Abstract:
A device for opening and closing a movable furniture part, in particular a drawer, door or shutter includes two trigger and drive units which each have a trigger member controllable by the action of an external force and a drive member coupled to the trigger member for moving the furniture part and one or more locking members for locking the furniture part in the closed position and release of the furniture part as a function of the action of an external force on one or more trigger members. The two trigger and drive units are coupled to one another synchronously and substantially without play by a path- and force-transmitting means.

Description:
FIELD OF THE INVENTION 
   The invention relates to a device for opening and closing a movable part of a piece of furniture, in particular a drawer, a furniture door, a shutter or the like. 
   BACKGROUND OF THE INVENTION 
   Such devices serve the purpose of enabling the opening and closure of drawers, doors, shutters and any other movable parts of a piece of furniture which, by way of example, for aesthetic reasons have no handle. Opening and closing such movable parts of a piece of furniture, for example by lateral operation of the front panel or another accessible part, is impractical and does not allow reliable operation. 
   Fittings for opening drawers are known which are operated in that the drawer is pushed in by a predetermined length of travel and then moved out by a spring mechanism. This function is achieved in known manner through what are known as touch latch fittings. 
   Fittings based on the touch latch principle are disclosed, for example, in the specifications DE 100 08 350 A1, DE 198 21 014 A1 or DE 295 07 917 U1. 
   Similar closure mechanisms, as described, for example, in DE 197 53 319 A1, use a closure mechanism based on a curved or sliding guideway. These mechanisms are relatively costly to produce. 
   In the fittings known in the state of the art it is disadvantageous that to push in the drawer an increased resistance must be applied for tensioning the spring mechanism. 
   Furthermore, the devices need a relatively large trigger path and in particular cannot be triggered and locked from any desired pressure point on a drawer facing or a door, etc, with exactly the same short trigger paths and with the same forces. 
   The object of the present invention is to specify a device which allows the opening and closure of a movable part of a piece of furniture by manual actuation at any point of this part of a piece of furniture with low opening and closure pressure and a small trigger path. 
   SUMMARY OF THE INVENTION 
   This task is solved according to the invention by the characteristics specified in the independent Claim  1 . 
   The device comprises according to the invention two trigger and drive units which each possess a trigger member controllable by external application of force and a drive member linked to the trigger member for moving the furniture part. There is at least one locking member for locking the furniture part in the closed position and releasing the furniture part as a function of the external application of force on at least one trigger member, wherein the two trigger/drive units are coupled to one another in synchronous manner substantially without play by path- and force-transmitting means. 
   Advantageous developments and refinements of the invention are specified in the subsidiary claims. 
   The two trigger and drive units are advantageously arranged at a distance from one another on opposite sides of the movable furniture part. 
   In a preferred development of the invention each trigger and drive unit comprises a disengaging lever mounted pivotably directly or indirectly on the movable furniture part and acted on by a spring which acting in conjunction with a limit stop arranged in fixed position on the carcass of the piece of furniture determines the closed and open position of the movable furniture part. In doing so in the closed state of the movable furniture part one end of the disengaging lever fits against the limit stop of the carcass of the piece of furniture. 
   To improve synchronous operation and the trigger and drive properties of the device it can be provided that the free end of the disengaging lever is of fork-like construction and acts in conjunction with a limit stop constructed in the form of a pin located in fixed position. 
   The force of the spring exerted on the disengaging lever, that is the initial tension in the spring, is preferably adjustable so that the desired travel of the drawer in opening can be determined as a function of the size of the drawer and the weight of the drawer. 
   The disengaging lever itself is preferably constructed as a guide bar having two legs whose first leg forms the trigger member and whose second leg is coupled via at least one path- and force-transmitting connecting member to the second leg of the respective other disengaging lever of the opposite trigger and drive member. 
   The locking member preferably comprises a spring-loaded latch temporarily actively connected to one of the two trigger/drive units which operates in the manner of a known touch latch locking mechanism. Two latches may also be provided which each act on one of the trigger and drive units. 
   In advantageous manner the trigger/drive unit and the locking member are arranged on a common assembly panel to be fastened to the movable furniture part which panel may be covered by a cover. The assembly panel and/or the cover is rigidly connected to the movable furniture part. 
   On the disengaging lever a setting device can be provided by means of which the position of the first leg can be altered relative to the position of the second leg. By this means fine adjustment of the limit stop position of the first leg of the disengaging lever relative to the limit stop on the carcass of the piece of furniture is possible. 
   In order to achieve a controlled and reproducible opening operation, means can be provided according to the invention for limiting the movement of the furniture part brought about by the drive member. 
   For the means for transmitting path and force between the disengaging levers of the two trigger and drive members mechanical, electromechanical, pneumatic or hydraulic means may be provided. For example, the mechanical connecting members can be constructed as rigid, inherently stiff members, as flexible members or as cable-like members depending on whether they must be put under load only by pulling or also by pushing. 
   The device according to the invention affords substantial advantages with respect to the devices known in the state of the art. 
   The movable furniture part opens and closes safely and reliably regardless of the point on the movable furniture part at which the opening and closing pressure is exerted. 
   The opening movement may be triggered at any point on the movable furniture part with an almost constant, very short trigger path. Jamming or one-sided opening or locking of the movable furniture part does not occur. 
   Furthermore, due to the device according to the invention the transfer of the momentum of the movable furniture part, ie the jolt when the mass of the furniture part encounters the carcass of the piece of furniture in the closing position, is absorbed without damage to the carcass of the piece of furniture, the movable furniture part or the mechanism. At the same time it is also prevented that the engagement between the latch and the disengaging lever is not inadvertently released due to the impact and the resultant change in direction of the movable furniture part (rebound). 
   Other advantages of the device are:
     suitable for heavy drawers,   especially suitable for very wide drawers,   when drawers are not too wide only one touch latch locking and unlocking member is needed on one side,   the front gap in drawers is adjustable by means of adjustable-length connecting members,   absolutely synchronous triggering and locking,   trigger forces selectable by means of different springs or adjustable elastic forces,   emergency unlocking possible because the drawer can always be pulled out manually,   retrofitting possible,   few and easily manufactured parts which can be used on the left and the right and   low overall height for fitting under the base of the top surface and between the drawers.   

