WO2025223530A1

WO2025223530A1 - Sitting furniture, especially swivel office chair

Info

Publication number: WO2025223530A1
Application number: PCT/CN2025/091089
Authority: WO
Inventors: Zhaogen YOU
Original assignee: Guangdong Je Furniture Co Ltd
Current assignee: Guangdong Je Furniture Co Ltd
Priority date: 2024-04-25
Filing date: 2025-04-25
Publication date: 2025-10-30
Anticipated expiration: 2026-10-25
Also published as: DE202024102092U1; CN120916671A

Abstract

A piece of sitting furniture (1), especially an office swivel chair, is described. The piece of sitting furniture (1) has here a base (2), a base support (8) which is coupled with the base (2), a pair of backrest links (10), and a sitting surface support (12). The backrest link (10) is coupled with the base support (8) in such a way that the backrest link is movable along a saggital plane. Furthermore, the sitting surface support (12) is movably coupled with the backrest links (10) and the base support (8) by means of at least one joint (20, 22, 26), which has at least two degrees of freedom for rotation, in each case.

Description

SITTING FURNITURE, ESPECIALLY SWIVEL OFFICE CHAIR

TECHNICAL FIELD

The present invention relates to sitting furniture, which is formed especially as a swivel office chair.

BACKGROUND

Sitting furniture is generally understood as a piece of furniture, on which at least one person currently using the piece of furniture can sit. It includes basically chairs, office chairs (both in an embodiment as swivel chair and as conference chair) as well as armchairs or sofas (also referred to as lounge furniture) . A piece of such sitting furniture usually has a sitting surface and a backrest, which engages the sitting surface at an angle and on which the user can lean.

An office chair is usually formed in such a way that it is rotatable and adjustable in height by designing a frame correspondingly, especially by means of a chair pillar, and is movable smoothly along the ground through rollers, which are held in most cases at cantilever arms of a cross-shaped base that are arranged in star shape. Armrests, if present, are often hinged at a support of the sitting surface, but can also optionally attached to a backrest link (or backrest links) of the backrest, so as to fully guide an inclination movement together with the backrest.

A modern office chair often allows the person sitting thereon to influence the dynamics of sitting fundamentally. In contrast to a rigid chair which only allows static, in particular motionless, sitting, an office chair facilitates the so-called dynamic sitting because of the integrated mechanisms and possibilities of adaptation. The dynamic (also moving) sitting causes especially variable loading of the back musculature, thereby being able to reduce or completely avoid tensions, fatigues, and back pains caused by longer sitting duration.

For this purpose, office chairs have a synchronous mechanism in most cases, through which the backrest is coupled with the sitting surface. A sitting link carrying the sitting surface (optionally directly over the sitting surface support) is here pivotably coupled with a backrest link for the backrest through a joint chain. In most cases, the backward inclination of the backrest and a synchronous and typically smaller inclination of the sitting surface, for example in a ratio of 3: 1 to 2: 1, are achieved here under the effect of an adjustable spring restoring force.

For the most anatomically advantageous support of the spine of the user, the backrests of office chairs often have a contour following the natural (sagittal) curve of the spine. Various "upholsteries (Bepolsterungen) " are provided to enable the most uniform clinging of the backrest, especially a cushion of the backrest, to the back of the person. For example, backrests with mesh cover or classic cushion structures are thus known (i.e. typically a cushion material covered by a cladding) . A mesh cover has in most cases the advantage that it allows ventilation of the back at high temperatures, while classic cushion structures often provide a more individual local support for the back.

SUMMARY

The invention is based on the objective of further improving moving sitting.

According to the present invention, this objective is solved by a piece of sitting furniture with the features of claim 1. Other embodiments and further developments of the present invention, which are advantageous and partly inventive themselves, are present in the dependent claims and the description hereafter.

The piece of sitting furniture according to the present invention has a base and a base support coupled with the base. Moreover, the piece of sitting furniture has a pair of backrest links (i.e. two backrest links) and a sitting surface support. The backrest links are here coupled with the base support in such a way that the backrest links are movable along a saggital plane. The sitting surface support is movably coupled with the backrest links and the base support by means of at least one joint, which has at least two degrees of freedom for rotation, in each case.

Preferably, the piece of sitting furniture is formed as a swivel office chair.

