Abstract:
A pull-out guide assembly for drawers, having on both sides of the drawer a support rail on the carcass and a pull-out rail on the drawer. The load of the drawer is transmitted between the rails by rollers that are borne in running carriages. The running carriages may be moved between a front end position and a rear end position in a differential manner. Locking means are provided for the running carriages and, in the event of a deviation from the differential running between the rails, they lock the running carriage on one of the rails at predetermined points between the two end positions. This locking is releasable by the movement of the rails with respect to one another.

Description:
BACKGROUND OF THE INVENTION 
   The invention relates to a pull-out guide assembly for drawers, having on both sides of the drawer a support rail on the carcass, and a pull-out rail on the drawer with the load of the drawer being transmitted between the rails by rollers that are borne in running carriages running between the rails between a front end position and a rear end position in differential manner, with the running carriages being provided with locking means. 
   As a result of the slip between the rollers and the guide profiled sections of the rails, it is not always guaranteed that, when the drawer is pulled and/or pushed in, the running carriages will cover exactly half the distance of the pull-out rails. This gives rise to so-called carriage running errors. In other words, the position of the running carriages in relation to the support rails and pull-out rails is not correct. Carriage running errors of this kind can in some cases result in the drawer staying open in normal use. 
   Carriage running errors are not new; they occur repeatedly with pull-out guide assemblies in which the load of the drawer is transmitted by rollers which are not borne on the rails but in separate running carriages. If the drawer is only moved manually, these errors are in many cases not noticed. If the drawer is pulled into the final closed position by a conventional closing system having springs, in most cases there is sufficient momentum for the carriage running error to be corrected by the dynamic of the drawer and for the drawer always to close. 
   In modern pull-out guides for drawers, closing devices are provided that are additionally equipped with a damping means so that the drawer is not pulled into the furniture carcass with too much force. However, these damping means reduce the closing dynamic of the drawer such that a carriage running error occurring while the drawer is moving can no longer be compensated because there is insufficient momentum at the movement. 
   OBJECT OF THE INVENTION 
   The object of the invention is to improve the pull-out guide assembly of the type mentioned at the outset such that the carriage running errors are corrected and hence correct closing of the drawer is achieved. 
   SUMMARY OF THE INVENTION 
   The object according to the invention is achieved in that, in the event of a deviation from the differential running between the rails and the running carriages, a locking device locks the running carriages on one of the rails at predetermined points between their two end positions, with this locking being releasable by the movement of the rails with respect to one another. 
   An example embodiment of the invention provides for each running carriage to be provided with two locking devices that lock the running carriage in opposing directions. 
   Advantageously, in this case it is provided for the locking devices to be formed by levers that are mounted rotatably on the running carriages. The levers are preferably constructed as double-arm levers. 
   A further example embodiment of the invention provides for the locking devices to be formed by resilient arms that project horizontally from the running carriages in the direction of movement, for the arm of a running carriage to abut against a stop of a rail upon locking, and for in each case a second rail to be provided with a counter-stop that abuts against the projecting arm of the running carriage on locking and so prevents deflection of the arm with respect to the stop on the first rail. 
   A further example embodiment of the invention provides for the locking devices to be formed by rockers that are borne tiltably on the running carriages and have two stop faces that abut against a stop of one of the rails in the event of a running carriage deviating from the differential running between the rails. 
   In a further embodiment of the invention a central rail is arranged between the support rail and the pull-out rail with a running carriage running between the support rail and the central rail and another running carriage running between the central rail and the pull-out rail. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be better understood from the accompanying drawings, in which: 
       FIG. 1  shows a view of a cabinet-like piece of furniture that is equipped with pull-out guide assemblies according to the invention; 
       FIG. 2   a  shows diagrammatically one side of a pull-out guide assembly having a pull-out rail, a running carriage and a support rail, in which the pull-out guide assembly is shown in the closed position; 
       FIGS. 2   b  to  2   d  show side views of the pull-out guide assembly in which the pull-out rail is shown in various intermediate positions, with a leading running carriage shown; 
       FIG. 2   e  shows a side view of the pull-out guide assembly, in which the pull-out rail is shown in the fully extended position of the draw; 
       FIGS. 3   a  to  3   e  show the same side views as  FIGS. 2   a  to  2   e , with a lagging running carriage shown; 
       FIGS. 4   a  to  4   e  show side views of the pull-out guide assembly in various positions, with the running carriage shown with two levers, 
       FIG. 5  shows a cross-section through an example embodiment of a pull-out guide assembly, 