   When used in drawers the best mode of operation of the device according to the invention is in association with what is known as a draw-in device which is present in almost all draw-out guides in modern drawers and is, accordingly, not described in more detail. The disengaging force of the disengaging lever is chosen to be greater than the draw-in force of the draw-in device. 
   Due to the force of the draw-in device the sensor ends of the disengaging levers when the touch latch is engaged are pulled against the limit stops on both sides of the carcass of the piece of furniture and by this means the drawer is held securely in the closed position. 
   A plurality of exemplified embodiments of the invention is described in more detail below with reference to the figures in the drawing. The exemplified embodiments provide further features, advantages and possible applications of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawing shows: 
       FIG. 1  a view from below of a drawer in the closed position fitted with a first embodiment of the device according to the invention; 
       FIG. 2  the embodiment shown in  FIG. 1  in the open position of the drawer by means of the device; 
       FIG. 3  a slightly modified embodiment with respect to  FIGS. 1 and 2  with a tension spring as energy storage device; 
       FIG. 4  an enlarged view of the device according to the invention shown in  FIGS. 1 and 2 ; 
       FIG. 5  a view in perspective of the device according to the invention as shown in  FIGS. 1 ,  2  and  3 ; 
       FIG. 6  another modified embodiment of the device according to the invention with a tension spring as energy storage device and fork-shaped disengaging lever in the closed position of the drawer; 
       FIG. 7  the embodiment according to  FIG. 6  using a torsion spring as the energy storage device in the open position of the drawer; 
       FIG. 8  a view of the device according to  FIG. 4  but with a two-piece, inherently adjustable disengaging lever; 
       FIG. 9  the embodiment according to  FIG. 8  with the cover closed having a catch device for setting the tension of the spring; 
       FIG. 10  an embodiment modified with respect to  FIG. 8  having a two-piece, inherently adjustable disengaging lever in the locked position; 
       FIG. 11  the embodiment of  FIG. 10  having a two-piece, inherently adjustable disengaging lever in the open position; 
       FIG. 12  coupling of the trigger and drive members by means of two connecting members laid crosswise; 
       FIG. 13  coupling of the trigger and drive members by means of a connecting member capable of being put under load by tension and pressure; 
       FIG. 14  coupling of the trigger and drive member by means of a short, central connecting member; 
       FIG. 15  direct coupling of the trigger and drive members by means of an oblong guide; 
       FIG. 16  coupling of the trigger and drive members by means of a rack-and-pinion gear; 
       FIG. 17  coupling of the trigger and drive members by means of a toothed belt; 
       FIG. 18  an illustration of the device according to the invention having means for limiting the opening travel. 
   

