EP1971245B1 - Permanent-contact mechanism - Google Patents

Abstract

The invention relates to a permanent-contact mechanism (1) for an office chair or the like. In order to obtain a comparatively flat permanent-contact mechanism (1), it is proposed to provide it with a seat frame (3), which can be positioned on a chair upright, with a backrest support (7), which is arranged on the seat frame (3) such that it can be pivoted about a transverse axis (6), and with at least one spring-activated or inherently resilient lever element (27), which interacts with the backrest support (7) such that the backrest support (7) is always pivoted counter to a spring force, the position of the point of rotation (35) of the lever element (27) differing from the position of the transverse axis (6).

Description

The invention relates to a permanent contact mechanism for an office chair or the like.

Permanent contact mechanisms, which are also referred to as asynchronous mechanisms, are characterized in that a backrest is movably connected to a fixed seat. The backrest follows the movements of the seated person from a front (upright) to a back ("lying") position and vice versa. Permanent contact mechanisms thus promote and support frequently changing seating positions, which for orthopedic reasons, u.a. because of the associated mutual load of the discs, are desired.

In order to ensure a safe and pleasant movement, the pivoting of the backrest takes place mostly against the force of a spring component. Often there is also provided an adjustment for changing the spring force. A disadvantage of the known from the prior art solutions, however, is that the design elements required for adjusting the spring force, such as worm gears, threaded rods, etc., significantly increase the required height of the permanent contact mechanism.

From the pamphlets DE 42 35 691 A1 and GB 1 165 135 A Mechanisms are known with a seat frame placeable on a chair column and with a pivotable about a pivot axis arranged on the seat frame backrest support, which also have at least one spring-loaded or self-springing lever element which cooperates with the backrest support such that a pivoting of the backrest support always takes place against a spring force, wherein the position of the fulcrum of the lever element is different from the position of the pivot axis.

An object of the present invention is to provide a relatively flat-construction permanent contact mechanism, which also has a particularly stable construction.

This object is achieved by a permanent contact mechanism according to claim 1. Thereafter, a permanent contact mechanism is provided with a placeable on a chair column seat frame, with a pivotable about a transverse axis on the seat frame backrest support, with at least one spring-loaded or selbstfedernden lever element which interacts with the backrest support such that a pivoting of the backrest support is always against a spring force wherein the position of the fulcrum of the lever member is different from the position of the transverse axis.

A basic idea of the invention is the positioning of the lever fulcrum of the backrest support acting on the lever element on the one hand and the position of the transverse axis about which the backrest support is verschenkbar, on the other hand.

This constructive arrangement ensures that the mitbewegende with the backrest support lever element covers a different path length than the backrest support. This forms the basis for a structurally very simple and thus inexpensive spring force adjustment, which can also be realized in the smallest space, in particular under realization of a particularly low height of the permanent contact mechanism.

Another basic idea of the invention is to provide a Federkrafseinstellung without a (pre) tensioning of a spring element must be done. In particular, it has proven to be advantageous if the length of the effective lever arm by changing the position of the articulation point of a lever arm of the lever member to the backrest support is changeable, without work against the spring force must be performed. In other words, a particularly light, "powerless" spring force adjustment is realized.

A particularly stable construction is realized with very little use of material in that the position of the fulcrum of the lever element is located directly above the chair column.

Fig. 1

eine Permanentkontaktmechanik in einer Seitenansicht,

Fig. 2

eine Permanentkontaktmechanik in einer ersten Explosionsdarstellung,

Fig. 3

eine Permanentkontaktmechanik in einer zweiten Explosionsdarstellung,

Fig. 4

eine Permanentkontaktmechanik ohne Sitzplatte in einer perspektivischen Ansicht,

Fig. 5

eine Permanentkontaktmechanik ohne Sitzrahmen in einer perspektivischen Ansicht,

Fig. 6

eine Permanentkontaktmechanik in einer Schnittdarstellung entlang der Linie VI-VI in Fig. 4,

