EP2724641B1 - Chair, in particular a rotating office chair - Google Patents

Description

FIELD OF THE INVENTION

The present invention relates to a chair with synchronous mechanism, in particular an office swivel chair.

TECHNICAL BACKGROUND

The present invention and the problem underlying it will be explained with reference to a modern office swivel chair, but without limiting the invention to that effect.

In modern office swivel chairs, the ergonomic adaptability to different body dimensions, which is also referred to as "personalization", plays an increasingly important role. To ensure this, there are a variety of adjustment, such as the adjustment of the seat height, the seat depth, the seat angle, the armrest height, the backrest and the like.

High-quality office chairs are also often equipped with a so-called synchronous mechanism, by means of which the seat and backrest together in a correlated movement pivot backwards and downwards when leaning back. A chair with synchronous mechanism is eg in the DE 196 40 564 A1 described. A person sitting on the seat is guided from a forward posture by shifting his weight to a reclining posture where relaxed sitting is possible. In the forward position, the seated person typically assumes a nearly horizontal seating position so that the upper body forms a substantially right angle with respect to the thighs. The pelvis in this sitting posture tends to turn backwards so that so that the natural S-shape of the spine becomes a so-called "round-back posture", which permanently burdens the intervertebral discs in the lumbar spine.

For these reasons, modern office chairs are often equipped with a adjustability of the basic inclination of the seat. This seat tilt adjustment reduces the distance between the pelvis and lumbar support, which relieves the lumbar spine. The seat tilt can be adjusted in different ways:

The German utility model DE 75 32 885 U1 and the DE 20 2005 010 944 U1 describe Sitzneigeverstellmechanismen using a gas spring or a bottom-acting against the seat spring. The springs must here permanently absorb the entire load of a person sitting on the seat in the loaded state. These (gas pressure) springs must be designed correspondingly complex so that they can reliably absorb the load for the life of the office chair, ie without significant material fatigue.

The German patent DE 10 2008 042 973 B3 describes a further mechanism for seat tilt adjustment, in which the return function, in which the seat is reset to the starting position, is provided by a comparatively small spring-elastic element. The recording of the force acting on the seat in the loaded state is not collected here on the elastic element, but rather on engaging in corresponding toothed rails gears, which is provided in a dedicated guide rail. This type of seat recliner has been found to be very effective, especially in terms of reduced material and part cost and enduring reliability.

SUMMARY OF THE INVENTION

The present invention has for its object to provide a more comfortable seat tilt adjustment.

According to the invention this object is achieved by a chair with the features of claim 1.

Accordingly, a chair is provided with a synchronous mechanism, in particular an office swivel chair, with a backrest, with a seat having a seat surface, a seat support and an adjusting mechanism, with a device for seat tilt adjustment, over which the seat is at least partially tilted in the vertical direction, with a synchronizing mechanism, which is coupled to the backrest and the seat and over which the backrest is pivotable relative to the seat in the horizontal direction to the rear, wherein the synchronizing mechanism is designed such that the device for seat tilt adjustment disables in a reclined state of the backrest is.

The underlying realization of the present invention is that in an office swivel chair equipped with an above-mentioned synchronizing mechanism, a forwardly inclined seat still remains slightly inclined forward even when the backrest is pivoted backwards. This is sometimes a bit uncomfortable for a person sitting on the office swivel chair, because then no longer the same predetermined angle between the upper body and thigh is present. After the backward pivoting of the backrest is usually used for relaxation, a relaxed sitting position is often more important to a seated person than a predetermined angle of the thighs, as is required, for example, during lordosis-relaxed upright sitting during work.

The idea underlying the present invention is now to deactivate or block the seat tilt adjustment when the backrest is pivoted backwards. If a seated person leans his back against the backrest and thus pivots the backrest to the rear, the seat is no longer inclined forward, but pivots about a fictitious axis of rotation slightly upwards and in the direction of the backrest. This reduces the distance between the pelvis and lumbar support so that the thighs have a better angle to the upper body or spine. Overall, so the discs of the lumbar spine are relieved, allowing a more relaxed sitting.

The synchronous mechanism includes a shift gate, which has a locking hole. Further, there is provided a spring-loaded locking hook provided on the pivot, which may be e.g. is displaceable by spring force in the axial direction of an axis of the rotary joint. Finally, a rigidly coupled to the locking hook locking bolt is provided which is displaceable in the aligned position in the locking hole and locked in this position, the device for seat tilt adjustment and thus deactivated.

Advantageous embodiments and further developments will become apparent from the other dependent claims and from the description with reference to the figures of the drawing.

In a preferred embodiment, the synchronizing mechanism is designed such that the device for adjusting the seat inclination is deactivated or blocked only in a fully reclined state of the backrest, in particular is completely disabled. This is advantageous because it does not swing back upwards with a slight swinging backwards the seat and swinging back up when swinging back.

In a particularly preferred embodiment, the shift gate is rigidly coupled to the rotary joint and arranged such that the introduced in the locking hole locking bolt acts as a driver and entrains the locking hook in the non-hooked state. When taking along, then the seat support lifts up relative to the backrest something.

In a preferred embodiment, the locking hook on a hook over which the locking hook on the housing of the seat support is hooked in such a way that a take away of the locking hook is blocked by the shift gate. In this state, for example, then the seat tilt is active and the seat can be tilted forward.

In a structurally preferred development, the synchronizing mechanism further comprises a confirmation mechanism which has an actuatable via an actuator spring element, which is resiliently coupled to the locking hook and over which the locking hook and thus the locking pin in the axial direction in the locking hole is displaceable.

Preferably, the actuating element is coupled via a Bowden cable with a push-push switch, which in turn is coupled via a jumper wire with the locking hook. Alternatively, the actuating element via a Bowden cable directly to the locking hook and / or the spring element coupled. Conceivable, however, would be other switching elements with the same or similar properties.

In a particularly preferred embodiment are aligned in the event that the synchronizing mechanism is activated and thus the backrest is moved backwards, the locking bolt and the locking hole to each other, so that the locking pin to block the seat tilt adjustment spring loaded in the locking hole can slide. The spring loading can be realized in a very elegant manner by means of a mounting device coupled to the locking hook and thus with the locking bolt compression spring. Alternatively or additionally, the locking bolt and the locking hole can also be aligned with each other, if the Sitzvorneigung is activated.

In a preferred embodiment, the chair support is coupled to the seat support via a front, stationary mounted swivel joint and a rear, movably mounted in a slotted guide pivot, wherein the rear hinge is fixed in the inclined position in a lower region of the slotted guide and in the starting position in an upper starting position of the slotted guide is located.

