EP1989962A1 - Synchronisation mechanism for office chairs - Google Patents

Abstract

The mechanism has a spring arrangement (16) for application of the mechanism against a synchronous adjusting movement of a seat support (6) and a backrest support (5). The spring arrangement has a helical spring, and an adjusting arrangement (24) is provided for a counter spring force of the spring arrangement. The adjusting arrangement has a latch, which is inserted into a winding channel (30) of the spring from an end of the spring. The spring is locked in an area of the channel against spring deformation, where the channel acts on the latch, and has variable engagement depths.

Description

The invention relates to a synchronous mechanism for office chairs with the features specified in the preamble of claim 1, as is known from a variety of documents, such as DE 103 57 165 A1 in its basic structure is known.

The term "synchronous mechanism" assemblies are understood in the seat base of an office chair, which provide for a mutually coupled, a certain relative movement of the seat and backrest with each other bringing kinematics. For this purpose, a base support is placed on a chair column, to which on the one hand a pivotable about a transverse axis, hingedly connected to the base support seat support and on the other hand also pivotable about a transverse axis, hingedly connected to the base support backrest support are mounted. On the seat support of the usually provided with a padded seat seat of the office chair is mounted. The backrest support, which extends in a conventional manner from the actual synchronizing mechanism to the rear, carries on an upwardly extending arm, the backrest of the office chair.

Seat support and backrest support are coupled so articulated that a pivoting movement of the backrest to the rear - as can be caused for example by leaning of the chair user to the backrest - induces a lowering movement of the rear edge of the seat down. This correlated seat-back movement provides a significant comfort advantage and is desirable for orthopedic reasons.

A fundamental issue with synchronous mechanisms is their spring action against the pivoting backwards. For this purpose, a variety of spring designs is known from the prior art. The construction according to DE 101 25 994 A1 provided spring assembly is based on two torsion springs, which are housed in the base support. The one leg of the spring is housed in an adjustment in the base support, whereas the second leg projects upwards in the direction of seat support, which is supported via a corresponding abutment on this leg and thus acted against its rearward pivoting direction.

In this adjustment arrangement, the legs of the leg spring which are supported therein are adjusted in their position to change their pretension, wherein it is necessary to work directly against the force of the leg spring. This requires a relatively high force during adjustment.

In the synchronous mechanism according to DE 103 57 165 A1 are provided as a spring assembly Schraubenzugfedern whose suspension point is adjustable via an adjustment in spring-length direction. As a result, the bias of the spring assembly and thus the counter-spring force is adjusted. Specifically, pivotally mounted suspension hooks are provided for the ends of the springs in the spring assembly. By a relatively complex gear, the rotational movement of an actuating shaft is converted into a pivotal movement of the receiving hooks, which thus produce a displacement of the suspension point of the springs and a variation of the spring preload.

Also in this adjustment for the spring preload is worked against the force of the spring, so either high actuation forces prevail or such a gear ratio are provided within the actuating mechanism that a large number of revolutions of the actuating shaft are necessary for the adjustment over a certain range. Both bring with it losses in the ease of use of the spring force adjustment with it.

The invention is therefore an object of the invention to provide a synchronous mechanism with an improved adjustment for the counter-spring force of the spring assembly, in which a high ease of use is ensured with constructive simplicity.

This object is achieved by the features stated in the characterizing part of claim 1. Accordingly, the adjusting arrangement is formed by a lock which can be introduced from one end of the at least one helical spring in its winding passages with a variable depth of engagement. As a result, the coil spring is locked in the region of the winding paths acted upon by the barrier against a spring deformation.

