EP0540711A1

EP0540711A1 - Working chair, especially office chair.

Info

Publication number: EP0540711A1
Application number: EP92910163A
Authority: EP
Inventors: Peter Tobler
Original assignee: EQUUS MARKETING AG
Current assignee: EQUUS MARKETING AG
Priority date: 1991-05-24
Filing date: 1992-05-22
Publication date: 1993-05-12
Anticipated expiration: 2012-05-22
Also published as: ES2094355T3; ATE142857T1; CA2087981A1; EP0540711B1; JPH06500944A; DE59207171D1; WO1992020262A1; AU1692092A

Abstract

The working chair has a seat bearer (11), a seat (15) articulated on the seat bearer (11) and a squab bearer (25) with a squab (29). The squab bearer (25) has a spindle (23) on the seat bearer (11). One arm (27) is articulated on the squab (29) and the other (31) on the seat (15). The simple mechanical arrangement (20, 22, 23, 25, 35) thus formed causes the seat to be moved in one direction of rotation (47) when the squab bearer (25) is moved in the other (43). As in lying down and relaxing, the knee and hip joints thus undergo an extension. This produces a sound lordosis. The spindle (23) and the articulation axis (35) lie in a plane (36) inclined at about 70 DEG to the horizontal. Regardless whether a person is heavy or light, relatively little force on the squab (29) is needed to raise the seat (15). As the seat (15) and the squab (29) remain close together during any movement, the tendency for the shirt to be pulled out is prevented. The movement of the seat backwards and downwards when the squab is tipped backwards prevents blood congestion at the back of the knees.

Description

Working chair, especially office chair

The invention relates to a work chair, ^'in particular Büro¬ chair, with a seat carrier, a seat horizontally pivotable forward on the seat support about a rotational axis also approximate and relative to the seat carrier is movable, a mit¬ means of a rotational axis of support on the seat support articulated Rückenlehnen¬ , which is connected to the seat via a pivot axis and a backrest, which is coupled to the backrest support.

A large part of the work chairs manufactured today, as they are mainly used as office chairs, are so-called synchronous work chairs, in which the adjustment of the inclination of the backrest support simultaneously adjusts the inclination of the seat. In known synchronous work chairs, pivoting the backrest in one direction causes the seat to pivot in the same direction. The pivoting of the seat is usually only half as large as the pivoting of the backrest (US-A-2 859 799, CH-A-629 945). These work chairs have five disadvantages in particular, namely a physiologically unnatural movement when pivoting the backrest, a negative influence on the sitting posture, a lack of neutrality in weight, a relatively complex construction and a clunky appearance that no longer meets today's aesthetic needs There are certain correlations between these disadvantages.If, for example, weight neutrality is lacking and the spring force of a compensation device which counteracts the force on the backrest which causes the weight of the user is poorly adjusted, this can also contribute to poor sitting posture, as subsequently is explained in more detail.

If one looks at the movement of a person's joints when standing up normally, one finds that both the knee joints and the hip joints are stretched or, as is said in medicine, an extension. The same applies to lying down and relaxing. Conversely, flexion occurs in both joints when sitting down. In contrast to the natural sequence of movements, for example in the work chair according to CH-A-629 945, when the backrest is pivoted backwards, the rear part of the seat is moved downwards, the pivoting of the seat plate being only about half as large as that of the backrest. This leads to a physiologically unnatural movement. So there is an extension of the hip joints, but a flexion of the knee joints.

In order to cause the swiveling backwards in a work chair according to CH-A-629 945, the user presses the upper body against the backrest and supports oneself with the legs firmly on the floor. There is a risk that the user will slide forward a little, especially if a relatively large amount of force has to be exerted for pivoting. Since the front edge of the seat also moves upward, blood congestion can occur in the area of the knee joints.

A lever is sufficient to raise the backrest. This releases the springs that were tensioned backwards when swiveling. The backrest and seat then return to the original position or to an intermediate position desired by the user. If the user slipped a little when swiveling backwards, his pelvis is now in an inclined position to the rear. He has a bad posture that can easily lead to back pain.

