chair

Abstract

This invention provides a chair. [Solution] The chair according to the present invention comprises a seat, a backrest, a support frame, and at least one S-shaped leaf spring. The S-shaped leaf spring is fixed to the support frame by a first section, the seat is attached to a second section, and the backrest is attached to a third section. A first curved section is provided between the first and second sections so that in the neutral position of the chair, the first and second sections are positioned substantially parallel to each other and spaced apart, and the third section is connected to the second section via a curved section opposite to the second. A compressible spacer is provided between the first and second sections, which is guided to be displaceable in the longitudinal direction of the first section.

Description

Technical Field

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

Background Art

[0002] In practice, a synchronization mechanism for synchronously adjusting a seat and a backrest is known. The backrest and the seating surface are flexibly coupled to each other and move relative to each other at a fixed ratio, for example, 3:1 or 2:1. To implement the synchronization mechanism, various pivoting mechanisms for coupling the backrest and the seat have been developed. One or more spring elements buffer the synchronous movement.

[0003] A chair having a seat, a backrest, and a support frame is known from European Patent No. 2047769. The seat is supported by a seat support, the backrest is supported by a back support, and the seat support and the back support together form an S-shaped spring element having at least two portions with different spring strengths formed from separate spring elements. The effective spring length of the rocking spring can be adjusted via an adjustment element due to the presence of a second element associated with the rocking spring. In addition, a slider for connecting the rocking spring to the second element is provided. Depending on the position of this slider, a longer or shorter portion of the rocking spring can deform independently of the second element.

[0004] Furthermore, U.S. Patent Application Publication No. 2002 / 0000745 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 in a first section, the seat is attached to a second section, the backrest is attached to a third section, a first curved portion is provided between the first and second sections, so that in the neutral position of the chair, the first and second sections are essentially parallel and spaced apart from each other, and the third section is adjacent to the second section via a second opposite curved portion. Furthermore, the second section is supported by the cross member via a first spring element. During downward seat movement, the first spring element is compressed and eventually operably contacts a second spring element provided between the first and second sections. The two spring elements enable stable, self-damping rotational motion of the seat and backrest, and limit the chair's maximum tilt position. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] European Patent No. 2047769 [Patent Document 2] U.S. Patent Application Publication No. 2002 / 0000745 [Overview of the project] [Problems that the invention aims to solve]

[0006] The object of the present invention is to improve the adjustability of the rotational motion. [Means for solving the problem]

[0007] This objective is achieved according to the features of claim 1. Further embodiments of the present invention are the subject of the dependent claims.

[0008] The chair according to the present invention comprises a seat, a backrest, a support frame, and at least one S-shaped leaf spring, the S-shaped leaf spring being fixed to the support frame by a first section, the seat being attached to a second section, the backrest being attached to a third section, a first curved section provided between the first and second sections, so that in the neutral position of the chair, the first and second sections are essentially parallel and spaced apart from each other, and the third section is adjacent to the second section via the second opposite curved section. A compressible spacer is provided between the first and second sections, which is guided to be displaceable in the longitudinal direction of the first section.

[0009] Displacement of the compressible spacer along the first section allows the effective lever arm of the second section to be modified, thereby adjusting the stiffness of the reclining motion and making it suitable for different user weights in particular.

[0010] Preferably, only one S-shaped leaf spring is provided, positioned mirror-symmetrically with respect to the longitudinal center plane of the chair. This reduces the number of components on the one hand, and facilitates the lateral rotational movement of the seat and backrest on the other hand. Thus, a chair designed in this way also allows for three-dimensional dynamic seating.

[0011] According to one preferred embodiment of the present invention, the compressible spacer is located in an intermediate region of the first section between the fastening portion to the support frame and the first curved portion. Furthermore, the compressible spacer having the first contact surface may be displaceably guided on the first section and may have a second contact surface at its opposite end, to which a second section of an S-shaped leaf spring is preferably loosely supported.

[0012] To displace the compressible spacer, it is preferable that the first section of the S-shaped leaf spring has at least one recess extending in the longitudinal direction of the first section. In this way, the effective lever arm of the second section of the leaf spring, and therefore the elastic force, can be easily changed by moving the compressible spacer.

