Chair

Abstract

The chair according to the invention comprises a seat, a backrest, a support frame and at least one S-shaped leaf spring, wherein the S-shaped leaf spring is fastened to the support frame by a first section, the seat is held by a second section and the backrest by a third section, wherein a first curvature is provided between the first and the second section, so that the first section and the second section are arranged substantially parallel to one another and spaced apart from one another in a rest position of the chair, and the third section adjoins the second section via an opposite second curvature. A compressible spacer is provided between the first and the second section, which is adjustably guided in the longitudinal direction of the first section, wherein - the first section of the S-shaped leaf spring has at least one recess extending in the longitudinal direction of the first section for adjusting the compressible spacer, - the compressible spacer is connected to an actuating element for displacing the compressible spacer along the recess and for releasably fixing the compressible spacer in a desired position, and - the actuating element is designed such that rotation of the actuating element causes a simultaneous displacement of the compressible spacer along the recess.

Description

[0001] The invention relates to a chair with a seat, a backrest, a support frame and a seat suspension which is formed by at least one S-shaped leaf spring.

[0002] Synchronous mechanisms for the synchronous adjustment of the seat and backrest are known in practice. The backrest and seat surface are flexibly coupled and move at a fixed ratio, for example, 3:1 or 2:1. To implement the synchronous mechanism, various pivoting mechanisms have been developed through which the backrest and seat are coupled. One or more spring elements cushion the synchronous movement.

[0003] EP 2 047 769 B1 discloses a chair having a seat, a backrest, and a supporting frame. The seat is held by a seat support, and the backrest by a backrest support, the seat support and backrest support comprising at least one rocker spring and together forming an S-shaped spring element having at least two sections with different spring strengths, which are formed from separate spring elements. The effective spring length of the rocker spring can be adjusted via an adjusting element by providing a second element accompanying the rocker spring. Furthermore, a slider is provided which connects the rocker spring to the second element. Depending on the location of this slider, a longer or shorter portion of the rocker spring is capable of deforming independently of the second element.

[0004] Furthermore, US 2002 / 0000745 A1 relates to a patient chair having a seat, a backrest, a support frame and two S-shaped leaf springs, wherein the S-shaped leaf springs are fastened to the support frame via a cross member with a first section, the seat is held on a second section and the backrest is held on a third section, wherein a first curvature is provided between the first and the second section, so that the first section and the second section are arranged substantially parallel to one another and at a distance one above the other in a rest position of the chair and the third section is connected to the second section via an opposite second curvature. Furthermore, the second section is supported on the cross member via a first spring element.During a downward seat movement, the first spring element is compressed and eventually comes into contact with a second spring element located between the first and second sections. These two spring elements enable a stable, self-damping swivel movement of the seat and backrest and limit the maximum tilt position of the chair.

[0005] US 2016 / 0 143 443 A1 describes an adjustable reclining system for chairs that allows the backrest and seat to be moved between an upright and a reclined position, whereby the system uses a combination of springs and an adjustment element to regulate the reclining force.

[0006] JP H07 - 29 877 Y2 describes a chair with a seat and a backrest, wherein the seat is hingedly coupled to a support frame at a front area and a spring-elastic damping element is provided between the seat and the support frame.

[0007] US Patent No. 4,889,385 A discloses a chair with a one-piece seat and backrest consisting of a U-shaped seat support and a substantially vertical backrest. The seat support has flexible sections that allow the upper part of the seat support to bend downward relative to the lower part and the backrest to bend backward and downward when pressure is applied.

[0008] DE 10 2011 120 753 A1 describes a piece of seating furniture with a one-piece connecting element which is connected to the backrest and the seat surface and is designed to resiliently counteract a pivoting movement of the backrest, wherein the connecting element is designed to pivot the seat surface in a predetermined ratio to the pivoting movement of the backrest, so that the backrest and the seat surface open to each other with an opening angle when the backrest is pivoted.

[0009] DE 20 2011 000 805 U1 relates to a chair with a seat, a backrest, a base, and at least one S-shaped spring clip. The S-shaped spring clip is fastened to the base by a first section, the seat is held by a second section, and the backrest is held by a third section. A locking element is provided between the first and second sections, which is movable back and forth along the seat in its longitudinal direction and which is supported downwards against the base. Furthermore, the seat is supported against the base by a compression spring provided in addition to the spring clip.

[0010] The invention is based on the object of improving the adjustability of the pivoting movement.

[0011] According to the invention, this object is achieved by the features of claim 1. Further embodiments of the invention are the subject of the subclaims.

