Seat, in particular office swivel chair

Abstract

A seat (1), in particular an office swivel chair, is described. The seat (1) is provided with a base (2), a base support (8) connected with the base (2), a pair of backrest connecting pieces (10) and a seat surface support (12). The backrest connecting piece (10) is connected with the base supporting piece (8) so that the backrest connecting piece can move along the sagittal plane. Furthermore, the seat surface support (12) is movably coupled to the backrest connection (10) and the base support (8), respectively, by means of at least one joint (20, 22, 26) having at least two rotational degrees of freedom.

Description

TECHNICAL FIELD

[0001] The present invention relates to a seat, in particular an office swivel chair. BACKGROUND

[0002] A seat is generally understood to be a piece of furniture on which at least one person using the piece of furniture can sit. Seats are generally understood to be chairs, office chairs (both in the form of swivel chairs and conference chairs) and armchairs or sofas (also referred to as leisure furniture). Such seats usually have a seat surface and a backrest which is joined at an angle to the seat surface and on which the user can lean.

[0003] Office chairs are usually designed to be rotatable and height-adjustable by means of a correspondingly designed frame, in particular by means of a chair column, and to be moved smoothly along the floor by means of castors, which are usually mounted on the arms of a star-shaped base. If an armrest is provided, it is usually hinged to a support of the seat surface, but can alternatively be attached to a backrest connection (or to a plurality of backrest connections) of the backrest, so as to be fully coupled with the backrest in the tilting movement.

[0004] Modern office chairs often allow the user to influence the seating dynamics fundamentally. In contrast to rigid chairs, which only allow static, in particular motionless, seating, office chairs facilitate so-called dynamic seating by means of their integrated mechanisms and adjustment functions. Dynamic, i.e. active, seating enables the back muscle groups to be subjected to variable loads, so that muscle tension, fatigue and back pain caused by sitting for long periods of time are reduced or completely avoided.

[0005] To this end, office chairs are usually equipped with a synchronization mechanism, by means of which the backrest is coupled to the seat surface. A seat surface connection (optionally directly to a seat surface support) carrying the seat surface is pivotally coupled to a connection of the backrest by means of a joint chain. In most cases, the backrest is synchronized with the inclination of the seat surface, which is usually small, for example in a ratio of 3:1 to 2:1, under the influence of an adjustable spring restoring force.

[0006] To achieve the most anatomically correct support of the human spine, office chair backrests are usually designed with a contour which follows the natural (sagittal) curvature of the spine. By providing various "Bepolsterungen" (cushioning structures), the backrest (in particular the backrest cushion) is brought into uniform contact with the human back. For example, it is known from the prior art to use a backrest which is covered with a mesh or a conventional cushioning structure (i.e. a cushioning material which is usually wrapped in an outer cover). Mesh coverings have the advantage in most cases of providing ventilation of the back in a warm environment, while conventional cushioning structures often enable more individualized local support of the back. SUMMARY

[0007] The present invention is intended to further improve dynamic seating.

[0008] According to the application, this object is achieved by a seat having the features of claim 1. Further embodiments and advantageous and partly inventive further developments of the application are specified in the dependent claims and in the following description.

[0009] The seat according to the application comprises a base and a base support connected to the base. Furthermore, the seat is provided with a pair of backrest connections, i.e. two backrest connections, and a seat surface support. The backrest connections are connected to the base support in a way that they are movable in the sagittal plane. The seat surface support is movably coupled to the backrest connections and the base support, respectively, by means of at least one joint having at least two rotational degrees of freedom.

[0010] Preferably, the seat is a swivel office chair.

[0011] The "sagittal plane" refers to a plane related to the human body, which runs from the "dorsal side" to the "ventral side", i.e. from the back to the belly. Based on the corresponding relationship between the seat and the human body when the seat is in use, the terms of the plane and the orientation of medical anatomy are used herein and hereinafter. The positioning of the corresponding plane and direction refers to the assumption that the human body is located on the seat in an ideal sitting position (i.e. not "deliberately" different, such as across the seat surface, etc.). Therefore, the sagittal plane of the seat corresponds to the plane extending from the backrest (formed by the backrest connections or extended) to the front side when used correctly, which is preferably perpendicular to the plane where the backrest is located.