In a likewise preferred embodiment, a device for adjusting the seat inclination is provided in particular for office and swivel chairs or chairs, with a spring-loaded guide lever which has a resilient element which can be fastened to a seat and which in the tensioned state on the guide lever a substantially vertical acting spring force, with at least one attachable to the seat, vertically oriented guide rail, which has a substantially vertically extending serrated rail inside, with a gear which is coupled via an articulated connection with the guide lever such that a gear portion of the gear arranged vertically movable inside the guide rail is so that at each seat tilt always first teeth of the gear portion engage in second teeth of the toothed rail.

Conventional (gas pressure) springs for adjusting the seat height have a dual function. This dual function includes on the one hand a return function, via which an inclined seat in the unloaded state is brought back to its original position. In addition, this (gas pressure) spring must be designed so that it can absorb the entire force acting on the seat even in the loaded state. The idea of the present invention is now to separate these two functions from each other. According to the invention, the return function is further provided by a resilient element. However, for this functionality of retrieving the seat to its initial position, it is not necessary to provide a very large, excessively sized spring. Rather, a resilient element with comparatively low spring force is sufficient here. The second functionality, that is, the inclusion of the force acting on the seat in the loaded state, according to the invention is no longer collected on the elastic element, but rather on engaging in corresponding toothed rails gears. This toothed rail is provided according to the invention in a specially provided guide rail. A respective toothed wheel is here arranged to be movable vertically in a guide rail assigned to it, wherein the corresponding toothed rails likewise have a vertical orientation within these guide rails. In this way, a very effective and beyond a mechanically very stable seat tilt adjustment is possible.

In addition, this solution according to the invention is also cost-attractive, since on the one hand a resilient element can be provided with significantly lower spring force. In addition, the elements of the adjusting mechanism, for example, the guide lever, the gear, the gear rail and the like, for. B. made of plastic, which z. B. is very easy and inexpensive to produce by spraying. The solution according to the invention thus offers, on the one hand, a mechanically extremely stable and safe seat tilt adjustment and, on the other hand, a very cost-effective adjusting mechanism.

In a preferred embodiment, the gear is designed as a cam-like gear. This gear thus has a gear portion and a lever portion, wherein the lever portion protrudes in the form of a cam-shaped formation of the gear. At this lever portion a specially provided bore is provided, on which the guide lever is articulated via an articulated connection. In addition, it would also be conceivable that this guide lever is coupled to the axis of a circular gear, for example via an axial connection.

In a likewise preferred embodiment, the guide lever has a rod-like shape. At one end of this guide lever, the resilient element via a fastening device, such as a pin, an eyelet or the like, attached. At the other end of the guide lever, this has a bore, over which the guide lever z. B. is coupled via the articulated connection to the gear or is coupled.

Preferably, the resilient element is designed as a spiral spring, coil spring, coil spring, conical spring or the like. This spring is preferably arranged within a sleeve-shaped or at least partially enclosed portion of the guide lever and thus against an external mechanical or otherwise harmful influence protected. Conceivable, of course, would be other types of elastic elements.

The spring force of the resilient element is dimensioned such that, for example, in a horizontal sitting position, the resilient element has a greater spring force than at a tilted relative to the horizontal seating position. For example, it can be provided that a maximum spring force in the horizontal sitting position of about 45 N is caused by the resilient element, whereas this spring force at a z. B. by a few degrees inclined seating position only about half, for example, 25 N is.

In a preferred embodiment, the resilient element is formed such that it has a maximum spring tension and thus a maximum spring force at maximum seat inclination. At a minimal seat angle, the z. B. corresponds to the initial position of the seat, the elastic element is not or only slightly stretched. Alternatively, the spring-elastic element can have no or minimum spring tension and thus also a minimal spring force even at maximum seat inclination and be maximally tensioned with a minimal seat inclination.

In a typical embodiment, the seat tilt adjustment is stepped. For this purpose, the guide lever on at least two locking holes, in which a corresponding pin of a locking device can be inserted for locking. When inserted pin so that the device for seat tilt adjustment is locked against the seat, so that a seat tilt adjustment is no longer possible. It is particularly preferred if three or four locking holes are provided, which in addition to a maximum and minimum Seat tilt adjustment also one or two middle seat inclinations are adjustable.

In a likewise preferred embodiment, an actuation device which can be attached to the seat is provided which, when actuated, makes possible an adjustment of the seat inclination. The actuating device further has a locking device which fixes the guide lever in the unactuated state against the seat and thus prevents movement of the guide lever in the horizontal direction. The actuator typically has an actuation button (eg, a button, a lever, a knob, etc.). Preferably, the locking device further comprises a spring-loaded pin. This spring-loaded pin is z. B. coupled via a Bowden cable with the actuating button spring force. To lock this spring-loaded pin is inserted into corresponding Arretierausnehmungen the seat and the guide lever at non-actuated button. Over this operation button, which is connected via a Bowden cable and a spring-loaded coupling with the locking pin, so that overload protection can be realized. In addition, it would also be conceivable to provide a locking device without such an overload protection, if the spring force coupling between the actuating button and locking pin is dispensed with.

Alternatively, it would also be conceivable to provide a stepless adjustment of the seat tilt. However, this stepless adjustment of the seat tilt is much more complex than the stepped seat tilt adjustment, since a greater effort in terms of the function of the locking device and the gear functionality must be made.

In a likewise preferred embodiment, a maximum stop of the seat inclination is via a first stop specified. In addition, a minimum stop of the seat inclination can be predetermined via a second stop. These attacks can z. B. within a respective guide rail can be provided by specially provided projections in the wall of this guide rail or can also be provided by corresponding construction elements of the seat and in particular the seat on which the device for seat tilt adjustment according to the invention is mounted. Such stops are useful to prevent the guide lever and coupled with the guide lever gears can move uncontrollably inside the seat, which could eventually lead to damage of these elements in the long term.

In a particularly preferred embodiment, two guide rails are provided. Further, a further gear is provided in addition to the gear, wherein the two gears are formed such that they are vertically movable within a respective associated guide rail. The two gears are preferably coupled together via a transverse coupling device, so as to enable a synchronous toothing of the two gears with their respective associated toothed rails within the respective guide rails. This transverse coupling device is formed, for example, as a crossbar, which are fitted in specially provided for this purpose central recesses of the two gears. This crossbar ensures that a force acting on the seat on both sides of the cross bar of the respective gears is uniformly transmitted to the respective associated guide rails.