[0012] The chair according to the invention has a seat, a backrest, a support frame and at least one S-shaped leaf spring, wherein the S-shaped leaf spring is fastened to the support frame by a first section, the seat is held by a second section and the backrest by a third section, wherein a first curvature is provided between the first and the second section, so that the first section and the second section are arranged substantially parallel to one another and at a distance one above the other in a rest position of the chair and the third section is connected to the second section by an opposite second curvature. A compressible spacer is provided between the first and the second section and is adjustably guided in the longitudinal direction of the first section.

[0013] The adjustment of the compressible spacer along the first section allows a change in the effective lever arm of the second section, whereby the hardness of the reclining movement can be adjusted and, in particular, adapted to different user weights.

[0014] Preferably, only one S-shaped leaf spring is provided, arranged mirror-symmetrically to the longitudinal center plane of the chair. This reduces the number of components and also facilitates lateral pivoting of the seat and backrest. A chair designed in this way thus also enables three-dimensional, dynamic sitting.

[0015] According to a preferred embodiment of the invention, the compressible spacer is arranged in a central region of the first section between the attachment to the support frame and the first curve. Furthermore, the compressible spacer can be adjustably guided with a first contact surface on the first section and can have a second contact surface at its opposite end, on which the second section of the S-shaped leaf spring is preferably loosely supported.

[0016] To adjust the compressible spacer, the first section of the S-shaped leaf spring preferably has at least one recess extending in the longitudinal direction of the first section. This allows the effective lever arm of the second section of the leaf spring, and thus the spring force, to be easily changed by moving the compressible spacer.

[0017] Furthermore, it is provided that the compressible spacer is connected to an actuating element for displacing the compressible spacer along the recess and for releasably fixing the compressible spacer in a desired position. A particularly simple and intuitive adjustment is achieved according to the invention in that the actuating element is designed such that rotation of the actuating element causes simultaneous displacement of the compressible spacer along the recess. This could be realized, for example, by designing the recess as an elongated hole with a toothing and the actuating element being in operative engagement with the toothing, so that rotation of the actuating element causes simultaneous displacement of the compressible spacer along the recess.In this way, the actuating element and the slot provided with the toothing can engage with each other, particularly in the manner of a self-locking rack and pinion toothing.

[0018] The S-shaped leaf spring is preferably made of steel. Compared to plastic or glass-fiber-reinforced plastic, steel has the advantage of a significantly lower carbon footprint. Furthermore, users perceive the spring behavior of steel as "crisper" and thus pleasantly dynamic. Within the scope of the invention, it has proven advantageous for the steel to have a yield strength of more than 500 MPa to ensure elastic recovery even with higher user weights. A further reduction of the carbon footprint can be achieved by making the seat and backrest from plywood.

[0019] To ensure the chair doesn't feel too soft when reclining, it's advisable for the compressible spacer to have a progressive spring characteristic. A suitable compressible spacer could be a steel coil spring and / or a Cellasto® disc.

[0020] According to a further embodiment of the invention, the S-shaped leaf spring is deflectable both in terms of bending and twisting. This enables three-dimensional sitting motion, so that the seat and backrest can pivot not only backward but also sideways. The compressible spacer is therefore also designed to support the lateral pivoting movement by also being laterally compressible. Furthermore, the recess extending in the longitudinal direction of the first section can also be designed in such a way that rotation of the first section about a longitudinal central axis of the first section, and thus lateral pivoting, is promoted.

[0021] The chair can also be fitted with optional armrests that are attached to the seat or to the second section of the S-shaped leaf spring.

[0022] Further embodiments of the invention are explained in more detail with reference to the following description and the drawing.

[0023] In the drawing show Fig. 1 a schematic side view of the chair with a spacer in a rear position, Fig. 2 a schematic side view of the chair with a spacer in a forward position, Fig. 3 a schematic representation of the S-shaped leaf spring with compressible spacer in the front position, Fig. 4 a schematic representation of the S-shaped leaf spring with compressible spacer in the rear position, Fig. 5 a three-dimensional bottom view of the representation according to Fig. 4, Fig. 6 a sectional view in the area of ​​the compressible spacer, Fig. 7a to 7h schematic representations of the rack and pinion gearing in different positions of the actuating element, Fig. 8 a schematic side view of the chair according to Fig. 1 in the reclined position, Fig. 9 a schematic side view of the chair according to Fig. 2 in the reclined position, Fig. 10 a schematic front view of the chair according to Fig. 1 in a sideways tilted position, Fig. 11 a schematic front view of the chair according to Fig. 2 in a sideways tilted position.

[0024] The one in the Fig. The chair shown in Figures 1 to 6 essentially consists of a seat 1, a backrest 2, a support frame 3 and at least one S-shaped leaf spring 4, wherein the S-shaped leaf spring 4 is fastened to the support frame 3 by a first section 4a, while the seat 1 is held by a second section 4b and the backrest 2 by a third section 4c. Between the first and the second section, a first curvature 4d is provided, so that the first section 4a and the second section 4b in the Fig. 1 are arranged substantially parallel to one another and spaced apart from one another in the rest position of the chair, and the third section 4c is connected to the second section 4b via an opposite second curvature 4e.

