Abstract:
The invention relates to a rail system for drawers, comprising a body rail to be fastened to a furniture body and at least one drawer rail that can be moved relative to the body rail, and comprising at least one gear rack arranged on a rail of the rail system, wherein the gear rack can be pivoted or bent relative to the rail to which said gear rack is fastened about an imaginary axis (A) extending in the pull-out direction of the rail and thus is mounted such that the gear rack can be moved vertically to a limited extent.

Description:
This application is a continuation of International Application No. PCT/AT2010/000424, filed Nov. 8, 2010. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention concerns a rail system for drawers, comprising a carcass rail to be fastened to a furniture carcass and at least one drawer rail movable relative to the carcass rail, and at least one rack arranged on a rail of the rail system. 
     The invention further concerns an arrangement of two rail systems of the kind to be described, which are to be mounted at opposite side walls of an article of furniture and which are connected together for the transmission of a synchronous movement by way of a synchronisation bar. 
     Such rail systems are usually employed to synchronize the movement of two drawer extension guides which are in opposite relationship on an article of furniture, relative to each other, by a rack-and-pinion arrangement. That permits precise parallel guidance of an extendable furniture part—in particular of a drawer. That parallel guidance relative to a furniture carcass is advantageous in particular when very narrow or very wide drawers are to be moved, in which case lateral tilting of the drawer is substantially prevented by the parallel guidance effect. The movement of the oppositely disposed rail systems is frequently synchronized by way of a synchronization bar extending transversely to the extension direction. Mounted at both end regions of the synchronization bar are pinions which respectively engage into the racks of the rail systems to be synchronized. EP 1 036 526 B1 discloses such a parallel guide assembly having a rack-and-pinion arrangement. With known rail systems, the positively locking connection between the rack and the pinion can lead to jamming of the rail system and thus unwanted blocking of the drawer in normal use. 
     DE 43 01 326 A1 describes a drawer extension arrangement, wherein toothed racks are mounted movably on the carcass rail and the drawer rail so that they can project freely over their length from the respective fastening end. The flexural axis of the rack extends in that case substantially at a right angle to the extension direction of the rails. 
     The object of the present invention is to propose a rail system of the general kind set forth above, having improved running properties. 
     SUMMARY OF THE INVENTION 
     According to the invention, the above object is attained by the features of the present invention. Further advantageous configurations of the invention are recited in the appendant claims. 
     Thus, the rack is pivotable or bendable (i.e., pivotable) with respect to the rail to which it is fastened about a notional axis extending in the extension direction of the rail and is thus mounted limitedly movably heightwise. 
     A limitedly heightwise movable mounting of the rack provides that, when pulling out and pushing in the drawer, it is possible to avoid twisting between the pinion and the rack, as the rack which is mounted resiliently in a heightwise direction can yield with respect to the pinion in possible jamming situations. However, the positively locking connection between the pinion and the rack is maintained. The rack can therefore be elastically preloaded towards the pinion, either by inherent elasticity or also by the force of a spring. 
     In an embodiment, the rack can be mounted limitedly movably heightwise by way of a resiliently yielding portion. The resiliently yielding region is such that, after vertical deflection, the rack is automatically moved back into the original starting position again. 
     In another embodiment of the invention, the rack can be connected to one of the rails by way of a film hinge. Such an integral hinge connection between the rack and the stationary or heightwisely immobile part of the rail can be implemented by a thin-wall connection (for example, by a groove extending in a longitudinal direction of the rail). It is equally advantageously possible to use a flexural hinge by which the rack is pivotable about a longitudinal axis. 
     In a possible development of the invention, the rack can be arranged or provided on an adaptor, wherein the adaptor is connected or can be releasably connected to one of the rails by at least one fastening location. In that respect, it may be desirable if the adaptor is substantially in the form of an L-profile, wherein in the mounted position one leg of the L-profile bears against a vertical limb of the carcass rail and another leg of the L-profile bears against a horizontal limb of the carcass rail. Simple fastening can be effected by the adaptor being fastened at the same time as mounting of the rail system to the furniture carcass. 