Fig. 7

eine schematische Darstellung der Lage des Kontaktschiebers in einer hinteren Position,

Fig. 8

eine schematische Darstellung der Lage des Kontaktschiebers in einer vorderen Position,

Fig. 9

eine Permanentkontaktmechanik in einer Schnittdarstellung entlang der Linie IX-IX in Fig. 6,

Fig. 10

eine Permanentkontaktmechanik in einer Schnittdarstellung entlang der Linie X-X in Fig. 6,

Fig. 11

eine Permanentkontaktmechanik in einer Schnittdarstellung entlang der Linie XI-XI in Fig. 6 in einer vorderen Position bei "leichter" Einstellung,

Fig. 12

eine Permanentkontaktmechanik in einer Schnittdarstellung entlang der Linie XI-XI in Fig. 6 in einer hinteren Position bei "leichter" Einstellung,

Fig. 13

eine Permanentkontaktmechanik in einer Schnittdarstellung entlang der Linie XI-XI in Fig. 6 in einer vorderen Position bei "härterer" Einstellung, und

Fig. 14

eine Permanentkontaktmechanik in einer Schnittdarstellung entlang der Linie XI-XI in Fig. 6 in einer hinteren Position bei "härterer" Einstellung.

An embodiment of the invention with further advantageous embodiments will be explained in more detail with reference to the drawings. Here are some simplified and schematic:

Fig. 1

a permanent contact mechanism in a side view,

Fig. 2

a permanent contact mechanism in a first exploded view,

Fig. 3

a permanent contact mechanism in a second exploded view,

Fig. 4

a permanent contact mechanism without seat plate in a perspective view,

Fig. 5

a permanent contact mechanism without a seat frame in a perspective view,

Fig. 6

a permanent contact mechanism in a sectional view along the line VI-VI in Fig. 4 .

Fig. 7

a schematic representation of the position of the contact slide in a rear position,

Fig. 8

a schematic representation of the position of the contact slide in a front position,

Fig. 9

a permanent contact mechanism in a sectional view taken along the line IX-IX in Fig. 6 .

Fig. 10

a permanent contact mechanism in a sectional view along the line XX in Fig. 6 .

Fig. 11

a permanent contact mechanism in a sectional view along the line XI-XI in Fig. 6 in a forward position with "lighter" setting,

Fig. 12

a permanent contact mechanism in a sectional view along the line XI-XI in Fig. 6 in a rear position with "lighter" setting,

Fig. 13

a permanent contact mechanism in a sectional view along the line XI-XI in Fig. 6 in a forward position at "harder" setting, and

Fig. 14

a permanent contact mechanism in a sectional view along the line XI-XI in Fig. 6 in a rear position with a "harder" setting.

The embodiment shows a permanent contact mechanism 1 for an office chair or the like, with a means of a cone holder 2 on the upper end of a chair column (not shown) placeable, fixed, ie non-movable seat frame 3 and with a mounted on the seat frame 3 seat plate 4, which forms a housing for the actual pivot mechanism together with the seat frame 3, see. Fig. 1 , The seat plate 4 extends significantly beyond the front edge 5 of the seat frame 3 addition. The seat frame is preferably made of a glass fiber reinforced plastic material (Pa6Gf30), while the seat plate is made of polypropylene.

In addition, the permanent contact mechanism 1 comprises a about a transverse pivot axis 6 pivotally mounted on the seat frame 3, in plan view forked backrest support 7, the cheeks 8 are arranged on both sides of the seat frame 3. On the seat plate 4, the seat is provided with a padded seat mounted, alternatively, instead of the seat plate 4 and a seat support or the like, the seat frame 3 close up (both not shown).

As in particular the Fig. 2 to 6 becomes clear, the entire permanent contact mechanism 1 with respect to a central longitudinal plane M (see. Fig. 4 ), which concerns the actual kinematics, constructed mirror-symmetrically. In that regard, it should always be assumed in the following description of pairwise existing construction elements of the actual swing mechanism.