[0025] The support frame 3 has a central column 3a and a base 3b with casters 3c. However, other support frames are also conceivable within the scope of the invention, particularly those with fixed feet.

[0026] Furthermore, the illustrated embodiment provides armrests 5, which are attached to the seat 1 or to the second section 4b of the S-shaped leaf spring 4. Between the first section 4a and the second section 4b, a compressible spacer 6 is also provided, which is adjustable in the longitudinal direction of the first section 4a. Fig. 1 shows the compressible spacer 6 in a rear position, while in Fig. 2, a front position is shown. The compressible spacer 6 is arranged in a central region of the first section 4a, i.e., between the attachment of the S-shaped leaf spring 4 to the support frame 3 and the first curvature 4d, wherein it is adjustably guided with a first contact surface on the first section 4a and has a second contact surface at its opposite end, on which the second section 4b of the S-shaped leaf spring 4 is (loosely) supported.

[0027] Depending on the design of the compressible spacer 6, in particular as a spiral spring, a guide element for the spacer 6 can also be provided in the area of ​​the second section 4b. According to an optional feature, the spacer has a progressive spring characteristic. The S-shaped leaf spring 4 is preferably made of steel with a yield strength of more than 500 MPa.

[0028] Fig. 10 and Fig. 11 show that only one S-shaped leaf spring 4 is provided, which is arranged mirror-symmetrically to or in the longitudinal center plane 7 of the chair.

[0029] Fig. 3 and Fig. 4 show the S-shaped leaf spring 4 in a three-dimensional representation, from which it can be seen that the first section 4a of the S-shaped leaf spring 4 has at least one recess 4f extending in the longitudinal direction of the first section 4a in the form of an elongated hole for adjusting the compressible spacer 6. The compressible spacer 6 is designed as a spiral spring in the illustrated embodiment. However, it can also, for example, as in Fig. 1 and Fig. 2, can be formed from a Cellasto disc or a combination of a spiral spring and a Cellasto disc.

[0030] The compressible spacer 6 is connected to an actuating element 8 for displacing the compressible spacer 6 along the recess 4f and for releasably fixing the compressible spacer 6 in a desired position. In the simplest case, this can be a screw-nut connection. In the embodiment according to Fig. 5 and Fig. 6, however, the actuating element 8 is designed such that a rotation of the actuating element 8 causes a simultaneous displacement of the compressible spacer 6 along the recess 4f. For this purpose, the recess 4f is designed as an elongated hole with a toothing 9, wherein the actuating element 8 is in operative engagement with the toothing 9, so that a rotation of the actuating element 8 causes a simultaneous displacement of the compressible spacer 6 along the recess 4f. In the illustrated embodiment, the toothing 9 is formed on a toothed rail 10 mounted on the underside of the first section 4a in the region of the recess 4f. However, it is also conceivable that the recess 4f provided in the first section 4a already has the toothing 9.

[0031] Ideally, the actuating element 8 and the slot 4f provided with the toothing 9 engage with each other like a self-locking pinion gear. This allows the actuating element 8, designed as a rotary handle, to remain in any position without additional measures. Fig. 7a to 7h show the engagement of the actuating element 8 in the toothing 9 for different positions of the actuating element or the associated compressible spacer 6. Fig. 6 and the Fig. 7a to 7h further show that the actuating element 8, on the side of the toothed rail 10 facing away from the compressible spacer 6, has a rotationally fixed first disc 8a, which has a diameter larger than the width of the recess 4f. Two rollers or pins 8b, 8c are arranged on the first disc 8a and mesh with the toothing 9. A second disc 8d, which has a diameter slightly smaller than the width of the recess 4f and is guided in the recess 4f during the displacement of the compressible spacer 6, is fastened to the two pins 8b, 8c. Furthermore, a third disc 8e is provided on the second disc 8d and is displaceably guided on the upper side of the first section 4a. On this third disc 8e, the compressible spacer 6 (here the spiral spring) is held in a suitable manner, for example by a holding element 8f.

[0032] The S-shaped leaf spring 4, in conjunction with the compressible spacer 6, is designed to allow the chair to bend into a reclined position. The seat 1 and backrest 2 can be tilted further backward and downward if the compressible spacer 6 is positioned further forward, i.e., closer to the first curve 4d, as shown in Fig. 9 compared to Fig. 8 is the case. In extension of the central column 3a of the support frame 3, an end stop 11 can optionally be provided, which limits the movement of the S-shaped leaf spring 4 under extremely high load, as shown in Fig. 9 is shown.

