WO2002038008A1

WO2002038008A1 - Device at a chair mechanism for adjustment of inclination and height of seat using one single operating lever

Info

Publication number: WO2002038008A1
Application number: PCT/SE2001/002457
Authority: WO
Inventors: Simon Kolsjö
Original assignee: SAMHALL AB
Current assignee: SAMHALL AB
Priority date: 2000-11-08
Filing date: 2001-11-07
Publication date: 2002-05-16
Anticipated expiration: 2003-05-08
Also published as: SE516095C2; SE0004084L; AU2002214456A1; SE0004084D0

Abstract

A chair mechanism fitted between a chair stand equipped and a chair seat has an operating lever (3) for adjustment of the seat height and chair seat rake. The chair mechanism comprises first (2a) and second frame parts rotatable relative to one another about an axis (2d). The first frame part (2a) is connected to the chair stand, the second to the seat. A catch mechanism is designed to lock the frame parts relative to one another in one of a number of selectable chair seat rakes and comprises a locking element (2e), which by means of the operating lever (3) can be moved into and out of openings in the second frame part defining the seat rakes. A spring element (5) between the frame parts produces a frictional engagement between the locking element (2e) and the openings, which when the seat is not under load renders it impossible to draw the locking element (2e) out of the respective opening. The spring element (5) is overcome when the seat is loaded by the weight of a person sitting thereon, it being possible to adjust the rake of the chair seat. The locking element (2e) takes the form of an element to which torsion can be applied about its longitudinal axis and is brought by the operating lever (3), in a transverse direction to the operating direction for adjustment of the seat rake, into engagement with a member for adjustment of the seat height, and when not acted upon by the operating lever (3) is disengaged under return spring action from the said member.

Description

Device at a chair mechanism for adjustment of inclination and height of seat using one single operating lever

The present invention relates to an arrangement according to the pre-characterizing clause of claim 1.

Chair mechanisms of the above-mentioned type, in which both the seat height and the seat/backrest rake can be adjusted by means of a single operating lever, are known. US-A-3,756,654, for example, discloses such a mechanism.

For safety reasons, a requirement has recently been introduced that adjustment of the seat/backrest rake should be possible only when the seat is loaded by the weight of a person sitting on the chair. Chair mechanisms that fulfil this requirement are also known.

The object of the present invention is to produce a chair mechanism of the aforementioned type, which has relatively few parts, which can be manufactured rationally and of which only a small number are moving parts and which are therefore cost effective to manufacture and assemble.

This object is achieved in that the chair mechanism according to the invention has the features specified in the characterising part of claim 1.

Further details of the chair mechanism according to the invention are set out in the subordinate claims and the. following description, making reference to the drawing attached, in which:

Fig. 1 in a diagrammatic side view shows a chair having a chair mechanism according to the invention. Fig. 2 shows an oblique view of the chair mechanism from beneath, and fig. 3 shows an exemplary embodiment of the structure of a frame part, forming part of the chair mechanism and having a locking element, by means of which the seat rake and seat height can be adjusted by means of a single operating lever. Fig. 4 shows the frame part in fig. 3 from a different perspective to that in fig.3. In the drawing, 1 generally denotes a chair having a seat la and backrest lb, which in this instance is rigidly connected to the seat la, as will be explained below. 2 generally denotes a chair mechanism according to the invention, having an operating lever 3 for adjusting the seat rake and seat height, it being possible to adjust the seat rake by moving the lever 3 backwards, that is towards the backrest lb, provided, however, that the seat la is loaded by the weight of a person sitting thereon. The seat height can be adjusted by moving the operating lever 3 upwards.

The chair mechanism 2 is connected to a chair stand comprising a gas-filled spring, only an upper part 4 of the chair stand, in which the gas-filled spring is located, being visible in figures 1 and 2.

The exterior structure of the chair mechanism can be seen from fig. 2, in which the upper part 4 of the chair stand is to be found. A first inner frame part 2a is connected to the chair stand. A second, outer frame part 2b is connected to the chair seat by way of a fixing plate 2c. It will be noted from fig. 1 that the rigid connection between the seat la and the backrest lb consists of two arms lc, which are fixed into the backrest and fitted to the frame part 2b.

The frame parts 2a, 2b are to a limited extent rotatable in relation to one another about an axis 2d, which lies across the chair mechanism. It will be appreciated from the above that this relative rotation involves an adjustment of the rake of the chair seat la in relation to the horizontal plane.

A catch mechanism that can be actuated by means of the operating lever 3 and is designed to lock the frame parts 2a, 2b relative to one another in a number of selectable chair seat rakes, acts between the frame parts 2a, 2b. Also acting between the frame parts 2a, 2b is a spring element 5 (see fig. 3) which in the embodiment shown in the drawing is a rubber cylinder, but which obviously may alternatively be a helical coil spring. The spring element 5 endeavours to turn the frame parts 2a, 2b away from one another, but is designed to be compressed when a person sits on the chair. The catch mechanism comprises a locking element 2e operatively connected to the operating lever 3. By means of the operating lever 3, this locking element 2e can be displaced transversely to the direction of the axis 2d in and out of engagement with openings 2b 1 arranged in a wall 2b2 in the frame part 2b aligned transversely to the locking element 2e.