In the case of CH-A-629 945, the backrest is pivoted backwards against the force of a gas spring and a compression spring, the prestressing of the compression spring being changeable by adjusting nuts. In practice, however, this does not allow a satisfactory adjustment to the weight of a particular user. A preload is therefore usually set which is adapted approximately to the weight of the average user. If a light person now uses the chair, they have difficulty to move the backrest backwards. There is a great risk that it will slide forward on the seat. In the opposite case, if a heavy person uses the chair, they find it uncomfortable when adjusting the backrest if it moves backwards with practically no noticeable resistance due to the heavy weight of the person.

The energy used to swivel the backrest is largely stored in the springs in the work chair of CH-A-629 945 and is released when a locking device is released in order to move the backrest and upper body of the chair user forward again. If the user leaves the chair without moving the backrest forward and is e.g. loosened the locking device by cleaning personnel, the backrest swings forward with great force and speed. This poses a significant risk of injury.

US-A-4, 834,454 describes a chair in which a seat on the front of the seat support is pivotable about an axis of rotation. An L-shaped backrest support can be pivoted about a pivot axis arranged on the seat support. The L-shaped backrest support is connected to the seat at the end of the horizontal beam of the L by means of a pivot axis. If the backrest is pivoted backwards, the backrest support, which is firmly connected to the backrest, lifts the rear part of the seat. At the same time, the seat is pushed back a little. It proves to be disadvantageous that at the beginning of a swiveling movement of the backrest, a very large force is required to lift the seat which is loaded by the user, because in the first part of the swiveling movement the articulation axis at the end of the horizontal bar has to be moved upwards . Another disadvantage is that a heavy user has to use considerably more force than a light user. It is also particularly unfavorable that the distance between the seat and backrest increases considerably when the backrest swivels backwards. This leads to the unpleasant shirt pulling effect. It is therefore an object of the present invention to at least partially avoid the described disadvantages of previously known work chairs. The aim is to create a work chair with a synchronous mechanism in which the user's body performs physiologically natural movements. The sequence of movements should in particular also lead to good sitting posture. The construction of the chair should be simple. However, it should also meet the highest possible aesthetic requirements that are placed on work chairs, in particular office chairs, today.

According to the invention, this is achieved in a chair according to patent claim 1. In such a chair, pivoting the backrest support in one direction causes the seat to pivot in the opposite direction. If, for example, the backrest support is pivoted backwards, the rear part of the seat moves upward about a pivot point in the front region of the seat. The body takes part in a natural sequence of movements by stretching, as in normal standing, for both the hip joint and the knee joint. In addition to this general movement sequence, details of the movement sequence are also of particular importance. The high angle of inclination defined in claim 1 has the consequence that the seat is also moved relatively far to the rear when the backrest is pivoted to the rear. This further promotes the extension of the knee joint and prevents blood build-up in the knee joints. The high angle of inclination also means that a relatively small force is required to initiate the pivoting of the backrest to the rear. The user therefore finds this movement convenient. The good movement sequence created in this way encourages active sitting. Active sitting promotes blood flow to organs and limbs and contributes to the general well-being of the chair user. Premature fatigue, which is typical for passive sitting, is prevented. Partial weight compensation through force compensation is also important. A force compensation is done by the force that is exerted on the backrest acts, counteracts the force caused by the weight of the user on the seat. Thanks to this force compensation, there is no need for weight adjustment for light and heavy people.

The invention also has the advantage of a particularly simple construction, which also allows an aesthetically particularly appealing design of the work chair. In practice, only one lever is required, namely the backrest support.

The angle of inclination of the plane in which the axis of rotation of the backrest support and the articulation axis of the backrest support are located on the seat is advantageously in the range from 60 to 70 degrees. Tests have shown that the chair is perceived as particularly comfortable by the user at such an angle of inclination. At this angle of inclination there is also a movement sequence of the seat and backrest which does not lead to a shirt pull-out effect.

The distance between the axis of rotation and the articulation axis is advantageously approximately 80 to 120 mm, preferably approximately 100 mm. This results in favorable conditions for a weight balance and an optimal way for backward movement of the seat when the backrest is pivoted backwards.

The backrest is expediently articulated to the backrest support. This enables a favorable movement of the backrest. In particular, if the backrest is designed as a pendulum backrest, the lordosis, i.e. the physiological curvature of the spine of the chair user towards the front is intensified.

Experiments have shown that it is expedient to arrange the articulation point of the backrest behind the axis of rotation at an angle of 10 to 20 degrees, preferably 15 degrees, to the vertical leading through the axis of rotation.