"Sagittal plane" is especially and generally understood as a plane with regard to the human body, which intersects with the body from "dorsal" side to "ventral" side, i.e. from the back side to the stomach side. With regard to the piece of sitting furniture, the medical terms of planes and directions are also used here and hereafter, because a person sits on the piece of sitting furniture in proper use. The orientation of the corresponding planes and directions is here especially understood with the assumption that a person sits with ideal positioning on the piece of sitting furniture (i.e. not "deliberately (bewusst) " different, for example, across on the sitting surface and the like) . Therefore, the sagittal plane of the piece of sitting furniture corresponds to a plane which extends from a backrest, which is formed by (or expanded from) the backrest links in proper use, to a front side and stands here preferably perpendicularly on a plane assigned to the backrest.

The sitting surface support is preferably configured to carry (for example, in the case of a classic upholstery) or to form (especially if the sitting surface is formed by a cover, for example in the case of a mesh surface) the sitting surface.

The coupling between the sitting surface support and the backrest links or the base support through the joint with a plurality of degrees of freedom for rotation enables a relatively free movement of the sitting surface support compared with the base support. Especially, because of this mounting position, the sitting surface support can also be inclined transversely, i.e. towards the sides.

Preferably, both of the backrest links are movable in their respective joints at least partly separately from each other.

According to a suitable embodiment, the backrest links are mounted at the base support by means of a torsion spring mechanism and are mounted swivelably relatively to each other. Preferably, the torsion spring mechanism is formed here in such a way that the movement of the backrest links along the sagittal plane is spring-loaded. Especially, the torsion spring mechanism is here designed in such a way that the backrest links can be moved out of their basic position under a preset load.

According to an optional further development, the torsion spring mechanism for each backrest link has a separately assigned torsion spring, especially a torsion bar. For example, this torsion spring is fixed with one end at the base support and is firmly, i.e. especially in a twist-proof way, connected with the other end to the assigned backrest link.

According to an alternative further development, the torsion spring mechanism has a torsion spring, especially a torsion bar, to which both of the backrest links are attached. Especially, both of the backrest links are hereby arranged at opposite ends of the torsion spring. The torsion spring is in addition preferably also fastened at the base support in a rotation-proof way, so that both of the backrest links are spring-loaded against the base support.

Optionally, the piece of sitting furniture has a pretension mechanism, which is configured and provided to change a pretension force of the (if appropriate, respective) torsion spring of the torsion spring mechanism. Thereby, the resistance of the backrest, which is formed by means of the backrest links in proper use, against a movement towards dorsal side can be increased or decreased, especially for adaptation of the mobility of the piece of sitting furniture or the backrest to the body weight of a user of the piece of sitting furniture.

"At least partly separately movable" is thus here and hereafter especially understood in such a way that both of the backrest links are not rigidly coupled with each other and are adjustable (swivelable) for example at least inside a first angle range or separately from each other, especially against each other, on the basis of different loads. However, if the adjustment angle is beyond this first angle range, a positive coupling of both of the backrest links may also occurs, especially through the torsion spring mechanism or another coupling, so that the backrest links are then adjusted (moved) together.

According to a specially suitable embodiment, both of the backrest links are attached to the base support in a (one and the same) front plane. It is reasonable in terms of the symmetry of the piece of sitting furniture as well as the symmetric movement.

According to a preferable embodiment, the joint arranged between the sitting surface support and the respective backrest link is formed as ball joint. Therefore, the sitting surface support is coupled with the backrest links by means of a ball joint in each case. The ball joint represents here a specially movable form of rotary joint and a simple embodiment of a joint with a plurality of degrees of freedom for rotation.

According to another preferable embodiment, the joint arranged between the sitting surface support and the base support is (especially also) formed as ball joint. In this case, the backrest link forms a (spatial) multi-joint chain together with the sitting surface support and the base support. Optionally, an additional connection member is used between the sitting surface support and the base support, so that a four-joint chain is established. Such a multi-joint or four-joint chain represents a coupling transmission and allows to preset a desired trajectory of individual points along the joint chain by choosing the lengths of the respective chain links suitably. Thus, movements of the sitting surface and the backrest can be preset, especially they can coordinate with each other (especially in the sense of a synchronous mechanism between the backrest and the sitting surface) , by suitably choosing the lengths of the portions of the backrest links between the joints, of the base support and of the sitting surface support (as well as of the connection member, if present) .

According to a suitable embodiment, a support bar (which forms especially the connection member mentioned above) is arranged between the joint, which is arranged between the sitting surface support and the base support, and the base support. The support bar is here also coupled with the base support articulately, preferably by means of a ball joint. Thus, the piece of sitting furniture also has a four-joint chain.

