EP2070446A1 - Office chair with adjustable backrest and means to limit the slope of the backrest - Google Patents

Abstract

The chair has an adjustable backrest (20) and a seat (10) tiltably coupled with the backrest over a synchronous mechanism that includes a housing (30) arranged at a seat, where the seat is supported at the housing by a front seat guide. A hand wheel is attached at a front seat guide (60), movable with the seat guide and coupled with a limiting unit such as pulley wheel and limit stop, by bowden cables for limiting inclination of the backrest. The limiting unit is mounted in a housing in a fixed manner. The limit stop is provided for a pin connected with the backrest.

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 the synchronous mechanism comprises a disposed under the seat housing, on which the seat is mounted on a front seat handlebar and means for limiting the possible inclination the backrest in the housing mounted fixed and adjustable by a handwheel.

STATE OF THE ART

Such an office chair is off EP 1 716 785 known. In this chair, the handwheel for adjusting the stationary mounted in the housing means for limiting the possible inclination of the backrest is also mounted stationary in the housing. The front seat link is relatively short and serves only to compensate for differences caused by the forced coupling of the seat with the backrest in view of the fact that these parts are hinged to different axes of rotation in the housing.

A general problem with office chairs with synchronous mechanism is a more or less pronounced iliac crest or lordosis loss and the so-called "shirt extraction effect", these effects on the change in the distances between the following reference points in the inclination of the seat and back can be attributed to a hip point on the Hip joint axis of the user, this point being assumed to be fixed relative to the seat; a iliac crest point at the front of the backrest at the level of the iliac crest bones of the user; and one Lumbar point also on 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.

PRESENTATION OF THE INVENTION

The invention is according to claim 1, an office chair of the type mentioned, in which the handwheel is mounted on the front seat link, moves with this and is coupled via Bowden cables with the stationary mounted in the housing means for limiting the possible inclination of the backrest.
The inventive design makes it possible to perform the front seat link much longer than necessary to compensate for the mentioned tolerances and move the seat with increasing inclination so far back against the backrest, that the mentioned iliac crest and lordosis losses or the mentioned shirt extraction effect largely avoided and without causing the handwheel to adjust the inclination limiting the backrest out of reach of the person sitting on the chair and can still be reached by this comfortable by hand.

By the Bowden cables, the relative displacement between the handwheel and the housing fixedly arranged means for limiting the possible inclination of the backrest is compensated.

Advantageous embodiments of the invention are characterized in the dependent claims.

Thereafter, in the housing fixedly mounted means for limiting the possible inclination of the backrest, for example, include a multi-stepped stepped end stop and a rotatably connected to the backrest Pawl, which can be brought by an adjustable positive guidance in the inclination of the backrest either in abutment at the different stages of the fixed end stop.

The adjustable positive guide may comprise a fixedly mounted in the housing sheave with a guide cam which engages in a guide slot of the pawl.

The Bowden cables serve in this case for rotational coupling of the handwheel with the pulley in both directions of rotation and are preferably each attached in opposite directions to this.

For elastic fixation of the adjustment in certain positions, the pulley can be fixed elastically in several rotational positions by elastic engagement of a cam in locking recesses.

BRIEF EXPLANATION OF THE FIGURES

Fig. 1

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

Fig. 2

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

Fig. 3

die Neigemechanik des Bürostuhls von Fig. 1 jedoch ohne das sie an sich einschliessende Gehäuse, in ihrer Position mit geringster Neigung der Rückenlehne;

Fig. 4

in einer Darstellung gemäss Fig. 3 die Neigemechanik in einer Position mit teilweise begrenzter Neigung der Rückenlehne;

Fig. 6

in vergrösserter Darstellung den Teil der Neigemechanik von Fig. 4, der eine einstellbare Begrenzung der Neigung der Rückenlehne bewirkt;

Fig. 6

in einer Darstellung gemäss Fig. 5 die Neigemechanik mit noch stärker begrenzter Neigung der Rückenlehne;

Fig. 7

die Teile zur Neigungsbegrenzung in perpektivischer Darstellung; und

Fig. 8

die Teile zur der Neigungsbegrenzung separat sowie jeweils in Ansicht von ihrer entgegengesetzten Seite her dargestellt.