[0012] The seat surface support is preferably configured to carry (e.g. a conventional cushion structure) or form (particularly in the case of a seat surface formed by a cover layer, such as a mesh structure) the seat surface.

[0013] By means of the joint having multiple rotational degrees of freedom, the seat surface support is coupled to the backrest connections or the base support, so that the seat surface support moves relatively freely with respect to the base support. In particular, based on this mounting position, the seat surface support can also be laterally tilted (i.e. tilted to both sides).

[0014] Preferably, the two backrest connections can move at least partially independently of each other at the respective joint.

[0015] According to an applicable embodiment, the backrest connections are mounted to the base support by means of a torsion spring mechanism and can be rotated relative to each other. Preferably, the torsion spring mechanism is configured such that the movement of the backrest connections in the sagittal plane is spring-loaded. In particular, the torsion spring mechanism is designed to allow the backrest connections to deviate from their reference position under a predetermined load.

[0016] According to an alternative refinement, each backrest connection is provided with an independently assigned torsion spring, in particular a torsion bar. For example, one end of the torsion spring is fixed to the base support and the other end is connected to the corresponding backrest connection in a stable manner (particularly in a torsion-proof manner).

[0017] According to another refinement, the torsion spring mechanism has a torsion spring, in particular a torsion bar, to which both backrest connecting elements are attached. In particular, the two backrest connecting elements are arranged at opposite ends of the torsion spring. The torsion spring is preferably also fixed in a rotationally fixed manner to the base support, so that both backrest connecting elements are spring-loaded against the base support.

[0018] Optionally, the seat is provided with a pretensioning mechanism which is configured to change the pretensioning force of the torsion spring (if applicable, of each torsion spring) in the torsion spring mechanism. Thereby, the resistance of the backrest (formed by the backrest connecting elements in normal use) against a movement towards the back can be increased or decreased, in particular for adjusting the mobility of the seat or the backrest in accordance with the weight of the user of the seat.

[0019] "at least partially independently movable" here and in the following in particular means that the two backrest connecting elements are not rigidly coupled and can be adjusted (rotated) within a first angle range, or independently adjusted (rotated) based on different loads, in particular can be adjusted (rotated) in opposite directions. However, when the angle of adjustment exceeds the first angle range, the two backrest connecting elements can be positively coupled by the torsion spring mechanism or other coupling means, so that the two backrest connecting elements are adjusted (moved) together.

[0020] According to a particularly suitable embodiment, both backrest connecting elements are attached to the (same) front side plane of the base support. This design corresponds to the symmetry requirements of the seat and to the principle of symmetrical movement.

[0021] According to a preferred embodiment, the joint between the seat surface support and each backrest connecting element is designed as a ball joint. Thus, the seat surface support is coupled to both backrest connecting elements by a ball joint mechanism. The ball joint here represents a special form of a rotary joint, which is also a simple embodiment of a multi- degree-of-freedom rotary joint.

[0022] According to another preferred embodiment, the joint between the seat surface support and the base support is also designed as a ball joint. In this case, the backrest connecting elements together with the seat surface support and the base support form a (spatial) multi-joint chain. Optionally, a connecting element is also provided between the seat surface support and the base support, so that a four-joint chain is formed. Such a multi-joint or four-joint chain is a coupling transmission, which allows to predefine the desired movement trajectory of specific points on the joint chain by a suitable selection of the lengths of the respective chain. Thus, by a suitable selection of the lengths of the backrest connecting element sections between the joints, the length of the base support and the length of the seat surface support (if present, including the connecting element), the movement characteristics of the seat surface and the backrest can be predefined, in particular to achieve a coordinated movement of the two (synchronization mechanism characteristics between backrest and seat surface).

[0023] According to a suitable embodiment, a support bar is provided at the joints between the seat surface support and the base support and between the base supports, which support bar in particular constitutes the aforementioned connecting elements. This support bar is likewise coupled to the base supports by means of joints, preferably ball-and-socket joints. As a result, the seat also has a four-joint chain.

[0024] By connecting the backrest connecting elements, which in particular also include the seat surface support in the respective embodiment, to one another and to the base supports (in the case of a seat surface support), the seat surface support can also be moved laterally, i.e. tilted to the side. In particular in a (spatial) four-joint chain, an asymmetric (lateral) forward or rearward inclination or a lateral inclination can occur, in which case the seat surface support and the backrest connecting elements can at least partially perform such an asymmetric movement. This contributes to the "active seating" described above.