This crossbar, together with the corresponding gears in operation, the entire load. For this reason, it is advantageous if the crossbar of a particularly break and strain-resistant material, such as a glass-reinforced or fiberglass reinforced plastic material. Such a high-quality plastic, for example, a polyamide material, in which glass or glass fiber material is added. It is particularly preferred if this plastic or the polyamide contains 30 to 50 percent by volume of glass or glass fiber material. In addition, it would also be conceivable if the crossbar consists of a break-resistant and stretch-resistant, aluminum-containing material, metal or steel.

In addition, it would also be conceivable if the crossbar is made of a metallic material or steel. It is particularly preferred if the gears and the guide rails are made of these materials. It is particularly preferred if a so-called Grivory material (for example GV-4H) is used for the transverse rod and / or the toothed wheels and the guide rails. Grivory is the generic term for a group of engineering thermoplastics manufactured and sold by EMS-Grivory. Grivory HT is z. PPA (PPA = Polyphtalamide) Grivory is characterized by a high-performance property profile, and injection molded parts made from this material are impressive in terms of dimensional stability even at high application temperatures.The property profile of Grivory extends far into the performance range of high-performance plastics. Further properties of Grivory are high rigidity and strength at elevated application temperatures, low influence on the properties due to water absorption, good dimensional stability and low tendency to warp, good chemical resistance, good surface quality and cost-effective, rational production.

In a preferred embodiment of the device according to the invention for seat tilt adjustment, this device so coupled to the seat and arranged relative to the seat, that the seat in the rear third on the device for seat tilt adjustment is vertically adjustable. Alternatively, of course, an adjustment in the front third of the seat would be conceivable. In a preferred embodiment, the seat has a seat shell, which is made of an aluminum die cast material or a plastic material.

The above embodiments and developments can, if appropriate, combine with each other as desired. Further possible refinements, developments and implementations of the invention also include combinations, not explicitly mentioned, of features of the invention described above or below with regard to the exemplary embodiments. In particular, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the present invention.

CONTENT OF THE DRAWING

Fig. 1

eine Seitendarstellungen eines erfindungsgemäßen Stuhls;

Fig. 2

anhand einer Querschnittsdarstellung ein erstes Ausführungsbeispiel einer Vorrichtung zur Sitzneigungsverstellung;

Fig. 3

anhand einer perspektivische Darstellung ein zweites Ausführungsbeispiel einer Vorrichtung zur Sitzneigungsverstellung;

Fig. 3A

eine Ausgestaltung des Führungshebels des Verstellmechanismus entsprechend Fig. 3;

Fig. 3B

eine Ausgestaltung der Betätigungseinrichtung des Verstellmechanismus entsprechend Fig. 3;

Fig. 3C

eine Ausgestaltung der Führungsschiene des Verstellmechanismus entsprechend Fig. 3;

Fig. 3D, 3E

Ausgestaltungen der Zahnräder des Verstellmechanismus entsprechend Fig. 3;

Fig. 4A, 4B

Querschnittsdarstellungen eines an einem Sitz angebrachten Verstellmechanismus entsprechend Fig. 3 von hinten und von der Seite in einer ersten Verstellposition;

Fig. 5A, 5B

Querschnittsdarstellungen eines an einem Sitz angebrachten Verstellmechanismus entsprechend Fig. 3 von hinten und von der Seite in einer zweiten Verstellposition;

Fig. 6

eine Seitendarstellung des Sitzes von außen gesehen;

Fig. 7A, 7B

Seitendarstellungen eines erfindungsgemäßen Stuhls mit Verstellmechanismus;

Fig. 8

einen erfindungsgemäßen Stuhl in einer Explosionsdarstellung zur Erläuterung der erfindungsgemäßen Synchronmechanik;

Fig. 9

einen perspektivischen Ausschnitt des in Fig. 8 dargestellten Stuhls im Bereich der Verstellmechanik im montierten Zustand;

Fig. 9A, 9B

eine Längsschnittdarstellung bzw. eine Querschnittdarstellung des Ausschnittes des erfindungsgemäßen Stuhls aus Fig. 9;

Fig. 10A-10C

schematische Seitendarstellung des erfindungsgemäßen Stuhls zur Erläuterung der Funktion der erfindungsgemäßen Synchronmechanik;

Fig. 11

einen erfindungsgemäßen Stuhl in einer Explosionsdarstellung gemäß einer weiteren Ausführungsform;

Fig. 12

einen perspektivischen Ausschnitt des in Fig. 11 dargestellten Stuhls im Bereich der Verstellmechanik im montierten Zustand;

Fig. 12A, 12B

eine Längsschnittdarstellung bzw. eine Querschnittdarstellung des Ausschnittes des erfindungsgemäßen Stuhls aus Fig. 9;

The invention will be described in more detail with reference to the embodiments indicated in the schematic figures of the drawing. It shows:

Fig. 1

a side views of a chair according to the invention;

Fig. 2

a cross-sectional view of a first embodiment of a device for seat tilt adjustment;

Fig. 3

a perspective view of a second embodiment of a device for seat tilt adjustment;

Fig. 3A

an embodiment of the guide lever of the adjusting mechanism accordingly Fig. 3 ;

Fig. 3B

an embodiment of the actuating device of the adjusting mechanism accordingly Fig. 3 ;

Fig. 3C

an embodiment of the guide rail of the adjusting mechanism accordingly Fig. 3 ;

Fig. 3D, 3E

Embodiments of the gears of the adjustment accordingly Fig. 3 ;

Fig. 4A, 4B

Cross-sectional views of an attached to a seat adjustment mechanism accordingly Fig. 3 from behind and from the side in a first adjustment position;

Fig. 5A, 5B

Cross-sectional views of an attached to a seat adjustment mechanism accordingly Fig. 3 from behind and from the side in a second adjustment position;

Fig. 6

a side view of the seat seen from the outside;

Fig. 7A, 7B

Side views of a chair according to the invention with adjustment mechanism;

Fig. 8

a chair according to the invention in an exploded view for explaining the synchronous mechanism according to the invention;

Fig. 9

a perspective section of the in Fig. 8 represented chair in the field of adjustment mechanism in the assembled state;

Figs. 9A, 9B

a longitudinal sectional view and a cross-sectional view of the section of the chair according to the invention from Fig. 9 ;

10A-10C

schematic side view of the chair according to the invention to explain the function of the synchronous mechanism according to the invention;

Fig. 11

a chair according to the invention in an exploded view according to another embodiment;

Fig. 12

a perspective section of the in Fig. 11 represented chair in the field of adjustment mechanism in the assembled state;

Figs. 12A, 12B

a longitudinal sectional view and a cross-sectional view of the section of the chair according to the invention from Fig. 9 ;

The accompanying drawings are intended to provide further understanding of the embodiments of the invention. They illustrate embodiments and, together with the description, serve to explain principles and concepts of the invention. Other embodiments and many of the stated advantages will become apparent with reference to the drawings. The elements of the drawings are not necessarily shown to scale to each other.

