WO2024013141A1

WO2024013141A1 - Synchronizing mechanism for a chair

Info

Publication number: WO2024013141A1
Application number: PCT/EP2023/069131
Authority: WO
Inventors: Eugen LETOW; Stefan Keller; Noah FRIEDLIN
Original assignee: Vitra Ag
Priority date: 2022-07-11
Filing date: 2023-07-11
Publication date: 2024-01-18

Abstract

The invention relates to a synchronizing mechanism (1) for a chair, in particular an office chair, comprising a base part (5) which defines a rotational axis (X), a backrest support (2) for supporting a backrest, and a seat support (3) for supporting a seat. The backrest support (2) is pivotally supported on the base part (5) about a first rotational point (D1), and the seat support (3) is pivotally supported on the backrest support (2) about a second rotational point (D2, D2'). The first rotational point (D1) of the backrest support (2) is fixed relative to the base part (5), and the second rotational point (D2, D2') of the seat support (3) is movable relative to the base part (5). In a basic setting, the second rotational point (D2, D2') is in a lower basic position, and the seat support (3) rests against a support structure (A, A'). In an upper end position, the movable second rotational point (D2, D2') moves substantially vertically into an upper end position, and the seat support (3) is arranged at a distance to the support structure (A, A').

Description

DESCRIPTION

title

SYNCHRONOUS MECHANICS FOR A CHAIR

Technical area

The invention relates to a synchronous mechanism for a chair, in particular an office chair, according to the preamble of independent claim 1.

Such a mechanism, which enables a synchronously adjustable alignment of the backrest and seat, is used in various chairs and armchairs. The corresponding chairs or armchairs should be designed for ergonomically dynamic sitting and have body-synchronous mobility. The adjustability of the backrest and seat is usually achieved mechanically, but in some cases also using motors.

State of the art

[0003] Known from US 7,614,697 A1 coupling mechanism for a seat and a backrest of a chair, which is intended to prevent the seat from tipping over when leaning back. The mechanism includes a pair of opposed front pivot brackets and a pair of opposed rear pivot brackets attached to a connecting base member on a bottom of a seat, each of the front and rear pivot brackets having a through hole. The mechanism further comprises a connecting element fixedly connected to a support tube of the seat, the connecting element having two opposing side wall sections. Each of the side wall sections has an inclined slot at each of its front and rear sections. The inclined slots are each inclined downwardly toward a rear end, the seat being movably disposed on the connecting member, with a first pivot shaft passing through the through holes of the front Pivot bracket parts and the front inclined slots of the connecting element is guided and a second pivot shaft is guided through the through holes of the rear pivot bracket parts and the rear inclined slots of the connecting element. Each of the side wall portions of the connecting member has an adjustment slot between the front and rear inclined slots. The mechanism further includes a connector member connected to the rear, the connector member having a mounting hole at a front portion and an inclined slot at a rear portion. The inclined slot slopes upward toward the rear end. The connection element and the connection element are connected to each other, with a third pivot shaft passing through the adjustment slots of the connection element and the fastening hole of the connection element, with the second pivot shaft passing through the inclined slot of the connection element. The connection member has a pivot portion between the mounting hole and the inclined slot; wherein the connecting element is pivoted to the connecting element at its pivoting section. Finally, the mechanism includes a positioning plate and an elasticity adjusting device installed on the positioning plate, the positioning plate being positioned under the adjustment slots of the connecting element and the connecting element. The elasticity adjusting device includes a spindle fixedly connected to the third pivot shaft passed through the adjusting slots of the connecting member, and an elastic member disposed around the spindle. The elastic member is designed to change its length when the elasticity adjusting device is rotated.

[0004] DE 20 2011 108 433 U1 describes an office chair which includes a base and an upwardly extending column. A base support is placed at the upper end of the column, with a seat support being mounted in the front area of the base support. In the rear area, the seat support and the base support are connected to each other using two pivot points and a coupling lever. The coupling lever is also positively guided in a bearing point by means of a back swing arm. The deflection angle of the coupling lever is open towards the back in the upright sitting position and does not exceed the horizontal axis in the reclined sitting position. The bearing point is preferably designed as a sliding swivel joint. The back swing is attached to the base support Swivel joint mounted. A spring element is supported on the base support and applies a restoring force to the back swing arm at an articulation point. The articulation point of the spring element can be changed in position relative to the swivel joint via a spiral eccentric, thus enabling the restoring force to be adjusted.

The present invention is based on the object of proposing a synchronous mechanism for a chair, in particular an office chair, which enables the chair to be moved safely from a basic position to an end position and back again, without the weight of the chair being affected User-dependent adjustment of the mechanics would be required.

Presentation of the invention

According to the invention, the object is achieved by a synchronous mechanism for a chair, in particular an office chair, as defined in independent claim 1.

