention is characterized in particular by the fact that it is a seat tilting mechanism 234 for a chair 232, in particular an office chair, which comprises a base support 237, 250, 258, 267, 271 connectable to a base column 233 of the chair, characterized in that two torsion springs 239, 252, 265, 270 of the seat tilting mechanism are integrally connected to the base support and, with respect to a vertical longitudinal center plane of the chair, are connected at their respective distal ends 255 to a lever 242, 256 of the seat tilting mechanism, wherein a backrest support 240 of the chair, together with the base support and the torsion springs, is formed integrally, in particular in one piece, from plastic and forms the levers of the seat tilting mechanism, wherein a seat element support of the chair consists of struts 243 articulated to the base support and rear elements arranged on the levers The swivel joints 247, which hold the seat element 235, are designedwherein at least one front pivot joint 248, which is slidable in an elongated hole 245, is formed between the struts and the seat element, wherein pivoting of the backrest support on the torsion bar springs 239, 252, 265, 270 causes a displacement of the seat element in the longitudinal direction of the chair relative to the base support 237, 250, 258, 267, 271.

[0086] Regarding the issues related to the Fig. 2 bis 12 The described embodiment of the invention is characterized in particular by the fact that it is an adjustment device 259 for a chair 232, in particular an office chair, wherein the adjustment device serves to adjust a spring constant of torsion springs 265, 270 of a seat tilting mechanism of the chair, wherein the torsion springs are formed from a rod-shaped profile section with a groove 264, 269 extending at least partially in a longitudinal direction of the profile section, wherein the adjustment device is formed from support elements that are longitudinally displaceable in the groove, wherein the support elements are each formed as a threaded pin 260 with an internal profile, the opposing threads of which engage transverse grooves 263 formed in the groove.wherein the support elements can be displaced in the longitudinal direction of the groove by means of a rotation of an actuating shaft 261 of the adjusting device 259 inserted in the inner profile.

[0087] A second embodiment of the invention is described below. In this embodiment, the invention is described in Fig. 1 The pivot joint 145 shown is replaced by a virtual pivot point using a cross brace according to the invention.

[0088] In the Fig. 13 bis 16 A chair 10 according to the invention is shown schematically, which is designed as an office chair and which is therefore adjustable with regard to its seat height, seat depth and tilt behavior.

[0089] The chair 10 comprises a base column not shown in detail, which is telescopically designed and at the lower end of which a roller cross of the usual design is arranged.

[0090] A seat tilting mechanism 11, a seat element 12, and a seat back 13 of the chair 10 are arranged on the base column. The seat tilting mechanism 11 comprises a base support 14 connected to the base column, to which a back support 15 and a seat element support 16 are hinged. The seat element 12 consists of a seat shell 17 with a seat cushion 18, and the seat back 13 consists of a back shell 19 with a back cushion 20.

[0091] The seat element 12 is connected to the seat back 13 via a hinge connection 21. The seat tilting mechanism 11 comprises two torsion bar springs 22, which are formed from a cross member 23. The torsion bar springs 22 are integrally formed with the base support 14 and have levers 25 at their outer, distal ends 24, which are connected to the seat shell 17 via a front pivot joint 26. Furthermore, a lower pivot joint 27 is formed on the base support 14, via which a projection 28 of the seat back 13 tilts the seat back, as shown in Fig. 14 shown, mounted so that it can swivel backwards.

[0092] Furthermore, a strut 29 is molded onto the seat back 13 or the extension 28, which is connected to the seat shell 17 via a rear pivot joint 30. As shown from Fig. 14 As can be seen, a backward-tilting seat back 13 at the lower pivot joint 27 leads to a displacement of the seat element 12, whereby the torsion springs 22 are twisted. The cross member 23, which forms the torsion springs 22, is designed with a groove 31 extending longitudinally along the cross member 23, which facilitates torsion of the cross member 23 and / or the torsion springs 22. The chair 10 is essentially formed from the base support 14, which is made of plastic in one piece, in particular in one piece, the backrest support 15, and the seat shell 17 or the seat element support 16.

[0093] In the Fig. 17 bis 21 A chair 32 according to the invention is shown, comprising a base column 33 with a roller cross (not shown in detail), a seat tilting mechanism 34, a seat element 35, a seat backrest 36, and a base support 37 connected to the base column 33. Here too, a crossbar 38 of the seat tilting mechanism 34 forms torsion bar springs 39.