In the figures of the drawing are the same, functionally identical and same-acting elements, features and components - unless otherwise stated - each provided with the same reference numerals.

DESCRIPTION OF EMBODIMENTS

Fig. 1 shows a cross-sectional view of a chair according to the invention with a Sitzneigungsverstellmechanismus. The chair designated here by reference numeral 10 is designed as an office / swivel chair. The chair 10 includes a seat support 14 that supports the seat 11. Furthermore, a backrest 12 is provided, which is fastened via a backrest support 15 to an adjusting mechanism 16. The seat support 14 and the backrest support 15 are each attached to the adjustment mechanism 16, which rests on the pedestal 13. The adjusting mechanism 16 comprises a synchronous mechanism.

The chair 10 also has a z. B. equipped with rollers foot area (not shown here) on which the pedestal 13 is attached. The chair 10 further includes a seat reclining device, which will be explained in detail below.

Before the synchronous mechanism according to the invention is explained, will be described below with reference to the Fig. 2 -7 first examples of an advantageous device for seat tilt adjustment explained.

Fig. 2 shows a side cross-sectional view of a first embodiment of a device for seat tilt adjustment. In Fig. 2 is denoted by reference numeral 20, the corresponding adjustment mechanism. The adjusting mechanism 20 has in the simplest form a guide lever 21, a gear 22 and a guide rail 23.

The guide lever 21 is typically mounted under the seat of a seat, not shown here. The guide lever 21 has a first and a second end 24, 25. At the first end 24, a resilient element 26 is attached. On the other hand, this resilient element 26 is attached to the seat pan of a seat. The guide lever 21 is arranged under the seat shell so that a directed, substantially horizontal movement of the guide lever in the horizontal direction X is possible. This horizontal direction X corresponds to the sagittal direction of a person sitting on the seat.

The gear 22 is formed here as a cam-shaped gear lever 22, which has a gear portion 27 and a lever portion 28 which projects in the form of a cam-shaped formation of the gear 22 has. The guide lever 21 is articulated via an articulated connection 29 with its second end 25 on this lever portion 28.

The guide rail 23 is over in Fig. 2 Not shown fastening sections, such as mounting straps, flanges or the like, attached to the seat of a seat and thus fixed there. The guide rail 23 is aligned substantially vertically and perpendicular to the alignment of the guide lever 21 and thus to the direction of movement X. The guide rail 23 is formed as an upwardly open, but otherwise substantially closed guide rail 23. The dimensioning of the guide rail 23 is selected such that the gear 22 is received in the interior 30 of the guide rail 23. On at least one wall of the guide rail 23, this has a toothed rail 31 which is formed such that the gear portion 27 of the gear 22 can engage in this toothed rail 31. In addition, the gear 22 can be inside 30 of the Guide rail 23 via the guide lever 21 vertically in the direction Y move up and down. The guide rail 23 thus provides a vertical movement in one direction.

In the unloaded state, the resilient element 26 pulls the guide lever 21 to the right, so that the coupled to this guide lever 21 gear 22 along the guide rail 23 is moved upward. If a force F is then applied in a vertical direction from above onto the seat (not shown here), then the guide lever 21 and thus also the gear 22 fastened thereto are pressed downwards in the direction Y, ie into the lower region of the guide rail 23. At the same time, the resilient element 26 stretches so that the guide lever 21 is also moved in the horizontal direction X in the direction of the guide rail 23. This realizes a seat tilt downwards. Is subsequently relieved of the seat, d. H. the force F is eliminated, then pulls the spring element 26, the guide lever 21 automatically by spring force again in the opposite horizontal direction X, so that the gear 22 is automatically moved within the guide rail 23 back up and the seat thus again in his z. B. horizontal starting position.

Fig. 3 shows a perspective view of a second embodiment of an adjustment mechanism for adjusting the seat angle. The device for seat tilt adjustment is shown here without attached seat element.

The adjusting mechanism 20 has here analogous to the first embodiment Fig. 2 a spring-loaded guide lever 21 on which a gear lever 22 is coupled, which in a specially provided, provided internally with a toothed rail 31 guide rail 23rd is vertically movable. In addition, the adjusting mechanism 20 also has an actuating device 32, a crossbar 33 and a second guide rail 23A.

Fig. 3A shows in detail an embodiment of the guide lever 21 of this adjusting mechanism 20. The guide lever 21 has at its first end 24 provided for in the interior of the guide lever 21 mounting pin 40 to which the resilient element 26 is attached, for example via an eyelet. The resilient element 26, which is formed for example as a spiral spring, for example, housed in a sleeve-like, hollow recess in the interior of the guide lever 21, so as to be protected, inter alia, from external damage. Only a portion of the resilient element 26, to which in turn a fixing lug 41 is used, protrudes from the sleeve-like end 24 of the Fünrungshebels 21 to be fastened via this mounting lug 41, for example, to a specially designated mounting pin on the seat. At the second end 25, the guide lever 21 has an angled region in which a bore 42 is provided. At this bore 42, the gear lever 22 can be fixed by means of a rotatable joint 29: In the middle region of the guide lever 21 has this in the example shown, three more holes 43-45. These holes 43-45 are part of a locking device, which will be explained in more detail below. About this locking holes 43 - 45 can be the guide lever 21 based on the seat lock and thus fix in a certain position. In these locking holes 43 - 45, for example, a latch pin an actuator engage. Each of these locking holes 43-45 is associated with a given seat inclination.

Fig. 3B shows a particularly preferred embodiment of the actuator 32. The actuator 32nd has an actuating button 50 and two telescoping sleeves 51, 52. The inner sleeve 51 is connected via a Bowden cable 53 with the actuating button 50 and is thus on actuation of the actuating button 50 in the direction Z, ie laterally away from the seat, pulled. The inner sleeve 51 is also connected via a spring 55 with the outer sleeve 52. If the actuation button 50 is actuated, then it likewise pulls the inner sleeve 51 and, via the spring 55, also the outer sleeve 52 in the direction Z. On the side opposite the button 50, the outer sleeve 52 has a latching pin 56 (or a locking pin). on, which is part of the locking device and can lock in the locked state in corresponding locking holes 43-45 of the guide lever 21 and the seat pan. The diameter D of this Einrastpins 56 is dimensioned such that it is at least slightly smaller than the diameter of the locking holes 43-45. About the spring force coupling of the spring 55 is a strain relief between the inner and the outer sleeve 51, 52 and thus the actuating button 50th realized. If z. B. the actuating button 50 is actuated and the Einrastpin 56 is still engaged in a corresponding locking hole 43 - 45, the compression spring 57 is first pressed together by means of a transmitted to the inner sleeve 51 tensile force. The overload spring 55 is pulled apart and exerts a tensile force on the Einrastpin 56. The Einrastpin 56 is only then pulled out of the locking holes 43-45 when the force exerted by the overload spring 55 on the Einrastpin 56 spring force is greater than the frictional force or clamping force between the Einrastpin 56 and the corresponding locking hole 43-45. This allows a better, more comfortable and elegant user operation and overload protection.

