Abstract:
The invention relates to a seat and/or backrest covering for a chair, in particular an office chair, having a frame-tensioned mesh-like fabric ( 3 ), which is penetrated by a large number of pins ( 4 ) provided on the periphery of a load-bearing frame ( 1 ) that surrounds the seat or backrest, and is held by means of a covering frame ( 2 ) fitted onto the load-bearing frame ( 1 ).

Description:
BACKGROUND OF THE INVENTION 
     FIELD OF THE INVENTION 
     The invention relates to a seat and/or backrest covering for a chair, in particular an office chair, having a frame-tensioned mesh-like fabric. 
     In an office chair disclosed by EP 0 856 269 A2 and having a synchronizing mechanism for adjusting the inclination of its seat/backrest unit, the seat and the backrest are covered by a mesh-like fabric. For this purpose, the mesh-like fabric is clamped in a flexible frame which, for its part, is inserted with a form fit into a peripheral groove of a load-bearing frame forming the load-bearing structure of the seat or the backrest. This type of mesh covering of the seat and/or of the backrest of a chair is very complicated in production terms. 
     SUMMARY OF THE INVENTION 
     The invention is therefore based on the object of specifying a comparatively simple type of mesh covering of the seat and/or the backrest of a chair, in particular an office chair. 
     According to the invention, this object is achieved by the features of claim  1 . For this purpose, the mesh-like fabric is held by means of a large number of bolt-like or needle-like pins, which are arranged on the periphery of a load-bearing frame forming the load-bearing structure of the seat or the backrest. The tensioning of the mesh or of the fabric is in this case carried out either when the mesh-like fabric is fitted directly onto the pins, for example by each or every second mesh or the mesh of fabric being led over such a pin. A covering frame fitted onto the load-bearing frame on the mesh side ensures that the mesh-like fabric is held on the load-bearing frame. 
     Alternatively, however, the tensioning of the mesh is carried out by means of the covering frame, by the fabric which is fitted onto the load-bearing frame and whose mesh is penetrated by the pins in the manner of a penetration technique being tensioned by means of contours and mating contours provided on the covering frame, on the one hand, and on the load-bearing frame, on the other hand, when the covering frame is joined to the load-bearing frame. 
     The covering frame is expediently positioned and/or held on the load-bearing frame by means of a tongue-and-groove joint which runs on the frame faces, facing the mesh-like fabric, of the covering frame and of the load-bearing frame, underneath the pins, which are preferably arranged in a comb-like manner. The groove is expediently provided on the load-bearing frame and the tongue on the covering frame. As a result, by means of the tongue contour provided on the covering frame, the mesh-like fabric held by the pins arranged peripherally on the frame is drawn into the groove provided on the load-bearing frame and tensioned in the process. If this tongue-and-groove joint is used only for positioning, then the covering frame is expediently held on the load-bearing frame by means of screws or the like. 
     At the same time as the covering frame and the load-bearing frame are joined, the pins arranged on the latter in a single-row or multi-row configuration penetrate into a corresponding groove which is provided in the covering frame and which advantageously clamps around the pins with a form fit. As a result, uniform mesh tensioning with simultaneously secure holding of the covering frame on the load-bearing frame is ensured in a simple way. Alternatively, instead of this groove, a row of holes accommodating the pins and having a number of holes which correspond with said pins and whose number corresponds to the number of pins. In this case, all or individual pins can be provided with a head, expediently a spherical head, that latches into the hole, which is then of corresponding design, in the manner of a clip-in or snap-in connection. This provides an additional or alternative method of holding the covering frame on the load-bearing frame. 
     Exemplary embodiments of the invention will be explained in more detail below using a drawing, in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1 a  and  1   b  show schematically, in a sectional illustration, a mesh-like fabric fixed on a load-bearing frame in the state in which it is not tensioned and tensioned by means of a covering frame, 
     FIGS. 2 a  and  2   b  show, in a detail, the load-bearing frame contour according to FIG. 1 with a two-row of single-row pin arrangement, 
     FIGS. 3 a  and  3   b  show an alternative embodiment with a fabric already tensioned on the load-bearing frame, in the unjoined and joined state of the frames, and 
     FIGS. 4 a  and  4   b  show, in an illustration according to FIGS. 2 a  and  2   b , the load-bearing frame contour according to the variant of FIG.  3 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Mutually corresponding parts are provided with the same reference symbols in all the figures. 
