EP0377138B1 - Chair - Google Patents

Description

The invention relates to a chair, in particular an office swivel chair, according to the preamble of patent claim 1.

Chairs which can be used in particular as office swivel chairs are known (for example from DE-A-30 36 993) which have a so-called "synchromechanics". These chairs react automatically or after actuation of a release in such a way that when the user leans back, the seat lowers slightly and the backrest tilts more backwards, the front edge of the seat maintaining approximately the same distance from the floor. This movement of the resulting opening of the angle between the seat and backrest comes close to the natural movement of the human body. If the user moves back from the reclined position to an upright working position, the chair automatically follows using a spring mechanism attached under the seat. Such a change of attitude makes it easier to adapt to different jobs in the workplace and is regarded by ergonomists and occupational physicians as a preventive measure against the health consequences of sedentary office work.

A chair according to the preamble of claim 1 is described in the unpublished older German patent application P 37 37 491.5. Here, a front lever is connected to the base frame and the seat via two swivel joints, while a rear lever is also connected to the base frame and the seat via two further pivot joints, this rear lever having an extension projecting upwards beyond the fourth swivel joint, that carries the backrest. In this version of the chair Relative positions of the connection plane between the first and second swivel joints with respect to the vertical on the one hand and the connection plane between the third and fourth swivel joints with respect to the vertical on the other hand should ensure favorable seating positions and displacements.

Furthermore, EP-A-250 207 also discloses a chair version in which at least one rear lever is connected to the base frame on the one hand via a first swivel joint and on the other hand to the rear end of the seat via a second swivel joint, while at least one front lever is connected via a third swivel is in turn connected to the base and a fourth swivel to the front end of the seat. A spring system is located between the central pillar of the base and the fourth swivel at the front end of the seat.

The invention has for its object to improve a chair of the type required in the preamble of claim 1 in such a way that it is particularly easy and well adapted to the natural movement of a person at a work table, especially by a relatively simple construction distinguished.

This object is achieved by the features specified in the characterizing part of claim 1, expedient refinements and developments of the invention being the subject of the subclaims.

In the practical implementation of this chair according to the invention, a user can first of all make a very natural and informal change of posture between the individual positions in an extremely advantageous manner. So in the neutral position, ie in the middle position of the backrest and seat, between the upper body and thigh as well as the upper and lower leg and also the lower leg to the floor, each angle of approximately 90 °. In the reclined position, on the other hand, the angle between the upper body and thigh opens, the pelvis sinks, the angle between the thigh and lower leg remains approximately 90 °, and a slightly obtuse angle is created between the lower leg and the foot or floor. Furthermore, the pelvis is raised in the prone position of the user, thereby avoiding an uncomfortable constriction between the trunk and thigh; In contrast, there is a slightly acute angle between the lower leg and foot.

Thus, this chair according to the invention also enables a change of posture that is largely adapted to the natural movement of the human body. The seat of the chair moves around a virtual pivot point that lies far below the resulting mechanical pivot points or axes of rotation.

It is of particular importance that this ideal kinematics of the chair can be achieved with extremely simple constructive means, ie for this it may already be sufficient to pull the or each back lever carrying the backrest through its lower end via only one swivel joint to the base frame connect, and the or each front connecting element between about the front seat half and the base frame can be formed by a relatively simple, limited bending elastic element, which is extremely effective in the very simple design and arrangement of the seat with a deflection movement of the backrest in the direction of its middle Prestressed neutral. The good kinematics of this chair is still due to the training and arrangement the rear lever supports.

Fig. 1

eine Seitenansicht des Stuhles in Form eines Bürodrehstuhles, wobei drei unterschiedliche Sitzpositionen angedeutet sind;

Fig. 2 - 4

drei Detail-Schnittansichten (etwa Ausschnitt II in Fig. 1) vom vorderen Sitzbereich des Stuhles, zur Erläuterung mehrerer verschiedener Ausführungsformen für das vordere Verbindungselement;

Fig. 5 und 6

je eine ähnliche Seitenansicht wie Fig. 1, jedoch von zwei anderen Ausführungsvarianten des Stuhles.

The invention will be explained in more detail below with reference to some exemplary embodiments illustrated in the drawing. Show in this drawing, some of which is very schematic

Fig. 1

a side view of the chair in the form of an office swivel chair, three different sitting positions are indicated;

Figs. 2-4

three detailed sectional views (such as detail II in Fig. 1) of the front seating area of the chair, to explain several different embodiments for the front connecting element;

5 and 6

each a similar side view as Fig. 1, but of two other variants of the chair.