Fig. 3C shows the cam-shaped gear lever 22, which is provided via a provided in the lever portion 28 bore 61 on the guide lever 21 can be attached. In the gear portion 27, the gear lever 22 has a hexagonal, continuous recess 60, in which the crossbar 24, which also has a corresponding hexagonal cross-section as accurate as possible, can be inserted.

Fig. 3D shows a corresponding gear 22A, which also has a hexagonal recess 60A for the crossbar 24.

Fig. 3E shows a guide rail 23, 23 A, as it can be used for both the gear lever 22 and the gear 22A. This guide rail 23, 23A has a housing 70, on whose upper portion hook-shaped fastening portions 71 are provided, via which the housing 70 can be inserted into corresponding recesses of the seat shell and clipped or otherwise secured there. The guide rail 23, 23A has on a first side wall a tooth portion 72 in the form of a toothed rail. The teeth (and the tooth gaps) of this tooth portion 72 are dimensioned such that the mating teeth (and the tooth gaps) of the gears 22, 22A can engage in this tooth portion 72 to receive the force transmitted by the gears 22, 22A form-fitting manner , Preferably, at least two teeth of the gears 22, 22A are always in engagement with at least two teeth of a tooth portion 72. The point of engagement should roll as well as possible, so that little wear and the power can be optimally absorbed. Therefore, for example, the shape of the tooth flank of the teeth of the gears 22, 22A and the tooth portion 72 is equal to either an involute or a cycloid. Preferably, however, an involute toothing is used.

At the tooth portion 72 opposite the second wall, a stop 73 is provided in the lower region, which has a lower limit for a vertical movement of the gears 22, 22A in the interior 36 of the housing 70 denotes. The guide rail 23, 23A also has a substantially closed wall 74 on a rear side, in which an elongate recess 75 is provided. This elongated recess serves to pass the transverse rod 33 into the interior of the guide rail 23, 23A, so as to be inserted in an exact fit into the respective recess 60, 60A of the respective gear 22, 22A. The vertical length of this elongate recess 75 is dimensioned such that the cross bar 33 is freely movable vertically up and down, both at a maximum and a minimum deflection of the guide lever 21 and thus the gear 22 coupled thereto.

Fig. 3 shows in the perspective view in the Fig. 3A - 3E shown elements of the adjusting mechanism 20 in the mounted state. The arranged between the two gears 22, 22A crossbar 33 allows synchronous teeth by cross-coupling, thereby a load on the gears 22, 22A and the two guide rails 23, 23A is evenly distributed to the left and right side of the seat. It is effectively prevented by this uniform load distribution that tilts the seat in the seat tilt adjustment.

Especially the vertically extending gears 22, 22A allow a mechanically stable height adjustment. These gears 22, 22A take on the largest part of the load. The locking takes place via the specially provided locking device. When the guide lever 21 is locked, the entire load is thus applied to the meshing gears 22, 22A and not to the resilient return member 26. This spring-elastic element 26 leaves dimensioned in this way smaller and therefore cheaper than is the case with known solutions.

The Fig. 4A, 4B or 5A, 5B respectively show cross-sectional views of an adjustment mechanism accordingly Fig. 3 from behind and from the side to explain two different adjustment positions. Fig. 6 shows a side view of the seat seen from the outside. In these figures, the adjusting mechanism 20 is shown mounted in a seat 11 state. The seat 11 has here a seat shell or seat plate 80, on which the seat cushion 81 is applied. The seat plate 80 has a box-like or frame-like construction, in the interior 82 of the adjusting mechanism 20 is arranged. Only the actuator 32 projects laterally out of the interior 82 of the seat support 80 out (see Fig. 5A, 5B . 6 ). This actuator 32 is z. B. laterally under the seat 11 ( Fig. 6 ) or is embedded in a specially designed recess in the housing of the seat 11, so that a person sitting on the seat support 11 person can actuate this actuator 32 during use of the chair easily and conveniently. An adjustment of the seat tilt in height is here z. B. by seat relief with simultaneous lever actuation of the actuator 32. An adjustment of the seat tilt in depth is carried out by actuation of the actuator 32 while loading the seat in the vertical direction.

In the example in the Fig. 4A, 4B attacks z. B. the Einrastpin 56 in the first locking hole 43 of the guide lever 21 a. In this state, the gear lever 22 engages in the provided in the lower region of the guide rail 23 teeth of the toothed rail 31 and is applied to the stop 73, for example. This housing portion 73 also forms a stop 73 for defining a minimum seat tilt adjustment. In this in Fig. 4A shown position, a minimal seat tilt is realized. The spring 26, which is attached to the pin 83 on the seat shell is here minimally stretched.

In example in the Fig. 5A, 5B engages the Einrastpin 56 in the third and thus last locking hole 45. Here, the teeth of the gear lever 22 engage in the upper teeth of the toothed rail 31 a. A housing portion 84 of the seat shell 80 also forms a stop for the maximum seat tilt adjustment. In this state, a maximum adjustment of the seat tilt is realized. The spring 26 is maximally stretched here. Upon release of the lock, this spring 26, the guide lever 21 and thus the seat 11 back to the starting position, as in the Fig. 4A, 4B shown is bring.

In addition, a central seat inclination would be realized, for example, when the Einrastpin 56 engages in the middle locking hole 44 (not shown in the figures).

The Fig. 7A . 7B show side views of a chair according to the invention with adjustment mechanism. In the Fig. 7A the adjustment mechanism 20 is shown in its initial position, ie the seat 11 is not tilted here, whereas in the example in Fig. 7B the seat 11 is inclined forwards by 4 ° via the adjusting mechanism 20. The pivot axis, over which the seat is inclined here, is designated by reference numeral 85. The inclination of the seat 11 relative to the horizontal is denoted by α. The inclination angle is in the example in Fig. 7A α = 0 °, whereas in the example in Fig. 7B the inclination angle α = 4 °.

Subsequently, the synchronous mechanism according to the invention is based on the 8 to 12 explained in more detail. The synchronous mechanism according to the invention is part of the adjustment mechanism 16 and sees an interaction of the device 20 for seat tilt adjustment (see Fig. 2 to 7B ) and the backrest adjustment.