   DETAILED DESCRIPTION 
   The embodiments described relate exclusively to a movable furniture part in the form of a drawer which is arranged to be pulled out in known manner in the carcass of a piece of furniture. The exemplified embodiments can, of course, be transferred in the same or modified form to other movable furniture parts such as by way of example furniture doors, shutters, etc. 
     FIGS. 1 and 2  show a view from below of a drawer  3  which is held in known manner in a furniture carcass  1  by means of draw-out rails, for example. The bottom  4  and the front  5  of the drawer  3  are visible. 
   According to the invention trigger and drive members  6  are arranged on the side edges of the bottom  4  of the drawer close to the front  5  of the drawer. The trigger and drive members  6  comprise an assembly panel  7  on which an approximately T-shaped disengaging lever  8  is arranged pivotably in a pivot bearing  9 . In the region of the pivot bearing  9  a torsion spring  10  is arranged which exerts an elastic force on the disengaging lever  8  so that its leg  11  forming a trigger member rests by its sensor roller  12  against a limit stop  2  of the furniture carcass  1 . Furthermore, on the leg  11  a catch projection  13  is provided in which a spring-loaded, pivotable latch  17  engages which as a single member forms a known touch latch fitting and holds the disengaging lever  8  in a tensioned position. On the ends of the leg  14  of the disengaging lever  8  articulated connecting members are fitted. The connecting members  16  connect the leg  14  in each case to the leg  14  of the disengaging lever  8  of the other trigger and drive unit  6  opposite. This means that the two opposite disengaging levers  8  are connected to one another synchronously and without play so that the movement of one disengaging lever  8  is transmitted in the same way to the other disengaging lever  8 . 
   Proceeding from the initial state shown in  FIG. 1 , if the drawer  3  is now pushed in slightly by hand in the direction of the arrow  18  the disengaging levers  8  are pivoted slightly since their sensor rollers  12  are resting against the limit stops  2  of the furniture carcass  1 . As a result of the movement of the disengaging levers  8  the latch  17  is released from the catch projection  3  and sets the disengaging levers  8  free which due to the force of the spring  10  push away from the limit stop  2  of the furniture carcass  1  and due to the force of the spring the drawer  3  runs out to the end position of the disengaging levers in the direction of the arrow  19  as illustrated in FIG.  2 . In this position the drawer is freely movable and can be fully opened by the user. It is important that the manual depression of the drawer for triggering the device can ensue at any point on the front panel since any movement of the drawer is transferred on account of the connecting members  16  in the same measure to both trigger and drive units  6  so that the latch  17  always responds reliably and releases or arrests the associated disengaging lever  8 . 
   On closing the drawer the sensor rollers  12  of the disengaging levers  8  encounter the limit stops  2  on the furniture carcass  1 . On further movement of the drawer the disengaging levers  8  are swivelled in and the spring  10  is put under tension. In the trigger position, that is in the position of being almost completely pushed in, the latch  17  captures one disengaging lever  8  and arrest it whereupon via the connecting members  6  the other disengaging lever  8  is arrested. In this position the drawer is preferably held closed by the known draw-in devices (not illustrated) in the draw-out guides. 
     FIG. 3  shows the embodiment of the device in  FIGS. 1 and 2 , wherein, however, the torsion spring  10  of the disengaging levers  8  is replaced by a tension spring  22  which fulfils the same function. 
     FIG. 4  shows an enlarged view of a trigger and drive member  6  as shown in  FIGS. 1 and 2 . The assembly panel  7  may be seen on which the disengaging lever  8  is pivotably mounted in the pivot bearing  9  and is pretensioned by the torsion spring  10 . The leg  11  of the disengaging lever is supported via the sensor roller  12  against the limit stop  2  of the furniture carcass  1 . The spring-loaded latch  17  is mounted pivotably in the pivot bearing  20  and is likewise pretensioned by a torsion spring  23 . The latch  17  engages in the catch projection  13  of the disengaging lever  8 . The connecting members  16  are hinged pivotably in a pivot bearing  21  on the leg  14  of the disengaging lever  8 . 
     FIG. 5  shows the trigger and drive member  6  in perspective view, wherein it may be seen that the entire device is preferably covered by a cover  15  which is fastened together with the assembly panel  17  on the bottom  4  of the drawer  3 . 
   The development in  FIGS. 6 and 7  corresponds in principle to the development in  FIGS. 1 and 2 , wherein in this case, however, the disengaging levers  8  are again pretensioned by a tension spring  22  and possess a fork-like leg  24  which engages in a limit stop pin  26  on the furniture carcass. Due to the fork-like legs  24  and the associated limit stop pins  25  a still better synchronous movement of the disengaging levers  8  can be achieved. 
     FIG. 8  shows an embodiment of the trigger and drive members  6  having a two-piece disengaging lever  26 . The disengaging lever comprises a sensor part  27  on which the sensor roller  12  is arranged and a control part  28  on which the connecting members  16  are articulated. The control part  28  possesses a pivot bearing  29  by means of which the sensor part  27  is pivotably mounted. At a distance from the pivot bearing  29  the sensor part  27  possesses an oblong hole  30  into which an adjusting screw having an eccentric pin arranged on the control part engages. If the adjusting screw  31  is turned the sensor part  27  pivots about the pivot bearing  29  whereby the sensor roller  12  can be adjusted in the direction of the arrow  32 . By this means the gap space on the front  5  of the drawer relative to the furniture carcass  1  can be determined. Furthermore, the limit stop position of one disengaging lever  8  can be matched to the limit stop position of the opposite disengaging lever  8 . 