     It is to be noted that at least one pinion engages into the rack of the rail system. The pinion engaging into the rack can be directly or indirectly coupled to the synchronization bar, as a parallel guidance pinion. In particular, there can be a non-rotatable connection between the pinion and the synchronization bar. 
     In a first embodiment, the rack is arranged on the carcass rail or the furniture carcass and the pinion is mounted on the drawer rail or the drawer. In an alternative embodiment, the rack can be arranged on the drawer rail or the drawer and the pinion can be mounted on the carcass rail or the furniture carcass. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further details and advantages of the present invention are described by means of the specific description hereinafter, with reference to the drawings in which: 
         FIG. 1  shows a perspective view of an article of furniture with drawers which are mounted displaceably relative to a furniture carcass by way of oppositely disposed rail systems, 
         FIGS. 2   a ,  2   b  show a perspective view of a rail system, wherein the rack provided for synchronization of the movement of the drawer is arranged on the carcass rail, and a perspective view of a rack arranged on the drawer, 
         FIGS. 3   a ,  3   b  show a sectional view of the rail system, wherein the rack is connected to the carcass rail by way of a film hinge, and an enlarged detail view thereof, 
         FIGS. 4   a ,  4   b  show a view from the rear and a perspective view of the rail system, 
         FIGS. 5   a ,  5   b  show an embodiment of the invention with an adaptor carrying the rack as a perspective exploded view and the mounted position of the rail system as a sectional view, and 
         FIGS. 6   a ,  6   b  show a possible embodiment of a synchronization bar provided for synchronizing a movement of two rail systems in opposite relationship on a furniture carcass, wherein the synchronization bar has a hinge. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a perspective view of an article of furniture  1  having a furniture carcass  2  in cabinet form, with drawers  3  mounted displaceably relative to the furniture carcass  2  by way of rail systems  4 . Disposed on each side of the drawer  3  is a rail system  4 , wherein the two rail systems  4  are to be fastened to mutually opposite side walls of the furniture carcass  2 . It is possible to see a synchronization bar  5  in the form of a torsion shaft, extending transversely relative to the extension direction of the drawer  3 . The movements of the two rail systems  4  can be synchronized relative to each other by the synchronization bar  5  whereby it is also possible to provide for precise parallel guidance of the drawer  3  relative to the furniture carcass  2 . The two rail systems  4  respectively have a carcass rail  6  to be mounted to the furniture carcass  2 , and at least one drawer rail  7  displaceable relative to the carcass rail  6 . The purpose of the synchronization bar  5  is to synchronize a movement of the left-hand and right-hand drawer rails  7  relative to each other so that the drawer  3  can be pulled out of the furniture carcass  2  and pushed thereinto without lateral tilting. At the end regions, the synchronization bar  5  has at least one rotatably mounted pinion  8  meshing with a rack  9  of the rail system  4 . It will be appreciated that as a mechanical reversal, it is also possible for the rack  9  to be mounted to the drawer  3  or to the drawer rail  7  and for the associated pinion  8  to be mounted to the carcass rail  6  or the furniture carcass  2 . 
