EP2070444B1 - Office chair - Google Patents

Abstract

The chair has an inclinable seat (10) forcibly coupled with an inclinable backrest (20) by a synchronous mechanism. The mechanism includes a housing (30) arranged below the seat. The seat is supported at the housing by a rear seat guide (50) with a housing-fixed bearing and a seat-fixed bearing. The backrest is supported at the housing in another housing-fixed bearing. The forcible coupling between the seat and the backrest in the housing is produced by a connection rod between the backrest and the guide, so that the seat is adjusted during the inclination of the backrest rearward to the seat.

Description

TECHNICAL AREA

The present invention relates to an office chair with tiltable backrest and a forcibly coupled via a synchronous mechanism with the backrest tiltable seat, wherein a pivoting movement of the backrest induces a downward movement of the rückwertigen part of the seat, wherein the synchronous mechanism comprises a housing disposed under the seat, on which the seat is mounted on a rear seat link with a first fixed housing and a second seat-fixed bearing.

STATE OF THE ART

Such an office chair is for example off DE 199 21 153 A1 known, wherein the seat is also mounted at its front end via a seat link in the housing. A pivotal 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 part of the seat, which is superimposed on a displacement of the seat to the rear. By the backrest is stored, inter alia, in the seat-fixed bearing of the rear seat arm, the distance between the seat and backrest, however, remains unchanged.

Out DE 100 48 783 A1 a chair is known with synchronous mechanism, wherein the distance of the seat from the backrest can be changed in order to change the seat inclination between two positions.

Out DE 86 14 186 U1 is a chair with tilting backrest known.

The object of the synchronous mechanism is to allow a dynamic sitting, in which the user can change his sitting posture between a front, substantially upright and a rear, slightly reclined sitting posture. The Synchronous mechanics should support the user in the best possible way. For design, practical and ergonomic reasons, however, must always be made in the realization of synchronous mechanisms compromises, so that a certain design can not meet all ergonomic requirements at once optimally. Typical weak points of known constructions including the aforementioned are a more or less marked iliac crest and / or lordosis loss and the so-called "shirt extraction effect".

For metrological and numerical recording of these effects, three reference points can be defined as follows: A hip point on the user's hip joint axis, this point being assumed to be fixed relative to the seat; a iliac crest on the front of the backrest at the level of the iliac crest of the user; and a lumbar point also at the front of the backrest but at the level of the user's lumbar spine.

A iliac crest loss occurs when starting from the anterior sitting posture in which the user has contact with the iliac crest by appropriate choice of his sitting position and thus the hip joint point on the seat, increasing the distance between the hip point and the iliac crest when reclining and thereby increasing the user's comfort loses this contact. The same applies to the loss of lordosis. The "shirt pull-out effect" occurs when the backrest is displaced parallel to the back of the user during pivoting under friction.

Another problem of known synchronous mechanisms is the so-called "whipping". This is a deflection with subsequent back-rest of the backrest, which is triggered by the user dropping "with momentum" on the seat.

PRESENTATION OF THE INVENTION

The invention has as its object to provide an office chair of the type mentioned, in which the iliac crest and lordosis loss and the "shirt extraction effect" over known constructions are reduced to a level that is at least no longer relevant to the user. In addition, the "whipping" should be avoided.

This object is achieved by an office chair with the features of claim 1. The inventive office chair is therefore characterized in that the backrest is mounted on the housing in a third housing fixed bearing and that the forced coupling between the seat and the backrest in the housing via at least one Connecting rod between the backrest and the rear seat handlebar and is translated so that the seat moves backwards towards the backrest with the inclination of the backrest and that the seat and the backrest are biased by a spring assembly (80) against a position of lowest inclination ,

Due to the displacement of the seat relative to the backrest, the distance between the hip point on the one hand and the iliac crest or lumbar point on the other hand can be kept substantially constant in all inclinations, so that it can not lead to a noticeable iliac crest / lordosis loss. In addition, due to the constant distances, a friction effect between the backrest and the back of the user is avoided, so that even the described "shirt pull-out effect" can not occur.

The inventive storage of the seat on the rear seat handlebars on the first, fixed bearing housing finally allows in a simple way to avoid the "whipping", provided that the lever arm between the first and the second bearing of the rear seat steering in the position with the lowest inclination of the seat and the backrest is aligned substantially vertically, as is the subject of claim 2.

Further preferred embodiments are characterized in the dependent claims 2-7.