Fig. 8 shows to explain the synchronous mechanism according to the invention first a chair 10 according to the invention in an exploded view. This chair 10 has a seat 11, a backrest 12 and a chair frame 17 in a known manner.

The chair frame 17 comprises a chair cross 19, on which a pedestal 13 is rotatably mounted. The pillar 13 carries the seat 11th

The seat 11 includes an adjustment mechanism 20, a seat support 14, and a generally padded seat surface 11A that is applied to the seat support 14.

The adjusting mechanism 16 comprises, as already with reference to the FIGS. 2 to 7 explained, the device 20 for seat tilt adjustment, which will not be discussed in detail here. In addition, the adjusting mechanism 16 also contains the synchronous mechanism according to the invention, which thus also includes an adjustment mechanism for the backrest adjustment. On this adjustment mechanism for backrest adjustment will be described below with reference to the Figures 9 and 10 detailed in detail.

The backrest 12 comprises a padded backrest element 18, for example, which can be fastened to the chair frame 17 or the seat 11 via the backrest support 15. For the purpose of adjusting the backrest 12, the backrest support 15 is fastened to the adjustment mechanism 16 with a fastening interface 90 provided for this purpose. The seat tilt adjustment device 20, which is part of the adjustment mechanism 20, here comprises, as already explained above, the resilient element 26, a transmission housing 23, gears 22A and the hexagonal crossbar 33 for coupling the gears 22A running in the transmission housing 23.

In addition, the adjusting mechanism 20 according to the invention also has a synchronizing mechanism for the backrest adjustment. This synchronizing mechanism comprises in the present embodiment, a locking hook 91 with rigidly attached thereto locking bolt 92, compression spring 93 and a shift gate 94. For actuating the Rückenlehnenverstellmechanik an actuating button 95 is provided, which via a Bowden cable 97 (in Fig. 8 not shown) is coupled to a push-push switch 96. The push-push switch 96 is connected via a biasable jumper wire 98 (in Fig. 8 not shown) coupled to the locking hook 91 and the compression spring 93. Furthermore, the synchronizing mechanism provides a hole 99 for insertion of the locking bolt 92, which is provided in the shifting gate 94 and into which the locking bolt 92 can be inserted provided that these are aligned with one another.

Fig. 9 shows a section of the in Fig. 8 illustrated chair according to the invention in the region of the adjusting mechanism 16 according to the invention with attached backrest support 15th Fig. 9 in particular shows the seat 11 Fig. 8 in the assembled state in a perspective view, but without the seat surface 11A, to thereby better represent the individual elements of the adjustment mechanism 16 according to the invention and their interaction. The Fig. 9A and 9B show a side view and a back side view of the section of the chair 10 according to the invention Fig. 9 Here, the seat 11A is shown.

The locking hook 91 is mounted on the hexagonal shaft 33 and can thus rotate about the hexagonal shaft 33. The locking hook 91 has a hook 91A on its free upper side. This hook is hooked in the starting position of the locking hook 91 at a corresponding point of the seat support 14. The locking pin 92 is rigidly coupled to the locking hook 91 and thus rotates in the event of rotation of the locking hook 91 with this. On the hexagonal shaft 33 is also a shift gate 94 with locking hole 99 rigid, so firmly attached.

As in Fig. 9 becomes clear, the actuating button 95 is connected to the backrest adjustment via a Bowden cable 97 with the push-push switch 96. The push-push switch 96 is in turn coupled via a jumper wire 98 with the locking hook 91 with locking pin 92. The jumper wire 98 is coupled to the locking hook 91 or the compression spring attached thereto such that in the event of actuation of the actuating button 95, the locking hook 91 is displaced along the hexagonal shaft 33. This shift takes place in the example shown resiliently using the compression spring 93. Thus, the attached to the locking hook 91 and thus firmly coupled with this locking bolt 92 along the hexagonal shaft 33 is moved. If the locking pin 92 is aligned with the provided in the gate cam 94 bore 99, it is pushed by spring force of the compression spring 93 into the locking hole 99, whereby the seat tilt mechanism is locked.

In the Fig. 9A and 9B Reference numerals 100, 101 denote the stationary front pivot point and the rear pivot point, respectively. The rear pivot 101 is movable and can be moved up and down in the slotted guide. Below is the operation of the in FIG. 9 illustrated synchronous mechanism based on Fig. 9 to 9B explains:

The locking pin 92 is mounted in the rear seat arm (rear pivot axis 101) and is laterally displaced with the locking hook 91. In the case of a counterclockwise rotation of the gears 22a, the seat support 14 and the seating surface 11A applied thereto rearwardly rear, thereby creating the seat inclination.

If the actuating button 95 is actuated, then the push-push switch 96 is actuated via the Bowden cable 97, wherein the push-push switch 96 holds this position. Thereby, the jumper wire 99 is triggered, whereby the hook 91A of the locking hook 91 compression spring applied on the axis of the hexagonal shaft is displaced until the hook 91A, the seat support 14 releases. In this state, the coupled via the gear 22A kinematically with the seat support 14 hexagonal shaft 33 is thus freely rotatable. The two elastic elements 26 designed as tension springs 26 pull the seat support 14 into the upper position by the rotational movement of the toothed wheels 22A. In this state, the locking hook 91 and thus the attached thereto locking pin 92 presses against the shift gate 94. If the locking pin 92 is aligned with a locking hole 99 in the shift gate 94, the locking pin 92 slides into the locking hole of the shift gate 94 and thus blocks further movement , As a result, the two gears 22a are coupled via the continuous hexagonal shaft 33 with the angular movement between the rear mechanical link and the seat carrier.

The 10A to 10C show partial schematic side views of the chair according to the invention to explain the function of the synchronous mechanism according to the invention.

Reference numeral 102 here denotes the (lordosis) supporting point of the back of a seated person on the backrest element 18 of the backrest 12. The backrest 12 is fastened to the adjusting mechanism 16 via a lever arm-like fastening interface 90 of the backrest support 15. This adjustment mechanism 16 includes the slotted guide 104, along which the hexagonal shaft 33, which is part of the seat support 14, is movable.

Fig. 10A shows the chair 10 with inactive seat pitch adjustment mechanism and inactive seat adjustment mechanism. The seat support 14 with padded seat surface 11A provided thereon is mounted so as to be fixedly rotatable on the adjustment mechanism 16 at a front rotation axis 100. The rear pivot axis 101 is movable and can be moved in the slotted guide 104 up and down. The rear axis of rotation 101 is formed by the hexagonal shaft 33 in the example shown.