The sitting surface support can also perform lateral movements, namely tilting to the sides, by coupling the backrest links and especially also the sitting surface support in corresponding embodiments with each other and with the base support (in the case of the sitting surface support) by means of ball joints. Especially in the case of the (especially spatial) four-joint chain, asymmetric (lateral) front-back leaning or leaning towards the side may occur, where the sitting surface support and the backrest links can also perform such an asymmetric movement at least partly. This facilitates the assistance of the "moving sitting" mentioned at the beginning.

According to another suitable embodiment, the joint arranged between the sitting surface support and the base support is arranged before the joint arranged between the sitting surface support and the backrest links in ventral direction. Especially, this joint is here also (viewed in ventral direction) arranged at the base support before the mounting position of the backrest links. Observing from a top side, the joint of the sitting surface support forms a triangle with a tip to the front (to ventral side) here. Preferably, the backrest links are also coupled with the base support ventrally before the coupling position with the sitting surface support.

Especially for the realization of the highest possible movement freedom of the backrest links to each other, the backrest links according to an advantageous embodiment do not have any additional rigid connection elements therebetween, except the base support and the sitting surface support.

In order to further increase the mobility of the backrest links, the backrest links according to an advantageous embodiment are formed at least in a region which is arranged distal to the mounting position at the base support and to the coupling position with the sitting surface support with an (especially in comparison with a "coupling region" located in the region of the coupling and mounting mentioned above) increased torsion flexibility. Optionally, this is done by means of changing a profile of the respective backrest link. Alternatively, the backrest link is designed to be soft to torsion ( "torsionsweicher" ) in the region mentioned above by means of choosing a suitable material. For example, the backrest link in this region is formed from a (suitably fiber-enhanced) plastic, optionally in combination with changing of the profile, while the coupling region is formed in contrast from a metal, especially steel or aluminum. Through the increased torsion flexibility, the backrest formed by means of the backrest links, especially in the case of a cover, is designed to be softer (more elastic) in an upper region of the back than in a lower region (especially in a region covering the sacroiliac joint and optionally the lumbar vertebrae region) . Preferably, the above-mentioned way of construction (with higher torsion flexibility) in the upper region is also chosen in such a way that a higher bending flexibility exists in comparison to the lower region.

According to a suitable embodiment, the piece of sitting furniture has a headrest. Here, the headrest is held at the backrest links by means of a flexible connector which is arched in ventral direction. "Flexible" is especially understood in this context as follows: this connector is deformable by force, which leads to movement of the backrest links in general usage. Preferably, the connector is formed through an arched plate, namely a plate, made from for example a metal plate or plastic plate arching to ventral side. The arching of the connector to ventral side especially reduces the risk that the connector punchesto the dorsal side under load, for example if the user leans his head against the headrest.

In principle, the above-mentioned connector can function as cushion support. However, alternatively, the connector can only provide an attaching point for a headrest cushion which is adjustable in height.

Moreover, according to a suitable embodiment, the piece of sitting furniture has a pair of armrests, among which one is respectively coupled with the respective backrest link or the sitting surface support, preferably rigidly. Thereby, the respective armrest is moved together with the corresponding backrest link or the sitting surface support.

However, it is also conceivable in principle that the armrests according to an optional embodiment are attached at the base support rigidly.

Further optionally, the backrest links are only covered to form the backrest, as already indicated above. For example, the cover is formed here as mesh cover or leather cover. Preferably, the piece of sitting furniture does not have any backrest cushion which is arranged on a cushion support (which is rigid and arranged between the backrest links) in any case.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will be explained in detail in accordance with drawings hereafter. In the figures:

Fig. 1 shows a piece of sitting furniture in a schematic side view,

Fig. 2 schematically shows the piece of sitting furniture in an explosion view,

Fig. 3 shows a sitting surface area of the piece of sitting furniture in a schematic partial sectional view,

Fig. 4 shows the piece of sitting furniture in a symmetrically loaded state in a schematic side view, and

Fig. 5 shows the piece of sitting furniture in the view according to Fig. 4 in an asymmetric loaded state.

DESCRIPTION OF THE EMBODIMENTS

The parts and values which correspond to each other are provided with the same reference signs in all figures.

