ES2342030T3 - 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

Office chair.

Technical field

The present invention relates to a chair of office with a tiltable backrest and a tilt-coupled seat necessarily with the backrest through a mechanism of synchronization so that when the backrest turns towards back, induces a downward movement of the back of the seat. The synchronization mechanism comprises a housing placed under the seat in which said seat is housed through a rear seat guide with a first fixed bearing in the housing and a second fixed bearing in the seat.

State of the art

Chairs of this type are known as, by example, the one presented by DE 199 21 153 A1, in this case the front end of the seat is also housed in the housing to through a seat guide. A backward turn of the backrest -like the one that can occur, for example, when the user of the chair reclines on the backrest - induces a downward movement from the back of the seat to which a seat shift back. Now the distance between the seat and the backrest remains unchanged due, between other things, that the backrest is housed in the fixed bearing in the seat of the rear seat guide.

DE 100 48 783 A1 also announces a chair with synchronization mechanism in which it can be modified the distance of the seat from the backrest in order to change the seat tilt between two positions.

DE 86 14 186 U1 unveils a chair with tilt backrest.

The role of the synchronization mechanism is to make possible a dynamic seat that allows the user  change the seating position from a previous position essentially upright to a somewhat horizontal rear position. He synchronization mechanism should provide the best possible support to user during this process. Now, due to reasons both constructive as practical and ergonomic, when performing mechanisms synchronization always have to adopt compromise solutions which means that a certain construction cannot satisfy at once all ergonomic requirements optimally. The weak points typical of known constructions, including those already mentioned, are a more or less pronounced loss of the crest  iliac and / or lordosis as well as the so-called "effect of removing Shirt".

To record these effects with techniques of measurement, so that they can be evaluated numerically, They can set three benchmarks as follows: a point of the hip on the axis of the user's hip joint which can be considered fixed in relation to the seat, a point of the iliac crest on the front face of the backrest at the height of the bones of the user's iliac crest and a point of lordosis also located on the front face of the backrest but at the height of the user's vertebral vertebrae.

Loss of the iliac crest occurs when, starting from the front seat position in which the user has contact with the point of the iliac crest by choosing adequate position on the seat and with it from the point of the hip joint, when lying back the distance between the point of the hip and the point of the iliac crest increases and, as a consequence, the user loses contact. The same can be told of the loss of lordosis. The "effect of taking off the shirt "occurs when the backrest takes place when turning Shifts parallel to the user's back with friction.

Another problem of the mechanisms of Known synchronization is the so-called "whiplash". In this case it is an adaptation movement with the subsequent abrupt backing of the backrest because the user is dropped "with momentum" in the seat.

Explanation of the invention.

This invention has been proposed as a task present an office chair of the type mentioned at the beginning in which the loss of the iliac crest and lordosis as well as the "effect of taking off his shirt" are reduced until such point against known constructions that at least no longer are relevant to the user. In addition, the "lash".

This objective is achieved, according to the invention, with an office chair with the characteristics set forth in patent claim 1. Thus the office chair according to the invention is characterized in that the backrest is housed in the housing in a third fixed bearing in the housing and the forced coupling between the seat and the backrest is produced in the housing through at least one tie bar between the backrest and the rear guide of the seat and is transmitted in such a way that, when tilting towards behind the backrest, the seat moves towards him and both, seat and backrest, are prestressed by means of a spring arrangement (80) towards a position with minimum inclination.

By moving the seat in relationship to the backup is essentially to keep the distance between the hip point on one side and the point of the iliac crest or lordosis point by another in all inclined positions, so that a noticeable loss of the iliac crest or lordosis. Also, at keeping these distances constant also avoids the effect of friction between the back and back of the user so that The "effect of taking off your shirt" can no longer occur described above

Finally, the seat housing, as to the invention, through the rear seat guide in the First fixed bearing in the housing allows to avoid easily the "whiplash", provided that the lever arm enters the first and the second bearing of the rear seat guide is arranged essentially vertically in the position with minimum inclination of the seat and backrest, as contemplated in the patent claim number 2

In claims derived from 2 to 7 Other preferred configurations are described.