       FIG. 2   a  shows a perspective view of a rail system  4  with the carcass rail  6  to be fastened to the furniture carcass  2 , and the displaceable drawer rail  7 . A middle rail  10  is mounted displaceably between the carcass rail  6  and the drawer rail  7  in a known manner in order to permit full extension of the drawer  3  relative to the furniture carcass  2 . For synchronization of the rail movement of an individual rail system  4 , there is provided a synchronization device  11  with a pinion mounted rotatably to the middle rail  10  and which can control the movable rails  7 ,  10  relative to each other in accordance with a progressive action slide, so that the drawer rail  7  moves at approximately twice the speed of the middle rail  10 . A mounting block  12  is fixedly connected to the extendable drawer rail  7 . The pinion  8  shown in  FIG. 1  which engages into the rack  9  is accommodated in that mounting block  12 . The rack  9  extends in the extension direction  13  of the drawer  3  and extends substantially over the entire length of one of the rails  6 ,  7 ,  10 . In the present case, the rack  9  extends over the entire length of the carcass rail  6 . It will be appreciated that it would also be possible for the rack  9  to also extend only over a part of the length of the rail  6 ,  7 ,  10 . When the drawer  3  is pulled out in the extension direction  13 , the drawer rail  7  is moved forwardly together with the mounting block  12  arranged thereon and together with the synchronization bar  5  along the rack  9 , with the pinion  8  also running along the rack  9 . The movement of the pinions  8  of two rail systems  4  in opposite relationship on the furniture carcass  2  can be synchronized by the synchronization bar  5 . 
       FIG. 2   b  only diagrammatically shows the mechanical reversal thereof, namely, showing that the mounting block  12  with the pinion  8  is mounted to the carcass rail  6  (or alternatively to the furniture carcass  2 ) and the rack  9  is mounted to the drawer rail  7  (or also to the drawer  3 ). 
       FIG. 3   a  shows a vertical section through the rail system  4  with the stationary carcass rail  6 , the middle rail  10  movable relative to the carcass rail  6 , and the drawer rail  7 . Displaceable running carriages  14   a ,  14   b  with load-transmitting rolling bodies are mounted between the rails  6 ,  7 ,  10 . In the illustrated embodiment, the rack  9  is connected by a resilient region  15  to the stationary part of the carcass rail  6 .  FIG. 3   b  shows an enlarged view of the region circled in  FIG. 3   a . The resiliently yielding region  15  is embodied in the illustrated embodiment by a film hinge  15   a  (that is to say, by a local weakening in the rail  6 ) extending in the longitudinal direction of the rail  6 ,  7 ,  10 , in the form of a groove  16 , thereby providing for partial flexibility (pivoting) of the rack  9  in an upward direction. The risk of jamming as between the pinion  8  and the rack  9  can be substantially reduced in that way. The heightwisely movable mounting of the rack  9  can also be implemented by way of a flexural pivoting hinge so that the rack  9  is mounted limitedly heightwisely movably (i.e., mounted so as to have some limited movement in the heightwise direction after mounting) as indicated by the illustrated double-headed arrow. The rack  9  is thus pivotable or bendable (i.e., pivotable) with respect to the rail  6  about a notional (longitudinal extension) axis (A) extending in the extension direction  13  ( FIG. 2   a ) and is thus mounted limitedly movably heightwise. It is to be noted that the hinge or axis (A) does not have to be at a well-defined location (for example by a weakening of the film hinge). Rather the rack  9  can be of an elastically bendable configuration in itself and can thus bend (pivot) downwardly at the free longitudinal edge. 
       FIG. 4   a  shows a view from the rear of the drawer  3  connected to the rail system  4 . The mounting block  12  is fixedly connected to the drawer rail  7 , the pinion  8  engaging into the rack  9  connected to the carcass rail  6 . The rotary movement of the pinions  8  of two rail systems  4  in opposite relationship on a furniture carcass  2  is synchronized relative to each other by the synchronization bar  5 . In the illustrated embodiment, the synchronization bar  5  has a two-part structure and includes two shaft portions  5   a  and  5   b  connected together by a joint  17 . The joint  17  of the synchronization bar  5  makes it possible to compensate for installation tolerances, height errors and possible angular displacement of two oppositely disposed rail systems  4 . The joint  17  has such a construction that a rotary movement of the two shaft portions  5   a ,  5   b  relative to each other is possible. 