The invention is based on the basic principle that by blocking windings of a coil spring, the remaining, non-blocked Windungsgänge for a given extension of the spring must deform more, so that a higher counter-spring force is generated, as if more or all Windungsgänge the coil spring are freely movable. As a result of the intervention of the barrier, turns are literally "shut down". The intervention of the lock takes place with a force that depends primarily only on the friction conditions between the lock and the Windungsgängen, but not of the spring force itself. In particular, when - as is provided in preferred embodiments - designed as a blocking block Lock can be screwed, for example, in the upright basic position of the synchronous mechanism under game in the Windungsgänge, a very leichgängige adjustment of the spring force can be achieved. This is particularly true for the embodiment in which the barrier is formed by a plurality of locking members, such as locking balls, which are successively inserted between the winding turns of the coil springs.

This ease of movement, in turn, requires that no excessive gear reduction must be installed in the manual drive of the lock, so that the maximum adjustment of the spring force adjustment with little turns of the manual drive can be covered.

Overall, therefore, results in a very comfortable adjustment of the counter-spring force with low operating force and short travel.

Fig. 1 und 2

Schnitte in der vertikalen Mittellängsebene in den zwei Endstellungen einer Synchronmechanik in einer ersten Ausführungsform,

Fig. 3

einen Horizontalschnitt der Synchronmechanik durch deren Sitzträger gemäß Schnittlinie III-III nach Fig. 1 in zwei unterschiedlichen Stellungen der Verstellanordnung für die Gegen-Federkraft,

Fig. 4 bis 6

Vertikalschnitte der Synchronmechanik in Querrichtung gemäß den Schnittlinien IV-IV, V-V und VI-VI gemäß Fig. 3,

Fig. 7

einen Schnitt gemäß der Schnittlinie VII-VII nach Fig. 8 einer Synchronmechanik in einer zweiten Ausführungsform,

Fig. 8

einen Horizontalschnitt dieser Synchronmechanik gemäß der Schnittlinie VIII-VIII nach Fig. 7 in komplett entsperrter Stellung der Verstellanordnung für die Gegen-Federkraft,

Fig. 9 und 10

Schnitte analog Fig. 7 und 8 der Synchronmechanik in maximal gesperrter Stellung der Verstellanordnung für die Gegen-Federkraft, und

Fig. 11

einen Vertikalschnitt der Synchronmechanik gemäß der Schnittlinie XI-XI nach Fig. 8.

Preferred developments of the synchronous mechanism are specified in the dependent claims, whose features, details and advantages will become apparent from the following description of embodiments with reference to the accompanying drawings. Show it:

Fig. 1 and 2

Sections in the vertical center longitudinal plane in the two end positions of a synchronizing mechanism in a first embodiment,

Fig. 3

a horizontal section of the synchronous mechanism by the seat support according to section line III-III after Fig. 1 in two different positions of the adjusting arrangement for the counter-spring force,

4 to 6

Vertical sections of the synchronous mechanism in the transverse direction according to the section lines IV-IV, VV and VI-VI according to Fig. 3 .

Fig. 7

a section according to the section line VII-VII according to Fig. 8 a synchronous mechanism in a second embodiment,

Fig. 8

a horizontal section of this synchronous mechanism according to the section line VIII-VIII Fig. 7 in the fully unlocked position of the adjusting arrangement for the counter-spring force,

FIGS. 9 and 10

Cuts analog Fig. 7 and 8th the synchronous mechanism in the maximum locked position of the adjustment arrangement for the counter-spring force, and

Fig. 11

a vertical section of the synchronous mechanism according to the section line XI-XI after Fig. 8 ,

How out Fig. 1 becomes clear, the synchronizing mechanism 1 as a supporting part on a base support 2, which is provided in the region of its rear end with a cone seat 3 for attaching the synchronizing mechanism to the upper end of the chair column 4. Other basic components of the synchronizing mechanism 1 are the backrest support 5 and the seat support 6. The backrest support 5 is located shortly before the cone seat 3 via an in Fig. 3 dash-dotted lines indicated, but not shown in detail in the drawings transverse axis 7 pivotally mounted on the base support 2. He has two back up-going side struts 8, 9, between them include a receiving plate 10 for mounting the backrest, not shown.

