EP1258211B1 - Synchronised mechanism for a coupled seat-and backrest-movement for office chairs - Google Patents

Abstract

Spring (11) has its own integrated force adjuster (17) and a bearing block (18) forcibly coupled for swivel with the backrest angle setting contains an abutment lever (19). The far lever end supports a compression spring (13). A manually operated control mechanism (26) within the block (18) space is used to space the swivel axis (24) from axis (8) along its slide guide (25) in block (18), normal to the spring force. The abutment lever (19) pivots on a support lever (33) which is spaced in front of the block (18) so that the support lever (33) rests under spring load on the block whenever the backrest support is out of swivel.

Description

The invention relates to a synchronous mechanism for the simultaneous Sitzflächen- and backrest pivoting movement in office chairs with the features specified in the preamble of claim 1.

These features reflect the basic construction of synchronous mechanisms for office chairs (see, for example, DE-A-4324545), according to which a seat panel and a backrest support are hinged on a quasi-backbone seat support. The two aforementioned components are articulated coupled, with different handlebar and Gelenkkettenanordnungen can be used to realize the typical movement of a synchronous mechanism. This is characterized by a coupled pivoting movement of the seat plate and backrest support between a substantially upright basic position and a more or less pivoted rearward rest position.

Usually, the synchronous mechanism is acted upon by a spring arrangement in the direction of the basic position, ie against the pivoting movement to the rear. Such spring arrangements can have a wide variety of types of springs, such as, for example, torsion springs, gas springs or helical compression springs. The latter are usually clamped between a stationary abutment on the seat support and an abutment coupled to the backrest support, whereby the latter must compress the compression spring when pivoting.

The applied by the spring assembly against the operation of the synchronous mechanism back pressure should be adjustable for ergonomic reasons, since a lighter person requires far less back pressure than a heavyweight. In that regard, such spring arrangements have suitable Spring force adjustments of different types. For example, one of the legs is adjustably mounted in leg springs, so that the spring force can be biased by a shift of this leg. In helical compression springs, it is customary to store at least one of the abutment slidably in the direction of action of the compression spring, so that by moving the abutment z. B. in the sense of greater compression of the spring whose bias and thus spring action is to increase. The disadvantage here is that when adjusting the bias against the full spring force must be worked.

Based on this, the present invention seeks to further develop a synchronous mechanism with spring action and spring force adjustment arrangement so that the adjustment practically "force-free", so without having to work directly against the bias of the spring can take place.

This object is achieved by the features specified in claim 1. Accordingly, coupled to the backrest support abutment of the compression spring is formed by a abutment link, which is pivotally connected via a pivot axis with a bearing block. The latter is forcibly coupled to the backrest support based on the pivoting movement. The pivoting movement of the bearing block is thus transferred to the abutment link, which thereby compresses the compression spring. As a further feature of the invention, the articulation axis along a sliding guide in the bearing block is positioned at different distances from the pivot axis substantially transversely to the direction of compression spring action, which is effected by an externally actuable control mechanism, ie by hand or by a corresponding positioning motor.

Due to the displaceability of the articulation axis transversely to the compression spring effective direction, it is achieved, on the one hand, that the lever arm acting in the transmission of the pivoting movement of the backrest support on the compression spring in the sense of compression is shortened or lengthened. Correspondingly, the effective compression travel of the spring is shortened or lengthened with a fixed pivoting angle, whereby the effective spring force is correspondingly reduced or increased by HOOKE's law. It is essential that must not be operated against the biasing force of the compression spring for this spring force adjustment by the shift transversely to the compression spring acting direction, so that the adjustment must be particularly low power and only against the kinematic system inherent inhibition and friction forces to work.

These forces can be reduced even further by the measure specified in claim 2. The thus provided support lever over-carries the biasing force of the spring directly onto the bearing block, so that the displaceable abutment link is completely released from the biasing force. Thus, the aforementioned internal forces of the system are greatly reduced.

According to a further preferred embodiment according to claim 3, the mentioned control mechanism for the positioning of the pivot axis is formed by a rack drive, so that the preset spring force characteristic is reliably maintained by the self-naming of this drive.