[0025] According to another suitable embodiment, the joint provided between the seat surface support and the base support is arranged in front of the joint between the seat surface support and the backrest connecting element in the ventral direction. In particular, the arrangement of this joint on the base support (when viewed in the ventral direction) is also located in front of the mounting position of the backrest connecting element. Viewed from the top, the joint of the seat surface support thus forms a triangle, the apex of which points in the front direction (ventral direction). Preferably, the point at which the backrest connecting element is coupled to the base support is also located ventrally in front of the coupling point of the backrest connecting element to the seat surface support.

[0026] In particular to achieve maximum freedom of movement of the backrest connecting elements relative to one another, according to a preferred embodiment, no further rigid connecting elements are provided between the backrest connecting elements in addition to the base supports and the seat surface support.

[0027] To further enhance the mobility of the backrest connecting elements, according to a preferred embodiment, the backrest connecting elements have a higher torsional flexibility in regions that are further away from the mounting position on the base support and from the coupling position to the seat surface support than in the "coupling region" located in the aforementioned coupling and mounting regions. Alternatively, this property is achieved by changing the profile of the respective backrest connecting element. Alternatively, the backrest connecting elements are made soft for torsion ("torsionsweicher") by choosing a suitable material. For example, the backrest connecting elements in this region are formed from plastic that is appropriately fibre-reinforced, possibly in combination with a change in profile, while the coupling region is formed from metal, in particular steel or aluminium. By virtue of the enhanced torsional flexibility, the backrest formed from the backrest connecting elements, in particular when equipped with a skin, is designed to be more flexible (more elastic) in the upper region than in the lower region, in particular over the region of the sacroiliac joint and optionally the lumbar spine. Preferably, the upper region, when designed in the aforementioned manner (with higher torsional flexibility), should also have a higher bending flexibility than the lower region.

[0028] According to an advantageous embodiment, the seat is equipped with a headrest. Here, the headrest is fixed to the backrest connection by means of a flexible connection, which is arched in the ventral direction. "Flexible" here means that the connection can be deformed by external forces, which leads to a movement of the backrest connection during use. Preferably, the connection is formed by an arched plate, i.e. a plate-like structure made of a material such as metal or plastic, which is arched in the ventral direction. The design of the connection arched in the ventral direction in particular reduces the risk of the connection collapsing ("durchschlagen") in the dorsal direction under load, for example when the user rests his head on the headrest.

[0029] In principle, the connection described above can also serve as a headrest cushion support. Alternatively, however, the connection can also only serve as an attachment point for a height-adjustable headrest cushion.

[0030] Furthermore, according to an advantageous embodiment, the seat is equipped with a pair of armrests, each of which is coupled to the corresponding backrest connection or seat surface support, preferably by means of a rigid connection. As a result, each armrest moves synchronously with the corresponding backrest connection or seat surface support.

[0031] It is readily conceivable that, according to an alternative embodiment, the armrests are attached to the base support in a rigid manner.

[0032] Further alternatively, as already mentioned above, the backrest is formed only by a cladding of the backrest connection. For example, the cladding can be made of a mesh material or a leather material. Preferably, the seat is not equipped with any backrest cushion arranged on the cushion support, which is rigid and located between the backrest connections. BRIEF DESCRIPTION OF DRAWINGS

[0033] Embodiments of the present application will be described in detail below with reference to the attached drawings. In the drawings: Figure 1 is a schematic side view of a seat, Figure 2 is a schematic exploded view of a seat, Figure 3 is a schematic partial sectional view of a seat surface region of a seat, Figure 4 is a schematic side view of a seat in a symmetrical load state, Figure 5 is a schematic view of a seat according to Figure 4 a perspective view in an asymmetrical load state. DETAILED DESCRIPTION

[0034] Corresponding parts are denoted by the same reference symbols in all the figures.