The essence of the invention is as follows: a synchronous mechanism for a chair, in particular an office chair, comprising a base part defining an axis of rotation, a backrest support for holding a backrest and a seat support for holding a seat. The backrest support is pivotally mounted on the base part about a first pivot point, the seat support being pivotally mounted on the backrest support about a second pivot point. The first pivot point of the backrest support is fixed relative to the base part and the second pivot point of the seat support is movable relative to the base part. In a basic position, the second pivot point is in a lower basic position and the seat support rests against a standing structure, and in an upper end position, the movable second pivot point is moved substantially vertically into an upper end position and the seat support is spaced from the standing structure.

[0008] The term “synchronous mechanism” is to be understood here in a broader sense, that is to say that a combination of seat support and backrest support movement also takes place when leaning back, but this is combined with a greater freedom of movement when sitting. By flexible mounting of the seat support with the seat plate, the user can control his sitting position solely using his lower legs and thighs and, if necessary, by shifting his weight. You can therefore also from a (flexible) weight-dependent kinematics concept for a chair, especially an office chair.

[0009] In the present case, the term “rotation matter” also means the central axis of the finished chair, which runs through the column of the chair and around which the seat can be rotated regularly.

In the present case, the “base part” serves in particular as a type of holder for the backrest support and for the column of the finished chair.

[0011] In the present case, the term “backrest support” is understood to mean the component on which the backrest of the chair is arranged.

[0012] In the present case, the “seat support” is the component on which the seat plate is arranged or mounted; In principle, the seat support and the seat plate can also be designed in one piece.

[0013] The “fixed first pivot point” does not change its position during the various movements or position changes of the synchronous mechanism, i.e. it always remains in the same place.

[0014] The “movable second pivot point”, on the other hand, changes its position during the various movements or changes in position of the synchronous mechanism, i.e. it does not remain in the same place. The movable second pivot point can be designed as a pivot point of a joint-like connection between the backrest support and the seat support; However, in another embodiment, it can also be designed as a fictitious pivot point, which lies outside the synchronous mechanism, in particular as a pivot point relative to a link guide of the backrest support, in which the seat support is guided.

[0015] In addition, it is also possible for the fixed first pivot point and/or the movable second pivot point to be implemented not only mechanically in the form of a joint or an axle, but also in the form of deformable structures, such as bending element arrangements or .Bending spring arrangements or the like. It is also conceivable to use plastic-glass fiber material arrangements, which provide a correspondingly flexible spectrum of movement. The “basic position” includes the basic state of a corresponding chair in which the movable second pivot point is in its lowest position, ie in its lower basic position, and in which the seat support with the seat is in an untilted state.

[0017] The seat support or the seat is held in the basic position on the “standing structure”, i.e. the standing structure can only be overcome by shifting the weight of a person on the chair forward, so that the seat support and the seat plate move forward in the sitting direction. i.e. tilted away from the backrest. The “standing point” is the support point or the support surface (i.e. in the case of a sliding block) of the seat support on the standing structure in the basic position.

[0018] The “end position” of the synchronous mechanism includes the state in which the second movable pivot point and thus also the seat support are in the highest position, i.e. at the greatest distance from the standing structure. In this end position, maximum pivotability of the seat support is guaranteed.

The “substantially vertical” movement of the movable second pivot point into the upper end position also includes a movement path that is curved upwards, i.e. in particular a movement path that is curved forward from the axis of rotation in the sitting direction.

[0020] In the present case, an arrangement “distanced” from the contact point can be achieved, for example, by lifting or pivoting the seat support upwards or by moving it laterally together with lifting or pivoting the seat support upwards.

Preferably, the second pivot point is fixed relative to the backrest support and can be moved essentially vertically upwards with the backrest support. This has proven to be advantageous with regard to a particularly flexible design of the chair mechanics. Preferably, in a first intermediate position of the synchronous mechanism, the second pivot point is moved essentially vertically upwards from the lower basic position into a first intermediate position and the seat support is arranged to tilt relative to the standing structure (ie forward in the seating direction) or to be tiltable. By shifting your weight forward accordingly, ie away from the backrest, a person can tilt the seat support forward, whereby at the same time the second pivot point moves slightly upwards and the backrest tilts slightly backwards. In this way, a particularly flexible use of a chair equipped with the synchronous mechanism according to the invention can be provided in an efficient manner.

Preferably, in a second intermediate position, the seat support and the seat plate (alone) can be controlled in angle or inclination by the upper and/or lower legs of the user (and not necessarily by the mechanics). Rather, the seat plate adapts to the user thanks to its, albeit limited, pivotability, which generates a special level of seating comfort.

In particular, in the second intermediate position, the second pivot point is moved essentially vertically upwards from the lower basic position into a second intermediate position, in which the seat support (and the seat plate) is raised to such an extent that it is in external contact (with its inner surface). with the standing structure, so that the seat support with the seat plate can be tilted around the second pivot point without being guided. The seat support with the seat plate is only connected to the backrest support or the chair mechanism via the second pivot point and can be tilted around it; Guide rods or other guide elements are not provided. Therefore, the inclination of the seat support with the seat plate can be controlled (alone and directly) by means of the user's lower legs and/or thighs and is essentially independent of the position of the backrest. There is no need for forced guidance by the mechanics.