The first embodiment of the chair, which is designed in particular as an office swivel chair, will first be explained with reference to the illustration in FIG. Here, the chair is shown in three different sitting positions, namely the representation in solid lines shows the neutral position A corresponding to the middle position, which - in the drawing - to the left inclined, dashed representation the maximum reclined position A 'and - in the drawing - The right-angled, dashed representation shows the maximum forward-inclined position A˝.

The office swivel chair shown contains a base frame 1, which may have a central column (rotating column) and, if appropriate, support or castors, and also one Seat 2 and a backrest 3.

In this exemplary embodiment (FIG. 1), the chair also has at least one rear lever 4 provided between the base frame 1 and the backrest 3. This rear lever 4 is connected to the seat 2 via a swivel joint 5, which is located at the rear end of the seat 2 is located and forms a swivel connection between seat 2 and backrest 3. The lower end of this rear lever 4 is connected via a swivel joint 6 to the base frame 1, in the present case preferably with an upper end 1a which is bent forward approximately at an angle. The rear lever 4 is here - starting from the lower first swivel 6 - extended beyond the second swivel 5 (at the rear end of the seat 2) straight back / up, this extension 4a of the rear lever 4 carrying the backrest 3 and thus firmly connected is.

At least one front connecting element 7 connects the underside of the seat 2 to the underframe 1 (preferably with the foremost end 1a 'of the upper, angled end 1a from the underframe 1. While the rear lever 4 is a rigid connecting element, this is Front connecting element 7 is formed by a limited flexurally elastic element which biases the seat 2 in the direction of its central neutral position A when deflected in one direction or the other (essentially in the horizontal direction), as shown in FIG. 1 by the three different positions A, A 'and A˝ illustrated and indicated by a double arrow 7a.

The flexible front connecting element 7 can generally be rigidly clamped at one end and connected at its other end via a swivel joint be. An arrangement of this flexible front connecting element 7 is very particularly advantageous and therefore preferred in such a way that its lower end 7b is rigidly clamped on the base frame 1 or on its bent front end 1a and at its upper end 7c with the seat 2 via a swivel joint 10 connected is. This connecting swivel joint 10 is generally located in the front half, particularly preferably in the front third of the seat 2. The design and arrangement of this front connecting element 7 enables and thus controls a limited relative movement between the seat 2 and the base frame 1.

As illustrated in FIGS. 2, 3 and 4, the limitedly elastic front connecting element 7 can be designed in various ways in any suitable manner.

2 it is assumed that this front connecting element 7 is formed by a helical tension spring. 3, this front connecting element 7 'can be designed in the form of a buffer element made of rubber or rubber-like plastic. Fig. 4 also shows a design according to which the front connecting element is designed in the form of an upright leaf spring element 7˝.

2-4, the corresponding, preferably individually manufactured front connecting element 7, 7 'or 7˝ each rigidly clamped with its lower end on the base 1 or 1a and via its upper end with the underside of the Seat 2 connected via a suitable rotary element, as described with reference to FIG. 1. Generally, these connections could go without saying also be carried out by other suitable means, for example by hooking, clamping, screwing, etc., it is also preferable to provide the or each connecting element 7, 7 'or 7' interchangeably.

Depending on the size and design, only a single front connecting element of the type described can be provided. In practice, however, it will generally be preferred to have several such flexurally elastic front connectors, preferably two or three, side by side, e.g. H. in relation to the different drawing figures. Arranged one behind the other perpendicular to the plane of the drawing, because the individual connecting elements can then be made relatively small and space-saving and at the same time ensure better directional stability (forward-backward movement).

Looking again at the embodiment of the swivel chair illustrated in FIG. 1, it can first of all be seen that the first swivel joint 6 connects the lower end of the rear lever 4 to the upper end of the actual, vertically extending central column of the underframe 1, while the second pivot 5 of the rear lever 4 is articulated at the rear end 2b of the seat 2. The upper end of the front connecting element 7 is approximately - as already mentioned - with the front third of the seat 2 in connection, i. H. the connecting swivel joint 10 is offset somewhat to the rear relative to the front end 2a of the seat.

The distance between the second swivel joint 5 and the upper end 7c of the front connecting element 7, which is connected to the seat 2 - via the swivel joint 10 - is approximately 1.5 to 2.5 times, preferably approximately twice the distance between the first pivot joint 6 and the lower end 7b of the front connecting element 7.

