EP2187782B1 - Back rest, especially for an office chair - Google Patents

Abstract

The invention relates to a back rest, especially for an office chair, comprising two back rest zones (3a, 3b) that are hinged, while forming an articulated connection (8) of the four-bar chain type, to a two-part back rest support (2) having a lower supporting guide (20) and an upper back rest guide (21), in such a manner that a flexible lumbar support (5) is formed between the back rest zones (3a, 3b).

Description

The invention relates to a backrest, in particular an office chair, according to the preamble of claim 1. An office chair with such a backrest is z. B. from the EP 0 815 778 A1 and in particular from the GB2 085 719 A known.

Especially in the office sector chairs are often used with high comfort. These allow this in the home or rest position due to the practically vertical position of the backrest reliable support of the back of a user person. The shape of the leaning front outer contour of the backrest can be more or less adapted to the typical S-shape of a spine here. Also, alternatively or additionally, a lumbar support may be provided in the lordosis area of the user's back.

From the DE 20 004 948 A1 is a backrest with an adjustable lumbar support known to set a manually operable mechanism is provided. In particular, in conjunction with a so-called synchronous mechanism for synchronously adjustable inclination of the backrest and seat, the mechanical complexity is not negligible.

The invention is therefore based on the object, a backrest, preferably for a chair, in particular for an office chair, specify, which has a particularly effective lumbar support while maintaining high comfort and low cost.

This object is achieved by the features of claim 1. Advantageous embodiments and further developments are the subject of the dependent claims.

Thus, the backrest is initially formed of two superimposed backrest areas, which are held on a backrest support. The two backrest areas are connected to one another in the lordosis region of the back of a user in an articulated manner. The two backrest areas are expediently each formed by rigid, substantially deformation resistant backrest cushion. Here, the two backrest areas are suitably arranged to form an S-shaped support or outer contour leaning front side gapless and back each other spaced apart. The lean or pad back release or gap contour allows in a simple and visually virtually invisible manner, the desired deformability between the two backrest areas with simultaneous deformation stiffness of the two backrest areas.

These backrest areas are hinged to the backrest support to form a four-bar linkage. The hinge points or axes are expediently positioned such that two preferably vertically offset one above the other provided in the backrest longitudinal direction joints are provided in the lower, seat-near region of the backrest front, while the other two, also vertically offset in the backrest longitudinally superimposed joints Lehnenrückseitig are realized on the backrest support ,

At the (lower) support arm of the backrest support a headrest is attached. This comprises a support or support frame, in particular with two support legs, which suitably enclose an obtuse angle with each other. At the (upper) free end of the support frame is then a headrest main, in particular a headrest pad attached.

The angled shape of the support frame is preferably selected such that the headrest or the head restraint head in a backrest position with a maximum curved lumbar support in the vertical direction is aligned with the upper backrest area and leaning in a Lehnenneigeposition the upper backrest area front overhangs.

Due to the rigid connection of this support frame with the (lower) support arm of the backrest support, the relative position of the headrest and the headrest pad relative to the (lower) support arm always remains the same even with a tilt of the backrest or the two backrest areas. In contrast, the upper, hinged to the lower backrest handlebar support arm moves in the direction of the support frame with the Headrest too. In the initial position in an upright sitting position thus forms the backrest contour including the headrest from the S-shape of the spine of an operator.

With an inclination of the back of the operator backwards so the head is always supported in a position in which a look forward is still possible. Thus, the position of the headrest and the corresponding support frame always remains the same relative to the lower support arm of the backrest support, while by pressing the backrest areas or the backrest cushion towards the backrest support to the tilting of the backrest, the distance of the upper backrest portion for headrest becomes increasingly larger the result is that the shoulder area of the operator tends to lean back more in comparison to the head.

A first joint of the joint connection, which is effective in the manner of a four-bar chain, is expediently formed between the upper back region and the lower back region and there again in the region of the lumbar support. A second joint is expediently formed between the lower back region and the (lower) support arm of the backrest support. About this hinge connection in the lordosis area interconnected backrest areas or backrest cushions are supported underneath the backrest support.

