Seat, in particular an office chair

Abstract

The invention relates to a seat (1), in particular an office chair, comprising a seat support (3) for a seating surface (6) and comprising a backrest support (4) of a backrest (5), which is held on the seat support (3) so as to be able to move in a tiltable manner to the side, wherein the backrest support (4) comprises two support arms (4a, 4b) which are configured to be flexible and/or articulated laterally and spaced apart from one another. Preferably, the seating surface (6) and/or the backrest (5) comprises a curved seat shell and/or backrest shell (6a, 5a) provided with a cover (6b, 5b) with a number of flexible curved ribs (15, 16) on the edge of the shell, wherein the cover is stretched by the seat shell and/or backrest shell (6a, 5a) such that when the cover (6b, 5b) is loaded, the bending of the curved ribs (15, 16) is altered.

Claims

1. A flexible backrest support for an office chair comprising: a shell having a plurality of laterally extending ribs separated from one another by a plurality of slots, the plurality of ribs defining free ends thereof; and a cover including a fold-over peripheral edge, the free ends of the plurality of ribs received within the fold-over peripheral edge, the cover spaced from a surface of the shell along a widthwise cross section of the shell, wherein the cover is held in tension when the free ends of the plurality of ribs are received within the fold-over peripheral edge of the cover such that when a force is applied rearward against the cover, the free ends of the plurality of ribs flex forward.

2. The backrest support of claim 1, wherein the flexible shell includes at least one backrest support arm extending vertically to support the backrest support.

3. The flexible backrest support of claim 2, wherein the at least one backrest support arm includes a pair of the backrest support arms.

4. The flexible backrest support of claim 3, wherein one of the pair of backrest support arms includes a first lateral side and the plurality of ribs includes a first set of ribs extending from the first lateral side, and the other of the pair of backrest support arms includes a second lateral side and a second set of ribs extending from the second lateral side.

5. The flexible backrest support of claim 4, wherein the backrest support arms each include an upper end connected by a horizontally extending connecting element, and wherein the plurality of ribs includes a third set of ribs extending vertically upward from the connecting element.

6. The flexible backrest support of claim 4, wherein when the cover is loaded, bending of the plurality of ribs is altered.

7. The flexible backrest support of claim 4, wherein the cover includes a first fold-over lateral edge and a second fold-over lateral edge, and wherein the first set of ribs is held by the first fold-over lateral edge and the second set of ribs is held by the second fold-over lateral edge.

8. The flexible backrest support of claim 7, wherein the backrest support arms and ribs are formed integrally as a one piece shell.

9. A flexible backrest support for an office chair comprising: a shell having a plurality of laterally extending curved ribs separated by a plurality of slots, the plurality of ribs defining free ends thereof and having front and rear surfaces; and a cover extending around the free ends of the plurality of ribs, from the front surface to the rear surface of the plurality of ribs, the cover spaced from a surface of the shell along a widthwise cross section of the shell, wherein the cover includes a fold-over peripheral edge and the free ends of the plurality of ribs are received within the fold-over peripheral edge, and the cover is held in tension such that when the cover is loaded, bending of the plurality of ribs is altered.

10. The flexible backrest support of claim 9, wherein the cover is fixedly attached to the free ends of the plurality of ribs.

11. The flexible backrest support of claim 10, wherein the cover is more flexible than the shell and is substantially non-stretchable relative to the range of bendable movement of the ribs.

12. The flexible backrest support of claim 11, wherein the cover is made of a plastic material.

13. The flexible backrest support of claim 11, wherein the cover is made of a woven fabric.

14. The flexible backrest support of claim 9, wherein the backrest support is coupled to a seat support by at least one upwardly extending support arm.

15. The flexible backrest support of claim 14, wherein the at least one support arm includes a pair of spaced apart support arms; one of the pair of support arms includes a first lateral side and the plurality of ribs includes a first set of ribs extending from the first lateral side, and the other of the pair of support arms includes a second lateral side and a second set of ribs extending from the second lateral side.

16. The flexible backrest support of claim 15, wherein a loading on the cover is capable of causing the plurality of ribs to bend asymmetrically, such that the first set of ribs bends to a different degree than the second set of ribs, depending on the position of the loading on the cover.