Another preferred embodiment is the design of the seat support itself. Thus, according to claim 10, the seat support is formed as a continuous thin-walled aluminum die-cast part with a vertical cross-section H-shaped base profile, the H-vertical leg are each formed by a substantially continuous side wall and its H-horizontal leg of functionally adapted Querverrippungen. Here are from the peripheral edges of the two side walls in opposite directions peripheral edge cheeks. By this profiling and design of the seat support an extremely high rigidity of this component can be achieved in particular in the longitudinal direction. Thick-walled thicknesses of the die-cast part in the order of magnitude of 3 mm are sufficient throughout. A further advantage is that the space enclosed by the peripheral edge cheeks on the outside of the two side walls space can serve as a mounting space, for example, for the spring assembly. Due to the boundary with the edge cheeks can be easily snapped to cover the entire kinematics from the outside a simple cover shell, the only suitable Dürchbrüche for axes and actuators such. B. the rotary handle to actuation of the control mechanism for spring force adjustment, must have.

Fig. 1

eine schematische teilweise Seitenansicht eines Bürostuhls mit Synchronmechanik,

Fig. 2

einen schematischen, vertikalen Längsschnitt der Synchronmechanik des Stuhls gemäß Fig. 1,

Fig. 3 bis 6

perspektivische Darstellungen der Federanordnung aus unterschiedlichen Blickrichtungen und

Fig. 7

einen schematischen, vertikalen Querschnitt durch den Sitzträger.

Further features, details and advantages of the invention will become apparent from the following description in which an embodiment is explained in detail with reference to the accompanying drawings. Show it:

Fig. 1

a schematic partial side view of an office chair with synchronous mechanism,

Fig. 2

a schematic, vertical longitudinal section of the synchronous mechanism of the chair of FIG. 1,

Fig. 3 to 6

perspective views of the spring assembly from different directions and

Fig. 7

a schematic, vertical cross section through the seat support.

As is clear from Fig. 1, an office chair designated as a whole by 1 to a chair column 2, on which a seat support 3 is placed with a cone seat 4. On the seat support a seat plate 5 is articulated at the front end, wherein in Fig. 1, only a simple pivot joint 6 is shown.

Further, a backrest support 7 is pivotally hinged in a pivot axis 8 on the seat support 3. The backrest support 7 holds the actual backrest 9 and is also connected to the seat plate via a handlebar 10 articulated. It should be noted that instead of the construction shown at the front end of the seat plate, a handlebar and rear a simple joint coupling between seat plate and backrest support can be made. Thus, the kinematic conditions with respect to FIG. 1 reverse.

In Fig. 1, a designated as a whole with 11 spring arrangement is also indicated, the exact structure will be explained in more detail with reference to the other figures. This spring arrangement 11 counteracts a pivoting of the synchronizing mechanism formed by the seat carrier 3, seat plate 5 and backrest support 7 backwards downwards (arrow 12) and acts on the synchronizing mechanism in the direction of the basic position shown in FIG. It should also be mentioned that the seat support 3 with respect to a plane parallel to the sheet 1 lying mid-plane is symmetrical, that is, that in Fig. 11 visible spring arrangement on the outside of the seat support 3 symmetrically on the opposite side of the seat support 3 is again present. In that regard, all components of the spring arrangement described below as individual parts are present in pairs on both sides of the seat support.

For a detailed description of the spring arrangement 11, reference is made to FIGS. 2 to 6, wherein in the perspective views according to FIGS. 3 to 6 the sake of clarity, the actual seat support 3 is omitted.

Core of the spring assembly 11 is a in Figs. 2 to 6 indicated as a cylinder, rigid helical compression spring 13 which is articulated in a stationary abutment 14 on the pivot joint 6 of the seat plate 5 forming axis 15. Thus, the abutment 14 is indeed pivotable, but effective with respect to the synchronous mechanism as a fixed support point. The opposite end of the helical compression spring 13 is seated in a variably adjustable abutment 16 which is coupled via a designated as a whole by 17 spring force adjustment arrangement in a manner to be explained in more detail with the backrest support 7.

The integrated into the spring assembly 11 spring force adjustment assembly 17 has now as a central part in a side view approximately quarter-circular bearing block 18 which is rotatably mounted on the pivot axis 8 of the backrest support 7. This is indicated by the hexagonal cross section of the pivot axis 8 in Fig. 3 to 6. The backrest support 7 is also rotatably connected to the pivot axis 8, so that a positive coupling based on the pivotal movement between the backrest support 7 and bearing block 18 is. As can be seen in particular from the perspective illustrations, the bearing block 18 is designed as a kind of support for a plurality of functional parts by extending from its area surrounding the pivot axis 8 two parallel, said quarter-circle shape determining side cheeks 20, 21 between which quasi a mounting space 22 is formed.