[0013] The compressible spacer may be connected to an actuation element for displacing the compressible spacer along a recess and for removably fixing the compressible spacer in a desired position. Particularly simple and intuitive adjustment can be achieved if the actuation element is designed such that the rotation of the actuation element results in the simultaneous displacement of the compressible spacer along the recess. This is achieved, for example, by the recess being formed as an elongated hole with teeth, and the actuation element being operationally coupled to the teeth, so that the rotation of the actuation element results in the simultaneous displacement of the compressible spacer along the recess. Thus, the actuation element and the elongated hole with teeth can mesh, in particular, like the teeth of a self-locking lantern gear.

[0014] S-shaped leaf springs are preferably made from steel. Compared to plastic or glass fiber reinforced plastic, steel has the advantage of a significantly smaller CO2 footprint. Furthermore, the spring behavior of steel is perceived by users as "snappier" and therefore more comfortably dynamic. Within the scope of the present invention, it has been advantageously shown that if the steel has a yield strength exceeding 500 MPa, elastic return is guaranteed even under considerably high user weights. Further reduction of the CO2 footprint can be achieved by manufacturing the seat and backrest from plywood.

[0015] To prevent the chair from feeling "too soft" when tilted backward, it is advantageous for the compressible spacer to have a progressive spring characteristic curve. For example, steel coil springs and / or Cellasto discs are suitable as compressible spacers.

[0016] According to a further embodiment of the present invention, the S-shaped leaf spring is deflectable with respect to both bending and rotation. In this way, three-dimensional dynamic seating is enabled, and the seat and backrest can be pivoted not only rearward but also laterally. Therefore, the compressible spacer is designed to support the lateral pivoting movement by being compressible laterally as well. Further, the recess extending in the longitudinal direction of the first section can also be designed to facilitate the rotation of the first section about the longitudinal central axis of the first section, and thus the lateral pivoting.

[0017] An armless chair can also be selectively provided on the seat or the second part of the S-shaped leaf spring.

[0018] A further embodiment of the present invention will be described in more detail based on the following description and drawings.

[0019] The drawings are as follows.

Brief Description of the Drawings

[0020] [Figure 1] A schematic side view of a chair with the spacer in the rear position is shown. [Figure 2] A schematic side view of a chair with the spacer in the front position is shown. [Figure 3] A schematic view of the S-shaped leaf spring with the compressible spacer in the front position is shown. [Figure 4] A schematic view of the S-shaped leaf spring with the compressible spacer in the rear position is shown. [Figure 5] A three-dimensional bottom view of the figure according to FIG. 4 is shown. [Figure 6] A cross-sectional view of the region of the compressible spacer is shown. [Figure 7] (a) to (h) show schematic views of the lantern gear teeth at various positions of the actuating element. [Figure 8] A schematic side view of the chair according to FIG. 1 in the reclined position is shown. [Figure 9] A schematic side view of the chair according to FIG. 2 in the reclined position is shown. [Figure 10] Figure 1 shows a schematic front view of the chair, which is positioned at a horizontal inclination. [Figure 11] Figure 2 shows a schematic front view of the chair, which is positioned at a horizontal inclination. [Modes for carrying out the invention]

[0021] 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, the S-shaped leaf spring 4 having a first section 4a fastened to the support frame 3, the seat 1 being attached to a second section 4b, and the backrest 2 being attached to a third section 4c. A first curved section 4d is provided between the first and second sections, so that in the neutral position shown in Figure 1, the first section 4a and the second section 4b are essentially spaced apart and parallel to each other, and the third section 4c is adjacent to the second section 4b via a second opposite curved section 4e.

[0022] The support frame 3 comprises a central column 3a and a cross-shaped base 3b equipped with rollers 3c. However, within the scope of the present invention, other support frames, particularly those having fixed legs, are conceivable.

[0023] Furthermore, in the illustrated exemplary embodiment, an armrest 5 is provided, fixed to the seat 1 or the second section 4b of the S-shaped leaf spring 4. In addition, a compressible spacer 6 is provided between the first section 4a and the second section 4b, which is displaceable in the longitudinal direction of the first section 4a. Figure 1 shows the compressible spacer 6 in a rear position, while the front position is shown in Figure 2. The compressible spacer 6 is located in the intermediate region of the first section 4a, i.e., between the fastening portion of the S-shaped leaf spring 4 to the support frame 3 and the first curved portion 4d. The compressible spacer, having a first contact surface, is displaceable on the first section 4a, and at its opposite end, has a second contact surface that (loosely) supports the second section 4b of the S-shaped leaf spring 4.