On the backrest support 7, a backrest 9 is attached, see. Fig. 4 and 5 , For this purpose, the upper free ends of the backrest support 7 have a receiving device 11, which is designed for a pivotable mounting of the backrest 9 about a pivot axis 12, cf. Fig. 2 , The Backrest 9 can in other words perform a pendulum motion. This serves to effectively avoid lordosis separation. In other words, a permanent contact of the lumbar region of the seated with the backrest 9 is effected. This pivoting mechanism for the backrest 9 preferably also includes a spring element (not shown) for returning the backrest 9 to its normal position as soon as the sitting person stands up. For the execution of the pendulum movement, therefore, the sitter must overcome a certain spring force. The backrest is preferably made of plastic (Pa6).

The backrest support 7 is connected to the front end 13 of its cheek 8, which extends starting from a horizontally extending cheek main element 14 starting approximately in the area of the cone seat 2 obliquely upward, hingedly connected to the seat frame 3. For this purpose, a the two cheeks 8 connecting, hollow cross member 15 in provided on both sides of the seat frame 3 U-shaped recesses 16 and is held there by arranged in the interior of the seat frame 3 and from above mountable counterparts 17 with also U-shaped recesses 18 , see. Fig. 4 , whereby a pivot bearing for the backrest support 7 is formed.

The position of the pivot axis 6, by which the backrest support 7 can be pivoted, is in a position corresponding to the constructive edge parameters, which effectively minimizes the so-called "shirt pull-out effect". For this purpose, the pivot axis 6 is not arranged directly below the actual hip pivot point of the seated person, but is offset in relation to the actual hip pivot point in the direction of the front edge 5 of the seat frame 3. In particular, the pivot axis 6 is seen in the longitudinal direction 19 before the cone seat 2, so offset from the cone seat 2 in the direction of the seat leading edge 21. In addition, the pivot axis 6 is in the immediate vicinity of the seat frame 3 final seat plate. 4

The transverse strut 15 as an integral part of the backrest support 7 is integrally connected to a detent plate 22 which extends in the direction of the trailing edge 23 of the seat frame 3 and at least whose underside 24 extends parallel to the cheek main elements 14. This locking plate 22 performs each movement of the backrest support 7 in the pivoting direction 25 and thereby moves inside the seat frame 3. The backrest support 7 with all its components (locking plate 22, ...) is preferably made of Pa6Gf30.

Inside the seat frame 3, a spring arrangement is provided with two leg springs 27 which are aligned with one another in the transverse direction 26. These are torsion springs with two legs each. The shorter, fixed legs 28 point in the direction of the front edge 5 of the seat frame 3 and are supported in openings 29 provided in the underside 31 of the seat frame 3, through which they protrude outwards. The longer free leg 32 points in the direction of the trailing edge 23 of the seat frame 3. It is supported on a contact slider 33 described in more detail below, which is in mechanical interaction with the detent plate 22. The torsion springs 27 themselves lie in prisms 34 provided for this, which are designed as part of the seat frame 3.

The torsion springs 27 thus form lever elements which cooperate with the backrest support 7 such that a movement of the backrest support 7 in the pivoting direction 25 always against the spring force of the torsion springs 27 takes place. The two legs (fixed leg 28 and free leg 32) act as lever arms. The centers 35 of the leg springs 27 form the fulcrums of the lever elements and are spaced from the position of the pivot axis 6.

Particularly advantageous is a realized in this embodiment design, in which the centers 35 of the leg springs 27 at any time on a horizontal plane 36 (shown in FIG Fig. 10 ) are located with the center of the pivot axis 6, cf. Fig. 10 to 15. This arrangement allows a very low overall height of the permanent contact mechanism 8 and at the same time a sufficient adjustment of the backrest support and thus represents an optimal middle ground between height and adjustment.