In this mounting space now runs a abutment link 19 which is pivotally coupled via an axis 23 with the variable abutment 16. The abutment 16 remote from the end of the abutment link 19 is slidably guided over a further (articulation) axis 24 in a slide-like sliding guide 25. This slide guide 25 is formed as a slot guide, wherein the slightly curved, slot-shaped link extends substantially vertically and thus transversely to the compression spring action direction K. With the help of the slide guide 25 is basically the compression spring 13 applied end of the abutment arm 19 so slidable that the defined by the axis 24 lever engagement point of the spring force on the bearing block 18 in its distance from the pivot axis 8 is variable.

To set this distance as a whole designated 26 control mechanism is provided which has a rack drive 27 for the axis 24 and thus the position of the abutment arm 19. This rack drive 27 consists of a pinion 28, which sits on a rotatably mounted in the bearing block 18 actuating shaft 29. This is rotatable about a not shown in the drawings rotary handle by hand.

The pinion 28 meshes with a rack 30, which is formed transversely to the compression spring-effective direction in a substantially in the bearing block Linear guide 30 is slidably guided. The underlying in Fig. 2 end of the rack 30 is formed as a laterally bent to the axis 24 towards Langlochöse 32, which receives the pivot axis 24 of the abutment arm 19. By a rotation of the pinion 28 and the corresponding displacement of the rack 30 so that the position of the pivot axis 24 of the abutment arm 19 is controllable.

Finally, in the direction of the helical compression spring 13 in front of the bearing block 18, an additional support lever 33 is pivotally mounted in a parallel to the previously mentioned axes extending further axis 34. Its opposite end carries the aforementioned axis 23, which defines the joint between the variable abutment 16 and the abutment link 19. In the non-deflected basic position of the synchronizing mechanism shown in FIG. 2, the support lever 33 is positioned in such a way that it frictionally rests against the bearing block 18 via a contact region 36 which is arcuate in side view. Thus, the spring force of the helical compression spring 1 is loaded directly on the bearing block 18 and relieves the control mechanism 26 in its interior.

This can be done by actuation of the rack drive 27, in particular in the basic position, a particularly low-force adjustment of the then acting during the pivoting counterforce.

Based on Fig. 2, the operation of the spring force adjustment can be explained. There, the control mechanism 26 is shown in a position in which the pivot axis 24 maximum distance A to the pivot axis 8 has. Upon pivoting of the backrest support 7 to the rear, this pivotal movement is transmitted to the bearing block 18 and there leads to a pivoting about the angle W. The pivot axis 24th passes through the arc path X1, which essentially corresponds to the compression travel of the helical compression spring 13.

If the abutment link 19 is now adjusted via the control mechanism 26 so that the articulation axis 24 lies at the upper end of the elongated slot guide 25, the effective distance a from the pivot axis 8 and thus the corresponding lever arm are markedly lower. Accordingly falls in a pivoting of the backrest support 7 and thus of the bearing block 18 in turn the angle W of the abutment arm 19 and thus from the variable abutment 16 traveled circular arc X2 significantly lower. This means that for the same pivot angle W, the helical compression spring 13 is compressed to a much lesser degree, which causes a much lower counterforce according to the aforementioned Federgesetz.

As is clear in particular from FIG. 5, a central gas spring 37, whose piston rod 38 is connected to the axis 15, can be used parallel to the helical compression springs 13. The end facing away from the gas spring 37 is struck on the bearing block 18 via the recognizable in Fig. 5 approach 39, so that the gas spring 37 acts in the same sense as the helical compression spring 13. In addition, it causes a damping of the entire kinematics and can be used for blocking the pivoting movement of the synchronous mechanism. For this purpose, only the arranged at the front end of the piston rod 38 release button 40 of the gas spring must be operated in a known manner, so that the synchronous mechanism is rigidly connected.

As further seen in particular in FIGS. 3 and 5, the compression spring 13 facing away from the trailing edge 41 of the slot-shaped sliding guide 25 for the pivot axis 24 with lined-up, flat locking recesses 42 provided. This results in a certain screening of the transverse position of the pivot axis 24 and thus the spring force adjustment.

As can be seen in Fig. 7 due to the heavily superimposed drawing detail is relatively difficult, the seat support 3 is formed as a continuous thin-walled aluminum die-cast part having a vertical cross-section approximately H-shaped base profile. The H vertical legs are formed by the respective continuous side walls 50, 51, which are connected between them by integrally molded functional Querverrippungen 52. By way of example, in Fig. 7, the only briefly truncated cone seat 4 in the lower region of the seat support 3 to call cross-ribbing 52.1. Above is a horizontal transverse rib 52.2 recognizable.