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

Fig. 1

an office chair according to the invention with the backrest in its lowest inclination position;

Fig. 2

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

Fig. 3

the tilt mechanism of the office chair of Fig. 1 however, without the housing enclosing it, in its position with the least inclination of the backrest;

Fig. 4

in a representation according to Fig. 3 the tilting mechanism in a position with partially limited inclination of the backrest;

Fig. 6

in an enlarged view the part of the tilt mechanism of Fig. 4 which causes an adjustable limitation of the inclination of the backrest;

Fig. 6

in a representation according to Fig. 5 the tilt mechanism with even more limited backrest tilt;

Fig. 7

the parts for inclination limiting in perpektivischer representation; and

Fig. 8

the parts for the tilt limitation shown separately and in each case in view from its opposite side.

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 mounted in a arranged under the seat 10, housing 30 pivotally. The housing 30 is supported by a pedestal 40 and is part of or incorporates parts of a synchronous mechanism for positively coupling the seat 10 to the seat back. The seat 10 has a lower seat panel 11 and an upper padding 12 thereon. The backrest 20 comprises a backrest support 21 and also a backrest plate 22, which is also provided with a padding 23.

Fig. 1 shows the seat 10 and the backrest 20 of their basic position with the lowest inclination, while Fig. 2 shows the seat 10 and the backrest 20 in their position with maximum inclination. Seat 10 and backrest 20 can only move together because of their mentioned positive coupling. At maximum inclination, the seat 10 is pivoted through an angle of 9.5 ° and the backrest 20 at an angle of 28.5 ° to the home position, so that the inclination 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 virtually no iliac crest and Lordosenverlust and also the mentioned "shirt extraction effect" does not occur.

The displacement of the seat 10 against the backrest 20 with inclination of the backrest 20 results from the articulation of the seat 10 on the housing 30 via a rear 50 and a front seat link 60 and by a positive coupling means of a connecting rod 70 (FIGS. Fig. 7 ) between the rear seat link 50 and a bearing 25 on the backrest support 21, wherein the backrest support 21 to a bearing 24th is mounted on the housing 30. The two seat links 50 and 60 are designed to be relatively long, so that the seat 10 is arranged significantly elevated above the housing 30.

To limit the possible inclination of the backrest and, connected to it, the seat 10 in a plurality of discrete positions 30 means are provided in the housing, which are adjustable via a hand wheel 63. These means comprise a fixedly mounted in the housing, multi-stepped graduated end stop 31 for a hinged to the aforementioned bearing 25 of the backrest support 21 pawl 26 and a housing 30 also fixedly mounted pulley 32 with a guide cam 33 in a guide slot 27 of the pawl 26 engages.

The hand wheel 63 is attached to the upper end of the front seat handlebar 60 where it is easily accessible by the user of the chair sitting by hand. If it were, as provided in the prior art, mounted on the housing 30, it would be located relatively low under the seat 10 because of the long Sitzlenlenker and there for the user is no longer so easily accessible.

The arrangement of the hand wheel 63 on the front seat arm 60 has the consequence that it moves with this. To compensate for this movement, the handwheel 63 is rotatably coupled to the stationary pulley 32 via two flexible bottom cables 64 and 65. The two Bowden cables are in each case coupled in opposite directions with the hand wheel 63 or a cable ring 66 mounted on its axis in a rotationally fixed manner, so that an adjustment of the cable pulley 32 in both directions of rotation with the handwheel 63 is possible.

The two bottom lines 64, 65 are preferably like this Fig. 8 shows executed with a common pull cable 67, whose two ends is fixed to the sheave 32 and the center of the ring 66 is / are.

By rotating the sheave 32 by turning the handwheel 63, the position of the guide cam 33 on the sheave 32 can be changed.