Particularly advantageous is a realized in this embodiment further design in which the centers 35 of the torsion springs 27 are directly above the cone seat 2 and thus directly above the chair column. This has the advantage that all areas which are subject to a high force influence, namely the steel cone holder 2, the storage (shaft 46, ...) of the back carrier 7 and the storage (prism 34) of the leg spring 27, close to each other , A particularly stable construction can be realized with very little use of material.

The contact slide 33 arranged centrally in the seat frame 3 is substantially T-shaped and is preferably made of plastic (Pa6). On the lower sides 37 of its two T-legs 38 extending in the transverse direction 26 it has in each case one extending in the longitudinal direction 19 U-shaped groove 39. In these grooves 39 are the free legs 32 of the torsion springs 27 a. The free legs 32 of the leg springs 27 are supported in other words on the T-legs 38 of the contact slide 33 from.

On the underside 41 of the T-base 42 of the contact slide 33, a rack 43 is fixed, which cooperates with a gear 44 to form a rack and pinion. The gear 44 is disposed in a recess provided therefor 45 of the cross member 15 and mounted on a shaft 46 which extends in the interior of the cross member 15 and at the same time serves as a pivot axis 6 for the backrest support 7. To actuate the gear 44, an actuating element (not shown) is attached to one end of the shaft 46, for example a handwheel.

The top 47 of the contact slide 33 cooperates with the bottom 24 of the detent plate 22 as follows: At the point where the two T-legs 38 of the contact slide 33 abut, ie in a central position, there is a cuboid, from the top 47 after above in the direction of detent plate 22 and seat plate 4 protruding block 48, which is preferably integrally connected to the contact slide 33 for reasons of better mechanical strength and resilience.

Right and left of this block 48, a number of locking elements 49 is provided on the upper side 47 of the contact slide 33. These are evenly spaced, tooth-like, arranged in the transverse direction 26 latching steps. These extend in the direction of the free ends 51 of the T-legs 38 approximately to the middle of the T-legs 38, so that the top sides 52 of the T-leg 38 are free of latching elements 49 in the region of their free ends 51 and corresponding to the selected material have smooth surfaces.

The underside 24 of the detent plate 22 has a center in the longitudinal direction 19 extending rectangular opening 53. On both sides of the opening 53 extend in the longitudinal direction 19 in turn a number of locking elements 54. These are formed as counter-elements to the locking elements 49 on the upper side 47 of the contact slide 33. On both sides of the locking elements 54, that is on the lateral edge regions 55 of the underside 24 of the detent plate 22, the surface is again in accordance with the selected material smooth.

Contact slide 33 and detent plate 22 are arranged to each other such that the arranged on the upper side 47 of the contact slide 33 block 48, the detent plate 22 never touches, but always in the region of the rectangular opening 53 is arranged.

When the backrest support 7 is pivoted to a rear position, the free "active" legs 32 of the leg spring 27 travel a greater distance than the backrest support 7. In other words, the pivoting movement of the free legs 32 takes place over a greater angular range than the pivotal movement of the backrest support 7 In the process, shearing forces occur in the design elements involved.

Is the backrest support 7 in a pivoted, rear position (see. FIG. 12 and 14 ), so are the contact slide 33 in the direction of the trailing edge 23 of the seat frame 3 acting force components of the torsion springs 27 greater than the frictional forces between the smooth surfaces on the top 47 of the contact slide 33 and the bottom 24 of the detent plate 22. According to the invention therefore the locking elements 49, 54 of contact slide 33 and detent plate 22 in this position into one another interlocked and thereby form a self-holding Rastgesperre, cf. Fig. 7 and 10 , As a result, the shear forces can be absorbed, whereby the mechanical stability of the construction is ensured with a pivoted backrest support 7. At the same time, the smooth outer regions 56 of the T-legs 38 of the contact slide 33 bear against the smooth edge regions 55 of the latching plate underside 24.