The base support 2 extends from the cone seat 3 in an arc forward above (see Fig. 1 and 2 ), where in its front end portion of the substantially flat, in plan view approximately rectangular pan formed seat support 6 is hingedly connected to its front end portion. Between base plate 2 and seat support 6 while a designated as a whole with 11 rotary-sliding joint is provided, the detailed structure here need not be explained in detail, since this is not significant for the invention. It should be noted that with the help of the rotary sliding joint 11 of the seat support 6 in the longitudinal direction L is slidably mounted and pivotable about a transverse axis 12 on the base support 2.

In its rear end region of the seat support 6 is also coupled to the backrest support 5 articulated. For this purpose, a transverse axis 13 is provided in the seat support 6, to which the backrest support 5 via two each of the side struts 8, 9 upwardly projecting bearing cheeks 14, 15 is pivotally coupled.

Due to the articulated coupling of the three components base support 2, backrest support 5 and seat support 6, a typical adjustment movement of the synchronous mechanism 1 can be achieved, as can be seen from a comparison of Fig. 1 and 2 results. Fig. 1 shows the synchronous mechanism 1 in its normal position in which the seat support 6 and thus the thereon (not shown) seat cushion unit substantially horizontally and the backrest support 5 are arranged so that also not shown, on the backrest support 5 fixed backrest is substantially upright.

Leaning the chair user now against the backrest, the backrest support 5 is backwards down (clockwise in accordance with Fig. 1 and 2 ) is pivoted about the transverse axis 7. In this case, the seat support 6 is pulled on the one hand over the transverse axis 13 to the rear bottom, simultaneously pivoted about the front transverse axis 12 and thus displaced in the rotary sliding joint 11 to the rear. The three components base support 2, backrest support 5 and seat support 6 then take the in Fig. 2 shown position with reclined seat cushion unit and backwards tilted backrest.

The synchronizing mechanism 1 is subjected to a force by means of a spring arrangement designated as a whole by 16 against the synchronizing adjustment movement explained above. This spring arrangement 16 has two symmetrical to the central longitudinal plane M ( Fig. 3 ) parallel to each other and to the seat surface arranged, open-wound helical compression springs 17, which in the following - like all other paired components - if necessary by the additional numbering ".1" or ".2" are distinguished.

The two helical compression springs 17 are supported by their front end 18 on a bearing block 19 in the seat support 6. With its rear end 20, the helical compression springs 17 are supported on the base strut 21 of a U-shaped counter-holder 22, which is connected to the free ends of its U-legs 23 pivotally connected to the base support 2 in the region of the rotary sliding joint 11.

As if from a comparison of Fig. 1 and 2 becomes clear, remains at an adjustment of the synchronous mechanism 1 of the anvil 22 due to its coupling to the base support 2 in a fixed longitudinal position, whereas the seat support 6 and thus the bearing block 19 are displaced to the rear. This shortens the distance between the bearing block 19 and the base strut 21, so that the helical compression springs 17 are compressed against the adjustment movement in order to act on the synchronizing mechanism 1.

In order to be able to vary the counterforce used, the spring arrangement 16 is associated with an adjusting arrangement denoted as a whole by 24, which is accommodated in the seat carrier 6 on the side of the bearing block 19 facing away from the helical compression springs 17. Core parts of this adjusting arrangement 24 are each one of the helical compression springs 17 associated locking blocks 25, which is substantially coaxial with the helical compression springs 17 arranged sleeve-like components with an external thread 26 and a längsaxial continuous guide channel 27. Thus, the locking blocks 25 are each set to a coaxial with them and the helical compression springs 17 in the seat support 6 rotatably mounted rotary drive pin 28. How out Fig. 4 and 5 becomes clear, the rotary drive pin 28 engage with its outer contour and the guide channel 27 of the locking blocks 25 each by a nut and spring-like cross-sectional training rotatably into each other, so that a rotational movement of the rotary drive pin 28 is converted into a rotational movement of the locking block 25, the latter, however, in the longitudinal axial direction telescopic slidably mounted on the rotary drive pin 28.