[0024] Preferably, however, the seat support has not yet reached its maximum pivotability in the second intermediate position.

Preferably, in the end position of the synchronous mechanism, the seat support can be pivoted to the maximum around the second movable pivot point relative to the backrest support. This allows the flexibility of use of a chair equipped with the synchronous mechanism according to the invention to be further increased.

Ultimately, the user should be able to carry out all possible movements (ie tilting forward, lifting and lying on his back) by shifting his weight or using his muscles alone. At With appropriate coordination of the pivot points and supporting structures, the use of springs and/or damping elements can in principle be dispensed with by means of the synchronous mechanism according to the invention. This means that the seat support with the seat plate can ideally adapt to the user thanks to the freedom of rotation (albeit limited to the front and back) and thus generate specially optimized seating comfort.

[0027] In the present context, the term “maximally pivotable” includes a maximum rotation or rotation and movement of the seat support in the end position, or the highest position of the second pivot point, between a first limiting means, which limits forward tilting of the seat support and a second limiting means which limits tilting of the seat support backwards.

In a first embodiment of the invention, the first limiting means is formed by the beveled front end of the backrest support or the side parts of the backrest support - against which the seat support comes into contact with the inner surface of its upper side when tilted forward - and the second limiting means is formed by the front lower edge of the backrest support or the side parts of the backrest support - against which the lower cross connection of the seat support comes into contact when tilting backwards.

In a second embodiment of the invention, the first limiting means is formed by the front end of the guide slot of the link guide of the backrest support or the side parts of the backrest support - against which the front guide pin of the seat support comes into contact when tilted forward - and the second limiting means the rear end of the guide slot of the link guide of the backrest support or the side parts of the backrest support - against which the rear guide pin of the seat support comes into contact when tilting backwards.

In both embodiments of the synchronous mechanism according to the invention, in the rearwardly tilted end position, the seat support or the seat plate assumes a maximum tilting angle perpendicular to the axis of rotation. This maximum tilt angle is preferably about 5° to about 40°, more preferably about 10° to about 30° and even more preferably about 15° to about 25°. In these areas, the weight independence of the mechanics can be used optimally.

The base part is preferably designed as a rigid component. In this way, the stability required for the synchronous mechanism according to the invention can be guaranteed.

Preferably, in a side view, the first pivot point is arranged behind the axis of rotation in the sitting direction and the second pivot point is arranged in front of the rotation axis of the base part in the sitting direction. In this way, optimal functionality of the synchronous mechanism according to the invention can be ensured.

Preferably, the standing structure is arranged in front of the axis of rotation of the base part in a lateral view in the sitting direction. This is intended so that the user must consciously shift their weight in order to be able to tilt the seat support forward.

Preferably, the movable second pivot point is movably arranged in a lateral view between the supporting structure and the first pivot point, i.e. on a substantially vertical movement path. Further preferably, the second pivot point is movably arranged in a lateral view between the contact point and the axis of rotation, i.e. on a substantially vertical movement path. This measure allows further fine-tuning of the mechanics to be achieved, which enables the user to change the positions of the chair purely based on body movements or muscle strength.

Preferably, in the basic position, a contact point of the seat support is located on the contact structure in the vertical direction above the first pivot point. This is also another measure for fine-tuning the individual components to one another.

Preferably, the seat support is designed as a U-shaped profile, which, open at the bottom, is arranged on the underside of the seat plate. In this way, a particularly effective articulation of the seat support on the backrest support and at the same time an optimal support of the seat support at the contact point can be achieved. Preferably, the supporting structure comprises a sliding block, which is preferably rotatably mounted about a third pivot point between two tab-like projections of the base part. The sliding block supports the seat support to stabilize the seat and serves as a seat support pivot point for the forward tilt according to the first intermediate position. Preferably, in the basic position and in the first intermediate position, the inner surface of the seat support rests on the sliding block (support point).

In another preferred embodiment of the invention, the backrest support has a link guide for the seat support. In this case, the second pivot point is outside the mechanics and is therefore also referred to as the fictitious pivot point. In this embodiment, the seat support is not only tilted forward when moving from the basic position to the first intermediate position, but at the same time it is also moved laterally forward, i.e. it also carries out a forward movement; The same applies when moving the seat support from the basic position to the end position. In other words, in this embodiment the seat support and the backrest support or the backrest of the chair move apart or in quasi opposite directions.

Preferably, in this embodiment, in a second intermediate position, the seat support and the seat plate can be controlled at an angle with the user's lower legs (and not necessarily by the mechanics). Rather, the seat plate adapts to the user thanks to its, albeit limited, pivotability, which generates a special level of seating comfort. In particular, in the second intermediate position, the second pivot point is moved essentially vertically upwards from the lower basic position into a second intermediate position, in which guide bolts operatively connected to the seat support via a link guide are raised to such an extent (i.e. together with the seat support and the seat plate) that they are out of contact with the base part, but the seat support has not yet reached its maximum pivotability.