Brief description of the drawings

The invention is detailed below by Examples of embodiment together with the corresponding drawings. The Drawings show the following:

Figure 1 an office chair according to the invention with the seat and backrest in its minimum position inclination;

Figure 2 the office chair of Figure 1 with the seat and the backrest in its position of maximum inclination;

Figure 3 the synchronization mechanism of the office chair of figure 1 in its minimum position tilt, in which the front cover of the housing to see the inside of it and the parts placed inside;

Figure 4 the synchronization mechanism of the Figure 3, the backup has also been deleted;

Figure 5 the synchronization mechanism in its position of maximum inclination in a representation according to figure 3;

Figure 6 the synchronization mechanism in its position of maximum inclination in a representation according to figure 4; Y

Figure 7 the synchronization mechanism in a) perspective and b) representation in exploded view

Modes of execution of the invention

In the office chair of figures 1 and 2 the number 10 designates the seat and 20 the backrest which in turn are rotatably housed in a housing 30 located under the seat 10. Housing 30 is supported by a vertical column 40 and is part or contains parts of a mechanism of synchronization for the forced coupling of the seat 10 with the backrest 20. Thanks to this coupling, seat 10 and backrest 20 can only move together. Seat 10 has a bottom seat plate 11 on which there is a padding of seat 12. The backrest 20 comprises a backrest support 21 as well as a backing plate 22 also provided with a padding 23. The support of the backrest 21 is made in the form of fork and grabs the housing 30 with two arms on both sides, although in figures 1 and 2 only the arm is seen Forward.

Figure 1 shows the seat 10 and the backrest 20 in its basic position, both with the minimum inclination, the plate 22 of the backrest 20 is almost upright. The figure 2 shows the seat 10 and the backrest 20 in its maximum position tilt, seat 10 has a turn of 9.5 ° and backrest 20 of 28.5º with respect to the basic position so that the gradient It is approximately 3: 1. In addition, compared to the position basic of figure 1, in the position of figure 2 the seat 10 has moved horizontally 36 mm back against the backrest 20. Thus, the separation between the point of the hip joint PH and iliac crest point PB and between the point of the hip joint PH and the point of the PL lordosis is approximately the same in both positions represented. Modifications of separation distance originated by the transition between both positions are less than 10% Thus, in the office chair represented here, it is not produce perceptible losses of the iliac crest or lordosis nor the aforementioned "effect of taking off his shirt".

As can be seen in Figure 7, the housing 20 is divided into two parts along a plane central vertical and features two identical housing covers inverted laterally 31. Otherwise, the mechanism of synchronization is also structured with that same investment lateral to the same vertical plane to the extent that this It is relevant to the present invention. As already described before, this also applies to the backrest support 21. That is why the rest of the description is limited only to the structure of one of the two halves inverted laterally.

In its rear area, seat 10 is housed through a rear seat guide 50 with a bearing 51 fixed in the housing located behind the vertical column 40 and a bearing 52 fixed in the seat. In the basic position that appears shown in figure 4 the rear seat guide 50 is arranged more or less vertically.

In the area of its front edge, seat 10 it is housed through a front seat guide 60 with a fixed bearing in housing 61 and a fixed bearing in seat 62. The backrest support 21 is housed in a fixed bearing in the housing placed in front of vertical column 40, as You can see in figure 3.

The forced coupling between the seat 10 and the backrest 20 is achieved through a tie bar 70 which is coupled to the rear seat guide 50 in a bearing 53 located under its fixed bearing in housing 51. To do this, the guide rear seat 50 is extended with a guide arm down more beyond the bearing 51 thus forming a two-arm lever. The tie bar 70 is coupled to the backrest support 21 in a bearing 25 below its fixed bearing in housing 24. The separation distance or lever arm between bearings 51 and 53 of the rear seat guide 50 is shorter, in concrete, it's only about half as long as the separation distance or lever arm between bearings 24 and 25 of the backrest support 21.