As now in particular from Fig. 3 is clear, the threads 29 of the external thread 26 of the locking blocks 25 in their pitch and cross-sectional shape are designed so that they are complementary to the Windungsgängen the helical compression springs 17 are. Thus, the locking blocks 25 can screw in rotation in each case in the front end 18 of the coil springs 17, whereby the threads 29 engage between the individual winding turns 30 of the helical compression springs 17 and lock them against a spring deformation. Due to the threaded engagement between locking block 25 and helical compression springs 17 of the locking block 25 is almost automatically pulled into the respective helical compression spring 17 when the locking block 25 is offset by means of the associated rotary drive pin 28 in a rotary motion.

This rotational movement of the rotary drive pin 28 is generated by means of the mounted in the horizontal transverse direction at the front end of the seat support 6 adjusting shaft 31 which is actuated by a handle 32. The adjusting shaft 31 is coupled via a bevel gear 33 with a central gear 34, which in turn engages with two each seated on the rotary drive pin 28 Abriebszahnrädern 35.

The operation of the adjustment assembly 24 is based on Fig. 3 to explain. In the illustrated in this drawing above the central longitudinal plane M helical compression spring 17.1 the associated locking block 25.1 is shown in its inactive position in which he retracted maximum forward on the rotary drive pin 28.1 and he just with one to two threads 29 in the front end 18.1 the helical compression spring 17.1 engages. Upon actuation of the synchronizing mechanism 1, the entire helical compression spring 17.1 is thus available for deformation, resulting in a minimum counterforce.

In the in Fig. 1 shown basic position in which the helical compression springs 17 are minimally compressed, the locking blocks 25 in the helical compression springs 17 are screwed by actuation of the adjusting shaft 31. In Fig. 3 is below the central longitudinal plane M, the maximum depth of engagement E of the locking block 25.2 shown in the helical compression spring 17.2. The lying on the locking block 25.2 Windungsgänge 30 of the helical compression spring 17.2 are blocked here by the engagement of these two components and - as already mentioned above - quasi "shut down". For a fixed adjustment of the synchronous mechanism 1, so for example for the complete adjustment between Fig. 1 and 2 are only the still freely movable Windungsgänge 30 of the helical compression spring 17.2 available, which must deform significantly more at a certain adjustment and thus produce an increased spring-counterforce.

Visible does not have to work against the helical compression springs 17 itself to vary the spring counterforce, but it must be overcome only the adjusting arrangement 24 inherent friction forces. In this context, it is advantageous if the threads 29 of the locking blocks 25 and the winding turns 30 of the helical compression springs 17 are matched in shape and dimension to each other so that at minimally deformed helical compression springs 17 in the in Fig. 1 shown basic position, the locking blocks 25 can be screwed under play in the winding turns 30 of the helical compression springs 17.

In the Fig. 7 to 11 an alternative embodiment of a synchronous mechanism according to the invention is shown. This differs from the embodiment according to Fig. 1 to 6 In order to avoid unnecessary repetition, therefore, components of the two embodiments of the synchronous mechanisms that match, provided with identical reference numerals and it can in this respect to the Description of the synchronous mechanism 1 according to Fig. 1 to 6 to get expelled.

The adjustment assembly 24 'for the counter-spring force of the two coil springs 17.1, 17.2 existing spring assembly 16 has to block Windungsgängen 30 of the coil springs 17 as locking members acting locking balls 36 which are arranged in radial recesses 37 of a disposed within the coil spring 17 support sleeve 38 , Like from the Fig. 7 to 11 becomes clear, are provided over the circumference of the support sleeve 38 evenly three longitudinally extending rows of radial recesses 37, each with a locking ball 36. The support sleeve 38 itself is fixed in the bearing block 19 of the seat support 6 with one end together with the corresponding front end 18 of the respective helical spring 17 and protrudes into the inner opening of this helical spring 17 approximately half the length. The outer diameter of the carrier sleeve 38 substantially corresponds to the free inner diameter of the respective helical spring 17. Its wall thickness is smaller than the diameter of the locking balls 36, so that in a position where they do not protrude beyond the outer contour of the carrier sleeve 38, into the inner opening of the carrier sleeve 38 stand in (see Fig. 7 . 8th ).