While the flexible front connecting element 7 is oriented substantially vertically, the connecting plane 8 between the first and second pivot 6, 5 of the rear lever 4 in the neutral position A by an angle α between 40 ° and 70 °, preferably 60 ° compared to Vertical V tilted backwards.

The maximum deflection of the backrest 3 from the neutral position A to the rear (item A ') is approximately 20 ° and from the neutral position to the front (item A˝) is approximately 10 °.

In this first embodiment illustrated in FIG. 1, the rear lever 4 is preferably designed as part of the backrest 3; the front connecting element 7, however, can - as explained above with reference to FIGS. 2-4 - be designed as a single, preferably exchangeable, flexible element.

In the neutral position A, the seat 2 and the backrest 3 - as mentioned - assume the middle position shown in solid lines. If the user now leans back in the chair, the backrest 3 swings backwards about the lower first swivel joint 6, for example into the maximum rear position A '. The seat 2 simultaneously performs an approximate horizontal movement and a greater lowering movement in the rear seat part than in the front seat part - in each case relative to the base frame - which is due to the combined handlebar-spring system formed by the rear lever 4 and the front connecting element 7 is effected and controlled.

The distance of the front seat end 2a from the floor increases only slightly. The angle between the user's upper body and thigh opens during this return movement, and at the same time the pelvis lowers. The angle between the thigh and lower leg remains about 90 °, while a slightly obtuse angle is created between the lower leg and foot.

If the user moves out of the neutral position A to the front, for example into the maximum front position A dargestellte shown in dashed lines, the backrest 3 straightens up and the seat 2 moves forward, ie. H. with the horizontal movement of the seat 2 approaching, the rear seat part performs a stronger lifting movement than the front seat part (again relative to the base frame 1). The user's pelvis is raised, which prevents an uncomfortable narrowing between the trunk and thigh. A slightly acute angle is created between the lower leg and foot.

As is also only indicated in a simplified manner in FIG. 1, the lower end of the rear lever 4 articulated on the first swivel joint 6 is connected to a suitable spring system 9, which is indicated in this FIG. 1 as a helical spring. For this purpose, the lower end of the rear lever 4 has an approximately lever-like projection 4b projecting downward beyond the first swivel joint 6, to which one end of the spring system 9 is connected, while the other end of a likewise projecting downward projection 1b of the forward bent upper end 1a is supported by the base frame 1.

In general, this spring system 9 can be designed in any suitable and known manner, for example as a compression spring system, as spring bars, as leg springs, leaf springs, torsion springs or also as gas springs. In this case, this spring system is intended to generate restoring forces which exert a counter pressure on seat 2 and backrest 3 when a deflection of the seat and backrest is brought about by a corresponding posture of the user.

In Fig. 5 is a slightly modified embodiment of the office swivel chair compared to the previously described embodiment is illustrated, the differences in particular in the arrangement of the seat, rear levers and backrest can be seen, while the execution options of the other parts can be retained essentially unchanged, so that in this embodiment variant according to FIG. 5 the same reference numerals are used as in FIG. 1 for parts of approximately the same design, as a result of which a renewed description of these parts is largely unnecessary.

Similar to the first exemplary embodiment, the seat 2 is also connected to the upper end 1a of the base frame 1 by the underside of its front third via at least one limited flexible front connecting element 7 (design and arrangement similar to that described with reference to FIGS. 1-4).

In this example (FIG. 5), however, two rear levers 14 are now arranged in pairs and approximately parallel to one another on both sides of the seat 2 and the backrest 13. The rear end 2b of the seat 2 projects over the second swivel joint 15 the rear lever 14 to the rear. Furthermore, the lower region 13a of the backrest 13 arched in a known manner in this case in the known - by solid lines - neutral position A a clear distance a from the seat 2, while it is in the rear position A 'shown in dashed lines Backrest 13 is located just above the seat 2, as can be clearly seen in FIG. 5. In addition, the side frame parts of the backrest 13 can be arranged in an approximately straight extension of the rear levers 14, ie in this case the extensions 14a of the two rear levers 14 projecting rearward / upward, which extend essentially straight beyond the second pivot joint 15, can be directly, at least in the side view pass into the backrest 13.