     FIGS. 1 a  and  1   b  show cross sections of a load-bearing frame  1  and of a covering frame  2  with a mesh-like fabric  3  which is located between them and is tensioned by means of the two frames  1  and  2 . In this case, the unjoined state of the two frames  1  and  2  is shown in the upper half of the figures, the mesh-like fabric  3  being penetrated by a large number of pins provided on the load-bearing frame  1 . While two rows of pins  4  are provided in the embodiment according to FIG. 1 a , the load-bearing frame  1  according to FIG. 1 b  has only one row of pins  4 . 
     The arrangement of the pins  4  along the periphery of the load-bearing frame  1 , which forms the load-bearing structure of the seat or of the backrest of a chair (not specifically illustrated), is shown in FIGS. 2 a  and  2   b  in relation to the two variants according to FIGS. 1 a  and  1   b . FIG. 2 a  reveals that, in the case of the two-row structure of the pins  4 , these are arranged uniformly and expediently equidistantly in a comb-like arrangement, offset in relation to one another, on the periphery of the load-bearing frame  1 . 
     The load-bearing frame  1  has a peripheral groove  5 , whose corresponding mating piece is integrally molded on the covering frame  2  in the form of a tongue  6 . This tongue-and-groove joint  5 ,  6  is used to position the frames  1 ,  2  in relation to each other when they are joined. The covering frame  2  can then be held on the load-bearing frame  1  by additional means, such as a screw fixing, or by means of a latch-in or snap-in connection between the two frames  1 ,  2 . In this case, the tongue-and-groove joint  5 ,  6  can already be designed as a latch-in connection. Alternatively, additional latching elements can be provided on the frames  1 ,  2 . 
     In addition, in the embodiment according to FIG. 1 b , the covering frame  2  has a single groove  7  and, in the embodiment according to FIG. 1 a , has two grooves  7   a  and  7   b , each of which corresponds with one of the rows of pins  4 . In the state illustrated in the lower half of FIGS. 1 a  and  1   b , in which the covering frame  2  is joined to the load-bearing frame  1 , the pins  4  preferably engage with a form fit into the corresponding grooves  7   a ,  7   b  and  7 , so that the respective groove  7   a ,  7   b  and  7  clamps around the corresponding row of pins  4 . Instead of the groove  7  or  7   a ,  7   b , a row of holes can also be provided in the covering frame  2  in a manner not specifically illustrated, the pins  4  engaging in these holes. Said pins can also, for example, be designed in the manner of spherical-headed pins and latch into the corresponding holes when the frames  1 ,  2  are joined. 
     When the covering frame  2  and the load-bearing frame  1  are joined, the tongue  6  draws the portion of the mesh-like fabric  3  which faces said tongue into the corresponding groove  5  in the load-bearing frame  1 . As a result, the mesh-like fabric  3  is tensioned. A step-like inner contour  8  on the covering frame  2  engages around the outer, upper edge  9  of the load-bearing frame  1 , so that when the two frames  1  and  2  are joined, overall an approximately oval outer or overall contour of the frame connection  1 ,  2  is formed. 
     In the embodiment according to FIGS. 3 a  and  3   b , the mesh-like fabric  3  is again penetrated by the pins  4  in a single-row or two-row design, and is already tensioned in the process. In the joined state illustrated in the lower half of FIGS. 3 a  and  3   b , the pins  4  again engage in corresponding grooves  7   a  and  7   b  or  7  or in holes in corresponding rows of holes. By means of a tongue-like contour  10  provided on the outer, upper frame edge  9  of the load-bearing frame  1 , on the one hand, and a corresponding groove-like contour  11  on the covering frame  2 , on the other hand, again a reliable tongue-and-groove joint is ensured in the joined state. The corresponding frame profile of the load-bearing frame  1  of this variant according to FIGS. 3 a  and  3   b  is shown in FIGS. 4 a  and  4   b.    
     Overall, the two frames  1  and  2  have corresponding inner profiles which are designed in order to provide a reliable joint in the manner of a tongue-and-groove contour.