A spring element is advantageously provided, which strives to move the backrest and the seat forward. This The spring element advantageously has a relatively steep characteristic, so that the spring force increases with increasing inclination of the backrest and thus counteracts the force on the backrest caused by the weight of the upper body of the chair user.

The articulation axis is expediently located in the region of the rear half of the seat. With this arrangement, there are favorable € ratios for the weight balance.

The front of the seat can be stored in different ways. So it is possible that the front seat is connected to the seat support by means of a flexible connecting piece. An expedient embodiment provides a connection via a support lever. This support lever is advantageously arranged approximately vertically in the front position of the backrest. The result of this is that when the backrest is pivoted backwards, the front part of the seat is slightly lowered. This slightly reduces the pressure on the body in the area of the hollow of the knee, which contributes to the desired relaxation of the body and promotes blood circulation.

However, it is also possible for the seat to be connected at the front to the seat support by means of a sliding piece running in a guide. This results in a simple construction.

The spring element is advantageously an elastomer block. Elastomer blocks, which are known under the name "cell volcano", also have movement-damping properties. This prevents the backrest from rapidly advancing. An elastomer block or a helical spring are advantageous because, in contrast to a gas spring, they have a relatively steep spring characteristic. The restoring force exerted by the elastomer block or the mechanical spring at the start of a backward movement of the backrest is therefore low. Thanks to the mechanism according to the invention, there is extensive force compensation in this area between the force acting on the seat and the force acting on the backrest. Towards the end of the backward movement of the backrest, however, the force acting on the seat is far from sufficient to compensate for the force acting on the backrest. For this reason, the high restoring force of the elastomer block is of great advantage in this area. The user feels the chair very comfortably and is encouraged to sit actively.

Various options remain open to the designer for the arrangement of the spring element. For example, engage the spring element directly on the backrest. However, it is particularly advantageous if the spring element is arranged practically parallel to the seat and acts on it. This allows the mechanism under the seat to be made very compact, which is desirable for aesthetic reasons.

The seat and backrest can be made from a single flexurally elastic part, e.g. Plastic part. It is also possible that the seat shell and backrest shell are made from a single part, e.g. Plastic part exist, which has an articulated section. Such constructions are made possible by the arrangement according to the invention of the axis of rotation of the backrest support and the articulation axis which connects the backrest support to the seat, because in this arrangement an undesired movement between the seat and backrest, which would lead to a shirt pulling-out effect, is avoided.

For locking the seat and the backrest in ^'the gewünsch¬ th position is advantageously used a clamping device, for example a slat clamping device. Since the seat in the design of the work chair according to the invention has a relatively large travel path when the backrest is moved, a locking device acting on the seat only has to absorb relatively small forces, so that a clamping device can be used for locking instead of the usual gas spring . Such clamping devices are cheap to manufacture and, in contrast to gas springs, also offer no disposal problems. The seat is advantageously strongly shaped, ie provided with depressions corresponding to the contours of the human body. As a result, the risk of slipping is counteracted even when the seat is inclined relatively strongly.

The arrangement of the axis of rotation, articulation axis and articulation point is expediently such that, in the normal position, the angle of inclination of the seat to the rear is approximately 3 degrees and an angle of approximately 103 with the plane in which the articulation axis and the articulation point of the backrest lie Degrees, and that when the backrest support is pivoted about 34 degrees backwards, the seat is pivoted upward about 5 degrees. This configuration has proven to be very practical ergonomically.

Embodiments of the invention will now be described with reference to the drawing. It shows:

1 shows a first exemplary embodiment of a work chair in the normal sitting position,

2 the work chair from FIG. 1 in the relaxation position, in which the backrest was moved backwards,