A piece of sitting furniture, in particular an office swivel chair ( "office chair" 1 for short) , is shown in a side view in Fig. 1 and in an explosion view in Fig. 2. The piece of sitting furniture has a cross-shaped base 2 with rollers 4 as base. The office chair 1 has in addition a gas spring 6, which is arranged at the cross-shaped base 2 and possesses a springing function and a height adjusting function. The office chair 1 has in addition a base support 8 held at the gas spring 6 and two backrest links 10 held swivelably at the base support 8. Both of the backrest links 10 are here hinged at the base support 8 in such a way that the backrest links are swivelable along a sagittal plane (it corresponds to the page plane in the drawing according to Fig. 1) in a rotary joint 11 in each case. Moreover, the office chair 1 has a sitting surface support 12, two armrests 14 and a headrest 16.

In the current embodiment, the sitting surface support 12 is cushioned to form a sitting surface 18. The backrest links 10 are covered with a mesh (not shown in detail) to form a backrest.

As can be seen better from Fig. 2, the sitting surface support 12 is connected to the backrest links 10 and the base support 8 by means of rotary joints with more than one degree of freedom for rotation. Here, each backrest link 10 is coupled with the sitting surface support 12 by means of a ball joint 20, and this backrest link is in turn coupled with the base support 8 by means of a ball joint 22. A connection element in the form of a support bar 24 is here also arranged between this ball joint 22 and the sitting surface support 12, the connection element itself being mounted at the base support 8 by means of another ball joint 26.

On the basis of the hinged coupling between the backrest links 10 and the base support 8 by means of the ball joints 20, 22 and 26, movement of the sitting surface support 12 is not only possible in the sagittal plane mentioned above (i.e. "pure" tilting backwards and, if appropriate, also forwards) , but is also possible to the sides, namely across or inclined to the sagittal plane. However, on the basis of the coupling with both of the backrest links 10, the backrest links are attached to the movement of the sitting surface support 12, and vice versa. This means that the backrest (namely the backrest links 10) drives the sitting surface support 12 to move "therewith" during the movement of the backrest in the sense of a conventional synchronous mechanism. By choosing the distances between the rotary joints 11 and the ball joints 20 as well as the length of the support bar 24 suitably, the movement transfer between the backrest links 10 and the sitting surface support 12 can be preset here, that is, to what extent the sitting surface support 12 should be adjusted (tilted) , when the backrest links 10 are moved (especially backwards) .

On the basis of Fig. 4, it can be seen here that the sitting surface 18 is adjusted by the sitting surface support 12 only to a relatively smaller extent during a backward (parallel) adjustment of the backrest links 10 (i.e. to dorsal side) , in particular with a back (dorsal) edge tilted downwards and a front edge tilted upwards.

Moreover, the backrest links 10 are not rigidly coupled with each other, but are movable fundamentally separately from each other. In the current embodiment, both of the backrest links 10 are spring-loaded by means of a torsion spring mechanism which is arranged in the rotary joints 11. This torsion spring mechanism has a torsion bar 30 (as torsion spring) , which extends through both rotary joints 11 and is coupled with both backrest links 10.

Moreover, the office chair 1 also has a pretension device 32 (see Fig. 3) . This pretension device has an adjustment spindle 34, a spindle nut 36, and an adjustment lever 38 which is coupled with the torsion bar 30. If the adjustment spindle 34 is adjusted, the spindle nut 36 "rides (reitet) " upwards or downwards and twists the torsion bar 30 by means of the adjustment lever 38. The torsion bar is thereby pretensioned (or relaxed, depending on the moving direction of the adjustment spindle 34) . Therefore, the backrest links 10 experience more or less strong resistance corresponding to the pretension under a load towards dorsal side in the rotary joint 11. However, if one of the backrest links 10 is loaded more than the other, for example because a user sits on the office chair 11 in a skewed way, leans only on one side backwards in order to be able to grip backwards, or the like, then this one backrest link 10 can twist the torsion spring 30 on the assigned side of the pretension device 32 (in particular of the adjustment lever 38) , which is especially installed in a middle part of the base support 8, more than on the other side. Thereby, the backrest can be writhed or at least asymmetrically deflected (see Fig. 5) . In Fig. 5, the right (viewed by a user sitting on the office chair 1) backrest link 10 is exemplarily adjusted more strongly backwards than the left backrest link 10. On the basis of the hinged coupling of the sitting surface support 12, it is here also tilted rightwards and backwards. This allows a specially moving sitting, since here not only the sitting surface, but also the backrest, allows for a transverse movement.

In order to support this relatively free mobility of both of the backrest links 10, they are not coupled with each other by connection elements (at least not by rigid connection elements) any more, except the connection through the torsion bar 30.