[0094] Here too, a cross member 38 of the seat tilting mechanism 34 forms torsion springs 39. Distal ends 40 of the torsion spring 39 are each screwed to the seat element 35 by screws (not shown in detail here). A lever 41 is integrally formed, in particular as a single piece, centrally on the torsion springs 39 and / or the cross member 38. The lever 41 is connected to the base support 37 via a front pivot joint 42. A lower pivot joint 43 is also formed on the base support 37 together with an extension 44 of the seat back 36. Furthermore, a rear pivot joint 45 is formed on the extension 44 together with the seat element 35. Tilting the seat back 36 backwards now causes, as in Fig. 18 It is evident that the seat element 35 is displaced in the longitudinal direction of the chair relative to the base support 37. In the embodiment of the chair 32 shown here, the extension of the seat back 36 is formed independently of a backrest support 46. Furthermore, a continuous groove is formed in the crossbar 38.

[0095] The Fig. 22 bis 26 show a chair 48, in which, unlike the chair made of Fig. 17 bis 21 A seat element support 49 is formed from a frame 50. The frame 50 forms a cross member 51 with the torsion bar springs 52. The frame 50, together with the torsion bar springs 52 and a lever 53 molded onto the torsion bar springs 52, is formed in one piece, in particular as a single unit, from plastic. A seat element 54 is placed on and attached to the frame 50.

[0096] Regarding the issues related to the Fig. 13 bis 26 The described embodiment of the invention is characterized in particular by the fact that it 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 tilting mechanism 11, 34, wherein the seat tilting mechanism comprises a base support 14, 37 connected to the base column, to 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 each other via a joint connection 21 of the seat tilting mechanism, characterized in that a cross member 23, 38, 51 of the seat tilting mechanism forms a spring device, wherein the cross member extends in the transverse direction 100 of the chair, wherein the spring device has at least one torsion bar spring 22, 39, 52. wherein the base support or the seat element support together with the torsion bar spring is formed in one piece, in particular in one piece,is made of plastic.

[0097] Advantageously, this chair is characterized by the fact that the spring device is designed with a preload.

[0098] Advantageously, this chair is characterized in that two torsion bar springs 22 of the spring device are integrally connected to the base support 14 and, with respect to a vertical longitudinal center plane of the chair, are connected at their respective distal ends 24 to a lever 25 of the seat tilting mechanism 11.

[0099] Advantageously, this chair is characterized in that the base support 14 together with the torsion bar springs 22 is formed in one piece, in particular in one piece, from plastic and forms the levers 25 of the seat tilting mechanism 11.

[0100] Advantageously, this chair is characterized in that the backrest support 15 is connected to the base support 14 via a lower pivot joint 27.

[0101] Advantageously, this chair is characterized in that the seat element support 16 is formed from at least one strut 29 articulated to the backrest support 15 and the levers 25 which hold the seat element 12.

[0102] Advantageously, this chair is characterized in that a rear pivot joint 30 is formed between the strut 29 and the seat element 12, and the levers 25 are each connected to the seat element via a front pivot joint 26, wherein a pivoting of the backrest support 15 at the lower pivot joint 27 causes a displacement of the seat element in the longitudinal direction of the chair relative to the base support 14.

[0103] In a further embodiment, the chair described above can advantageously be characterized in that two torsion bar springs 39 of the spring device are connected at their respective distal ends 40 to the seat element 35 with respect to a vertical longitudinal center plane of the chair and are connected via a lever 41 integrally formed with the torsion bar springs to a front pivot joint 42 of the seat tilting mechanism on the base support 37.In this case, this chair is advantageously also characterized in that the distal ends 40 of the torsion bar springs 39 are screwed to or formed on the seat element 35 and / or this chair is characterized in that a rear pivot joint 45 is formed between the seat element support and the seat element 35, and the lever 41 is connected to the base support 37 via the front pivot joint 42, wherein a pivoting of the backrest support 46 at the lower pivot joint 43 causes a displacement of the seat element in the longitudinal direction of the chair relative to the base support.

[0104] In a further embodiment, the chair described above can advantageously be characterized in that the seat element support 49 is formed from a frame 50 which forms the cross member 51, wherein two torsion bar springs 52 of the spring device are connected to the frame at their respective distal ends with respect to a vertical longitudinal center plane of the chair and are connected to a front pivot joint 42 of the seat tilting mechanism on the base support 37 via a lever 53 formed integrally with the torsion bar springs. In this case, this chair is also advantageously characterized in that a rear pivot 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 pivot joint, wherein pivoting the backrest support at the lower pivot joint 43 causes a displacement of the seat element 54 in the longitudinal direction of the chair relative to the base support 37.