3 shows a second embodiment of a work chair in the normal sitting position,

3a shows a variant for the backrest support,

4 shows the work chair from FIG. 3 in the relaxation position,

Fig. 5 shows a third. Embodiment of a work chair in the normal sitting position,

FIG. 6 the work chair from FIG. 5 in the relaxation position. In the embodiment of FIGS. 1 and 2, the seat support 11 is carried in the usual manner by a base with a standpipe 13 and a height lift. Of these parts, only the stand pipe 13 is indicated in the drawing. The seat 15 is advantageously strongly shaped, that is to say has a recess 16 at the rear which counteracts slipping forward. Upholstery 18 can also be provided. The backrest 29 can also have padding 30. The seat 15 is supported in the region of its front end on the seat support 11, for example by means of a support lever 17. The support lever 17 has an articulated connection 19 with the seat support 11 and an articulated connection 21 with the seat 15. However, the seat 15 could also be supported on the seat support 11, for example by means of a flexible connecting piece made of elastomeric material. The chair also has a backrest support 25 which is articulated to the seat support 11 with an axis of rotation 23. This backrest support 25 is a two-armed lever. One arm 27 of the two-armed lever is coupled to the backrest 29, which is designed as a pen backrest. The other arm 31 of the two-armed lever 25 is coupled to the seat 15. The arm 27 is coupled approximately in the middle or somewhat below the center of the backrest 29, for example by means of a joint 33. The other arm 31 is coupled in the region of the rear half of the seat 15 via the articulation axis 35. There is a distance between the joints 21 and 35 which is approximately half the seat length or slightly more, for example two thirds of the seat length.

The position of the articulation axis 35 with respect to the axis of rotation 23 is of particular importance. The articulation axis 35 is located at a location which lies in front of and above the axis of rotation 23. It is important that in the normal sitting position, ie with the backrest 29 in a practically vertical position, the angle of inclination of the plane 36 in which the two axes 23, 35 lie is in the range from 45 to 80 degrees, advantageously 60 to 70 degrees. From this area, when the backrest 29 is pivoted backwards, the articulation axis 35 moves in the direction of the arrow 45. This requires a relatively small force necessary. The seat 15 is also moved relatively strongly to the rear. The distance between the axes 23 and 35 is approximately 80 to 120 mm, advantageously approximately 100 mm. This results in favorable conditions for weight compensation.

On the two-armed lever 25 there is a nose 37, to which a spring element 39 engages. This spring element 39 tends to move the backrest 29 forward, i.e. to put them back in their normal sitting position. The spring element 39 is advantageously a coil spring, e.g. a compression spring which is guided by a telescopic device 41. However, an elastomer block, e.g. from "Zellvulkolan", find use.

A locking device 42 with an actuating lever 44 is shown schematically. A simple clamping device, e.g. Slat clamping device, serve. Because, as mentioned in the introduction, a weight balance takes place and the seat has a relatively large travel path, only relatively small forces have to be absorbed when locking, so that a clamping device is sufficient.

Comparing the positions of the chair of FIGS. 1 and 2, it can be seen that a force on the backrest 29 in the direction of arrow 43 causes the seat 15 to move back and up in the direction of arrow 45. The seat 15 rotates about the joint 21 in the direction of the arrow 47 so that the front edge of the seat is lowered. The torques exerted on the arms 27, 31 counteract each other, so that they are relative Little energy has to be used by the chair user - be it light or heavy - to move from the position in FIG. 1 to the position in FIG. 2.

FIGS. 3 and 4 clearly show that the backrest follows the upper body faithfully and that the shirt is therefore not removed. In summary, it can be stated that the advantages achieved by the mechanics described are considerable for the user, namely more pleasant because of natural movement, comfortable sitting for light and heavy users thanks to force compensation between the seat and backrest, prevention of blood congestion at the back of the knee thanks to the ergonomic movement of the seat, prevention of the shirt pull-out effect and especially good lordosis.

The exemplary embodiment according to FIGS. 3 and 4 differs from the previously described exemplary embodiment essentially by the other support of the seat 15 on the seat support 11 and the different arrangement of the spring 39. Thus, an inclined guide 20, e.g. Elongated hole, provided in which a slider can slide. This can e.g. be a rod 22 which is supported by the tabs 24 of the seat 15. The spring element 39, e.g. an elastomer block ("cell volcano") is arranged practically parallel to the seat 15 and is supported at one end at 26 on the seat support 11 in order to act on the seat 15 at the other end. The Feder¬ element 39 transmits its force via the rod 22 and the tabs 24 to the seat 15 and strives to move the seat 15 forward to the position of FIG. 3.