The tendency of the spring element 5 to turn the frame parts 2a, 2b away from one another produces a frictional engagement between the locking element 2e and the opening 2b 1 into which it is introduced, a frictional engagement great enough to allow the locking element 2e to be drawn out of the opening by means of the operating lever 3 only when the force of the spring element 5 is overcome by the weight of a person sitting on the chair seat la; the gravitational force exerted by the person in question naturally tends to turn the frame parts 2a, 2b towards one another.

The operating lever 3 is articulated in a wall 2al in the frame part 2a running transversely to the axis 2d, in such a way that it can be moved horizontally for adjustment of the seat rake and vertically for adjustment of the seat height, as will be explained later.

As can be seen from fig. 4, after the support in the wall 2al, the inner end 3 a of the operating lever 3 is bent in a U-shape, passes through an oblong opening 2el in the locking element 2e and is terminated by a part 6, fixed to the end 3a, widening out across the locking element 2e, as can be seen from fig. 3. A helical coil spring 7, which extends essentially in the longitudinal direction of the locking element 2e, acts between the part 6 and the locking element 2e. The spring force of the spring 7 is here selected so that when the operating lever 3 is actuated and the seat la is not under load, it is overcome by the frictional engagement between the locking element 2e and the opening 2b 1, into which the remote end of the locking element is introduced. The operating lever 3 can consequently be moved forwards against the spring force but nothing further happens. When the seat la is loaded by the weight of a person sitting thereon, the spring is able to transmit the movement of the operating lever 3 to the locking element 2e and draw the latter out of engagement with the opening 2b 1. Another chair seat rake may now be selected; the remote end of the locking element 2e automatically snaps in the corresponding opening 2b 1 under the action of the spring 7 without the need to move the operating lever 3.

According to the invention, the locking element 2e takes the form of an element to which torsion can be applied about, its longitudinal axis, such as a leaf spring, which at its edge 2e2 situated nearest the wall 2al of the frame part 2a is supported by the operating lever 3, but which, when the said lever is raised, is acted upon by the part 6, so that the opposite edge 2e3 is forced downwards by the turning of the locking element 2e. The locking element 2e is thereby brought into engagement with an operating pin 8 belonging to the gas-filled spring, see fig. 4, which permits adjustment of the seat height. When the operating lever 3 is released, the locking element 2e returns to its original shape and the engagement with the pin 8 ceases.

Claims

1. Arrangement in a chair mechanism (2) fitted to a chair stand equipped with a gas-filled spring, the mechanism having an operating lever (3) for adjustment of the seat height and chair seat rake comprising a first frame part (2a) connected to the chair stand and a second frame part (2b) connected to the chair seat (la), the frame parts (2a, 2b) being rotatable relative to one another about an axis, which is situated transversely to the chair mechanism (2), and a catch mechanism, acting between the frame parts, actuatable by means of the operating lever (3) and designed to lock the frame parts (2a, 2b) relative to one another in a number of selectable chair seat rakes, the catch mechanism comprising a locking element (2e), operatively connected to the operating lever (3) by way of a spring (7) and designed to be moved by means of the operating lever (3) into and out of openings (2bl), defining the seat rakes, in a wall (2b2) in the second frame part (2b) aligned transversely to the locking element, a spring element (5) acting between the frame parts (2a, 2b) being designed to produce a frictional engagement between the locking element (2e) and the openings (2b 1) in the wall (2b2) of the second frame part (2b), which when the seat (la) is not under load renders it impossible to draw the locking element (2e) out of the respective opening (2b 1), and to be overcome when the seat (la) is loaded by the weight of a person sitting thereon, it being possible to adjust the rake of the chair seat and to lock the frame parts (2a, 2b) relative to one another under the action of the spring (7) acting on the locking element (2e), characterised in that the locking element (2e) takes the form of an element to which torsion can be applied about its longitudinal axis and is designed, when acted upon by the operating lever (3) in a transverse direction to that for adjustment of the seat rake, to be brought into engagement with a member (8) for adjustment of the seat height, and when not acted upon by the operating lever to be disengaged under return spring action from the said member (8).

Arrangement according to claim 1, characterised in that the first frame part (2a) comprises an inner frame part supported inside the second, outer frame part (2b).

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3 j Arrangement according to claim 1, characterised in that the spring force of the spring (7) is selected so that when the operating lever (3) is actuated the spring force is overcome by the said frictional engagement when the seat (la) is essentially not under load, but is capable of transmitting tensile force from the operating lever (3) to the locking element (2e) when the seat (la) is loaded by the weight if a person using the chair.