A third joint of this four-bar chain or articulated connection is formed between the (lower) support arm and an articulated on this (upper) back arm of the backrest support. The fourth joint of the four-bar linkage is then expediently formed between the upper backrest region and the (upper) backrest link of the backrest support. About this upper joint, the two backrest areas and backrest cushions leaning on the top of the backrest support are hinged, in particular suspended on the backrest support quasi.

The functional principle of the four-bar linkage is thus realized by the members connecting the four joints themselves are each rigid between the articulated backrest support on the one hand and the flexible connection between the two backrest areas. The thus formed between the two backrest areas flexible area is located at the height of about the lordosis of the operator and forms the flexible lumbar support there.

As a result of an action on the backrest in the transition region between the two backrest areas by the operator, the degree of curvature of the flexible lumbar support, whose convexity directed towards the operator's back is maximized in an upright sitting position, decreases continuously depending on the pressure exerted on the backrest (contact pressure) that the lumbar support is increasingly flattening. Due to the four-bar linkage here, the buckling decrease takes place practically independent of where the force or pressure is applied along the backrest. The reason for this is that with such a pressure or force on the backrest along the two backrest areas of the upper backrest arm of the backrest support quasi stretches and thus the upper, relatively long backrest area is pulled vertically upwards at the upper back end. In other words: As a result of a force applied to the backrest pivoted - forced on the four-bar linkage - the comparatively short upper backrest of the backrest support to the third joint of the four-bar linkage with the result that the lumbar support - and thus the first joint located there - also after moved towards the back of the backrest. To this end, the lower, comparatively short backrest area pivots forwards about the (lower) second joint via the four-bar chain.

In an advantageous embodiment, the joint connection, which is effective in the manner of a four-bar chain, is spring-supported at a suitable location. A spring element suitable for this purpose can be provided on the joints of the articulated connection or also in the area of the lumbar support of the two-part backrest. The spring force of the spring element acts in the direction of the lordosis of the operator, with an inclination of the backrest, this spring force must be overcome and thus the backrest automatically exerts an increasing counterforce against the back of the operator. In contrast, no or little pressure on the backrest, especially in the lumbar region, exercised when the operator sits vertically.

A corresponding spring element may be provided in the form of a leg spring, in particular on the third joint. Alternatively, a tension spring can be provided backwards between the two backrest areas or backrest cushions. However, a leaf spring in the region of the lumbar support on the side facing the back of the operator (back of the backrest) of the backrest cushion is particularly advantageous, since at this point the spring element or the leaf spring can be completely and thus invisibly upholstered in a particularly simple manner.

Since the two mutually connected to form the flexible lumbar support backrest areas or cushions are advantageously resistant to deformation and thus rigid, move under a load or force of the backrest, especially in a tilt of the backrest in an alternative embodiment with a synchronous mechanism between the backrest and the Seat of a chair, although the two backrest areas relative to each other, but remain undeformed itself. This rigid design of the two backrest areas also ensures the reliable operation principle of the four-bar chain, in which the four individual, hingedly interconnected links to ensure this functional principle are rigid. This embodiment thus causes the backrest of an operator against the backrest and also at their additional inclination in the embodiment with a synchronous mechanism, the area spanned by the four-bar chain surface with increasing contact pressure against the backrest area is increasingly smaller.

The advantages achieved by the invention are in particular that as a result of a flexible, articulated design of the intermediate region between two superimposed back regions of a backrest and the embodiment of attachment or suspension of this backrest areas on a two-part, articulated backrest support in a particularly simple and reliable manner in an upright seating position sufficient support in the lumbar region of an operator is ensured. At the same time, this backrest construction provides a decreasing lumbar support in the operation of a four-bar chain with increasing inclination to a reclined seating position of the operator. This effectiveness and this functional principle corresponds to the natural behavior and comfort desire an operator, while in the upright seating position desires support from the lumbar backrest, such support in a reclined sitting position - in an extreme position in a recumbent position. -but not needed or desired. This comfort behavior or comfort desire is due to the fact that in the upright sitting position, a vertical load on the spine, while such a burden decreases with increasing inclination of the spine in the horizontal position. So it is more comfortable with increasing inclination in the horizontal position, although the support in the lumbar region decreases accordingly.

This desire for comfort is in a simple manner, the backrest of the invention justice by the flexible lumbar support in the upright seating position ensures sufficient support in the lumbar region of an operator, with increasing inclination in a reclined sitting position, however, automatically provides a decreasing lordosis support.