Description

(1) Exemplary embodiments of the invention are described in more detail hereinafter with reference to the drawings, in which:

(2) FIG. 1 shows schematically in a side view an office chair as a seat comprising a seat support for a seat (seating surface) and comprising a backrest support of a backrest which may be inclined laterally,

(3) FIGS. 2a and 2b show the office chair according to FIG. 1 in a rear view with flexible support arms of the backrest support arranged in a V-shape in the initial position of the backrest and/or in a backrest position inclined to the right,

(4) FIGS. 3a and 3b show in a plan view the office chair according to FIGS. 2a and/or 2b,

(5) FIGS. 4a and 4b show in a view according to FIGS. 2a and 2b a variant with the support arms of the backrest support connected in an articulated manner on the backrest side, in the initial position and/or in the position of the backrest inclined to the right,

(6) FIGS. 5a and 5b show in a view according to FIGS. 2a and 2b an alternative of the variant comprising the support arms of the backrest support connected in an articulated manner on the backrest side and seat side, in the initial position and/or the position of the backrest inclined to the right,

(7) FIGS. 6a to 6d show in a sectional view a seat shell or backrest shell (support shell and/or bearing shell) with a cover as a seating surface and/or backrest surface under different loads,

(8) FIG. 7 shows in a perspective view the office chair in an embodiment of the seat shell and backrest shell without covers,

(9) FIG. 8 shows the office chair according to FIG. 7 in a rear view with support arms of the backrest support arranged in a V-shape and flanking a backrest opening to the side, in the initial position of the backrest,

(10) FIG. 9 shows the office chair according to FIGS. 7 and 8 in a side view with the seat cover and backrest cover, and

(11) FIG. 10 shows the office chair according to FIG. 9 in a perspective side view.

(12) Parts corresponding to one another are provided in all the figures with the same reference numerals.

(13) The seat 1 configured as an office chair according to FIG. 1 comprises a seat support 3 connected fixedly to a pedestal (base) 2, to which a backrest 5 is connected via a backrest support 4. A so-called synchronous mechanism may be incorporated in the seat support 3, said mechanism performing a synchronous movement of a seating surface (seat) 6 bearing on the seat support 3, with the backrest 5, when said backrest is deflected from the initial position shown into a position inclined to the rear. The seat support 3 and thus the seating surface and/or the seat 6 and the backrest 5 connected to the seat support 3 via the backrest support 4, are connected and/or coupled rotatably to the pedestal 2, which in the exemplary embodiment comprises three or four arms 7 with chair casters 8 fastened on the pivoting side at the end.

(14) As may be seen from FIGS. 2a and 2b, the backrest support 4 comprises two support limbs, denoted hereinafter as support arms 4a, 4b, which are arranged relative to one another in a V-shape. The support arms 4a, 4b extend in the vertical direction z from the seat support 3 to a central region of the backrest 4. The connection of the support arms 4a, 4b and thus of the backrest support 4 to the backrest 5, i.e. on the rear face thereof, takes place via a connecting element 9 on the backrest side, which extends in the horizontal direction y. The support ends 9a, 9b of the support arms 4a and/or 4b on the backrest side are connected to said connecting element 9. In a similar manner, the support ends 10a, 10b of the support arms 4a and/or 4b on the seat side are connected by means of a connecting element 10 on the seat side.

(15) In the exemplary embodiment shown, according to FIGS. 2a and 2b, the connecting element 9 on the backrest side and the connecting element 10 on the seat side are configured integrally with the two support arms 4a and 4b. Alternatively, also another type of rigid, in particular material, connection of the support arms 4a, 4b may be provided to the connecting elements 9, 10.

(16) As a result of and/or for producing the V-shape of the arrangement of the two support arms 4a, 4b, the spacing a.sub.1 thereof on the seat side is smaller than the spacing a.sub.2 thereof on the backrest side relative to one another (a.sub.1<a.sub.2). The support arms 4a, 4b are made from a flexible material, for example from a correspondingly stable plastics material or a spring steel. Additionally, the support depth d.sub.1 of the support arms 4a and 4b expediently decreases from the support ends 10a, 10b thereof on the seat side to the support ends 9a and/or 9b thereof on the backrest side continuously to a support arm depth d.sub.2. The support arm depth d.sub.2 on the support end 9a, 9b on the backrest side is thus smaller than the support arm depth d.sub.1 on the support end 10a, 10b of the support arms 4a and/or 4b on the seat side (d.sub.2<d.sub.1).

