Back Rest for a Stool or a Chair, and Stool or Chair Provided with such a Back Rest

Abstract

The invention relates to a back rest for a stool or a chair, comprising two adjacent, spring-mounted back supports ( 3.1 ), each of which is fixed to a separate carrier part ( 4.1 ). Said back rest is characterised in that each carrier part ( 4.1 ) forms the first limb of an essentially L-shaped carrier ( 4 ), and the second limb ( 4.2 ) of each carrier ( 4 ) is fixed beneath the stool or chair seat in such a way that it can be pivoted about a horizontal axis against an elastic force.

1 .- 31 . (canceled) 
     
     
         32 . A backrest for a stool or a chair, the backrest comprising:
 a first and a second substantially L-shaped support members each comprised of a first leg and a second leg, wherein the first legs form a carrier part, respectively;   a first and a second back supports each arranged in a springy fashion and arranged laterally adjacent to one another;   wherein the first and second back supports are attached to the carrier parts;   wherein the second legs are attached below a seat of the stool or the chair so as to be pivotable against a spring force about a horizontal pivot axis;   wherein the first and second support members are connected to one another by a guide bar that is oriented substantially perpendicularly to the first and second support members in a rest position of the first and second support members, which guide bar is supported in or on a seat understructure and connected to the first and second support members such that upon movement of one of the first and second back supports in a first direction to the front or to the rear of the stool or the chair the other one of the first and second back supports is moved in a second direction opposite to the first direction, respectively.   
     
     
         33 . The backrest according to  claim 32 , wherein the guide bar has ends that are pivotably connected to the first and second support members, respectively, by a ball joint that is supported in an elastically deformable sleeve. 
     
     
         34 . The backrest according to  claim 33 , wherein the guide bar is supported at a connecting point between the ends connected pivotably to the first and second support members on the seat or a seat understructure. 
     
     
         35 . The backrest according to  claim 34 , wherein the guide bar is supported by a ball joint at said connecting point between the ends. 
     
     
         36 . The backrest according to  claim 32 , wherein the guide bar is guided in arc-shaped guide grooves provided in or on a seat understructure, wherein imaginary axes of the arc-shaped guide grooves extend parallel to the horizontal pivot axis of the first and second support members and, relative to the front end of the chair, are curved from the top to the rear and from the rear to the bottom. 
     
     
         37 . The backrest according to  claim 33 , wherein the guide bar is connected pivotably to the second legs of the first and second support members. 
     
     
         38 . The backrest according to  claim 37 , wherein the second legs each have an upwardly oriented projection and said projections are supported by first springs that, in the rest position of the first and second support members, are uniformly pressure-loaded. 
     
     
         39 . The backrest according to  claim 38 , wherein the first springs are coil springs whose longitudinal axis are perpendicular to the horizontal pivot axis of the first and second support members and are arranged in the area of the seat understructure. 
     
     
         40 . The backrest according to  claim 39 , further comprising pressure plates mounted on the projections and supported by plungers on first springs. 
     
     
         41 . The backrest according to  claim 38 , wherein the pretension of the first springs is changeable. 
     
     
         42 . The backrest according to  claim 41 , wherein the first springs have ends opposite the pressure plates and said ends rest against blocks movable in a longitudinal direction of the first springs, wherein the blocks are supported on cams of a camshaft which camshaft is turnable from the exterior. 
     
     
         43 . The backrest according to  claim 42 , wherein said guide bar is attached to a seat understructure supported by second springs such that the seat understructure upon pivoting of the first and second support members is movable to the front or to the rear relative to a seat frame. 
     
     
         44 . The backrest according to  claim 32 , wherein the back supports are attached in a springy fashion on the carrier parts. 
     
     
         45 . The backrest according to  claim 32 , wherein the back supports are attached to the carrier parts so as to be pivotable about a substantially vertically oriented axis, respectively. 
     
     
         46 . The backrest according to  claim 32 , wherein the back supports are positionable along the carrier parts at different height positions. 
     
     
         47 . The backrest according to  claim 46 , wherein the back supports are attached to securing members that are slidable along the carrier parts. 
     
     
         48 . The backrest according to  claim 47 , wherein the securing members each have a body attached thereto so as to be pivotable against a first spring force about a horizontal axis, wherein said bodies are attached to the back supports, respectively, so as to be pivotable against a second spring force about a vertical axis. 
     
     
         49 . The backrest according to  claim 32 , wherein the first and second back supports are connected to one another by an elastically deformable transverse stay and wherein a strength of the transverse stay is selected such that the first and second back supports function as individual supports and a movability of one of the first and second back supports relative to the other one of the first and second back supports maintained to a limited extent. 
     
     
         50 . Chair furnished with a backrest according to  claim 32 . 
     
     
         51 . Seating furniture comprising a seat, a support unit, and a column, wherein the seat is attached with said support unit to the column, and further comprising a backrest that has two back supports that are arranged laterally adjacent to one another and secured in a springy fashion, wherein the backrest further has a first and a second substantially L-shaped support members each comprised of a first leg and a second leg, wherein the first legs form a substantially vertically extending carrier part, respectively, and wherein the two back supports are attached to the carrier parts and wherein the second legs are attached below the seat so as to be pivotable against a spring force about a horizontal pivot axis, wherein the support members each have a separate spring element. 
     
     
         52 . Seating furniture according to  claim 51 , wherein the force of the spring elements acting on the support members is jointly changeable. 
     
     
         53 . Seating furniture according to  claim 51 , wherein the second legs of the support members are configured as a two-arm lever, wherein the spring force acts on a free lever end of the two-arm lever. 
     
     
         54 . Seating furniture according to  claim 53 , wherein the spring force is effected by a spring element that is substantially oriented vertically. 
     
     
         55 . Seating furniture according to  claim 53 , wherein a free lever end of the two-arm lever of the second leg has a bent section oriented upwardly or downwardly, wherein an essentially horizontally oriented spring element acts on the bent section. 
     
     
         56 . Seating furniture according to  claim 55 , wherein the bent section is oriented upwardly and wherein the spring element is a tension spring and wherein ends of the tension springs of the support members are attached to an adjusting member that is securable relative to the horizontal pivot axis at different spacings for changing the force acting on the support members. 
     
     
         57 . Seating furniture according to  claim 51 , wherein the back supports each are attached height-adjustably on the carrier parts, respectively. 
     
     
         58 . Seating furniture according to  claim 51 , wherein the back supports each are attached in a springy fashion on the carrier parts, respectively. 
     
     
         59 . Seating furniture according to  58 , wherein the back supports each are pivotable relative to the carrier parts about a horizontal axis, respectively. 
     
     
         60 . Seating furniture according to  claim 58 , wherein the back supports are pivotable about a vertical axis relative to the carrier parts, respectively. 
     
     
         61 . Seating furniture according to  claim 58 , wherein the back supports are attached to securing members that are securable along the carrier parts, respectively, at different height positions. 
     
     
         62 . Seating furniture according to  claim 61 , wherein the back supports each are attached by intermediate positioning of at least on elastically deformable spring element on the securing members, respectively. 
     
     
         63 . Seating furniture according to  claim 62 , wherein the securing members each have a body attached thereto so as to be pivotable against a first spring force about a horizontal axis, wherein said bodies are attached to the back supports, respectively, so as to be pivotable against a second spring force about a vertical axis. 
     
     
         64 . Seating furniture according to  claim 51 , wherein the support members are fixedly securable at different spacings from one another along the horizontal pivot axis.