In the inclination of the backrest 30 of the backrest support 21 pivoted in the representation of FIGS. 1-7 clockwise about the bearing 24, wherein the am Bearing 25 hinged pawl 26 is pivoted against the stepped end stop 31 back. The guide cam 33 on the pulley 32 controlled by its engagement in the guide slot 27, the tip of the pawl 26 against a certain stage of this end stop 31, whereby the possible inclination of the backrest 20 is more or less limited. By changing the position of the guide cam 33, the desired tilt limit can be changed and adjusted.

In Fig. 3 the backrest is not or only slightly inclined, so that the tip of the pawl 26 is still spaced from the end stop 31. In Fig. 4 the backrest is more inclined and the tip of the pawl 26 are in abutment with the uppermost step of the end stop 31, whereby a further inclination is prevented. Fig. 5 shows the same conditions in an enlarged section. In Fig. 6 is the tip of the pawl 26 in abutment at the lowest level of the end stop 31, whereby the inclination of the backrest is already limited at a lower inclination angle. In the FIGS. 5 and 6 are clearly the two different rotational positions of the pulley 32 and the guide cam 33 can be seen, which have the stop of the pawl 26 at the two different stages of the end stop 31 result.

Thus, the pawl 26 always comes clearly with a certain stage of the end stop 31 into engagement, the pulley 32 may be elastically fixed in a plurality of defined rotational positions by elastic engagement of an integrally formed locking cam in locking recesses of an adjacent wall. In Fig. 8 Such a locking cam 34 on the back of the sheave 32 and also such an adjacent wall 35 are shown. The locking recesses for the locking cam 34 are located at the in Fig. 8 invisible front of the wall 35.

In Fig. 8 are on the sheave 32 and the ring 66 and the cylinder nipple 68 and 69 of the pull cable 67 can be seen, with which this fixed to the pulley 32 and the ring 66. is. The two cams 36 on the pulley 32 serve as end stops for their rotation.

NAME LIST

10

Seat

11

seat plate

12

upholstery

20

backrest

21

backrest support

23

upholstery

22

Back panel.

30

casing

40

pedestal

50

rear seat handlebar

24

Bearing of the backrest support on the housing

25

Bearing 25 on the backrest carrier

26

pawl

27

Guide slot 27 of the pawl

31

graduated end stop

32

sheave

33

guide cam

34

locking cams

35

wall

36

cam

60

front seat handlebar

63

handwheel

64

Bowden

65

Bowden

66

rope ring

67

rope

68

cylinder nipple

69

cylinder nipple

70

connecting rod

PH

hip point

PB

Iliac crest point

PL

Lordosenpunkt

Claims (5)

An office chair with a tiltable backrest (20) and a seat (10) forcibly coupled to the backrest via a synchronous mechanism, the synchronizing mechanism comprising a housing (30) arranged under the seat, on which the seat is mounted via a front seat link (60) and wherein means (31, 32) are mounted for limiting the possible inclination of the backrest in the housing fixed and adjustable by a handwheel (63), characterized in that the handwheel (63) is mounted on the front seat link (60) moves with this and via Bowden cables (64, 65) is coupled to the fixedly mounted in the housing means for limiting the possible inclination of the backrest. An office chair according to claim 1, characterized in that the means fixed in the housing for limiting the possible inclination of the backrest comprise a multi-stepped stepped end stop (31) for a rotatably connected to the backrest pawl (26) and an adjustable positive guide, by which at the inclination of the backrest, the pawl can be selectively brought into abutment at the different stages of the fixed end stop. An office chair according to claim 2, characterized in that the adjustable positive guide comprises a fixedly mounted in the housing sheave (32) with a guide cam (33) which engages in a guide slot (27) of the pawl (26). An office chair according to claim 4, characterized in that the Bowden cables (64, 65) for rotational coupling of the handwheel (63) with the sheave (32) serve in both directions of rotation and are each gegensinning attached to this. Office chair according to one of claims 3 or 4, characterized in that the pulley (32) is resiliently fixed in several rotational positions by elastic engagement of a latching cam (34) in locking recesses.

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