(17) As additionally illustrated with reference to FIGS. 3a and 3b, a lateral action of force F oriented in the horizontal y-direction, for example by a corresponding sidewards movement of a user of the office chair 1, leads to a lateral inclination or tilting of the backrest 4, in the exemplary embodiment shown, i.e. in FIGS. 2b and 3b in the y-direction to the right. The sidewards inclination of the backrest 4 takes place substantially in the yz-plane, wherein in particular as a result of the V-shaped arrangement of the support arms 4a, 4b, and the rigid connection thereof to the seat support 3 as well as the backrest 4 by means of the connecting elements 10 and/or 9 a rotation of the backrest 4 about a (virtual) rotational axis 11 located between the connecting elements 9, 10 is associated with the tilting or inclination.

(18) The support arms 4a, 4b also extend in the direction x toward the seating surface 6 in a V-shaped and/or trapezoidal manner. The support arms 4a, 4b in this case extend in the direction x toward the seating surface 6 at an acute angle of inclination or trapezoidal angle α relative to one another. Relative to the Cartesian coordinate system shown, the seating surface 6 is located in the xy-plane and the backrest 5 extends accordingly in the z-direction. Thus the arm length l (FIG. 2a) of the support arms 4a, 4b extends in the z-direction and the arm depth d (FIG. 2b) of the support arms 4a, 4b in the y-direction, whilst the arm width b (FIG. 3a) of the support arms 4a, 4b is oriented in the x-direction.

(19) In the view shown in FIGS. 3a and 3b it may be seen that the support arms 4a, 4b—relative to a mean perpendicular S to the normal N of the seating surface 6 extending between said support arms—extend at an angle α to one another.

(20) The arm width b of the support arms 4a, 4b is greater than the arm depth d.sub.1, d.sub.2 thereof. As a result, it is achieved and/or ensured that as a result of a lateral action of force F the bending of the support arms 4a, 4b always takes place only in the y-direction and not in the x-direction.

(21) The V-shaped path of the support arms 4a, 4b along the arm width b thereof toward the seating surface 6 leads to a circular movement of the backrest 5 indicated by the movement arrow P in FIG. 3b, as a result of the laterally oriented force or action of force F. The radius which is adapted, for example, to the curved contour of the backrest 5 and/or the edge of the seating surface K facing said backrest is such that the laterally displaced or tilting backrest 5 does not move toward or away from the seating surface 6, at least not perceptibly.

(22) The embodiment of the backrest support 4 in the variant of the office chair 1 shown in FIGS. 4a and 4b, differs from that according to FIG. 2a and/or 2b by an articulated connection of the support arms 4a, 4b to the backrest 5 and/or to the connecting element 9 on the backrest side. To this end, the support ends 9a, 9b of the support arms 4a, 4b are connected to the connecting element 9 on the backrest side via rotary joints 12a and/or 12b. The connection of the support arms 4a, 4b on the seat side via the integral or material connection thereof of the support ends thereof 10a and/or 10b to the connecting element 10 on the seat side, corresponds to the embodiment according to FIGS. 2a and 2b. Accordingly, also in the variant according to FIG. 4a and/or 4b, the support arms 4a, 4b of the backrest support 4 are in turn at least flexible to this extent, at least in the application region on the seat side, i.e. in the connection to the connecting element 10 on the seat side.

(23) In the variant according to FIGS. 5a and 5b, the support arms 4a, 4b of the backrest support 4 are connected both on the backrest side and on the seat side via rotary joints 12a, 12b and 13a, 13b to the backrest 5 and/or to the connecting element 9 at that point as well as to the seat support 3 and/or the connecting element 10 at that point. In this variant, rigid, i.e. flexurally rigid, support arms 4a, 4b may be used.

(24) The mode of operation and inclination and/or tilting movement of the backrest 5 as a result of a force acting in the horizontal direction y, corresponds to the motion path of the variants shown in FIGS. 2a and 2b as well as 4a and 4b.