       FIG. 4   b  shows a perspective view from the rear of the rail system  4  in the closed position. The rail system  4  has a limiting device  18  which limits the depth of engagement of the pinion  8  relative to the rack  9  in such a way that the teeth  8   a  of the pinion  8  only partially engage into the corresponding tooth gaps  9   a  in the rack  9 . The limiting device  18  includes a runner wheel  18   a —preferably in the form of a friction wheel—which is mounted rotatably coaxially relative to the pinion  8 . The diameter of the runner wheel  18   a  is smaller than that of the pinion  8 . It is possible to see a—preferably elastically yielding—spacer part  18   b  which can extend substantially over the entire length of the rack  9 . The runner wheel  18   a  runs on or along a running surface of the spacer part  18   b  which is made of plastic material, whereby the teeth  8   a  of the pinion  8  cannot engage completely into the tooth gaps  9   a  in the rack  9 . That makes it possible to effectively prevent jamming between the pinion  8  and the rack  9 , thereby also preventing the risk of jamming of the drawer  3  in normal use. The limiting device  18  also includes a limb  18   c  which engages under the rack  8  and by which the lift-off height of the pinion  8  relative to the rack  9  can be limited. In the illustrated embodiment, the limb  18   c  is part of the mounting block  12  and can be moved along the stationary rack  9  upon movement of the drawer  3 . The plastic spacer part  18   b  acts virtually as a cushion between the pinion  8  and the rack  9  whereby the pinion  8  is guided in a play-free fashion and with a low level of noise. 
       FIG. 5   a  shows an exploded view of a rail system  4 , wherein the rack  9  is provided on a substantially L-shaped adaptor  19 . The adaptor  19  includes two legs  19   a  and  19   b  substantially arranged at a right angle to each other, the rack  9  being mounted on the leg  19   b . The adaptor  19  is also suitable in particular for equipping a commercially available extension guide for drawers  3 —comprising a carcass rail  6  and at least one drawer rail  7  displaceable relative thereto—with a rack  9 , as from the factory, or also subsequently. The adaptor  19  can be made from plastic material or metal. The adaptor has fastening locations  21   a  and  21   b  aligned with the fastening locations  16   a ,  16   b  of the carcass rail  6 . In the mounting operation, therefore, screws are passed through the fastening locations  6   a ,  6   b  of the carcass rail  6  and through the fastening locations  21   a ,  21   b  of the adaptor  19  and screwed into the furniture carcass  2 . The fastening locations  21   a ,  21   b  of the adaptor  19  are only a few of the possible configurations. In particular, it is also possible to provide a snap connection between the adaptor  19  and the rail system  4 . 
       FIG. 5   b  shows the carcass rail  6  of  FIG. 5   a , fastened to the furniture carcass  2 . In the mounting operation, the leg  19   a  of the adaptor  19  is screwed between the carcass rail  6  and the furniture carcass  2 . The lower leg  19   b  of the adaptor is resilient so that the rack  9  mounted thereon is mounted limitedly heightwisely movably in order thus to prevent jamming between the pinion  8  and the rack  9  during the movement of the drawer  2 . 
       FIG. 6   a  shows an embodiment of a synchronization bar  5  provided for synchronization of two rail systems  4  in opposite relationship on a furniture carcass  2 . The synchronization bar  5  is of a two part configuration and includes two shaft portions  5   a  and  5   b  connected together by way of a joint  17 . The joint  17  permits radial mobility of the two shaft portions  5   a  and  5   b  relative to each other. The joint  17  can be in the form of a shaft joint, in particular a cardan joint or a ball joint. It is possible in that way to compensate for the relative displacement of two rail systems  4  in opposite relationship on a furniture carcass  2 .  FIG. 6   b  shows a sectional view of the synchronization bar  5  with the two shaft portions  5   a ,  5   b  of  FIG. 6   a . It is possible to see the gear head  20  which is arranged on the shaft portion  5   a  and which engages into a corresponding tooth arrangement of the joint  17 . 
     The present invention is not limited to the illustrated embodiments and includes or extends to all technical equivalents which can fall within the scope of the claims appended hereto. The positional references adopted in the description such as for example up, down, lateral and so forth are also related to the directly described and illustrated Figure and are to be appropriately transferred to the new position upon a change in position.