     FIG. 9  shows the control part  28  of the disengaging lever  26  illustrated in  FIG. 8  which is fastened pivotably on the assembly panel  7 . The disengaging lever  26  is pretensioned by a torsion spring  33  which in this embodiment has an extended adjusting lever by means of which the force of the spring, ie the pretensioning of the spring  33 , is adjustable. For this purpose the cover  15  possesses a toothed arrangement  34  which makes it possible to engage the adjusting lever of the spring  33  into different positions of the toothed structure  34 . Each position corresponds to a certain initial tension in the spring  33 . In this way the force exerted as a whole on the disengaging levers  8  can be adjusted. The toothed arrangement  34  with the adjustable spring  33  is also readily discernible in FIG.  18 . 
   Furthermore, in  FIG. 9  the bearings for the connecting members  16  on the leg  28  may be seen which can possess an eccentric bush  35  by which means the differences in length of the connecting members may be compensated. 
     FIGS. 10 and 11  show another embodiment of the trigger and drive member  6  having a two-piece disengaging lever  36 . The two possible end positions of the disengaging lever  36  are illustrated in each case. The disengaging lever  36  comprises a sensor part  37  having a sensor limit stop  38  instead of a sensor roller. The sensor limit stop  38  preferably consists of a noise-muffling, flexible plastic or rubber material. The control part  40  on which the connecting members  16  are hinged has a pivot bearing  39  at the front end in which the sensor part  37  is pivotably mounted. The sensor part  37  is connectable by means of a catch connection  43  to the control part  40 . An oblong hole  41  is arranged in the control part  40  and into the oblong hole  41  engages an eccentric pin of an adjusting screw  42  which is held in the sensor part  37 . As already described in connection with  FIG. 8  by turning the adjusting screw  42  it is possible to adjust the position of the sensor limit stop  38  with respect to the limit stop  2  of the furniture carcass  1 . The torsion spring  33  constructed with an adjusting lever which allows adjustment of the force exerted by the spring  33  may also be seen.  FIG. 10  shows the disengaging lever in the engaged position of the latch  17  when the drawer is closed whereas  FIG. 11  shows the disengaging lever in its end position when the drawer is open. 
   In  FIGS. 12  to  17  different variants and refinements of the connecting members  16  are illustrated.  FIG. 12  shows the T-shaped disengaging levers  8  illustrated in the preceding figures with connecting members in the form of a double crossover connection, each connecting member  16  being capable of loading only by tension. The connecting members  16  may be designed as belt- or rod-shaped members or alternatively as cable or Bowden controls. 
     FIG. 13  shows approximately L-shaped disengaging levers  44  having a simple cross connection by means of a connecting member  16  capable of being put under load by tension and compression which in this development is constructed by way of example in the form of rigid profile members. 
     FIG. 14  illustrates straight disengaging levers  45  mounted at approximately half their length in the bearings  9  which levers are connected to one another via connecting member  16  constructed as a short central guide bar. 
   In  FIG. 15  straight disengaging levers designed in a fashion similar to  FIG. 14  are illustrated, wherein one disengaging lever  46  has a pin which engages in an oblong hole of the other disengaging lever  47  and the two disengaging levers  46  and  47  are coupled to one another in a manner transmitting path and force. 
     FIG. 16  shows the possibility of coupling the disengaging levers by means of a toothed rack  49 , wherein both disengaging levers  48  possess a gear wheel arranged fixedly on the lever and are rotatable about the axis of rotation  9 . 
     FIG. 17  shows a cross-connection by means of a chain, toothed belt or the like, wherein a disengaging lever  50  is provided with a gear wheel which is connected via a toothed belt or a chain  51  to a gear wheel  52 . The gear wheel  52  meshes with a wider gear wheel of the disengaging lever  50  located opposite and thus ensures the reversal of direction necessary for synchronous path of the disengaging levers  50 . 
     FIG. 18  shows a possibility for limiting the automatic opening movement of the drawer by the spring-loaded disengaging levers  8 . The draw-out guide  53  of the drawer and a trigger and drive member  6  fastened to the bottom of the drawer (not shown) may be seen. On the cover  15  of the trigger and drive member  6  a leaf sprig  54  oriented approximately parallel to the draw-out guide  53  is fastened. This leaf spring  54  moves together with the drawer and the trigger and drive member  8  parallel to the draw-out guide  53 . The automatic opening movement of the drawer is now stopped by the leaf spring after a certain opening travel in that a limit stop slope  55  of the leaf spring strikes against a limit stop  56  arranged in fixed position on the draw-out guide  53  or the furniture carcass. The drawer can now be pulled out further by hand by overcoming the spring tension of the leaf spring  54 , whereby the limit stop slope  55  slides over the limit stop  56  and releases the drawer. On pushing in the drawer a run-in slope  57  of the leaf spring  54  slides with little resistance over the limit stop  56 . The leaf spring  54  is now once again in the position to stop the opening movement of the drawer. 
   