[0024] In particular, depending on the design of the compressible spacer 6 as a coil spring, guide elements for the spacer 6 may be provided in the region of the second section 4b. According to an optional feature, the spacer has a progressive spring characteristic curve. The S-shaped leaf spring 6 is preferably made of steel having a yield strength greater than 500 MPa.

[0025] As is clear from Figures 10 and 11, only one S-shaped leaf spring 4 is provided, which is arranged mirror-symmetrically with respect to or within the longitudinal central plane 7 of the chair.

[0026] Figures 3 and 4 show the S-shaped leaf spring 4 in three dimensions, and it is clear that the first section 4a of the S-shaped leaf spring 4 has at least one recess 4f in the form of an elongated hole that extends in the longitudinal direction of the first section 4a to displace the compressible spacer 6. In the illustrated exemplary embodiment, the compressible spacer 6 is designed as a coil spring. However, as shown in Figures 1 and 2, it can also be formed from a Cerast disc or a combination of a coil spring and a Cerast disc.

[0027] The compressible spacer 6 is connected to an actuation element 8 for moving the compressible spacer 6 along the recess 4f and for removably fixing the compressible spacer 6 in the desired position. In the simplest case, this may be a screw-nut connection. However, in the exemplary embodiments shown in Figures 5 and 6, the actuation element 8 is designed such that rotation of the actuation element 8 results in simultaneous displacement of the compressible spacer 6 along the recess 4f. For this purpose, the recess 4f is designed as an elongated hole with teeth 9, and the actuation element 8 is in an actuation engagement with the teeth 9, so that rotation of the actuation element 8 results in simultaneous displacement of the compressible spacer 6 along the recess 4f. In the illustrated embodiment, the teeth 9 are provided on a toothed track 10 located on the bottom surface of section 4a in the region of the recess 4f. However, it is also conceivable that the recess 4f provided in section 4a already has teeth 9.

[0028] Ideally, the actuating element 8 and the elongated hole 4f, which is provided with the teeth 9, engage with each other like the teeth of a self-locking lantern gear. Thus, the actuating element 8, designed as a rotary handle, can remain in any position without additional means. Figures 7(a) to 7(h) show the engagement between the actuating element 8 and the teeth 9 at various positions of the actuating element or the compressible spacer 6 connected thereto. Also, as is evident from Figures 6 and 7(a) to 7(h), on the toothed track 10, opposite to the compressible spacer 6, the actuating element 8 has a first disc 8a that is rotatably and fixedly connected, the diameter of which is greater than the width of the recess 4f. The first disc 8a has two rollers or pins 8b, 8c that engage with the teeth 9. Next, a second disc, whose diameter is slightly smaller than the width of the recess 4f, is fixed to the two pins 8b, 8c and guided within the recess 4f during the displacement of the compressible spacer 6. Next, a third disk 8e, which is displaceably guided on the upper surface of the first section 4a, is provided on the second disk 8d. A compressible spacer 6 (in this case, a coil spring) is appropriately attached to this third disk 8e, for example, by a mounting element 8f.

[0029] The S-shaped leaf spring 4, which interacts with the compressible spacer 6, is designed to allow the chair to bend to a reclined position. The seat 1 and backrest 2 can be tilted further rearward and downward when the compressible spacer 6 is positioned further forward, i.e., closer to the first curved section 4d, as in Figure 9 compared to Figure 8. An optional end stop 11 may be provided on the extension of the central column 3a of the support frame 3, as shown in Figure 9, to limit the movement of the S-shaped leaf spring 4 under extremely high loads.

[0030] When the movement of the chair to the reclined position shown in Figures 8 and 9 is initiated by the person sitting in the chair, this not only results in the descent of the second section 4b around a virtual pivot point within the region of the first curved section 4d, but also results in an increase in the angle between the seat 1 and the backrest 2, similar to conventional synchronous mechanisms implemented by a swivel mechanism. The increase in the angle between the seat 1 and the backrest 2 is evident in Figures 8 and 9 from the solid line diagram of the backrest 2 compared with the dashed line diagram of the backrest. The angle between the seat 1 and the backrest 2 may change, for example, by about 5°.

[0031] However, the S-shaped leaf spring 4 is designed to bend not only in terms of bending to the rearward-tilted position shown in Figures 8 and 9, but preferably also in terms of rotation, so that a person sitting in a chair can tilt the chair laterally, as is evident from Figures 10 and 11. Here again, the position of the compressible spacer affects the degree of lateral tilting motion, so that a compressible spacer 6 located further forward (Figures 2 and 9) allows for greater lateral tilting motion than a compressible spacer 6 located further rearward (see Figure 11) as shown in Figures 2, 9, and 12.