[0040] Preferably, in a side view, the link guide comprises an upwardly convexly curved guide slot for the seat support, which extends in any case partially over an upper edge of the base part. In this way, a guide is created for the seat support or for its guide bolts, which protrude through the guide slot in the link guide, the front one Guide pin rests on a stop point (in the basic position) defined by the upper edge of the base part and the curved guide slot.

Preferably, the fixed first pivot point and/or the movable second pivot point is/are realized by means of a deformable structure. In particular, a bending element arrangement, such as a spiral spring arrangement, can be provided here. In this way, the movement sequence can be made particularly efficient for the user.

A further aspect of the invention relates to a chair, in particular an office chair, with a synchronous mechanism of the type described above. With such a chair, the effects and advantages described above in connection with the mechanics according to the invention can be implemented in an efficient manner.

Brief description of the drawings

Further advantageous embodiments of the invention result from the following description of exemplary embodiments of the invention with the aid of the schematic drawing. In particular, the mechanism according to the invention and the chair according to the invention will be described in more detail below with reference to the accompanying drawings using exemplary embodiments. Show it:

Fig. 1: a perspective view of a first embodiment of a synchronous mechanism according to the invention;

Fig. 2: a side sectional view of the first embodiment of the synchronous mechanism according to the invention in the basic position with a horizontal seat support;

Fig. 3: a side sectional view of the first embodiment of the synchronous mechanism according to the invention in the first intermediate position with the seat support tilted forward;

Fig. 4: a side sectional view of the first embodiment of the synchronous mechanism according to the invention in a second intermediate position with a raised and essentially horizontal seat support;

Fig. 5: a side sectional view of the first embodiment of the synchronous mechanism according to the invention in an end position with the seat support in the highest position; Fig. 6: a side sectional view of the first embodiment of the synchronous mechanism according to the invention in the end position with the seat support tilted backwards;

Fig. 7: a side sectional view of a second embodiment of the synchronous mechanism according to the invention in the basic position with the seat support tilted slightly backwards;

Fig. 8: a side sectional view of the second embodiment of the synchronous mechanism according to the invention in the first intermediate position with the seat support tilted forward;

Fig. 9: a side sectional view of the second embodiment of the synchronous mechanism according to the invention in the second intermediate position with a raised seat support;

Fig. 10: a side sectional view of the second embodiment of the synchronous mechanism according to the invention in the end position with the seat support in the highest position; and

Fig. 11: a side sectional view of the second embodiment of the synchronous mechanism according to the invention in the end position with the seat support tilted backwards.

Weq(e) for carrying out the invention

Certain terms are used in the following description for convenience and are not intended to be limiting. The words "right", "left", "bottom" and "top" indicate directions in the drawing to which reference is made. The terms "inward", "outward", "below", "above", "left", "right" or similar are used to describe the arrangement of designated parts relative to one another, the movement of designated parts relative to one another, and the directions toward or away from geometric center of the invention and named parts thereof as shown in the figures. These spatial relative information also include positions and orientations other than those shown in the figures. For example, when a part shown in the figures is turned over, elements or features described as "below" are then "above". The terminology includes the words expressly mentioned above, derivatives thereof and words of similar meaning. In order to avoid repetition in the figures and the associated description of the various aspects and embodiments, certain features should be understood as common to various aspects and embodiments. The omission of an aspect in the description or a figure does not imply that this aspect is missing in the associated exemplary embodiment. Rather, such an omission may serve to provide clarity and prevent repetition. In this context, the following stipulation applies to the entire further description: If reference symbols are included in a figure for the purpose of graphic clarity but are not mentioned in the directly associated description text, reference is made to their explanation in the previous descriptions of the figures. If reference symbols that are not included in the corresponding figure are also mentioned in the description text that directly belongs to a figure, reference is made to the preceding and following figures. Similar reference numbers in two or more figures represent similar or identical elements.

1 shows a perspective view of a first embodiment of the synchronous mechanism 1 according to the invention for a chair, in particular an office chair. The synchronous mechanism 1 includes a base part 5 with a receptacle 11 for a column of a chair and two side parts 5a and 5b. At the rear end of the side parts 5a and 5b there is an articulated connection with the side parts 2a and 2b of a backrest support 2, which serves to hold a backrest, the articulated connection comprising the fixed first pivot point D1. In the front area of the two side parts 2a and 2b of the backrest support 2, a U-profile seat support 3 is articulated with its two side parts 3a and 3b, this articulated connection comprising the movable second pivot point D2. The second pivot point D2 is thus arranged fixedly relative to the backrest support 2 and can be moved essentially vertically upwards with the backrest support 2. The U-profile seat support 3 is arranged essentially centrally on the underside of a seat plate 4. With the inner surface of its top side 7, the U-shaped seat support 3 rests on a sliding block 6, which is rotatably mounted between two tab-like projections 5c and 5d of the base part 5 and which serves as a seat stabilization and as a seat support pivot point, ie for tilting the seat support 3 with the seat plate 4 in the seating direction forward, serves. In the synchronous mechanism 1 according to the invention, the side parts 3a and 3b of the seat support 3 are on the outside arranged and the two side parts 5a and 5b of the base part 5 are arranged inside and the two side parts 2a and 2b of the backrest support 2 are arranged between them. The individual movement sequences of the synchronous mechanism 1 according to the invention are described in detail below.