In addition, the concatenation of the mutually articulated elements of the backrest, namely the two backrest areas and the two arms of the backrest support over a simple flexibly formed Lordosenstützbereich offers the advantage that regardless of where on the backrest a corresponding pressure is exercised, the Always move elements of the backrest parts that are connected by the four-bar chain to the same position.

Fig. 1

schematisch in einer Seitendarstellung den Lehnen-Sitz-Bereich eines Stuhls mit einer eine flexible Lordosenstütze aufweisenden Rückenlehne mit zeichnerisch hervorgehobener Viergelenkkette in der Ausgangsposition,

Fig. 2

in einer Darstellung gemäß Fig. 1 die Rückenlehne in einer kraft- bzw. druckbeaufschlagten Position mit abgeflachter Lordosenstütze,

Fig. 3

die Rückenlehne gemäß Fig. 1 mit Kopfstütze,

Fig. 4

die Rückenlehne gemäß Fig. 3 in einer Position der Rückenlehne gemäß Fig. 2,

Fig. 5

die Ausgestaltung der Rückenlehne gemäß Fig. 3 in Verbindung mit einer Synchronmechanik zwischen der Sitzfläche und der Rückenlehne in Ausgangsposition, und

Fig. 6

die Ausführungsform nach Fig. 5 bei synchron geneigter Rückenlehne und Sitzfläche.

Embodiments of the invention will be explained in more detail with reference to a drawing. Show:

Fig. 1

schematically in a side view the backrest-seat area of a chair with a flexible lumbar support having backrest with graphically highlighted four-bar chain in the starting position,

Fig. 2

in a representation according to Fig. 1 the backrest in a force- or pressurized position with a flattened lumbar support,

Fig. 3

the backrest according to Fig. 1 with headrest,

Fig. 4

the backrest according to Fig. 3 in a position of the backrest according to Fig. 2 .

Fig. 5

the design of the backrest according to Fig. 3 in conjunction with a synchronous mechanism between the seat and the backrest in starting position, and

Fig. 6

the embodiment according to Fig. 5 with synchronously inclined backrest and seat.

Corresponding parts are provided in all figures with the same reference numerals.

The trained as an office chair chair 1 according to the Fig. 1 to 6 includes one with a in the FIGS. 5 and 6 indicated stand connected backrest support 2 to which a two-part backrest 3 is held articulated with an upper backrest portion 3a and a lower back portion 3b. The backrest support 2 comprises a lower support arm 20 and an upper backrest link 21 which is articulated therewith. The comparatively short, comparatively short L-limb 20b extending in the z-direction and extending in the z-direction approximately vertically extends the L-limb 20a a seat 4.

The upper backrest region 3a of the backrest 3, which is also referred to below as the backrest cushion, is connected to the comparatively short lower back region 3b to form a lumbar support 5 in such a way that upon application of a contact pressure F in the direction of the in Fig. 2 Arrow oriented in the x-direction bulge 6 of the lumbar support of the in Fig. 1 shown maximum degree of curvature in the in Fig. 2 Flattening degree is flattened.

This flexible connection between the comparatively long, upper back region 3a and the comparatively short, lower back region 3b is produced in the exemplary embodiment by a back recess or recess 7 within the otherwise dimensionally stable or deformation-resistant - and thus rigid - backrest cushion 3. It is essential that Both the upper back region 3a and the lower back region 3b are correspondingly rigid or rigid, while the intermediate region, in which the lumbar support 5 is located, is flexible and, in particular, flexibly deformable. This flexibility or malleability in turn is such that virtually in this area of the lumbar support 5 between the otherwise rigid upper backrest area and the likewise rigid lower backrest area 3b quasi a (first) joint 8a of an effective manner of a four-bar linkage joint 8 is formed.

Like the first joint 8a, there is also a second joint 8b on the back of the backrest and offset there in the (-) x-direction and in the z-direction below the first joint 8a. The two further joints 8c and 8d of the four-bar linkage 8 are located at the back of each other on both sides of the upper backrest link 21. Concretely, the third articulation 8c forming the articulated connection between the support link 20 and the backrest link 21 is located above the first articulation 8a and in the z direction. -) offset x direction to the second joint 8b.