[0032] The rotational capability of the first section 4a of the S-shaped leaf spring 4, about the longitudinal central axis 12 (Figures 5, 10, and 11), and therefore the lateral tilting capability of the chair, is facilitated by the recess 4f extending longitudinally in the first section 4a. [Explanation of symbols]

[0033] 1 sheet 2 Backrest 3. Support frame 3a center pillar 3b Cross-shaped base 3c Laura 4 S-shaped leaf springs 4a Section 1 4b Section 2 4c Section 3 4d First curved section 4e Curved section 4f recess, elongated hole 5 Armrest 6. Compressible Spacer 7 Longitudinal center plane 8 Operating elements 8a First disk 8b pin 8c pin 8d Second disc 8e Third disc 8f Mounting element 9 Teeth 10-toothed track 11 End Stops 12 Longitudinal central axis

Claims

1. A chair having a seat (1), a backrest (2), a support frame (3), and at least one S-shaped leaf spring (4), The S-shaped leaf spring (4) is fixed to the support frame (3) in the first section (4a), the seat is attached to the second section (4b), the backrest (2) is attached to the third section (4c), the first curved portion (4d) is provided between the first section (4a) and the second section (4b), so that in the neutral position of the chair, the first section (4a) and the second section (4b) are essentially parallel to each other and spaced apart, the third section (4c) is adjacent to the second section (4b) via a second opposite curved portion (4e), and the compressible spacer (6) is provided between the first section (4a) and the second section (4b). The chair is characterized in that the compressible spacer (6) is guided so as to be displaceable in the longitudinal direction of the first section (4a).

2. The chair according to claim 1, characterized in that it is provided with a single S-shaped leaf spring (4), the S-shaped leaf spring (4) is arranged in mirror symmetry with respect to the longitudinal central plane (7) of the chair.

3. The chair according to claim 1 or 2, characterized in that the compressible spacer (6) is positioned in an intermediate region of the first section (4a) between the fastening portion to the support frame (3) and the first curved portion (4d).

4. The chair according to any one of claims 1 to 3, characterized in that the first section (4a) of the S-shaped leaf spring (4) has at least one recess (4f), particularly an elongated hole, extending in the longitudinal direction of the first section (4a) for the displacement of the compressible spacer (6).

5. The chair according to claim 4, characterized in that the compressible spacer (6) is connected to an actuation element (8) for displacing the compressible spacer (6) along the recess (4f) and for removably fixing the compressible spacer (6) in a desired position.

6. The chair according to claim 5, characterized in that the actuation element (8) is designed such that the rotation of the actuation element (8) causes simultaneous displacement of the compressible spacer (6) along the recess (4f).

7. The chair according to claim 5, characterized in that the recess (4f) is designed as an elongated hole with teeth (9), and the actuating element (8) is actuarially engaged with the teeth (9), so that the rotation of the actuating element (8) results in a simultaneous displacement of the compressible spacer (6) along the recess (4f).

8. The chair according to claim 7, characterized in that the actuation element (8) and the elongated hole having the teeth (9) are interlocked with each other like the teeth of a self-locking lantern gear.

9. The chair according to any one of claims 1 to 8, characterized in that the S-shaped leaf spring (4) is made of steel.

10. The chair according to claim 9, characterized in that the steel has a yield strength of 500 MPa or more.

11. The chair according to any one of claims 1 to 10, characterized in that the compressible spacer (6) has a progressive spring characteristic curve.

12. The chair according to any one of claims 1 to 11, characterized in that the compressible spacer (6) is formed of a steel coil spring and / or a Cerast disc.

13. The chair according to any one of claims 1 to 12, characterized in that it is also provided with an armrest (5) fixed to the second section (4b) of the seat (1) or the S-shaped leaf spring (4).

14. The chair according to any one of claims 1 to 13, characterized in that the S-shaped leaf spring (4) is displaceable with respect to both bending and rotation.

15. The chair according to claim 4 or 14, characterized in that the recess (4f) extending in the longitudinal direction of the first section (4a) is designed to facilitate rotation of the first section (4a) about the longitudinal central axis of the first section (4a).

16. The chair according to claim 1, characterized in that the compressible spacer (6) having a first contact surface is displaceably guided on the first section (4a), and has a second contact surface at its opposite end that supports the second section (4b) of the S-shaped leaf spring (4).

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