In the example shown the Fig. 10A with Nitzneigeverstellmechanismus disabled and deactivated Rückenverstellmechanismus the seat surface 11A is in a substantially non-inclined, horizontal starting position. The rear axis of rotation 101 is located in the upper region of the slotted guide 104.

Fig. 10B shows the chair 10 in a situation in which a seat tilt is actuated. In the example in Fig. 10B the backrest adjustment is not actuated. In this state, the seat surface 11A is inclined at a predetermined angle, for example 4 °, from the home position. The seat carrier 14 is thereby rotated about the front axis of rotation 100 counterclockwise, whereby the seat support 14 pivots due to the degree of freedom of the seat support 14 in the region of the rear axis of rotation 101, that is due to the slide guide 104, at least partially upwards. This upward pivoting results from the fact that the slotted guide 104 is moved upward relative to the rear axis of rotation 101.

In the example in Fig. 10B , ie, when the backrest 12 is not actuated, there results an optimum angle between the thighs and the upper body of a person sitting on the chair 10.

Fig. 10C shows the chair 10 in a situation in which a seat inclination and the Rückenlehnenverstellmechanismus (ie the synchronizing mechanism) are actuated. In this state, the seat tilt adjustment is blocked or deactivated when confirming the mechanism of the backrest adjustment, for example, analogous to the above with reference to Fig. 9 to 9B explained. The seat support 14 is pulled down along the sliding guide 104, whereby the seat surface 11A due to the synchronizing mechanism something to the backrest 12, or rather closer to the support point 102, passes. The position of the seat surface 11A to the support point 102 of the backrest element 18 thus substantially corresponds to the state without activated seat tilt. The support point 102 of the backrest 12 is thus optimal in relation to the seat surface 11A.

The FIGS. 11 to 12B show a further embodiment of a chair 10 according to the invention. It is a question of a large part of the chair 10 according to the FIGS. 8 to 9B same embodiment, which is why in the following only the differences will be discussed.

The embodiment of the FIGS. 11 to 12B differs in particular in that the actuating button 95 is coupled via a Bowden cable 111 directly to the locking hook 110. This represents an advantageous number of components reduced construction.

It is a cover 112 is provided, which is formed with a bearing 112 A for the outer shell of the Bowden cable. Between the cover and the locking hook 110, a compression spring 113 is provided. The Bowden cable 111 is coupled to the locking hook 110 or the pressure spring 113 attached thereto in such a way that, in the event of actuation of the actuating button 95, the locking hook 110 is displaced along the hexagonal shaft 33. This shift takes place in the example shown resiliently using the compression spring 113. Thus, the attached to the locking hook 110 and thus firmly coupled with this locking pin 92 along the hexagonal shaft 33 is moved. If the locking pin 92 is aligned with the provided in the gate cam 94 bore 99, it is pushed by spring force of the compression spring 113 into the locking hole 99, whereby the seat tilt mechanism is locked.

In order to deactivate the seat inclination, the actuating button 95 is actuated in the unloaded state of the seat 11 and the seat 11 or its seat surface 11A is subsequently pressed downwards. By actuating the actuating button 95, the locking hook 110 is viewed via the Bowden cable 111 from the sitting direction or in perspective Fig. 12B moved to the right. As a result, the locking of the locking bolt 92 is released in the shift gate 94. The seat support 14 and seat 11A are then movable to a lower position by loading on the seat. In this case, the hook 110 A is guided via an insertion bevel in a hooked position with the seat support 14.

To activate the seat tilt the operating button 95 is pressed briefly in the unloaded state of the seat 11. Characterized the locking hook 110 is moved over the Bowden cable 111 in the seat direction to the right, whereby the hook 110A, the seat support 14 releases. The tension springs 26 rotate the gears 22, 22A about the hexagonal shaft 33 fixedly rotatable within the adjustment mechanism 16 to a position in which the gears 22, 22A pivot the seat support 14 upwardly about the front rotation axis 100 due to the meshing engagement, thereby increasing the seat tilt of the seat surface 11A is reached. The compression spring 33 then pushes the locking bolt 92 into the locking hole 99 of the shift gate 94 that is aligned in this position. The two gears 22, 22A are non-rotatably coupled to the shift gate via the continuous hexagonal shaft 33. Thus, the rotational degree of freedom of the gears 22, 22 A is set after insertion of the locking bolt 92 into the locking hole 99. Due to the toothing of the seat support 14 is then also determined in this position.

Although the present invention has been fully described above with reference to preferred embodiments, it is not limited thereto but is modifiable in a variety of ways.

Also, the invention does not necessarily relate to swivel chairs and / or office chairs, but can also be used advantageously in any other chairs with synchronous mechanism, seat tilt adjustment and backrest adjustment.

The present invention is not necessarily limited to the above concrete construction of a Sitzneigeverstellmechanismus. Rather, it would also be conceivable on the crossbar and providing a second vertical To dispense with guide rail, although this would be less advantageous, in particular for stability reasons.

Although the lock on a spring-loaded locking pin by means of operation of a Bowden cable with or without overload protection is beneficial, of course, can also use a different locking option. In the present embodiment, three different seat heights can be adjusted by a locking device of the guide lever is locked in each case at three different horizontal positions. Of course, only two adjustable seat inclinations or more than three adjustable seat inclinations would be conceivable. In addition, it would also be conceivable to realize a stepless seat tilt adjustment, if for the locking another than the above-described, Einrastpin-related locking is used.

Although the present invention has been described in the above embodiments essentially to the use of guide rails, gear levers and linear guide rails, a variation of these elements by substantially the same effect elements would be conceivable.

The construction of the guide rails and the gears can of course vary without departing from the subject invention. Also, the crossbar and the corresponding recesses in the gears need not necessarily be hexagonal, but may also be square, triangular, polygonal or about round or oval.

The specified materials, sizes and dimensions are to be understood as exemplary only.

It goes without saying that the interaction between the locking bolt and the locking hole can also be reversed without deviating from the subject matter of the invention. In this case, for example, the locking hole would be provided on the locking hook and the locking bolt attached to the shift gate.