If, in this embodiment according to FIG. 5, the connection plane 8 between the rotary joints 15 and 6 is again considered, then in this case the connection plane 8 is in the neutral position A with respect to the vertical V by an angle α 'between approximately 15 ° and 40 °, preferably tilted backward by approximately 25 °, d. H. that is, the connecting plane 8 between the swivel joints 15 and 6 of the two rear levers 14 is steeper than in the case of FIG. 1.

If one finally compares the spacing between the two rear levers 14 and the flexible front connecting element 7, then in the case of FIG. 5 the distance between the second swivel joint 15 and the connecting swivel joint 10 at the upper end of the connecting element 7 is approximately 1.2- up to 1.8 times, preferably about 1.4 times, the distance between the first pivot 6 and the lower end 7b of this front connecting element 7.

Otherwise, a similar spring system 9 can also be clamped between the lower end of at least one rear lever 14 and the base frame 1, as described in FIG. 1, in the example of FIG. 5.

In the neutral position of this chair version (FIG. 5), the seat 2 and backrest 13 again assume approximately the A position. If the user leans back in the chair, the backrest 13 and the first swivel 6 swivel backwards, at most up to about position A '. The seat 2 here simultaneously performs an approximately horizontal movement to the rear and in its rear part 2b a stronger lowering movement (compared to the lifting movement in the front seat part) relative to the base frame 1, which in turn is formed by the handlebar formed by the pair of levers 14 and the flexible front connecting element 7 Spring system is effected and controlled. The distance of the front edge 2a of the seat 2 from the floor also increases only very slightly in this case. The angle between the upper body and thigh opens during the return movement, whereby the user's pelvis is lowered at the same time. The angle between the thigh and lower leg remains about 90 °, and a slightly obtuse angle is created between the lower leg and foot.

If the user moves from the neutral position A to the front up to position A maximal, the backrest 13 straightens up and the seat 2 moves forward. The pelvis is slightly raised, which prevents an uncomfortable narrowing between the trunk and thigh. Between the lower leg and foot there is a slightly acute angle (everything again in accordance with the example in FIG. 1).

6 finally shows a further embodiment variant of the office swivel chair, in particular a simplified embodiment variant of the exemplary embodiment last described with reference to FIG. 5, so that in FIG. 6 the same reference numerals as in FIGS. 5 and 1 are used for parts of approximately the same design can be and these parts usually do not need to be described again in detail.

The two rear levers 14, which are elongated rearward / upward, are in turn held in pairs and approximately parallel to each other on both sides of seat 2 and backrest 23 in a manner similar to that of the upper sections of the lever extensions 14a as in the previous example (FIG. 5).

In the present case (FIG. 6), however, the seat 2 is integrally connected to one another via its rear end 2b and the backrest 23 via its lower end 23a by means of a flexurally elastic connecting part 20 which is curved towards the rear (outside). H. in this case the backrest 23 is rigidly connected to the upper lever extensions 14a and - via the arched connecting part 20 - is connected to the rear end 2b of the seat 2 in a spring-movable manner.

Because of this one-piece, spring-moving connection between the seat 2 and the backrest 23, the seat 2 in this embodiment variant only needs to be supported directly on the base frame 1 or its forwardly bent upper end 1 a via the flexible front connecting element 7, ie the seat 2 or its front half (better its front third) only has a direct support connection to the flexible front connecting element 7 Base 1 or 1a. Of course - as explained above in connection with FIGS. 1-4 - several such flexible front connecting elements 7 can be provided next to one another in a suitable design and arrangement.

The pair of rear levers 14 are in this case only connected to the lower lever ends via the first, lower joint 6 to the upper end of the underframe 1 (similar to the previous examples), while the second joint provided in the previous embodiments (between these rear levers 14 and the seat 2) can be omitted.

The sequence of movements when using this office swivel chair variant is practically the same as that described above with reference to FIGS. 1 and 5, so that here only the middle neutral position A and the maximum rear and front positions A 'and A˝ in Fig. 6 needs to be pointed out.

In all variants of the chair according to the invention, the seat and the backrest are thus mounted on the base frame via at least one flexible front connecting element and at least one lever via at least one swivel joint in such a way that when the backrest is pivoted forwards or backwards, the seat is at the same time an approximately horizontal movement and thereby the rear part performs a stronger lifting or lowering movement than the front seat part.