[0033] If the movement of the chair into the reclined position is carried out according to the Fig. 8 and Fig. 9 triggered by a person sitting on the chair, not only does the second section 4b lower around a virtual pivot point in the area of ​​the first curve 4d, but the angle between seat 1 and backrest 2 also increases, as in a conventional synchronous mechanism implemented by a pivoting mechanism. The increase in the angle between seat 1 and backrest 2 is shown in the Fig. 8 and Fig. 9 by depicting the backrest 2 with solid lines compared to the dashed representation of the backrest. The angle between seat 1 and backrest 2 can change by approximately 5°, for example.

[0034] However, the S-shaped leaf spring 4 is not only designed to bend into a backward position according to the Fig. 8 and Fig. 9, but is preferably also deflectable with respect to a rotation, so that the chair can be tilted sideways by the person sitting on the chair, as can be seen from the Fig. 10 and Fig. 11. Here too, the position of the compressible spacer influences the extent of the lateral tilting movement, so a compressible spacer 6 arranged further forward ( Fig. 2 and Fig. 9) a stronger lateral tilting movement (see Fig. 11) than the further rearward arranged, compressible spacer 6 according to the Fig. 2, Fig. 9 and Fig. 12.

[0035] The rotatability of the first section 4a of the S-shaped leaf spring 4 around the longitudinal central axis 12 ( Fig. 5, Fig. 10 and Fig.11) and thus the lateral tilting possibility of the chair is facilitated by the recess 4f extending in the longitudinal direction of the first section 4a.

Claims

[1] A chair with a seat (1), a backrest (2), a support frame (3), and at least one S-shaped leaf spring (4), wherein the S-shaped leaf spring (4) is fastened to the support frame (3) by a first section (4a), the seat (1) is held by a second section (4b), and the backrest (2) is held by a third section (4c), wherein a first curvature (4d) is provided between the first section (4a) and the second section (4b), so that the first section (4a) and the second section (4b) are arranged substantially parallel to one another and spaced apart from one another in a rest position of the chair, and the third section (4c) adjoins the second section (4b) by an opposite second curvature (4e), and wherein a compressible spacer (6) is provided between the first section (4a) and the second section (4b), characterized bythat the compressible spacer (6) is adjustable in the longitudinal direction of the first section (4a), wherein - the first section (4a) of the S-shaped leaf spring (4) has at least one recess (4f) extending in the longitudinal direction of the first section (4a) for adjusting the compressible spacer (6), - the compressible spacer (6) is connected to an actuating element (8) for displacing the compressible spacer (6) along the recess (4f) and for releasably fixing the compressible spacer (6) in a desired position, and - the actuating element (8) is designed such that a rotation of the actuating element (8) causes a simultaneous displacement of the compressible spacer (6) along the recess (4f). [2] Chair according to claim 1, characterized bythat only one S-shaped leaf spring (4) is provided, which is arranged mirror-symmetrically to the longitudinal center plane (7) of the chair. [3] Chair according to claim 1 or 2, characterized by that the compressible spacer (6) is arranged in a central region of the first section (4a) between the attachment to the support frame (3) and the first curvature (4d). [4] Chair according to claim 1, characterized by that the recess (4f) is designed as an elongated hole with a toothing (9) and the actuating element (8) is in operative engagement with the toothing (9), so that a rotation of the actuating element (8) causes the simultaneous displacement of the compressible spacer (6) along the recess (4f). [5] Chair according to claim 4, characterized by that the actuating element (8) and the elongated hole provided with the toothing (9) engage in the manner of a rack and pinion toothing. [6] Chair according to one or more of the preceding claims, characterized by that the S-shaped leaf spring (4) is made of steel. [7] Chair according to claim 6, characterized by that the steel has a yield strength of more than 500 MPa. [8] Chair according to one or more of the preceding claims, characterized by that the compressible spacer (6) has a progressive spring characteristic. [9] Chair according to one or more of the preceding claims, characterized by that the compressible spacer (6) is formed by a spiral spring made of steel. [10] Chair according to one or more of the preceding claims, characterized by that armrests (5) are also provided which are fastened to the seat (1) or the second section (4b) of the S-shaped leaf spring (4). [11] Chair according to one or more of the preceding claims, characterized by, the S-shaped leaf spring (4) can be deflected both in terms of bending and twisting. [12] Chair according to claims 1 and 11, characterized by that the recess (4f) extending in the longitudinal direction of the first section (4a) is designed such that a rotation of the first section (4a) about a longitudinal central axis (12) of the first section (4a) is promoted. [13] Chair according to claim 1, characterized by that the compressible spacer (6) is adjustably guided with a first contact surface on the first section (4a) and has a second contact surface at its opposite end, on which the second section (4b) of the S-shaped leaf spring (4) is supported.

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