BRIEF EXPLANATION OF THE FIGURES

Fig. 1

einen Bürostuhl nach der Erfindung mit dem Sitz und der Rückenlehne in ihrer Position mit geringster Neigung;

Fig. 2

den Bürostuhl von Fig. 1 mit dem Sitz und der Rückenlehne in ihrer Position mit maximaler Neigung;

Fig. 3

die Synchronmechanik des Bürostuhls von Fig. 1 in ihrer Position mit geringster Neigung, wobei die vordere Gehäuseschale weggelassen ist, um den Blick in das Innere des Gehäuses und auf die darin angeordneten Teile freizugeben;

Fig. 4

die Synchronmechnik von Fig. 3, wobei zusätzlich die Rückenlehne weggelassen wurde;

Fig. 5

in einer Darstellung gemäss Fig. 3 die Synchronmechanik in ihrer Position mit maximaler Neigung;

Fig. 6

in einer Darstellung gemäss Fig. 4 die Synchronmechanik in ihrer Position mit maximaler Neigung; und

Fig. 7

die Synchronmechanik unter a) in perspektivischer und unter b) in Explosionsdarstellung.

The invention will be explained in more detail with reference to an embodiment in conjunction with the drawings. Show it:

Fig. 1

an office chair according to the invention with the seat and the backrest in their lowest inclination position;

Fig. 2

the office chair of Fig. 1 with the seat and the backrest in their position with maximum inclination;

Fig. 3

the synchronous mechanism of the office chair of Fig. 1 in its lowest inclination position, with the front housing shell omitted to reveal the view of the interior of the housing and the parts disposed therein;

Fig. 4

the synchronous technique of Fig. 3 in addition, the backrest has been omitted;

Fig. 5

in a representation according to Fig. 3 the synchronous mechanism in its position with maximum inclination;

Fig. 6

in a representation according to Fig. 4 the synchronous mechanism in its position with maximum inclination; and

Fig. 7

the synchronous mechanism under a) in perspective and b) in an exploded view.

WAYS FOR CARRYING OUT THE INVENTION

At the office chair of Fig. 1 and 2 Denote 10 the seat and 20, the backrest, which are each pivotally mounted in a housing 10 arranged under the housing 30. The housing 30 is supported by a pedestal 40 and is part or includes parts of a synchronous mechanism for positive coupling of the seat 10 with the backrest 20. Due to the forced coupling seat 10 and backrest 20 can only move together. The seat 10 has a lower seat plate 11 and thereon a seat pad 12. The backrest 20 comprises a backrest support 21 and also provided with a padding 23 backrest plate 22. The backrest support 21 is fork-shaped and surrounds the housing 30 with two arms from both sides, wherein in the FIGS. 1 . 2 only the front arm can be seen.

Fig. 1 shows the seat 10 and the backrest 20 of their basic position, each with the lowest inclination, wherein the backrest plate 22 of the backrest 20 is approximately perpendicular. Fig. 2 shows the seat 10 and the backrest 20 in its position with maximum inclination shows, the seat 10 pivoted by an angle of 9.5 ° and the backrest 20 by an angle of 28.5 ° relative to the basic position are such that the tilt ratio is about 3: 1. In addition, the seat 10 is in the position of Fig. 2 towards the basic position of Fig. 1 horizontally 36 mm shifted backwards against the backrest 20. The distances between the hip joint point PH and the iliac crest point PB and between the hip joint point PH and the lordosis point PL are thus approximately the same in both illustrated positions. The changes in the distance between the two positions are less than 10%. This results in the office chair shown no noticeable iliac crest and lordosis and also the mentioned "shirt extraction effect" does not occur.

Like this in Fig. 7 can be seen, the housing 30 is divided into two along a central vertical plane and has two mirror-image housing shells 31. Incidentally, as far as that is of importance for the present invention, the synchronous mechanism is also constructed in mirror image to this vertical plane. As already described, this also applies to the backrest carrier 21. The further description is therefore limited to the structure of only one of the two game-pictorial halves.

In its rear region, the seat 10 is mounted via a rear seat link 50 with a bearing 51 fixed to the housing, arranged behind the pedestal 40, and a seat-fixed bearing 52. In the in Fig. 4 In the illustrated basic position, the rear seat handle 50 is oriented approximately vertically.

In the region of its front edge of the seat 10 is mounted on a front seat arm 60 with a housing-fixed bearing 61 and a seat-fixed bearing 62. The backrest support 21 is, as in Fig. 3 can be seen, stored in a housing-fixed, arranged in front of the pedestal 40 bearing 24.