For actuating the locking balls 36 radially outwards, an actuating slide 40 which is displaceably mounted in the inner opening of the carrier sleeve 38 is provided which is divided in its longitudinal direction into a front release area 41, a rear stop area 42 and an intermediate conical transition 43. The actuating slide is between a maximum of the support sleeve 38 pulled forward release position ( Fig. 7 and 8th ) and a maximum in the support sleeve 38 inserted blocking position ( Fig. 9 and 10 ) by one as a whole displaceable with 44 designated drive device. This consists of the provided with a handle 32 adjusting shaft 31, as in the embodiment according to Fig. 1 to 6 Use finds. In the embodiment according to the Fig. 7 to 11 This adjusting shaft 31 drives a circulating toothed belt 45 via a driven gear 46. The toothed belt 45 is further on a Umlenkzahnrad 47 ( Fig. 8 and 10 ) and coupled via a transverse axis 48, each with a fixing eye 49 at the front ends of the actuating slide 40 with this. A rotation of the adjusting shaft 31 is thus converted into a circulating movement of the toothed belt 45, which in turn leads to a displacement of the actuating slide 40 in the longitudinal direction L within the support sleeve 38.

• In der in Fig. 7 und 8 dargestellten Freigabestellung steht den Sperrkugeln 36 der Freigabebereich 41 des Betätigungsschiebers 40 gegenüber. In diesem Freigabebereich, dessen Außendurchmesser deutlich geringer als der Innendurchmesser der Trägerhülse 38 ist, sind die Sperrkugeln 36 in die Trägerhülse 38 zurückgezogen. Somit können alle Windungsgänge 30 der Schraubenfedern 17 zur Gegen-Federkraft beitragen, bei einer Verschwenkung der Synchronmechanik wirkt also eine minimale Gegenkraft.

The adjustment of the counter-spring force of the coil springs 17 can be done as follows:

• In the in Fig. 7 and 8th shown release position is the locking balls 36 of the release portion 41 of the actuating slide 40 against. In this release region, whose outer diameter is significantly smaller than the inner diameter of the carrier sleeve 38, the locking balls 36 are retracted into the carrier sleeve 38. Thus, all Windungsgänge 30 of the coil springs 17 contribute to the counter-spring force, with a pivoting of the synchronizer mechanism thus acts a minimum drag.

For their adjustment, the adjusting shaft 31 is actuated, so that over the toothed belt 45, the actuating slide 40 are gradually inserted into the support sleeve 38. It is thus successively pushed from the front end of the coil springs 17 ago the locking balls 36 via the conical transition 43 radially outward and between the Windungsgänge 30 of the coil springs 17. Through the blocking area 42 they are in fixed this blocking position. With increasing depth of engagement of the actuating slide 40 thus engage more and more locking balls 36 between the winding turns 30 of the coil springs 17, so that these respective Windungsgänge 30 are blocked. They are no longer available for a spring deformation, so that for a given deflection of the synchronous mechanism, the still free Windungsgänge 30 must be more deformed. It thus sets a greater counter-spring force. The Fig. 9 to 11 show the maximum retracted position of the actuating slide 40, in which all the locking balls 36 engage radially outward between the corresponding winding turns 30 of the coil springs 17 and block them.