[0105] In a further embodiment, the chair described above can advantageously be characterized in that the torsion spring 22 is formed from a rod-shaped profile section with a groove 31 extending at least partially in a longitudinal direction of the profile section. In this case, this chair is also advantageously characterized in that the spring assembly comprises a further torsion spring made of spring steel for each torsion spring, wherein the further torsion spring is inserted into the groove and is fixed against rotation at its proximal end to the base support or the seat element support and at its distal end to the lever of the seat tilting mechanism.

[0106] Regarding the issues related to the Fig. 13 bis 26 The described embodiment of the invention is characterized in particular by the fact that it is a seat tilting mechanism 11, 34 for a chair 10, 32, 48, in particular an office chair, comprising a base support 14, 37 connectable to a base column 33 of the chair, a projection 28, 44 of a backrest support 15, 46 of the chair articulated to the base support, and a seat element support 16, 49, characterized in that two torsion springs 22, 39, 52 are integrally connected to the base support or the seat element support and, with respect to a vertical longitudinal center plane of the chair, are connected at their respective distal ends 24, 40 to a lever 25 of the seat tilting mechanism or to the seat element support, wherein the projection is connected to the base support via a lower pivot joint 27, 43, wherein the seat element support consists of at least the projection and the lever which moves the seat element halter, is trained,wherein a rear pivot 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 a front pivot joint 26, 42, wherein pivoting the backrest support with the extension at the lower pivot joint causes a displacement of the seat element in the longitudinal direction of the chair relative to the base support.

[0107] In all embodiments, a seat element support in the broader sense is understood to be a part that supports or holds the seat element. If the seat element consists on the one hand of a seat frame or seat shell or the like, and on the other hand of padding, a cover or the like, then in preferred embodiments a seat element support in the narrower sense also includes the seat frame or seat shell, since these parts also perform a supporting or holding function for the actual seat surface. The seat element support is always hinged to the base support. According to the in Fig. 1 In the illustrated basic structure, the term seat element support can, for example, include the seat frame 3 and / or the front coupling element 141. In the case of chair 232, as shown in the Fig. 2 bis 4 As shown, for example, the seat shell 244 and / or the front swivel joint 248 serve as seat element supports. For chairs 10, 32 according to Fig. 13 bis 26For example, seat element supports 16, 49 are provided. The seat shell 17 or the seat frame 50 can also serve as seat element supports there. Reference symbol list

[0108] 1 Base support 2 Foot column 3 Seat element support, seat frame 4 Backrest support 7 Swivel direction 10 Chair 11 Seat tilt mechanism 12 Seat element 13 Seat backrest 14 Base support 15 Backrest support 16 Seat element support 17 Seat shell 18 Seat cushion 19 Backrest shell 20 Backrest cushion 21 Joint connection 22 Torsion bar spring 23 Crossbar 24 Distal end 25 Lever 26 Front pivot joint 27 Rear pivot joint 28 Extension 29 Strut 30 Rear pivot joint 31 Groove 32 Chair 33 Foot column 34 Seat tilt mechanism 35 Seat element 36 Seat backrest 37 Base support 38 Crossbar 39 Torsion bar spring 40 Distal end 41 Lever 42 Front pivot joint 43 Lower pivot joint 44 Extension 45 Rear swivel joint 46 Backrest support 47 Groove 48 Chair 49 Seat element support 50 Frame 51 Cross brace 52 Torsion bar spring 53 Lever 54 Seat element 100 Chair transverse direction 139 Synchronous mechanism 140 Rear coupling element 141 Seat element supportfront coupling element 142 first pivot joint 143 second pivot joint 144 third pivot joint 145 fourth pivot joint 146 chair longitudinal direction 232 chair 233 foot column 234 seat tilt mechanism 235 seat element 236 seat backrest 237 base support 238 cross member 239 torsion bar spring 240 backrest support 241 leg 242 lever 243 strut 244 seat shell 245 elongated hole 246 axle 247 rear pivot joint 248 front pivot joint 249 groove 250 base support 251 spring assembly 252 torsion bar spring 253 cross member 254 groove 255 distal end 256 lever 257 flange 258 base support 259 adjustment device 260 Threaded pin 261 Actuating shaft 262 Crank 263 Transverse groove 264 Groove 265 Torsion bar spring 266 Cross strut 267 Base support 268 Additional torsion bar spring 269 Groove 270 Torsion bar spring 271 Base support