[0035] Figure 1The image shows a side view of a chair, specifically an office swivel chair (referred to as "office chair 1"). Figure 2 This is an exploded view of the chair. The chair has a cross-shaped base 2 with casters 4 as its base. The office chair 1 is also equipped with a gas spring 6, which is mounted on the cross-shaped base 2 and has cushioning and height adjustment functions. The office chair 1 also includes a base support 8 supported by the gas spring 6, and two backrest connectors 10 rotatably held on the base support 8. Both backrest connectors 10 are hinged to the base support 8 via a swivel joint 11, allowing the two backrest connectors 10 to move along the sagittal plane (corresponding to...). Figure 1 The drawing page shown can be rotated. In addition, the office chair 1 is also equipped with a seat support 12, two armrests 14 and a headrest 16.

[0036] In this embodiment, the seat support 12 is provided with a pad to form the seat surface 18. The backrest connector 10 is covered with a mesh (not shown in detail) to form the backrest.

[0037] from Figure 2 As can be seen more clearly, the seat support 12 is connected to the backrest connector 10 and the base support 8 via a swivel joint having more than one degree of rotational freedom. Each backrest connector 10 is connected to the seat support 12 via a ball joint 20, and the backrest connector is in turn connected to the base support 8 via a ball joint 22. A connecting element in the form of a support rod 24 is also provided between the ball joint 22 and the seat support 12, and this connecting element itself is mounted on the base support 8 via another ball joint 26.

[0038] Based on the hinged connection between the backrest connector 10 and the base support 8 via ball joints 20, 22, and 26, the seat support 12 can move not only in the aforementioned sagittal plane (i.e., "pure" backward tilt and appropriate forward tilt), but also to the sides, i.e., lateral movement or tilting in the sagittal plane. However, based on the connection relationship with the two backrest connectors 10, the backrest connectors will move in tandem with the seat support 12, and vice versa. This means that in the sense of a traditional synchronization mechanism, the backrest (i.e., the backrest connector 10) will drive the seat support 12 to "follow" the movement of the backrest. By reasonably selecting the distance between the rotary joint 11 and the ball joint 20 and the length of the support rod 24, the motion transmission relationship between the backrest connector 10 and the seat support 12 can be preset, i.e., the degree of adjustment (tilt) of the seat support 12 when the backrest connector 10 moves (especially backward).

[0039] according to Figure 4 As can be seen, when the backrest connector 10 is adjusted backward (parallel) (i.e., moved to the back side), the seat surface 18 only undergoes a relatively small adjustment through the seat surface support 12, specifically manifested as the rear (back side) edge tilting downward and the front edge tilting upward.

[0040] Furthermore, the two backrest connections 10 are not rigidly coupled, but rather are substantially independently movable. In the present embodiment, both backrest connections 10 are spring-loaded by means of a torsion spring mechanism arranged in the rotary joints 11. This torsion spring mechanism comprises a torsion bar 30 (as torsion spring) which extends through both rotary joints 11 and is coupled with both backrest connections 10.

[0041] Furthermore, the office chair 1 is also provided with a pre-tensioning device 32 (see Figure 3 ). This pre-tensioning device comprises an adjustment shaft 34, a shaft cap 36 and an adjustment lever 38 coupled with the torsion bar 30. When the adjustment shaft 34 is adjusted, the shaft cap 36 is "reited" upwards or downwards and twists the torsion bar 30 via the adjustment lever 38. The torsion bar is thereby pre-tensioned (or relaxed, depending on the direction of movement of the adjustment shaft 34). Thus, when the backrest connections 10 are subjected to a load in the back direction at the rotary joints 11, different degrees of resistance are generated depending on the degree of pre-tensioning. However, if one of the backrest connections 10 is subjected to a greater load than the other (for example due to the user sitting in a slanted position, leaning back on one side in order to reach something behind, etc.), this backrest connection 10 will cause the torsion spring 30 on the corresponding side of the pre-tensioning device 32 (in particular the adjustment lever 38) to be twisted more than the other side, which is mounted in the middle of the base support 8. Thus, the backrest can be twisted or at least asymmetrically deflected (see Figure 5 ). Figure 5 It is exemplarily shown that the right (from the perspective of a seated user) backrest connection 10 is subjected to a greater degree of back leaning than the left backrest connection 10. Based on the articulated relationship of the seat surface support 12, this also tilts to the right rear here. This allows a special dynamic seating, since not only the seat surface, but also the backrest, allows lateral movement.