(25) FIGS. 6a to 6d show in simplified sectional views the construction of a preferred embodiment of the seating surface and/or seat 6 with a support shell 6a denoted hereinafter as the seat shell, and a cover 6b. The seat shell 6a is indirectly or directly fixed to the seat support 3 via a central piece 14. In the horizontal direction y in each case a curved arm and/or a curved rib 15 is adjoined to the central piece 14. The curved ribs 15 may taper toward the respective free end thereof, the spacing thereof from the central piece 14 being the greatest. The curved ribs 15 are raised with their free ends in the z-direction. In other words, the curved ribs 15 at the free end side in the vertical direction z are spaced apart from the central piece 14. At the free end side, the cover 6b is attached to the curved ribs 15, said cover covering the central piece 14. The cover 6b consists of a non-stretchable material or at least a material which is relatively not easily stretchable. The cover 6b denoted hereinafter as the seat cover serves as the seating region of the seat and/or office chair 1. The curved seat shell 6a with and without the seat cover 6b is shown in relative detail in FIGS. 7 to 10.

(26) In FIG. 6b a loading of the cover 6b in the downward direction is shown, i.e. a loading in the z-direction toward the central piece 14. The loading takes place in this case centrally in the y-direction. The cover 6b is curved (bulged) downwards. Due to the absent, or at least relatively low, stretchability of the cover 6b relative to the support shell, the flexible curved ribs 15 and specifically the free ends thereof are bent upward toward the central piece 14. Due to the elasticity of the curved ribs 15, a force acts counter to the bending thereof and thus against the loading. If the loading is generated by a user, a resilient action is present as the loading is generally not uniform, generally as a result of an at least partial movement of the user. This is perceived by the user as pleasant.

(27) In comparison with FIG. 6b, in FIGS. 6c and 6d loading is shown which no longer takes place centrally in the y-direction but, for example, further to the left and/or to the right. The left or right curved rib 15 is not raised but bent downward, if the loading is relatively high or relatively far to the left and/or right. So that such bending usually does not take place or only takes place relatively seldom, the rigidity of the curved ribs 15 is relatively high and adapted to the weight of the user.

(28) However, the right and/or left curved rib 15 is positioned relatively raised. Due to this asymmetry of the bending of the curved ribs 15, the cover 6b is also asymmetrically bulged inward so that by means of the cover 6b a type of incline is formed. The user, if the loading on one side is undesirable, is prompted to alter automatically the seating position again so that the loading is substantially central between the curved ribs 15, as shown in FIG. 6b. Also, it is possible for the user, if comfortable, to adopt a seating position with an asymmetrical loading of the cover 6b. To this end, the user does not have to carry out any adjustment to the seat 1. As a result, different users with variable seating preferences may use the seat 1 without an adjustment of the seat 1 having to be altered between each use thereof.

(29) Due to the reaction of the curved ribs 15, on the one hand, as well as the inclination associated therewith of the backrest 5, on the other hand, the user feels a high degree of seating comfort, as neither hard resistance or edges may be felt on the inclined backrest 5 or on the deforming seat 6. Instead, due to the force applied by the curved ribs 15, it may be desirable for the user to alter continuously at least partially the seating position, wherein the backrest 5 always follows said position change.

(30) Alternatively, the simplified construction shown in FIGS. 6a to 6d may also be a bearing shell 5a denoted hereinafter as the backrest shell with a cover 5b of the backrest 5, as shown in relative detail in FIGS. 7 to 10. The bearing shell 5a in turn comprises curved ribs 16. The curved ribs 16 of the backrest shell 5a are raised with their free ends in the x-direction. At the free end side, the cover 5b denoted hereinafter as the backrest cover, is attached to the curved ribs 16. The backrest cover 5b, in turn, consists of a non-stretchable material or a material which is at least relatively not easily stretchable.

(31) FIGS. 7 to 10 show in different views a preferred, relatively structurally detailed view of the chair 1 without a cover (FIGS. 7 and 8) and with a cover 5b, 6b (FIGS. 9 and 10). As is relatively clearly visible from FIG. 7, the support shell or seat shell 6a comprises a central recess which forms a seat opening 17 on the shell base side.

(32) Slots 18 opening onto the shell periphery side and extending toward the seat opening 17 are incorporated into the seat shell 6a. Between two of said slots 18, in each case a curved rib 15 is formed. On the opposing seat sides or shell sides, two curved ribs 16 are arranged diametrically opposing one another. On the front face or front side slots 18 are also incorporated into the seat shell 6a, wherein between two slots 18 a curved rib 15 is in turn formed. The rear face of the seat shell facing the backrest 5 is unslotted and thus relatively rigid relative to the slotted front face of the seat shell.