2 shows a side sectional view of the first embodiment of the synchronous mechanism 1 according to the invention in the basic position with a horizontal seat support 3 and a correspondingly horizontal seat plate 4. The basic position includes the basic state of a corresponding chair in which the movable second pivot point D2 is at its lowest Position, ie its lower basic position, and the seat support 3 with the seat plate 4 is in an untilted, ie horizontal, state. The fixed first pivot point D1 and the movable second pivot point D2 are approximately at the same height but on different sides of the rotation axis X, with the fixed first pivot point D1 on the rear side regularly being somewhat further away from the rotation axis the front side. The U-shaped seat support 3 lies with its inner surface 7a on the sliding block 6, the sliding block 6 being arranged between the two tab-like projections 5c and 5d of the base part 5 so that it can rotate about the third pivot point D3. This support area of the seat support 3 on the sliding block 6 includes the contact point P of the contact structure A, which is formed here by the tab-like projections 5c and 5 and by the sliding block 6. The user must overcome the standing structure A if he wants to move from the basic position of the synchronous mechanism to a first intermediate position, which is explained further below. The contact point P (and also the third pivot point D3) lies regularly, seen in the vertical direction along the rotation axis X, above the movable second pivot point D2 as well as above the fixed first pivot point D1 and in the horizontal direction further away from the rotation axis Pivot point D2 and also further away from the central axis X than the fixed first pivot point (on the rear side) to ensure optimal functionality of the mechanics. A backward tilting of the seat support 3 with the seat plate 4 is prevented in this position with the backrest support 2 not deflected by the lower cross connection 13 of the seat support 3, which rests here on the front lower edge 14 of the backrest support 2 or its side parts. 3 now shows a side sectional view of the first embodiment of the synchronous mechanism 1 according to the invention in a first intermediate position with the seat support 3 tilted forward and the seat plate 4 tilted forward. For this movement, a shift in the user's weight on the seat plate 4 is regularly required, to overcome the standing structure A, ie to rotate the seat support 3 about the fixed third pivot point D3. During this movement or due to the weight shift, the movable second pivot point D2 is pivoted essentially vertically upwards together with the backrest support 2, which also leads to a slight backward inclination of the backrest support 2 (and possibly a corresponding backrest). The forward inclination or the forward tilting of the seat support 3 with the seat plate 4 is limited by the front bevel 12 of the backrest support 2.

4 illustrates a side sectional view of the first embodiment of the synchronous mechanism 1 according to the invention in a second intermediate position with a raised and essentially horizontal seat support 3. For this second intermediate position, the user must lean back from the basic position, in which the backrest support 2 or its front part is pivoted upwards about the fixed first pivot point D1 so that the movable second pivot point D2 moves further upwards into a second intermediate position moved. The inner surface 7a of the U-shaped seat support 3 moves accordingly upwards away from the standing structure. The backrest support 2 is here with its front lower edge 14 out of contact with the lower cross connection 13 of the seat support 3, but with its beveled front end 12 not yet in contact with the inner surface 7a of the seat support 3. The second intermediate position represents a quasi-flexible transition position Synchronous mechanism 1 on the way to the end position (highest position of the second pivot point D2) according to the following Fig. 5, and if necessary back to the basic position according to Fig. 2.

In the second intermediate position according to FIG. 4, in contrast to conventional synchronous mechanisms, the seat support 3 and the seat plate 4 can be controlled at an angle without any guidance, ie without supporting guide rods or other guide elements, alone and directly by the user's lower legs and not necessarily through the mechanics. The seat plate 4 fits here thanks to its, Although limited, pivoting is ideal for the user, generating specially optimized seating comfort.

5 shows a side sectional view of the first embodiment of the synchronous mechanism 1 according to the invention in the end position, in which the seat support 3 with the movable second pivot point D2 is in the highest position or the upper end position of the movable second pivot point D2. Here the second pivot point lies approximately above the upper edge 10 of the base part 5 or above its side parts. When the user leaned back further, the bevelled front end 12 of the backrest support 2 was pivoted further upwards around the fixed first pivot point D1 compared to the second intermediate position according to FIG. 4, with the beveled end 12 of the backrest support 2 or its side parts in contact with the inner surface 7a of the U-shaped seat support 3 comes and rests against it. The backrest support 2 is now with its beveled front end 12 in flat contact with the inner surface 7a of the seat support 3, so that the seat support 3 with the seat plate 4 is supported by the bevelled front end 12 of the backrest support 12 essentially in a horizontal orientation. In this upper end position of the movable second pivot point D2, the seat support 3 can now be rotated around the latter, but the rest on the beveled front end 12 (first limiting means) of the backrest support 2 prevents the backrest support from moving into the end position shown here when leaning back 2 at the same time the seat support 3 with the seat plate 4 can tilt forward from the horizontal, which would possibly lead to the user undesirably slipping on the chair.