Claims (15)

Comprising synchronous mechanism for office chairs a base support (2) which can be placed on a chair column (4), a backrest support (5) pivotable about a transverse axis (7), pivotable on the base support (2), - A seat support (6) in the region of its front end via a hinge (11) about a transverse axis (12) pivotally and substantially in the seat longitudinal direction (L) displaceable with the base support (2) and in the region of its rear end about a transverse axis (13) is pivotally coupled to the backrest support (5), - A spring arrangement (16) for acting on the synchronous mechanism against the synchronous adjustment of the seat (6) and backrest support (5) with at least one coil spring (17), and an adjusting arrangement (24, 24 ') for the counter-spring force of the spring arrangement (16),
characterized in that - the adjusting arrangement (24, 24 ') one of one end (18) of the coil spring (17) in whose winding turns (30) with variable depth of engagement (E) einbringbare lock (25, 36, 38, 40), wherein the coil spring ( 17) in the region of the barrier (25, 36, 38, 40) acted upon Windungsgänge (30) are locked against a spring deformation. Synchronous mechanism according to claim 1, characterized in that the lock is a variable engagement depth (E) in the Windungsgänge (30) screw-lock block (25). Synchronous mechanism according to claim 2, characterized in that the locking block (25) is provided with an external thread (26) whose threads (29) have a pitch and cross-sectional shape which is complementary to the winding turns (30) of the helical spring (17). Synchronous mechanism according to claim 3, characterized in that the external thread (29) of the locking block (25) is dimensioned such that it can be screwed into it with a defined basic position of the coil spring (17) with slight play. Synchronous mechanism according to one of claims 2 to 4, characterized in that the blocking block (25) is telescopically displaceably mounted on a rotary drive pin (28) for rotation therewith. Synchronous mechanism according to claim 5, characterized in that rotary drive pin (28) and locking block (25) are rotatably mounted to each other via a groove-like in cross-section engagement contour. Synchronous mechanism according to claim 5 or 6, characterized in that the rotary drive pin (28) via a transmission (33, 34, 35) with a manually operable adjusting shaft (31) is coupled. Synchronous mechanism according to claim 1, characterized in that the lock comprises a plurality of within the coil spring (17) arranged locking members (36) which successively radially outwardly between the Windungsgänge (30) of the coil spring (17) to block at a variable depth of engagement (E) are insertable. Synchronous mechanism according to claim 8, characterized in that the locking members (36) in a within the coil spring (17) arranged support sleeve (38) slidably mounted in radial recesses (37) and of a successively insertable actuation slide (40) in the engaged position in the coil spring -Gewindegängen (30) are spendable. Synchronous mechanism according to claim 9, characterized in that the locking members are formed as locking balls (36) and the actuating slide (40) in its longitudinal direction in a release area (41) and a contrast enlarged locking area (42) is divided, wherein between release and blocking area (41, 42) of the actuating slide (40) has a conical transition (43). Synchronous mechanism according to claim 9 or 10, characterized in that the actuating slide (40) via a transmission, preferably a toothed belt transmission (45, 46, 47) with a manually operable adjusting shaft (31) is coupled. Synchronous mechanism according to one of the preceding claims, characterized in that the coil spring (17) at its the lock (25) facing the end (18) on a bearing block (19) on the seat support (6) is counteracted, the lock (25, 40) be upheld. Synchronous mechanism according to one of the preceding claims, characterized in that a symmetrical to the vertical central longitudinal plane (M) of the synchronous mechanism (1) arrangement of two substantially parallel to each other and the seat arranged coil springs (17.1, 17.2) in the seat support (6), each with an adjustment ( 24, 24 ') for the counter-spring force is provided. Synchronous mechanism according to claim 13, characterized in that the two adjusting arrangements (24, 24 ') via a common adjusting shaft (31) are actuated. Synchronous mechanism according to claim 14, characterized in that the adjusting shaft (31) in the front region of the seat support (6) arranged in the transverse direction and via a deflection gear (33; 45, 46, 47) with the at least one adjusting arrangement (24) is coupled, whose locks (25, 40) in the longitudinal direction (L) of the synchronous mechanism (1) are displaceable.

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