The fourth joint 8d forms an articulated connection between the upper backrest link 21 of the backrest support 20 and the upper side of the upper backrest region 3a. This fourth joint 8d is positioned in the z-direction above the third joint 8c and in the z-direction between the second joint 8b and the third joint 8c. The rigid chain links associated with the formation of the four-bar chain 8 are illustrated by the virtual connecting lines between the four joints 8a to 8d. The realization of these rigid joints is ensured by the rigid arms 20,21 of the backrest support 20 on the one hand and by the rigid back areas 3a and 3b on the other.

As from the representations of Fig. 1 and 2 it can be seen, causes a force exerted by the back of an operator pressing force F in the direction of arrow ((-) x-direction) pivoting of the upper Lehnenlenkers 21 to the third joint 8c, with the result that the upper backrest portion 3a quasi in the z-direction vertically upward is pulled. At the same time, pivoting of the lower back region 3b about the second joint 8b takes place again in the (-) x direction, with the result that the first joint 8a likewise points in the (-) x direction to the direction shown in FIGS Fig. 1 to 4 stationary lower support arm 20 to move. As a result, the degree of curvature of the bulge 6 of the lumbar support 5 increases in accordance with the maximum bulge 6 Fig. 1 in the minimum bulge 6 according to Fig. 2 from. Here, the by the four-bar chain 8 spanned surface increasingly smaller, as by comparing the representations of Fig. 1 and 2 is apparent.

The restoring force required for a reversible change of the bulge 6 of the lumbar support 5 is generated by a spring element, which can in principle be arranged at different points or positions of the four-bar chain 8. So shows Fig. 3 Alternative positions and configurations of the spring element in the form of a leaf spring 9, a tension spring 10 and / or a leg spring 11. When using the leaf spring 9, this is expediently provided in the region of the lumbar support 5 and there in the region of the first joint 8a of the four-bar chain 8. A leg spring 11 is expediently used in the region of the third joint 8c. Additionally or alternatively, when using the tension spring 10, this backrest is provided between the two backrest areas 3a and 3b in the recess 7 extending transversely to the xz plane and connected there on the one hand to the upper backrest area 3a and on the other hand to the lower backrest area 3b.

The otherwise with the embodiments according to the Fig. 1 and 2 same embodiment according to the 3 and 4 additionally has a headrest 12. This consists essentially of a turn about L-shaped angled support or support frame 13 and an example pillow-like headrest main body 14. The headrest 12 is held on the headrest main 14 remote from the L-leg 13a of the support frame 13 at the lower support arm 20 of the backrest support 2. The L-leg 13b of the supporting frame 13, which is held between this L-leg 13a and the headrest main 14, is dimensioned such that the actual headrest, ie the headrest main 14 in a backrest position with a maximum convex lumbar support 5 in vertical or z-direction with the upper back portion 3a is aligned, as is out Fig. 3 is apparent. In contrast, the head restraint head 14 projects beyond in the in Fig. 4 Lehnenneigeposition shown the upper backrest portion 3a in the x direction.

The FIGS. 5 and 6 show an embodiment of the realized in the functioning of the four-bar chain 8 backrest of the chair 1 with a synchronous mechanism 15 between the two backrest portions 3a, 3b and the seat surface 4. The synchronous mechanism 15 essentially comprises two seat arms 16, 17, which are articulated on the seat carrier 18, which is indicated only schematically. For this purpose, the front seat link 16 via hinges 16a and 16b with the seat surface 4 on the one hand or with the seat support 18 on the other hand hinged. Analogously, the rear seat link 17 via articulated joints 17a and 17b with the seat surface 4 on the one hand and the seat support 19 on the other hand hinged.

As in Fig. 6 illustrated synchronous mechanism 15 causes a synchronous tilting movement of both the backrest and the seat surface 4 back and down. The relationships relative to the backrest itself with respect to the relative movement between the two backrest portions 3a and 3b and the two-part backrest support 2 corresponds to the movement behavior of the backrest according to the Fig. 1 to 4 with a continuous decrease in the degree of curvature of the bulge 6 of the lumbar support 5 with increasing contact pressure F or pressurization with the difference that at the same time the backrest support 2 tilts backwards and downwards.