[0042] In order to support the relative freedom of movement of the two backrest connections 10, they are no longer coupled with each other by means of a connecting element, at least not by means of a rigid connecting element, in addition to the connection by means of the torsion bar 30.

[0043] It can be seen from Figure 2 that the headrest 16 is provided with a flexible connector between the backrest connections 10, so that their independent mobility shown in Figure 5 is not negatively affected. This connector is formed by an arc-shaped plate 40, here in the form of a "strip" of fiber-reinforced plastic curved in the ventral direction (dome-shaped). The dome-shaped structure here prevents the arc-shaped plate 40 from collapsing backwards when the headrest 16 is pressed. Furthermore, the dome-shaped structure also provides greater "length", so that when the backrest connections 10 move away from each other (see Figure 5), the arc plate 40 is only stretched without hindering displacement. When the backrest connecting member 10 moves towards, the arc plate 40 only enhances its arching degree. Optionally, the arc plate 40 is attached to the backrest connecting member 10 through a ball joint (not shown in detail).

[0044] The subject matter of the present application is not limited to the embodiments described above. Rather, a person skilled in the art can derive further embodiments of the present application from the above description.

[0045] List of reference signs 1 office chair 2 cross-shaped base 4 roller 6 gas spring 8 base support 10 backrest connecting member 11 rotary joint 12 seat support 14 armrest 16 headrest 18 seat surface 20 ball joint 22 ball joint 24 support rod 26 ball joint 30 torsion rod 32 pre-tightening device 34 adjustment shaft 36 shaft cap 38 adjustment lever 40 arc plate

Claims

1. A seat (1), in particular an office swivel chair, comprising - a base (2), - a base support (8) coupled with the base (2), - a pair of backrest connections (10), and - a seat surface support (12), wherein the backrest connections (10) are coupled with the base support (8) such that they are movable in a sagittal plane, and wherein the seat surface support (12) is movably coupled with the backrest connections (10) and the base support (8) by at least one joint (20, 22, 26), the seat surface support (12) having at least two rotational degrees of freedom at each joint.

2. The seat (1) according to claim 1, wherein the backrest connections (10) are mounted to the base support (8) by torsion spring mechanisms and are rotatable relative to the base support (8).

3. The seat (1) according to claim 2, wherein each backrest connection (10) is individually provided with a torsion spring, in particular a torsion bar (30).

4. The seat (1) according to claim 2, wherein, the torsion spring mechanisms have a torsion spring, in particular a torsion bar (30), to which both backrest connections (10) are connected.

5. The seat (1) according to any one of claims 1 to 4, wherein the joint provided between the seat surface support (12) and the respective backrest connection (10) is formed as a ball joint (20).

6. The seat (1) according to any one of claims 1 to 5, wherein the joint provided between the seat surface support (12) and the base support (8) is formed as a ball joint (22).

7. The seat (1) according to any one of claims 1 to 6, wherein a support bar (24) is provided between the joint (22) provided between the seat surface support (12) and the base support (8) and the base support (8), the support bar being hingedly coupled with the base support (8).

8. The seat (1) according to any one of claims 1 to 7, wherein the joint (22) provided between the seat surface support (12) and the base support (8) is located in a ventral direction in front of the joint (20) provided between the seat surface support (12) and the backrest connection (10), in particular also in front of the mounting position of the backrest connection (10) at the base support (8).

9. The seat (1) according to any one of claims 1 to 8, wherein, there are no additional rigid connecting elements between the two backrest connections (10) other than the base support (8) and the seat surface support (12).

10. The seat (1) according to any one of claims 1 to 9, wherein, the backrest connections (10) have an enhanced torsional flexibility at least in the region of the mounting position remote from the base support (8) and the coupling position with the seat surface support (12).

11. The seat (1) according to any one of claims 1 to 10, comprising a headrest (16) held to the backrest connector (10) by a flexible connection, in particular by an arched plate (40) which arches in the ventral direction.

12. The seat (1) according to any one of claims 1 to 11, comprising a pair of armrests (14) coupled, preferably rigidly coupled, to the respective backrest connector (10) or to the seat surface support (12).

13. The seat (1) according to any one of claims 1 to 12, wherein the backrest connector (10) being covered to form a backrest cushion.

Images