[0052] On the other hand, the user can cause the seat support 3 with the seat plate 4 to tilt backwards from the end position of the synchronous mechanism 1 according to FIG Backrest support 2 and the movable second pivot point D2 no longer change their position. This backward tilting is limited by the front lower edge 14 (second limiting means) of the backrest support 2 or by its side parts, against which the seat support 3 comes into contact with its lower cross connection 13. In other words, in the end position there is maximum pivotability or maximum rotation of the seat support about the pivot point D2, namely between the beveled one front end 12 of the backrest support 2 as a first limiting means, which limits tilting of the seat support 3 from the horizontal to the front, and the lower front edge 14 of the backrest support 2 as a second limiting means, which limits tilting of the seat support backwards (ie by the lower cross connection 13 of the seat support 3 comes into play here). In the end position with the seat support 3 tilted backwards, the seat plate 4 is essentially parallel to the backrest support 2. In the backwards tilted end position, the seat plate 4 accordingly assumes a maximum tilting angle a perpendicular to the rotation axis X, as illustrated in FIG .

7 now shows a side sectional view of the second embodiment of the synchronous mechanism 1 according to the invention in the basic position. In the second embodiment of the synchronous mechanism according to the invention, the side parts of the seat support 3 are also arranged on the outside and the two side parts of the base part 5 are arranged on the inside. The two side parts of the backrest support 2 are again arranged in between. In this second embodiment, however, the side parts of the backrest support 2 have a link guide 8, which has a guide slot 9 which is convexly curved upwards, in which guide bolts 11a, 11b, which movably connect the seat support 3 to the backrest support 2, are guided. The link guide 8 itself has a corresponding upwardly convex curvature like the guide slot 9. The seat support 3 rests with the inner surface 7a on the top of the link guide 8 (support point P 'of the support structure A', which is formed here by the link guide 8 ). At the rear end of the side parts of the base part 5, an articulated connection to the side parts of the backrest support 2 is again provided, which includes the fixed first pivot point D1. The movable second pivot point D2 'is designed here as a "fictitious" pivot point, which lies outside the synchronous mechanism 1, namely as the pivot point of the seat support 3, which moves essentially vertically upwards with the backrest support 2 from the basic position, i.e. here also somewhat laterally moved forward (due to the mobility of the seat support or its guide bolts 11a, 11b in the guide slot 9), which results in an upwardly curved movement path of the movable second pivot point D2 '. The individual movement sequences of the second embodiment of the synchronous mechanism according to the invention are described in detail below. In the basic position, in this embodiment, the seat support 3 and the seat plate 4 are slightly inclined backwards relative to the rotation axis X. However, the basic position here also includes the basic state of a corresponding chair in which the movable second pivot point D2 'is in its lowest position, ie its lower basic position, and the seat support 3 with the seat plate 4 is in a non-tilted, ie slightly backwards inclined state. The rear guide pin 11b of the seat support 3 rests on the rear end of the guide slot 9, which initially prevents a further or greater backward tilt, and the front guide pin 11a rests on the stop point H in the area of the front end of the base part 5. At the stopping point H, in the basic position, the curvature of the guide slot 9 together with the upper edge 10 of the base part 5 basically prevents a forward tilting movement of the seat support 3 and the seat plate 4. Here too, the user's weight must be shifted on the seat plate 4 in order to support the standing structure A ' (and the stopping point H) if the user wants to move from the basic position of the synchronous mechanism 1 to a first intermediate position, which is explained further below. The movable second pivot point D2' lies below the fixed first pivot point D1. The two pivot points D1 and D2' lie on different sides of the rotation axis X, with the fixed first pivot point D1 on the rear side regularly being somewhat closer to the rotation axis

8 now shows a side sectional view of the second embodiment of the synchronous mechanism 1 according to the invention in the first intermediate position with the seat support 3 tilted forward, with the seat support and the seat plate 4 being tilted from the slightly backwards inclined position to a substantially horizontal orientation reach. For this forward tilting movement, as mentioned, the user's weight must be shifted on the seat plate 4 in order to overcome the standing point P' (and the stopping point H). During this weight shift, the movable second pivot point D2 'is pivoted essentially vertically upwards together with the backrest support 2, which accordingly also leads to a slight backward inclination of the backrest support 2 and to a piecemeal lifting of the curved guide slot 9 relative to the base part 5. In this way, the front guide pin 11a can move up to approximately the front edge 15 of the base part 5, but not beyond, because further movement is blocked by the curvature of the guide slot 9 in interaction with the base part 5. This Blockage at stopping point H can be removed by further lifting the seat support 3.