LIST OF REFERENCE NUMBERS

1

Office / chair

2

backrest support

3

Back / back pad

3a

Upper backrest area

3b

lower backrest area

4

seat

5

lumbar support

6

bulge

7

Recess / -nehmung

8th

Four-link chain / articulation

8a

first joint

8b

second joint

8c

third joint

8d

fourth joint

9

leaf spring

10

mainspring

11

Leg spring

12

headrest

13

Support / support stand

13a, b

L-leg

14

Headrests main / -poister

15

synchronous mechanism

16

seat link

16a, b

Joint / link

17

seat link

17a, b

Joint / link

18

seat support

20

support links

20a, b

L-leg

21

backrest link

F

contact force

Claims (12)

1. Backrest with two backrest regions (3a, 3b) which are coupled, with the formation of an articulated connection (8) in the manner of a four-bar chain, to a two-part backrest support (2) having a lower supporting link (20) and having an upper backrest link (21) in such a manner that a flexible lordosis support (5) is formed between the backrest regions (3a, 3b), characterized by a head restraint (12) with a carrying frame (13) which is held on the supporting link (20) of the backrest support (2), the carrying frame (13) being angled in such a manner that, in a backrest starting position, the head restraint (12, 14) is aligned in the vertical direction (z) with the upper backrest region (3a) with the lordosis support (5) arched to the maximum and, in a backrest inclination position, protrudes above the upper backrest region (3a) on the backrest front side.
2. Backrest according to Claim 1, characterized in that a first joint (8a) of the articulated connection (8), in particular on the backrest front side, is formed between the upper backrest region (3a) and the lower backrest region (3b).
3. Backrest according to Claim 1 or 2, characterized in that a second joint (8b) of the articulated connection (8), in particular on the backrest front side, is formed between the lower backrest region (3b) and the supporting link (20) of the backrest support (2).
4. Backrest according to one of Claims 1 to 3, characterized in that a third joint (8c) of the articulated connection (8), in particular on the backrest rear side, is formed between the supporting link (20) and the backrest link (21) of the backrest support (2).
5. Backrest according to one of Claims 1 to 4, characterized in that a fourth joint (8d) of the articulated connection (8), in particular on the backrest rear side, is formed between the upper backrest region (3a) and the backrest link (21) of the backrest support (2).
6. Backrest according to one of Claims 1 to 5, characterized in that the two backrest regions (3a, 3b) are formed by an at least approximately deformation-resistant backrest cushion.
7. Backrest according to one of Claims 1 to 6, characterized in that the two backrest regions (3a, 3b) are held in an articulated manner one above the other on the backrest support (2) without a gap on the backrest front side and spaced apart from each other on the backrest rear side, with the formation of an S-shaped supporting contour.
8. Backrest according to one of Claims 1 to 7, characterized in that the supporting link (20) of the backrest support (2) is approximately L-shaped, one L limb (20a) thereof being connected to the backrest support (21) and the other L limb (20b) thereof being designed for the fastening of a seat surface (4), and one of the joints (8b) of the articulated connection (8) being provided in the region between the L limbs (20a, 20b).
9. Backrest according to one of Claims 1 to 8, characterized by a spring element (9, 10, 11) for producing a restoring force (F) directed towards an operator's lordosis.
10. Backrest according to Claim 9, characterized in that the spring element, in particular a leaf spring (9) or leg spring (11), is provided in the region of one of the joints (8a to 8d) of the articulated connection (8), in particular in the region of the first or third joint (8a or 8b).
11. Chair (1), in particular office chair, with a backrest (2, 3) according to one of Claims 1 to 10, and with a seat surface (4), wherein the degree of curvature of the arching (6), which is directed towards a person's back, of the lordosis support (5) is at maximum in an upright sitting position of a person and decreases depending on the contact pressure force (F) exerted on the backrest (3) by the person.
12. Chair (1) according to Claim 11, with a synchronizing mechanism (15) for the synchronous inclination movement of the backrest (2, 3) and of the seat surface (4) as a result of pivoting of the backrest (2, 3) from a vertical starting position into an inclined position, wherein, as the inclination movement of the backrest (2, 3) increases as a consequence of the contact pressure force (F) exerted by a person, the degree of curvature of the arching (6) of the lordosis support (5) decreases.

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