From the peripheral edges 53 of the side walls 50, 51 are each in opposite directions edge cheeks 54, 55 from, on the one hand serve a significant stiffening of the entire arrangement. On the other hand, they define a mounting space in which, for example, a part of the spring assembly 10 can be accommodated. This is indicated in Fig. 7 in the left part by the plurality of superimposed lines.

The seat support 3 can be covered on both sides with a simple cover 56, 57, which indicated in Fig. 1 by dashed lines, slot-shaped openings 58, 59 for various actuators, such as the actuating shaft 29 has.

Claims (10)

1. A synchronizing mechanism for simultaneous, pivoted seat-and-backrest motion in office chairs, comprising

   - a seat carrier (3);

   - a seat (5) articulated thereto;

   - a backrest carrier (7) which is also pivotably linked thereto and which the seat (5) is articulated to; and

   - a spring assembly (11) for actuation of the synchronizing mechanism backwards counter to the pivoting motion thereof, with the spring assembly (11) comprising a compression spring (13) which is clamped between a stationary abutment (14) on the seat carrier (3) and an abutment which is coupled with the backrest carrier (7);

   characterized

   - by a spring-load adjusting arrangement (17) which is integrated into the spring assembly (11), having

   -- a pivoted bearing block (18) which is coupled with the backrest carrier (7) for forced pivoting motion thereof;

   -- an abutment connecting rod (19) which is articulated to the bearing block (18) by way of an articulated axle (24) and on which the compression spring (13) supports itself on the side of the backrest carrier; and

   -- a control mechanism (26) which is in particular manually operable and disposed in the bearing block (18) and by which the articulated axle (24) is able to be positioned along a sliding guide (25) in the bearing block (18) substantially crosswise of the direction K of compression-spring action at varying distances from the pivoted axle (8).
2. A synchronizing mechanism according to claim 1, characterized in that the abutment connecting rod (19) is suspended on a supporting lever (33) which is pivotably articulated to the seat carrier (3) and which is positioned in front of the bearing block (18) in such a way that, when the backrest carrier (7) is not pivoted, the supporting lever (33) rests on the bearing block (18), with the spring load acting directly on the bearing block (18).
3. A synchronizing mechanism according to claim 1 or 2, characterized in that the control mechanism (26) comprises a rack-and-pinion drive (27) with a manually rotatable pinion (28) disposed in the bearing block (18) and a rack (30) which engages therewith and which the articulated axle (24) is coupled with and which is guided in a linear guide (31) for displacement in the bearing block (18).
4. A synchronizing mechanism according to claim 3, characterized in that the coupling between the articulated axle (24) and the rack (30) is configured by an oblong eyelet (32) on the end of the rack (30), the oblong eyelet (32) accommodating the articulated axle (24).
5. A synchronizing mechanism according to one of claims 1 to 4, characterized in that the articulated axle (24) is additionally guided in an oblong-hole-type guide (25) in the bearing block (18).
6. A synchronizing mechanism according to claim 5, characterized in that the rear flank (41), turned away from the compression spring (13), of the oblong-hole-type guide (25) comprises successive, flat, snap-in locking depressions (42) for the articulated axle (24).
7. A synchronizing mechanism according to one of claims 1 to 6, characterized in that the bearing block (18) is a part which is separate from the backrest carrier (7) and which is seated on the articulated axle (8) of the backrest carrier (7) for rotation there-with, with the articulated axle (8) also being connected for rotation with the backrest carrier (7).
8. A synchronizing mechanism according to one of claims 1 to 7, characterized in that all the components of the spring assembly (11) and the spring-load adjusting arrangement (17) thereof are disposed in pairs on both sides of the seat carrier (3).
9. A synchronizing mechanism according to one of claims 1 to 8, characterized in that a gas spring (37) is incorporated substantially parallel to the compression spring or springs (13), acting as an additional damping, spring-loading and blocking element between the seat carrier (3) and backrest carrier (7).
10. A synchronizing mechanism according to one of claims 1 to 9, characterized in that the seat carrier (3) is a continuous, thin-walled aluminum diecast part of a vertical cross-sectional shape of an H, each of the vertical legs of the H being a substantially continuous side wall (50) and the horizontal leg of the H being configured by functionally adapted transverse ribs (52), with rim cheeks (54) projecting from the peripheral rims (53) of the two side walls (50) and encircling in directions that face away from one another.

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