As a result, this means that the contact slide 33 can no longer be displaced in the longitudinal direction 19. Therefore, no adjustment of the spring force of the torsion springs 27 can take place in this rear position. At the same time the mentioned construction elements are coordinated so that in the rear position of the backrest support 7 of the block 48 rests freely in the rectangular opening 53 and the bottom 57 of the seat plate 4 is not affected.

If the backrest support 7 in its forward position (see. Fig. 11 and 13 ), the distance 58 between the block 48 and the bottom 57 of the seat plate 4 decreases more and more, until the block 48 rests against the seat plate 4. The underside 57 of the seat plate 4 is designed accordingly.

If the backrest support 7 is then further pivoted into its front position (see pivoting direction 25 in FIG Fig. 7 ) the block 48 abuts against the immovable seat plate 4. This causes - as the contact slide 33 with the free ends 51 of its T-leg 38 on the free legs 32 of the torsion springs 27 is supported - a bending of the contact slide 33 in the head region, ie in the region of the T-leg 38. In this case, the contact slide 33rd the farther the backrest support 7 is pivoted back with its contact plate 22.

If the backrest support 7 is pivoted back into its starting position, the smooth outer regions 56 of the T-legs 38 of the contact slide 33 still rest against the smooth edge regions 55 of the latching plate underside 24. However, the locking elements 49, 54 of contact slide 33 and locking plate 22 are no longer interlocked, but are exposed, see. Fig. 8 , Since no shear forces occur in this position, a gearing is no longer required. On the contact slide 33 act in the direction of the trailing edge 23 of the seat frame 3 no force components of the torsion springs 27, since backrest support 7 and leg springs 27 are parallel to each other and the angle of rotation is zero.

As a result, this means that the contact slide 33 can now be moved in the longitudinal direction 19. An adjustment of the spring force of the torsion springs 27 can now take place.

To determine the front position serve blocking wedges 59 which are arranged in the interior of the seat frame 3 to a blocking device 60 and can be pivoted in the pivoting direction 61 from a rest position to a blocking position in which they attack with their free ends 62 on the bottom 24 of the locking plate 22 and a pivoting of the detent plate 22 and thus a pivoting of the Prevent backrest support 7. The blocking wedges 59 can be actuated by means of an actuating element, not shown, from outside the seat frame 3. For this purpose, a fastening for a Bowden cable is provided on the blocking device 60, by means of which the blocking device can be pivoted as a whole.

In a renewed pivoting of the backrest support 7 to the rear, a separation of the block 48 from the bottom 57 of the seat plate 4. This results in that the contact slide 33 relaxes again and the bottom 24 of the locking plate 22 approaches. The locking elements 49, 54 engage again, so that adjusting the spring force of the torsion springs 27 is again not possible.

To adjust the spring force in the forward position, the gear 44 is actuated, whereby a change in position of the contact slide 33 in the longitudinal direction 19 takes place. At the same time, the positions of the U-shaped grooves 39 on the free legs 32 of the leg springs 27 and thus the pivot points 63 of the leg springs 27 on the backrest support 7, which rests against the contact slide 33.

The Federkrafseinstellung now according to the invention "powerless", namely such that by changing the position of the pivot points 63 of the free leg 32 of the leg springs 27 on the locking plate 33 of the backrest support 7, the length of the effective lever arm - ie the smallest, ie vertical distance between the Line of action of the spring force and the fulcrum 35 - is changeable, without working against the spring force of the Leg springs 27 must be performed. This is a particularly light spring force adjustment possible.

The permanent contact mechanism can. "lighter" or "harder" are set. In a "light" setting (as in Fig. 4 . 5 . 9 . 10 . 11 and 12 shown) are the pivot points 63 in the grooves 39 on the T-legs 38 by means of the rack gear in the direction of the free ends 64 of the free legs 32 of the torsion springs 27 to move so that comparatively long lever arms arise. The pivoted state (see. Fig. 12 ) acting on the contact slide 33 toward the rear edge 23 of the seat frame 3 force components of the torsion springs 27 are comparatively small.