As can be seen from Fig. 2, the headrest 16 has a flexible connector between the backrest links 10, so that their independent mobility shown in Fig. 5 will not be influenced negatively. The connector is here formed by an arched plate 40, here a "stripe" made from a fiber-enhanced plastic that is bent (arched) in ventral direction. Here, this arching should prevent the arched plate 40 from punching backwards when the headrest 16 is loaded. Furthermore, a larger "length" can also be provided by the arching, so that, during a displacement of the backrest links 10 away from each other (see Fig. 5) , the arched plate 40 is only stretched without blocking the displacement. During the movement of the backrest links 10 towards each other, the arched plate 40 is only arched more heavily. Optionally, the arched plate 40 is attached to the backrest links 10 by means of the ball joints (not shown in detail) .

The subject of the present invention is not limited to the embodiments described above. On the contrary, other embodiments of the present invention can be derived from the above description by a person skilled in the art.

Reference sign list

1 Office chair

2 Cross-shaped base

4 Roller

6 Gas spring

8 Base support

10 Backrest link

11 Rotary joint

12 Sitting surface support

14 Armrest

16 Headrest

18 Sitting surface

20 ball joint

22 ball joint

24 support bar

26 ball joint

30 torsion bar

32 Pretension device

34 Adjustment spindle

36 Spindle nut

38 Adjustment lever

40 Arched plate

Claims

A piece of sitting furniture (1) , especially a swivel office chair, comprising

- a base (2) ,

- a base support (8) which is coupled with the base (2) ,

- a pair of backrest links (10) , and

- a sitting surface support (12) ,

wherein the backrest links (10) are coupled with the base support (8) in such a way that the backrest link is movable along a saggital plane, and wherein the sitting surface support (12) is movably coupled with the backrest links (10) and the base support (8) by means of at least one joint (20, 22, 26) , in each case the sitting surface support (12) has at least two degrees of freedom for rotation.
The piece of sitting furniture (1) according to claim 1,

wherein the backrest links (10) are mounted at the base support (8) by means of a torsion spring mechanism and are mounted swivelably relatively to each other.
The piece of sitting furniture (1) according to claim 2,

wherein the torsion spring mechanism for each backrest link (10) has a torsion spring assigned separately, especially a torsion bar (30) .
The piece of sitting furniture (1) according to claim 2,

wherein the torsion spring mechanism has a torsion spring, especially a torsion bar (30) , to which both of the backrest links (10) are attached.
The piece of sitting furniture (1) according to any one of claims 1 to 4,

wherein the joint which is arranged between the sitting surface support (12) and the respective backrest link (10) is formed as ball joint (20) .
The piece of sitting furniture (1) according to any one of claims 1 to 5,

wherein the joint which is arranged between the sitting surface support (12) and the base support (8) is formed as ball joint (22) .
The piece of sitting furniture (1) according to any one of claims 1 to 6,

wherein a support bar (24) is arranged between the joint (22) and the base support (8) , the joint (22) is arranged between the sitting surface support (12) and the base support (8) , and the support bar is coupled with the base support (8) in an articulated manner.
The piece of sitting furniture (1) according to any one of claims 1 to 7,

wherein the joint (22) arranged between the sitting surface support (12) and the base support (8) , is arranged in ventral direction before, the joint (20) arranged between the sitting surface support (12) and the backrest links (10) , especially also before the mounting position of the backrest links (10) at the base support (8) .
The piece of sitting furniture (1) according to any one of claims 1 to 8,

wherein, except the base support (8) and the sitting surface support (12) , the backrest links (10) do not have any additional rigid connection elements therebetween.
The piece of sitting furniture (1) according to any one of claims 1 to 9,

wherein the backrest links (10) are formed with an increased torsion flexibility at least in a region which is arranged distal to the mounting position at the base support (8) and to the coupling position with the sitting surface support (12) .
The piece of sitting furniture (1) according to any one of claims 1 to 10,

comprising a headrest (16) , which is held at the backrest links (10) by means of a flexible connector, which is especially arched in ventral direction, especially by means of an arched plate (40) .
The piece of sitting furniture (1) according to any one of claims 1 to 11,

comprising a pair of armrests (14) , which are coupled with, preferably rigidly coupled with the respective backrest link (10) or the sitting surface support (12) .
The piece of sitting furniture (1) according to any one of claims 1 to 12,

wherein the backrest links (10) are covered to form a back cushion.