Claims (13)

1. Chair, particularly an office swivel chair, comprising

   a) a pedestal (1),

   b) a seat (2) and a back rest (3, 13, 23) which are capable of limited movement relative to one another and relative to the pedestal,

   c) at least one front connecting element (7) provided between the pedestal (1) and the seat (2),

   d) at least one rear lever (4, 14) which is provided between the pedestal (1) and the back rest (3, 13, 23) and is connected via a swivel joint (6) to the pedestal, in which

   e) a tilting movement of the back rest (3, 13, 23) towards the front or towards the rear results in an approximately horizontal movement of the seat (2) with the rear part of the seat carrying out a greater lifting or lowering movement than in the front part of the seat,

   characterised by the following feature:

   f) the front connection element (7, 7', 7'') is formed by a flexible element which is rigidly clamped at one end (7b) and connected at the other end (7c) by means of a swivel joint (10).
2. Chair as claimed in claim 1, characterised in that the front connecting element (7, 7', 7'') is rigidly clamped on the pedestal (1) and is connected to the seat (2) via a swivel joint (10).
3. Chair as claimed in claim 1, characterised in that the front connecting element is constructed in the form of a spiral tension spring (7).
4. Chair as claimed in claim 1, characterised in that the front connecting element is constructed in the form of a buffer element (7') made from rubber or rubber-like plastic.
5. Chair as claimed in claim 1, characterised in that the front connecting element is constructed in the form of an upright leaf spring element 7''.
6. Chair as claimed in claim 1, in which the rear lever (4) is connected via the first swivel joint (6) to the pedestal (1) and via a second swivel joint (5) to the rear end of the seat (2) and the extension (4a) of the said lever projects in a straight line over this second swivel joint towards the back/top and bears the back rest (3), characterised in that the distance between the second swivel joint (5) and the upper end (7c, 10) of the front connecting element (7) which is connected to the seat (2) is 1.5 to 2.5, preferably approximately 2, times the distance between the first swivel joint (6) and the lower end (7b) of the front connecting element.
7. Chair as claimed in claim 6, characterised in that the plane of connection (8) between the first and the second swivel joint (6, 5) in the central position corresponding to the neutral position A is inclined towards the rear by an angle (α) between 40° and 70°, preferably approximately 60° with respect to the vertical (V).
8. Chair as claimed in claim 6, characterised in that the second swivel joint (5) is located at the rear end (2b) of the seat (2).
9. Chair as claimed in claim 1, in which the rear lever (14) is connected via the first swivel joint (6) to the pedestal (1) and via a second swivel joint (15) to the rear half of the seat (2) and the extension (14a) of the said lever, which projects over this second swivel joint towards the rear/top, bears the back rest (13, 23) and is firmly connected thereto, characterised in that the distance between the second swivel joint (15) and the upper end (7c, 10) of the front connecting element (7) which is connected to the seat (2) is 1.2 to 1.8 times, preferably approximately 1.4, times the distance between the first swivel joint (6) and the lower end (7b) of the front connecting element (7).
10. Chair as claimed in claim 9, characterised in that two rear levers (14) are arranged as a pair and approximately parallel to one another on both sides of the seat (2) and the back rest (3) and the seat (2) juts out towards the rear over the second swivel joint (15) and the lower region (13a) of the back rest (13) which is curved towards the rear is located at a distance (a) in the central position corresponding to the neutral position (A) and just above the seat (2) in the rear position (A') of the back rest.
11. Chair as claimed in claim 10, characterised in that the plane of connection (8) between the first and second swivel joints (6, 15) in the neutral position (A) is inclined backwards with respect to the vertical (V) by an angle (α') of approximately 15° to 40°, preferably in the region of approximately 25°.
12. Chair as claimed in claim 1, characterised in that

    a) two rear levers (14) which are extended approximately towards the rear/top are provided as a pair and approximately parallel to one another on both sides of the seat (2) and the back rest (23),

    b) the rear end (2b) of the seat (2) and the lower end (23a) of the back rest (23) are connected to one another in one piece but flexibly by a rearwardly curved connecting piece (20), and

    c) the seat (2) only has a direct supporting connection to the pedestal (1) with its front half via the flexible front connecting element (7).
13. Chair as claimed in claim 1, in which a spring system (19) produces a force which acts on the seat (2) and the back rest (3, 13, 23) and opposes a deflection towards the rear, by means of which an equalising counterpressure is achieved depending upon the body position, characterised in that the spring system (9) is clamped between the pedestal (1) and the lower end (4b) of the rear lever (4, 14) which is articulated on the first swivel joint (6).

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