     
       
             
           
             
             
             
             
           
         
             
                 
             
             
               Legend to the drawing 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
               1 
               Furniture carcass 
               31 
               Adjusting screw with 
             
             
               2 
               Limit stop 
                 
               eccentric pin 
             
             
               3 
               Drawer 
               32 
               Direction of arrow 
             
             
               4 
               Bottom of drawer 
               33 
               Torsion spring with 
             
             
               5 
               Front of drawer 
                 
               adjusting lever 
             
             
               6 
               Trigger and drive member 
               34 
               Toothed arrangement 
             
             
               7 
               Assembly panel 
               35 
               Eccentric bush 
             
             
               8 
               Disengaging lever (T-shaped) 
               36 
               Disengaging lever 
             
             
               9 
               Pivot bearing 
                 
               (two-piece) 
             
             
               10 
               Tosion spring 
               37 
               Sensor part 
             
             
               11 
               Leg 
               38 
               Sensor limit stop 
             
             
               12 
               Sensor roller 
               39 
               Pivot bearing 
             
             
               13 
               Catch projection 
               40 
               Control part 
             
             
               14 
               Leg 
               41 
               Oblong hole 
             
             
               15 
               Cover 
               43 
               Catch connection 
             
             
               16 
               Connecting members 
               44 
               Disengaging lever 
             
             
               17 
               Latch 
                 
               (L-shaped) 
             
             
               18 
               Direction of arrow 
               45 
               Disengaging lever 
             
             
               19 
               Direction of arrow 
                 
               (straight) 
             
             
               20 
               Pivot bearing 
               46 
               Disengaging lever 
             
             
               21 
               Pivot bearing 
                 
               (with pin) 
             
             
               22 
               Tension spring 
               47 
               Disengaging lever 
             
             
               23 
               Torsion spring 
                 
               (with oblong hole) 
             
             
               24 
               Forked leg 
               48 
               Disengaging lever 
             
             
               25 
               Limit stop pin 
                 
               (with gear wheel) 
             
             
               26 
               Disengaging lever (two-piece) 
               49 
               Toothed rack 
             
             
               27 
               Sensor part 
               50 
               Disengaging lever 
             
             
               28 
               Control part 
                 
               (with gear wheel) 
             
             
               29 
               Pivot bearing 
               51 
               Toothed belt 
             
             
               30 
               Oblong hole 
               52 
               Gear wheel 
             
             
                 
                 
               53 
               Draw-out guide 
             
             
                 
                 
               54 
               Leaf spring 
             
             
               55 
               Limit stop slope 
               56 
               Limit stop 
             
             
               57 
               Run-in slope