The positive coupling between the seat 10 and the backrest 20 is made via a connecting rod 70, which is hinged to the rear seat arm 50 in a bearing 53 below the housing 51 fixed to the bearing. The rear seat link 50 is extended beyond the bearing 51 out with a handlebar down and thereby forms a two-armed lever. On the backrest support 21, the connecting rod 70 is articulated in a bearing 25 below the housing-fixed bearing 24. The distance or lever arm between the bearings 51 and 53 am rear seat link 50 is shorter and only about half as long as the distance or lever arm between the bearings 24 and 25 on the backrest support 21st

With an inclination of the backrest 20 of the backrest support 21 pivots and with him the bearing 24, on which the connecting rod 70 is hinged, clockwise about the housing fixed bearing 24. The connecting rod 70 exerts a train on the lower bearing 53 of the rear seat steering 50 and also twists this around its housing-fixed bearing 51 in a clockwise direction. Because of the different length lever arms between the bearings 24 and 25 on the one hand and the bearings 51 and 53 on the other hand, the rear seat link 50 rotates at a greater angle than the backrest 20. By comparing the Figures 3 or 4 with the FIGS. 5 or 6 , which each show the position with the maximum inclination of the backrest, this is clearly visible. Due to the different angle of rotation of the seat 10, as determined by comparing the Figures 3 or 4 with the FIGS. 5 or 6 can also be seen, moved backwards against the backrest 10 out. This shift follows the front seat link 60, where it pivots about its housing fixed bearing 61.

Between the bearing 25 on the backrest support and an adjustable point on the front seat arm 60, a spring 80 is clamped, which is compressed at inclination of the backrest 20 and the backrest 20 is acted upon by a restoring force in its basic position. Upon return of the seat back 20 from an inclined position, the connecting rod 70 acts as a push rod and rotates the rear seat handle 50 counterclockwise.

Due to the mounting of the seat 10 on the substantially vertically oriented rear seat arm 50 on the housing-fixed bearing 51, it can not come to a tilt adjustment under load of the seat 10 without leaning against the backrest 20. For a tilt adjustment, it comes only by pushing back the backrest 20 against the action of the spring 80. A whipping of the backrest 20 in shock-like load of the seat 10, as occurs in other synchronous mechanisms, is thereby avoided.

NAME LIST

10

Seat

11

lower seat plate

12

seat upholstery

20

backrest

21

backrest support

23

upholstery

22

back panel

24

fixed bearing of the backrest carrier

25

Bearing of connecting rod on backrest support

30

casing

31

housing shells

40

pedestal

50

rear seat handlebar

51

fixed to the housing of the rear seat arm

52

seat-tight bearing of the rear seat arm

53

Bearing of the connecting rod on the rear seat handlebar

60

front seat handlebar

61

fixed to the housing of the front seat arm

62

seat-proof bearing of the front seat arm

70

connecting rod

80

feather

PH

hip point

PB

Iliac crest point

PL

Lordosenpunkt

Claims (7)

1. Office chair with an inclinable back rest (20) and an inclinable seat (10) coupled for automatic inclination with the back rest by way of a synchronous mechanism, a backwards swivelling movement of the back rest inducing a lowering movement of the rear part of the seat, the synchronous mechanism comprising a housing (30) arranged under the seat, on which housing (30) the seat is mounted by way of a rear seat link (50) with a first bearing (51) attached to the housing and a second bearing (52) attached to the seat, characterised in that the back rest is mounted on the housing at a third bearing (24) attached to the housing and in that the coupling for automatic inclination between the seat and the back rest is produced in the housing by way of at least one connecting rod (70) between the back rest and the rear seat link with transmission such that the seat is displaced towards the back rest when the latter is inclined backwards, and in that the seat and the back rest are pretensioned by a spring arrangement (80) towards a position with the least possible inclination.
2. Office chair according to Claim 1, characterised in that in the position with the least possible inclination the rear seat link (50) is oriented substantially vertically.
3. Office chair according to either one of Claims 1 or 2, characterised in that the first fixed bearing (51) for the rear seat link (50) is arranged in the housing (30) behind the third fixed bearing (24) for the back rest (20).
4. Office chair according to any one of Claims 1 - 3, characterised in that the at least one connecting rod (70) is coupled to the rear seat link (50) at a fourth bearing (53) below the first bearing (51) thereof, in that the at least one connecting rod (70) is coupled to the back rest (20) at a fifth bearing (25) below the third bearing (24) thereof and in that the lever arm between the first bearing (51) and the fourth bearing (53) is shorter than the lever arm between the third bearing (24) and the fifth bearing (25).
5. Office chair according to any one of Claims 1-4, characterised in that the seat (19) is mounted at its front edge by way of a front seat link (60) in the housing (30).
6. Seating according to any one of Claims 1 - 5, characterised in that the ratio of inclination between the back rest (20) and the seat (10) is between 2.8:1 and 3.2:1 and in that, when the back rest is inclined by 26 - 30°, the seat is displaced horizontally by a distance of 30 - 40 mm.
7. SeaLing according to any one of Claims 1 - 6, characterised in that, when the back rest (20) is inclined, the seat is displaced towards the back rest to such an extent that the distances between the hip point (PH) and the lumbar point (PL) and between the hip point (PH) and the pelvic point (PB) change by at most 10%.

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