9 illustrates a side sectional view of the second embodiment of the synchronous mechanism 1 according to the invention in a second intermediate position with the seat support 3 raised and essentially horizontal or slightly inclined backwards. For this second intermediate position, the user must lean back from the basic position, in which the backrest support 2 or its front part is pivoted upwards about the fixed first pivot point D1 so that the movable second pivot point D2 'corresponds further upwards moves to a second intermediate position. The guide slot 9 with the guide pins 11a and 11b together with the seat support 3 and the seat plate 4 is lifted upwards away from the base part 5 and at the same time the guide pins 11a and 11b of the seat support 3 move laterally in the guide slot 9 of the link guide 8 A little further forward, but the front guide pin 11a does not yet come into contact with the front end 9a of the guide slot 9. The second intermediate position represents a flexible transition position of the synchronous mechanism 1 on the way to the end position according to the following FIG. 10 (and if necessary back to the basic position according to FIG. 7).

In the second intermediate position according to FIG. 9, the seat support 3 and the seat plate 4 can be controlled at an angle by the user's lower legs and not necessarily by the mechanics, in contrast to conventional synchronous mechanisms. Here the seat plate 4 adapts to the user thanks to its, albeit limited, pivotability, which generates a special seating comfort.

10 shows a side sectional view of the second embodiment of the synchronous mechanism 1 according to the invention in the end position, in which the seat support 3 with the movable second pivot point D2 'is in the highest position or its upper end position, in which the movable second Pivot point D2 'is here slightly below the front edge 15 of the base part 5 or its side parts. By further leaning back with a corresponding shift in the user's weight, the front part of the backrest support 2 with the link guide 8 was raised further upwards and downwards compared to the second intermediate position according to FIG tilted at the back. At the same time, the seat support 3 with the seat plate 4 has moved laterally forward together with the guide pins 11a and 11b, that is, until the front guide pin 11a rests on the front end 9a of the guide slot 9. The seat support 3 and the seat plate 4 have maintain their slightly backward inclination, in which they are supported here. In this upper end position of the movable second pivot point D2 ', the seat support 3 can now be freely rotated around it or moved in the guide slot, but this is prevented by the contact of the front guide pin 11a on the front end 9a (first limiting means) of the guide slot 9 that when leaning back into the end position of the backrest support 2 shown here, the seat support 3 with the seat plate 4 can simultaneously tilt further forward from the horizontal, which would possibly lead to the user slipping down from the chair.

In this respect, from the end position of the synchronous mechanism 1 according to FIG the movable second pivot point D2' no longer changes its position. This backward tilting is limited accordingly by the rear end 9b (second limiting means) of the guide slot 9, on which the seat support 3 comes to rest with the rear guide pin 11b. In other words, in the end position there is a maximum pivotability or a maximum rotation or movement of the seat support 3 about the pivot point D2 'between the front end 9a of the guide slot 9 as the first limiting means, which prevents the seat support 3 from tilting slightly backwards Inclination limited to the front, and the rear end 9b of the guide slot 9 as a second limiting means, which limits tilting of the seat support 3 backwards (i.e. by the rear guide pin 11b of the seat support 3 coming into contact here). In the rearwardly tilted end position, the seat plate 4 is again essentially parallel to the backrest support 2. In the rearwardly tilted end position, the seat plate 4, as illustrated in FIG. 11, assumes a maximum tilting angle a perpendicular to the rotation axis X (or . a maximum inclination).

[0060] From the above statements it is clear that by means of the synchronous mechanism according to the invention both according to the first and according to the second Embodiment, a practically fluid adjustment of a corresponding chair can be carried out by the user solely based on his body posture and / or his muscle strength without the need for further support or restoring elements. Nevertheless, it is fundamentally possible to use such elements in connection with the synchronous mechanism according to the invention.

List of reference symbols:

1 synchronous mechanism

2 backrest supports

2a, b side panels

3 seat supports

3a, b side panels

4 seat plate

5 base part

5a, b side panels

5c, d tab-like projections

6 sliding stone

7 Top seat support

7a Inner surface of the top of the seat support

8 Scene tour

9 guide slot

9a front end guide slot

9b rear end guide slot

10 Top edge of base part

11a, b guide elements seat support

11 Holder for column

12 beveled front end backrest supports

13 lower cross connection seat support

14 front lower edge of backrest supports

15 Front edge of base part

A, A' queuing structure

P, P' standing point D1 fixed first pivot point

D2, D2' movable second pivot point

D3 third pivot point (sliding stone)