When the backrest 20 bends the support of the same 21 revolves around the fixed bearing in the housing 24 in the clockwise and also rotates bearing 24 to which the connecting bar 70 is attached. At the same time the bar of connection 70 exerts traction on the lower bearing 53 of the guide rear seat 50 and rotates around its fixed bearing in the housing 51 also clockwise. Because the different length of the lever arms between the bearings 24 and 25 on one side and bearings 51 and 53 on the other, the guide rear seat 50 describes a greater angle of rotation than the backrest 20. This is clearly perceived when comparing figures 3 or 4 with figures 5 or 6 showing the position with maximum backrest inclination. Due to the different angles of rotation the seat 10 moves back against the backrest 20, such and as can also be seen when comparing figures 3 or 4 with the Figures 5 or 6. The front seat guide 60 follows this displacement rotating around its fixed bearing in the housing 61.

Between the bearing 25 of the backrest support and an adjustable attack point in the front seat guide 60 is a spring 80 has been fitted which is compressed when the backrest 20 and push backrest 20 with recoil force up to Your basic position. When backrest 20 moves back into position basic from an inclined position the connecting rod 70 works like a connecting rod and turn back the rear seat guide 50 counterclockwise.

Due to the seating of seat 10 in the fixed bearing in housing 51 through the seat guide rear 50, essentially arranged vertically, when loading weight in the seat 10 without leaning on the backrest 20 does not produce a tilt adjustment. Only one adjustment of the tilt by backing pressure of the backrest 20 against the effect of spring 80, in this way the lash of the backrest 20 when the seat 10 is suddenly overloaded, as is the case with Other synchronization mechanisms.

List of designations

10

Seat

eleven

Lower seat plate

12

Seat padding

twenty

Back

twenty-one

Backup support

2. 3

Padded

22

Backrest iron

24

Bearing of the fixed back support in the Case

25

Bearing of the tie rod in the support of the back

30

Case

31

Housing covers

40

Vertical column

fifty

Rear seat guide

51

Fixed rear seat guide bearing on the Case

52

Rear seat guide bearing fixed on the seat

53

Bearing of the tie rod in the seat guide later

60

Previous seat guide

61

Front seat guide bearing fixed on the Case

62

Front seat guide bearing fixed on the seat

70

Tie bar

80

Spring

PH

Hip joint point

PB

Point of the iliac crest

PL

Lordosis Point

Claims (7)

1. Office chair with tilting backrest (20) and a tilting seat (10) necessarily coupled to the backrest through a synchronization mechanism, in which a backward swing movement induces a downward movement of the part rear seat, in which the synchronization mechanism comprises a housing (30) placed under the seat, in which the seat is housed through a rear seat guide (50) with a first bearing of the rear seat guide fixed in the housing (51) and a second bearing of the rear seat guide fixed in the seat (52), characterized in that the backrest is housed in the housing in a third bearing (24) attached to the housing and why the Forced coupling between the seat and the backrest occurs in the housing through at least one tie bar (70) between the backrest and the rear guide of the seat and is thus transmitted, because the seat moves in direction to the backrest at the time of tilting it back, and that the seat and the backrest are prestressed towards a minimum tilt position by means of a spring arrangement (80). 2. Office chair according to claim 1, characterized in that in the minimum inclination position the rear seat guide (50) is essentially oriented vertically. 3. Office chair according to any one of claims 1 or 2, characterized in that the first fixed bearing (51) relative to the rear seat guide (50) is mounted in the housing (30) behind the third bearing (24 ) fixed in relation to the backrest (20). 4. Office chair according to any one of claims 1 to 3, characterized in that at least one connecting bar (70) is coupled to the rear seat guide (50) in a fourth bearing (53) under the first bearing (51) thereof, because the at least one tie bar (70) is coupled to the backrest (20) in a fifth bearing (25) under the third bearing (24) thereof and because 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 to 4, characterized in that the seat (10) is mounted at the level of its anterior tip in the housing (30) by an anterior seat guide (60). 6. Seat according to any one of claims 1 to 5, characterized in that the inclination ratio between the backrest (20) and the seat (10) is between 2.8: 1 and 3.2: 1 and why a backrest inclination of 26º to 30º the seat moves horizontally over a distance of 30 to 40 mm. 7. Seat according to any one of claims 1 to 6, characterized in that at the time of the inclination of the backrest (20) the seat moves in the direction of the backrest at a distance such that the spacing between the hip point (PH) and the lordosis point (PL), as well as between the hip point (PH) and the pelvis point (PB) are not modified by more than 10%.