In a "hard" setting (as in Fig. 13 and 14 shown), the pivot points 63 are moved by means of the rack gear in the direction of the pivot points 35 of the torsion springs 27, so that there are comparatively short lever arms. The pivoted state (see. Fig. 12 ) acting on the contact slide 33 toward the rear edge 23 of the seat frame 3 force components of the torsion springs 27 are comparatively large.

With the construction described in the present invention, there is provided a per-pin contact mechanism 1 having an extremely flat configuration. This is achieved essentially by the inventive separation of the position of the pivot point 35 of the torsion springs 27 from the position of the pivot axis 6 of the backrest support 7.

Instead of a self-resilient lever element, such as the leg spring 27 used here, other constructive arrangements can of course be used to achieve the function according to the invention. In particular, non-resilient construction parts can be used as lever elements which are acted upon by a spring, for example a tension or compression spring.

LIST OF REFERENCE NUMBERS

1

Permanent contact mechanism

2

cone holder

3

seat frame

4

seat plate

5

Front edge of the seat frame

6

Swivel axis of the backrest support

7

Backrest support

8th

cheek

9

backrest

10

(free)

11

cradle

12

Swivel axis of the backrest

13

front end of the backrest support

14

Wangen main element

15

crossmember

16

recess

17

counterpart

18

recess

19

longitudinal direction

20

(free)

21

Front seat edge

22

detent plate

23

Rear edge of the seat frame

24

Bottom of the detent plate

25

pan direction

26

transversely

27

Leg spring

28

solid leg

29

opening

30

(free)

31

Bottom of the seat frame

32

free thigh

33

contact slide

34

prism

35

Center of the leg spring

36

horizontal plane

37

Bottom of the T-thigh

38

T-leg

39

groove

40

(free)

41

Bottom of the T-base

42

T-Base

43

rack

44

gear

45

recess

46

wave

47

Top of the contact slide

48

block

49

locking element

50

(free)

51

Freeing the T-thigh

52

Top of the T-thigh

53

opening

54

locking element

55

border area

56

outdoors

57

Bottom of the seat plate

58

distance

59

blocking wedge

60

blocking device

61

pan direction

62

Freeing of the blocking part

63

articulation

64

Freeing the free thigh

Claims (5)

1. Permanent contact mechanism (1) for an office chair or the like,

   - with a cone mount (2),

   - with a seat frame (3) placeable on a chair column by means of the cone mount (2),

   - with a chair back frame (7) arranged pivotably about a pivot axis (6) on the seat frame (3),

   - with at least one spring-loaded or intrinsically resilient lever element (27) which cooperates with the chair back frame (7) such that pivoting of the chair back frame (7) occurs constantly against a resilient force, characterized in that the position of the lever fulcrum (35) of the lever element (27) is different from the position of the pivot axis (6) and is located directly above the cone mount (2).
2. Permanent contact mechanism (1) according to Claim 1, wherein the position of the lever fulcrum (35) of the lever element (27) is substantially on a horizontal plane with the position of the pivot axis (6).
3. Permanent contact mechanism (1) according to Claim 1 or 2, with a resilient force adjustment such that the length of the effective lever arm can be changed without effort having to be directed against the resilient force via a change in the position of the articulation point (63) of a lever arm (32) of the lever element (27) on the chair back frame (7).
4. Permanent contact mechanism (1) according to Claim 3, wherein a change in the position of the articulation point (63) takes place via shifting a contact element (33) arranged between chair back frame (7) and lever arm (32) on the lever arm (32), whenever the chair back frame (7) is in a non-pivoted position.
5. Permanent contact mechanism (1) according to Claim 4, wherein shifting of the contact element (33) when the chair back frame (7) is in a pivoted position is prevented by a device (22) arranged on the chair back frame (7) itself.

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