H breakpoint

X rotation axis a max. tilt angle

Claims

EXPECTATIONS

Claim 1: Synchronous mechanism (1) for a chair, in particular an office chair, comprising a base part (5) defining an axis of rotation (X), a backrest support (2) for holding a backrest and a seat support (3) for holding a seat, the Backrest support (2) is mounted on the base part (5) so that it can pivot about a first pivot point (D1), the seat support (3) being mounted on the backrest support (2) so that it can pivot about a second pivot point (D2, D2 '), the first Pivot point (D1) of the backrest support (2) is fixed relative to the base part (5) and the second pivot point (D2, D2 ') of the seat support (3) is movable relative to the base part (5); wherein in a basic position the second pivot point (D2, D2') is in a lower basic position and the seat support (3) rests on a standing structure (A, A'), and wherein in an upper end position the movable second pivot point (D2, D2' ) is moved essentially vertically into an upper end position and the seat support (3) is spaced from the standing structure (A, A').

Claim 2: Synchronous mechanism (1) according to claim 1, wherein the second pivot point (D2, D2 ') is fixed relative to the backrest support (2) and can be moved essentially vertically upwards with the backrest support (2).

Claim 3: Synchronous mechanism (1) according to claim 1 or 2, wherein in a first intermediate position the second pivot point (D2, D2') moves essentially vertically upwards from the lower basic position into a first intermediate position is and the seat support (3) is arranged to tilt relative to the standing structure (A, A ').

Claim 4: Synchronous mechanism (1) according to one of the preceding claims, wherein in the end position the seat support (3) can be pivoted to the maximum around the second pivot point (D2, D2 ') relative to the backrest support (2).

Claim s: Synchronous mechanism (1) according to one of the preceding claims, wherein the base part (5) is designed as a rigid component.

Claim s: Synchronous mechanism (1) according to one of the preceding claims, wherein in a side view the first pivot point (D1) is arranged behind the rotation axis (X) in the seat direction and the second pivot point (D2, D2 ') in the seat direction in front of the rotation axis (X ) of the base part (5) is arranged.

Claim 7: Synchronous mechanism according to one of the preceding claims, wherein the standing structure (A, A ') is arranged in front of the rotation axis (X) of the base part (5) in a lateral view in the sitting direction.

Claim s: Synchronous mechanism (1) according to claim 7, wherein the second pivot point (D2, D2 ') is arranged in a side view between the standing structure (A, A') and the fixed first pivot point (D1).

Claim 9: Synchronous mechanism (1) according to one of the preceding claims, wherein in the basic position a contact point (P, P') of the seat support (3) on the contact structure (A, A') lies in the vertical direction above the first pivot point (D1). .

Claim 10: Synchronous mechanism (1) according to one of the preceding claims, wherein the seat support (3) is designed as a U-shaped profile which, open at the bottom, is arranged on the underside of the seat plate (4).

Claim 11: Synchronous mechanism (1) according to one of the preceding claims, wherein the standing structure (A, A ') comprises a sliding block (6), which preferably rotatable about a third pivot point (D3) between two tab-like projections (5c, 5d) of the base part (5).

Claim 12: Synchronous mechanism (1) according to claim 11, wherein in the basic position and in the first intermediate position the seat support (3) rests with the inner surface (7a) of its top side (7) on the sliding block (6).

Claim 13: Synchronous mechanism (1) according to one of claims 1 to 10, wherein the backrest support (2) has a link guide (8) for the seat support (3).

Claim 14: Synchronous mechanism (1) according to claim 13, wherein in a side view the link guide (8) for the seat support (3) comprises an upwardly convexly curved guide slot (9), which is at least partially over an upper edge (10) of the base part ( 5) runs.

Claim 15: Synchronous mechanism according to one of claims 1 to 9 and 12 to 13, wherein the seat support (3) is configured to carry out a lateral forward movement from the basic position to the first intermediate position and from the basic position to the end position.

Claim 16: Synchronous mechanism according to one of claims 1 to 12, wherein in a second intermediate position the second pivot point (D2) is moved essentially vertically upwards from the lower basic position into a second intermediate position in which the seat support (3) is raised to such an extent that it is out of contact with the standing structure (A), so that the seat support (3) with the seat plate (4) can be tilted around the second pivot point (D2, D2 ') without being guided.

Claim 17: Synchronous mechanism according to claim 15, wherein in the second intermediate position the seat support has not yet reached its maximum pivotability.

Claim 18:Synchronous mechanism according to one of claims 1 to 8 and 12 to 16, wherein in a second intermediate position the second pivot point (D2 ') moves essentially vertically upwards from the lower basic position into a second Intermediate position is moved, in which guide bolts (11a, 11b) operatively connected to the seat support (3) via a link guide (8) are raised to such an extent that they are in external contact with the base part (5), but the seat support (3) is not yet in its position maximum pivotability has been achieved.

Claim 19: Synchronous mechanism according to one of the preceding claims, wherein the fixed first pivot point and/or the movable second pivot point is/are realized by means of a deformable structure.

Claim 20: Chair, in particular office chair, with a synchronous mechanism (1) according to one of the preceding claims.