LIST OF REFERENCE NUMBERS

10

chair

11

Seat

11A

seat

12

backrest

13

pedestal

14

seat support

15

Backrest support

16

Adjustment mechanism, adjustment mechanism

17

chair frame

18

Backrest element

19

chair cross

20

Adjustment mechanism, seat tilt adjustment device

21

guide lever

22

cam-shaped gear, gear lever

22A

gear

23

Guide rail, gear housing

23A

Guide rail, gear housing

24

End of the guide lever

25

End of the guide lever

26

elastic element, spiral spring

27

gear portion

28

lever portion

29

articulated connection

30

Inside of the guide rail

31

Locking rails, gear section

32

actuator

33

Crossbar, hexagonal shaft

40

fixing spin

41

securing eye

42

drilling

43

locking bore

44

locking bore

45

locking bore

50

actuating button

51

(inner) sleeve

52

(outer) sleeve

53

Bowden

55

Overload spring

56

Snap pin, locking pin

57

compression spring

60

Hexagonal recess for the crossbar

60A

Hexagonal recess for the crossbar

61

drilling

70

Housing of the guide rail

71

hook-shaped sections, fastening sections

72

tooth portion

73

attack

74

rear wall

75

Recess for the crossbar

80

Seat shell, seat plate

81

pad

82

Inside of the seat shell

83

fixing spin

84

attack

85

Swivel axis, rotation axis

90

Mounting interface

91, 110

locking hook

91A, 110A

Hook, hook area

92

locking bolt

93, 113

compression spring

94

shift gate

95

actuating button

96

Push-push switch

97, 111

Bowden

98

jumper wire

99

locking hole

100

front axis of rotation

101

rear axis of rotation

102

(Lordosis) support point

103

support direction

104

link guide

112

cover

112A

Bearing for outer shell of the Bowden cable

X

horizontal adjustment direction

Y

vertical adjustment direction

Z

operating direction

F

force

D

Diameter of the latch pin

α

tilt angle

Claims (14)

1. Chair (10) comprising a synchro mechanism, in particular an office swivel chair,

   - comprising a backrest (12),

   - comprising a seat (11), which has a seat surface (11A), a seat support (14) and an adjustment mechanism (16),

   - comprising a device (20) for adjusting seat inclination, by means of which the seat surface (11A) can be inclined at least in part in a vertical direction (y),

   - comprising a synchro mechanism, which is coupled to the backrest (12) and the seat (11) and by means of which the backrest (12) is pivotable rearward in a horizontal direction relative to the seat (11), wherein the synchro mechanism is formed in such a way that the device (20) for adjusting seat inclination is deactivated when the backrest (12) is inclined rearwards, and wherein the synchro mechanism comprises:

   • a switching slide (94), which has a locking hole (99),

   • a locking hook (91; 110), which is provided on a rotary joint (100), is loaded with spring force, and is displaceable in the axial direction of a shaft of the rotary articulation (100),

   • a locking bolt (92), which is rigidly coupled to the locking hook (91; 110), is displaceable into the locking hole (99) in a flush position, and in this position locks and thus deactivates the device (20) for adjusting seat inclination.
2. Chair according to claim 1,
   characterised in that the synchro mechanism is formed in such a way that the device (20) for adjusting seat inclination is not deactivated until the backrest (12) is fully rearwardly inclined.
3. Chair according to either claim 1 or claim 2, characterised in that the switching slide (94) is rigidly coupled to the rotary articulation (100) and arranged in such a way that the locking bolt (92) introduced into the locking hole (99) acts as a tappet and entrains the locking hook (91; 110) when it is not hooked in.
4. Chair according to claim 3,
   characterised in that the locking hook (91; 110) has a hook region (91A; 110A) via which the locking hook (91; 110) can be hooked in on the housing of the seat support (14) in such a way that the switching slide (94) is blocked from entraining the locking hook (91; 110).
5. Chair according to any of claims 1 to 4, characterised in that the synchro mechanism further has an actuation mechanism (93, 95, 96, 97, 98; 95, 111, 113) having a spring element (93; 113), which can be actuated via an actuation element (95) and is resiliently coupled to the locking hook (91; 110), and via which the locking hook (91; 110) and thus the locking bolt (92) are displaceable into the locking hole (99) in the axial direction.
6. Chair according to claim 5,
   characterised in that the actuation element (95, 111; 113) is coupled to the locking hook (91; 110) and/or the spring element (93; 113) directly via a Bowden cable (111).
7. Chair according to claim 5,
   characterised in that the actuation element (93, 95, 96, 97, 98) is coupled via a Bowden cable to a push-push switch (96), which is in turn coupled to the locking hook (91) and/or the spring element (93) via a hook-up wire (98).
8. Chair according to any of claims 1 to 7, characterised in that the locking bolt (92) and the locking hole (99) are mutually flush whenever the forward seat inclination is activated and/or the synchro mechanism is active.
9. Chair according to any of the preceding claims, characterised in that the adjustment mechanism (16) is coupled to the seat support (14) via a front rotary articulation (100), which is mounted stationary, and a rear rotary articulation, which is mounted movable in a slide guide (104), the rear rotary articulation (101) being fixed in a lower region of the slide guide (104) in an inclined position of the seat and being located in an upper initial position of the slide guide (104) in the initial position.
10. Chair according to any of the preceding claims, characterised in that the device (20) for adjusting seat inclination is formed in such a way that the seat surface
    (11A) can be brought from a substantially horizontal initial position through a predetermined angle into a position inclined forwards with respect to the backrest (12).
11. Chair according to any of the preceding claims, characterised in that the device (20) for adjusting seat inclination comprises:

    - a spring-loaded guide lever (21), which has a resilient element (26), which can be fixed to a seat (11) and when tensed exerts a substantially horizontally acting spring force on the guide lever,

    - at least one vertically orientated guide rail (23, 23A), which can be attached to the seat (11) and has in the interior (30) a substantially vertically extending toothed rail (31),

    - a gearwheel (22), which is coupled to the gear lever (21) via an articulated connection (29) in such a way that a gearwheel portion (27) of the gearwheel (22) is arranged vertically movable in the interior (30) of the guide rail (23, 23A), in such a way that, for any seat inclination, first teeth of the gearwheel portion (27) always engage in second teeth of the toothed rail (31).
12. Chair according to claim 11,
    characterised in that the gearwheel (22) is formed as a cam-like gearwheel (22), which has a gearwheel portion (27) and a lever portion (28), which protrudes from the gearwheel (22) in the form of a cam-shaped moulding and to which the guide lever (21) is articulated via the articulated connection (29).
13. Chair according to either claim 11 or claim 12, characterised in that the resilient element (26) is maximally tensed at the maximum seat inclination and minimally tensed at the minimum seat inclination.
14. Chair according to any of claims 11 to 13, characterised in that two guide rails (23, 23A) are provided, and in that a further gearwheel (22A) is provided alongside the gearwheel (22), the two gearwheels (22, 22A) being formed in such a way that they are each vertically movable within a guide rail (23, 23A) assigned thereto and/or a transverse coupling device (33) being provided which couples the two gearwheels (22, 22A) to one another.

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