(33) Supporting webs 17a, 17b are connected at the side to the seat opening 17 of the support shell 6a, which extend in the vertical direction z downward to a substantially horizontal L-shaped limb 4c of the backrest support 4. The backrest support 4 is to this end of L-shaped configuration with a substantially vertical L-shaped limb forming the support arms 4a, 4b and with the horizontal L-shaped limb 4c, which extends below the seating surface 6 in the x-direction. The supporting webs 17a, 17b are preferably connected in an articulated manner in the front region of the seat opening 17 remote from the backrest 5 to the horizontal L-shaped limb 4c.

(34) Similar to the seat shell 6a, the backrest shell 5a of the backrest 5 is also provided with slots 18 on the peripheral side of the shell, and which open into the shell edges and extend toward a central recess and/or backrest opening 19. Between two slots 18 a curved rib 16 is formed, in turn. As in the seat shell 6a, two curved ribs 16 are also arranged opposing one another diametrically in the backrest shell 5a. Whilst the shell upper face of the backrest shell 5a is in turn provided with slots 18, the backrest underside of the backrest shell 5a facing the rear face of the seat shell 6a is unslotted.

(35) As is relatively clearly visible from FIGS. 8 and 10, the support arms 4a, 4b extending in a V-shaped manner, as well as the connecting element 9 on the backrest side, flank the backrest opening 19 practically on three sides. The connecting element 10 on the seat side is located at an intersection with the substantially horizontal L-shaped limb 4c of the backrest support 4. The armrest supports 20a, 20b extending in the y-direction are attached here, on which armrests 21 which are adjustable in the z-direction are held. An inclination of the backrest 5 accordingly leads to a corresponding inclination of the armrests 21.

(36) As visible from FIGS. 9 and 10, the seat cover 6b on the seat shell 6a is guided with a sufficient tension around the outer edges of the shell, forming a cover or fold-over edge 22 encompassing the seat shell 6a on the shell underside, and thus held reliably on the seat shell 6a. In a similar manner, the backrest cover 5b fully covering the backrest shell 5a is stretched around the outer edge thereof, forming a cover and/or fold-over edge 23 which encompasses the backrest shell 5a on the rear face of the backrest.

(37) Whilst the seat shell 6a and the backrest shell 5a are preferably made from a flexible plastics material, the seat cover 6b and the backrest cover 5b expediently consist of a non-stretchable but sufficiently flexible woven material. The support frame 4a, 4b and the connecting element 9 on the backrest side are expediently integrally formed on the backrest shell 5a. In this case, the integrally formed region of the support arms 4a, 4b extends from the connecting element 9 on the backrest side, only over part of the arm length of the support arms 4a, 4b. The corresponding integrally formed region B of the support arms 4a, 4b on the backrest shell 5a is approximately a third, up to half, of the arm length of the support arms 4a, 4b extending in the vertical or z-direction.

(38) TABLE-US-00001 List of reference numerals 1 Seat/office chair 2 Pedestal/base 3 Seat support 4 Backrest support 4a, b Support arm 4c Horizontal L-shaped limb 5 Backrest 5a Bearing shell/backrest shell 5b Backrest cover 6 Seating surface 6a Support shell/seat shell 6b Seat cover 7 Arm 8 Chair caster 9 Connecting element on backrest side 9a, b Support end on backrest side 10 Connecting element on seat side 10a, b Support end on seat side 11 (Virtual) rotational axis 12a, b Rotary joint on backrest side 13a, b Rotary joint on seat side 14 Central piece 15 Curved arm 16 Curved rib 17 Seat opening 17a, b Supporting web 18 Slot 19 Backrest opening 20a, b Armrest support 21 Armrest 22, 23 Cover/fold-over edge a.sub.1 Spacing on seat side a.sub.2 Spacing on backrest side b Support arm width d Support arm depth d.sub.1 Support arm depth on seat side d.sub.2 Support arm depth on backrest side I Support arm length B Integrally formed region F Force/action of force K Seating surface edge N Seating surface normal S Mean perpendicular α Angle of inclination/ trapezoidal angle y Horizontal direction z Vertical direction