The backrest support 25 can be given various shapes. A possible variant is shown in Fig. 3a. The possibility of connecting the axes 23, 35 and 33 in different ways gives the designer many options for a pleasant design of the work chair. For example, a backrest support 25 can be provided on each side, the two backrest supports being connected to one another by the hinge axis 23. An extension 46 can also serve as an armrest (FIG. 3a).

The embodiment according to FIGS. 5 and 6 differs from that of FIGS. 3 and 4 essentially in that the rear part of the seat 15 and the lower part Part of the backrest (29 to 28) are connected to one another in an articulated manner. The seat shell and backrest shell can therefore consist of a single elastic part, for example a plastic part, or a single part which has an articulated section 28.

Claims

1. work chair, in particular office chair, with a seat carrier (11), a seat (15) which can be pivoted about an axis (21) at the front on the seat carrier and is also approximately horizontally movable relative to the seat carrier (11), one by means of an axis of rotation (23) articulated backrest support (25), which is connected to the seat (15) via an articulation axis (35), a backrest (29) which is coupled to the backrest support (25), the articulation axis ( 35) in front of the axis of rotation (23) and higher than this, and the angle of inclination of the plane (36), in which the two axes (35, 23) are located, in the range from 45 to 80 degrees to the horizontal lies when the work chair is in the normal position.

2. Work chair according to claim 1, characterized in that the angle of inclination is in the range from 60 to 70 degrees.

3. Work chair according to claim 1 or 2, characterized gekennzeich¬ net that the distance between the axis of rotation (23) and articulation axis (35) is about 80 to 120 mm, preferably 100 mm.

4. Work chair according to one of claims 1 to 3, characterized in that the backrest (29) is articulated to the backrest support (25) at an articulation point (33).

5. Work chair according to one of claims 1 to 4, characterized in that the articulation point (33) of the backrest (29) behind the axis of rotation (23) at an angle of 10 to 20 degrees, preferably 15 degrees, to which by Vertical axis of rotation (23) is arranged.

6. Work chair according to one of claims 1 to 5, characterized in that a spring element (39) is provided , which strives to move the backrest (29) forward.

7. Work chair according to one of claims 1 to 6, characterized in that the articulation axis (35) is located in the region of the rear half of the seat (15).

8. Work chair according to one of claims 1 to 7, characterized in that the backrest (29) is a pen backrest.

9. Work chair according to one of claims 1 to 8, characterized in that the seat (15) is connected at the front to the seat support (11) by means of a flexible connecting piece.

10. Work chair according to one of claims 1 to 8, characterized in that the seat (15) is articulated at the front with the seat support (11) via a support lever (17).

11. Work chair according to claim 10, characterized in that in the normal position of the backrest (29) the support lever (17) is arranged approximately vertically.

12. Work chair according to one of claims 1 to 11, characterized in that the seat (15) at the front is connected to the seat support (11) by means of a slide piece (22) running in a guide (20).

13. Work chair according to one of claims 6 to 12, characterized in that the spring element (39) is an elastomer block.

14. Arbeitεstuhl that the spring element (39), a Schrau¬ is benfeder according to any one of claims 6 to 13, characterized ^'.

15. Work chair according to claim 10, characterized in that the spring element (39) engages on the backrest support (25).

16. Work chair according to claim 10, characterized in that the spring element (39) is practically arranged parallel to the seat (15) and engages it.

17. Work chair according to one of claims 1 to 16, characterized in that the seat (15) and backrest (29) consist of a single flexurally elastic part, e.g. Plastic part.

Work chair according to one of claims 1 to 16, characterized in that the seat (15) and backrest (29) are made from a single part, e.g. There are plastic parts which have an articulated section (28).

19. Work chair according to one of claims 1 to 18, characterized in that a clamping device, e.g., for locking the seat (15) and the backrest support (25) in the desired position. a lamella clamping device is provided.

20. Work chair according to one of claims 1 to 19, characterized in that the seat (15) is strongly shaped.

21. Work chair according to one of claims 4 to 20, characterized in that ^' the arrangement of the axis of rotation (23), articulation axis (35) and articulation point (33) is such that in the normal position the angle of inclination of the seat (15) to the rear is approximately 3 Degree and with the plane in which the articulation axis (35) and the articulation point of the backrest (29) are at an angle of about 103 degrees, and that when the backrest support (25) is pivoted about 34 degrees to the rear, the seat is pivoted about 5 degrees upwards.