Claims

1. A chair (10, 32, 232), in particular an office chair, comprising a base frame with a base column (33, 233), on which, via a seat inclination mechanism (34, 234), a seat element (12, 35, 235) and a backrest (36, 236) are mounted, wherein the seat inclination mechanism (34, 234) comprises a basic support (37, 237, 250, 258, 267, 271, 14) which is connected to the base column (33, 233), on which a backrest support (15, 240, 46) and a seat element support (16, 49) are articulated, and the seat element (12, 35, 235) and the backrest (36, 236) are connected to one another via a joint (21) of the seat inclination mechanism (34, 234), wherein a transverse strut (38, 238, 253, 266, 51) of the seat inclination mechanism (34, 234, 11) forms a spring device (251), wherein the transverse strut (38, 238, 253, 266, 51) extends in the chair transverse direction (100) and wherein the spring device (251) has at least one torsion element, in particular a torsion bar spring (39, 239, 252, 265, 270, 22, 52), and wherein the torsion element, together with the basic support (37, 237, 250, 258, 267, 271, 14) and / or the backrest support (15, 240, 46) and / or the seat element support (16, 49), is formed integrally, in particular in one piece, from plastic.

2. The chair (10, 32, 232) as claimed in claim 1, characterized in that two torsion elements of the spring device (251), in particular torsion bar springs (39, 239, 252, 265, 270, 22, 52), are integrally attached to the basic support (37, 237, 250, 258, 267, 271, 14) and, with respect to a vertical chair longitudinal center plane, are attached at their respective distal ends (255, 24) to a lever (242, 256, 25, 93, 85) of the seat inclination mechanism (34, 234).

3. The chair (10, 32, 232) as claimed in claim 1 or 2, wherein the at least one torsion element is attached to the basic support (37, 237, 250, 258, 267, 271, 14) and, together with the backrest support (15, 240, 46) and the basic support (37, 237, 250, 258, 267, 271, 14), is formed integrally, in particular in one piece.

4. The chair (10, 32, 232) as claimed in claim 3, characterized in that the backrest support (15, 240, 46), together with the basic support (37, 237, 250, 258, 267, 271, 14) and the torsion bar springs (39, 239, 252, 265, 270, 22, 52), is formed integrally, in particular in one piece, from plastic and forms the levers (242, 256) of the seat inclination mechanism (234), in particular in such a way that the seat element support is formed from struts (243), which are articulated on the basic support (37, 237, 250, 258, 267, 271, 14), and rear rotary joints (247), which are arranged on the levers (242, 256) and which hold the seat element (235).

5. The chair (10, 32, 232) as claimed in claim 1 or 2, wherein the at least one torsion element, together with the basic support (37, 237, 250, 258, 267, 271, 14) or the seat element support (16), is formed integrally, in particular in one piece.

6. The chair (10, 32, 232) as claimed in claim 5, characterized in that the basic support (37, 237, 250, 258, 267, 271, 14), together with the torsion bar springs (39, 239, 252, 265, 270, 22, 52), is formed integrally, in particular in one piece, from plastic and forms the levers (25) of the seat inclination mechanism (11), and in that the backrest support (15, 240, 46) is connected to the basic support (37, 237, 250, 258, 267, 271, 14) via a lower rotary joint (27), in particular in such a way that the seat element support (16) is formed from at least one strut (29), which is articulated on the backrest support (15, 240, 46), and the levers (25), which hold the seat element (12).

7. The chair (10, 32, 232) as claimed in claim 5 or 6, characterized in that, with respect to a vertical chair longitudinal center plane, two torsion bar springs (39, 239, 252, 265, 270, 22, 52) of the spring device are attached at their respective distal ends (40) to the seat element (35) and are attached, via a lever (41) formed integrally with the torsion bar springs, to a front rotary joint (42) of the seat inclination mechanism on the basic support (37, 237, 250, 258, 267, 271, 14), in particular in such a way that the distal ends (40) of the torsion bar springs (39, 239, 252, 265, 270, 22, 52) are screwed to or integrally formed on the seat element (35).

8. The chair (10, 32, 232) as claimed in claim 5 or 6, characterized in that the seat element support (49) is formed from a frame (50) which forms the transverse strut (38, 238, 253, 266, 51), wherein, with respect to a vertical chair longitudinal center plane, two torsion bar springs (39, 239, 252, 265, 270, 22, 52) of the spring device are attached at their respective distal ends to the frame and are attached, via a lever (53) formed integrally with the torsion bar springs, to a front rotary joint (42) of the seat inclination mechanism on the basic support (37, 237, 250, 258, 267, 271, 14).

9. The chair (10, 32, 232) as claimed in claim 8, characterized in that a rear rotary joint (45) is formed at a rear end of the frame (50), and the backrest support (15, 240, 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, 237, 250, 258, 267, 271, 14).

Images