       FIGS. 6   a  to  6   f  show side views of a further example embodiment of a pull-out guide assembly according to the invention, in various positions, 
       FIG. 7  shows an end view of a further example embodiment of a pull-out guide assembly according to the invention, 
       FIG. 8  shows a view of a further example embodiment of a running carriage according to the invention, 
       FIG. 9  shows a cut-away diagram of a rocker, 
       FIG. 10  shows a view of a running carriage according to the invention, in which one wall has been cut away to show the rocker, 
       FIG. 11  shows a view of a rocker, 
       FIG. 12  shows a further view of a rocker, 
       FIGS. 13   a  to  13   e  show diagrammatic side views of a pull-out guide assembly according to the invention in the region of the running carriage, in which the pull-out rail is moved to the right and an ideal movement sequence with no carriage running errors is shown, 
       FIGS. 14   a  to  14   e  show a purely diagrammatic side view of a pull-out guide fitting according to the invention in the region of the running carriage, in which the pull-out rail is moved to the left and once again an ideal movement sequence with no running carriage errors is shown, 
       FIGS. 15   a  to  15   e  show a purely diagrammatic side view of a pull-out guide assembly according to the invention in the region of the running carriage, in which the pull-out rail is moved to the right and a movement sequence with carriage running errors is shown, 
       FIGS. 16   a  to  16   e  show a purely diagrammatic side view of a further example embodiment of a pull-out guide fitting according to the invention in the region of the running carriage, in which the pull-out rail is moved to the left and a movement sequence with carriage running errors is shown, 
       FIGS. 17   a  to  17   e  show a diagrammatic side view of a pull-out guide assembly according to the invention in the region of the running carriage, in which the pull-out rail is moved to the left and a movement sequence with carriage running errors is shown. 
       FIG. 18  shows a diagrammatic side view of a pull-out guide assembly according to the invention in which a central rail is provided, the rails being shown in their rearmost position, and 
       FIG. 19  shows a diagrammatic vie of the pull-out guide assembly of  FIG. 18 , the rails being shown in their foremost position. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In each embodiment described below, only one side of a pull-out guide fitting will be described, as arranged on one side of the drawer. The opposite side of the drawer is of analogous construction. 
   The pull-out guide assembly according to the invention may be constructed as a simple pull-out guide assembly having on each side of the drawer a support rail  1  on the carcass and a pull-out rail  2  on the drawer. However, the assembly may also be constructed as a differential pull-out means, in which case a central rail  27  is arranged on each side of the drawer between the pull-out rail  2  and the support rail  1  (see  FIGS. 18 and 19 ). 
   In the embodiments shown in  FIGS. 2 to 17 , the pull-out guide assembly comprises on each side of the drawer a support rail  1  on the carcass and a pull-out rail  2  on the drawer, with a running carriage  3  arranged between the rails  1 ,  2  and serving as a cage for rollers  4 . 
   In the example embodiments, the rollers  4  are constructed as cylindrical rollers. However, they may also be constructed as balls, or a running carriage  3  may be equipped with a combination of balls and rollers. 
   In the example embodiment according to  FIGS. 2 to 5 , the running carriage  3  is provided in its center with two double-arm levers  6  that are tiltable about a horizontal axis pin  5  and which serve as locking devices. The levers  6  are acted upon by pressure springs  7 . 
   In  FIGS. 2   a  to  2   d  and  3   a  to  3   d , for the sake of better clarity, only one of the levers  6  coming into operation in one direction upon locking is shown on the running carriage  3  in each case. 
     FIGS. 2   a  to  2   e  show a particular situation of a leading running carriage  3 . The running carriage  3  is too far in front with respect to the rails  1 ,  2 . When the pull-out rail  2  is moved into the furniture carcass (in an inward direction from left to right; figures are in the order  2   e  to  2   a ), the leading running carriage  3  runs along with the pull-out rail  2  until the lever  6  abuts against the stop  8  of the support rail  1  by means of its hook, which is constructed on the free end, and is caught there. The running carriage  3  is locked at this point, while the pull-out rail  2  continues to move in the inward direction into the furniture carcass, in relation to the running carriage  3  and the support rail  1 . 
   A stop  9  is constructed on the pull-out rail  2 . When the stop  9  comes up against the upper end of the lever  6 , the pull-out rail  2  is in the correct position relative to the running carriage  3 . The lever  6  is tilted (rotated) clockwise and locking of the running carriage  3  against the stop  8  is released, whereupon the running carriage  3  moves in the inward direction into the end position with precise differential movement between the pull-out rail  2  and the support rail  1 . 
   Thus, in this case, the running carriage  3  moves in the inward direction until encountering stop  8 , at which time it becomes locked to support rail  1 . After being released by stop  9  on pull-out rail  2 , the running carriage  3  can continue to move in the inward direction until reaching the final end position. 
   In cases in which the pull-out rail  2  is moved into its final end position by a relatively weak pull-in device, such as a pull-in device having a damping means, the running carriage  3  does not constitute any obstacle. 
     FIGS. 3   a  to  3   e  show the situation with a lagging running carriage  3 . The running carriage  3  is too far behind with respect to the movement of the pull-out rail  2  (see  FIG. 3   e ). Once the pull-out rail  2  has been brought into the position shown in  FIG. 3   d  when the drawer is pushed in, the running carriage  3  is so far behind that the pull-out rail  2  latches into the hook-like end of the lever  6  by means of the hook  10  thereof. When the pull-out rail  2  is moved into the position shown in  FIG. 3   c , it carries the running carriage  3  along with it, in other words the running carriage  3  does not travel in differential manner between the pull-out rail  2  and the support rail  1  but is moved at the same speed as the pull-out rail  2 . 
   As soon as the pull-out rail  2  and the running carriage  3  have reached the position shown in  FIG. 3   b , the lever  6  abuts (by means of its lower end) against the stop  11  of the support rail  1  and is uncoupled from the stop  10  of the pull-out rail  2 . In the next section of the push-in travel, the running carriage  3  runs correct by differential between the pull-out rail  2  and the support rail  1 . Once again, there is no braking action acting on the pull-out rail  2 . 
   As can be seen from  FIG. 5 , the two levers  6  are arranged on one side of the running carriage  3 . The stops  8 ,  9 ,  10  and  11  are constructed on horizontal webs  2 ′,  1 ′ of the pull-out rail  2  and the support rail  1 , and are laterally offset with respect to the rollers  4 . Both when the running carriage  3  is leading and when the running carriage  3  is lagging, the position of the running carriage  3  is corrected before it reaches the end region of the push-in travel. At this point, the pull-out rail  2  is still being pushed into the carcass, or moved with momentum, by the person using the drawer. The relatively weak pull-in device is not yet engaged at this time. The pull-in device is only engaged in the end region of the pull-in travel, and the running carriage  3  is then in the correct position. 
   In the embodiment according to  FIGS. 6   a  to  6   f , the locking means for the running carriage  3  is formed by a horizontal arm  12  projecting in the direction of displacement of the running carriage  3 . The arm  12  is provided with a lug  13  at its free end. 
   The support rail  1  has a stop  14  at the front and the pull-out rail  2  has a stop  15 . If the drawer and hence the pull-out rail  2  are pushed out of the extended position shown in  FIG. 6   f  into the furniture carcass, the running carriage  3  runs at first differentially between the pull-out rail  2  and the support rail  1 . If the running carriage  3  leads, as shown in  FIGS. 6   a  to  6   f , the lug  13  abuts against the stop  14  while the stop  15  of the pull-out rail  2  is still above the arm  12 . The stop  15  thus prevents the resilient arm  12  from being able to be deflected by the stop  14 . 
   While the pull-out rail  2  is being pushed further into the furniture carcass, the running carriage  3  is locked by the stop  14  and remains stationary on the support rail  1 . 
   As soon as the stop  15  of the pull-out rail  2  is moved out over the arm  12 , as shown in  FIG. 6   c , the arm  12  can be deflected by the stop  14  by means of the lug  13 , whereupon the running carriage  3 , which is now in the correct position in relation to the pull-out rail  2 , is moved on differentially between the pull-out rail  2  and the support rail  1 . 
   In the example embodiments according to  FIGS. 7 to 17 , the running carriage  3  is provided in its center with a rocker  17  that can tilt about a horizontal axis pin  18  and serves as a locking means for the running carriage  3 . 
   The pull-out rail  2  has an upper horizontal web  2 ′ with an opening  50  that serves as a deflection unit. The support rail  1  has a tab  19  that projects laterally from a vertical web  1 ′ and forms a stop for the rocker  17 . 
   In the embodiment according to  FIGS. 9 to 16 , the rocker  17  is constructed in two parts and has a first part  20  that is borne directly on the axis pin  18 , preferably snapped onto the latter, and a second part  21  that is borne on the first part  20  such that it can tilt about an axis pin  24 . The parts  20 ,  21  each have a stop face  22 ,  23 . A spring  16 , preferably a leg spring, is borne in the rocker  17  and tilts the part  21  upward in relation to the part  20 . 
     FIGS. 13   a  to  13   e  show an ideal movement sequence with no carriage running errors, in which the pull-out rail  2  is moved to the right (a first direction). The running carriage  3  is also moved to the right (the first direction), and the rocker  17  abuts against the stop of the support rail  1 , this stop being formed by the tab  19 . This movement turns the rocker  17  clockwise as viewed in the drawing. During this movement, the upper (second) part  21  of the rocker  17  moves into the opening  50  in the pull-out rail  2 . As the pull-out rail  2  is moved further to the right, the rocker  17  is turned clockwise until the upper part  21  of the rocker  17  moves down out of the opening  50  ( FIGS. 13   d ,  13   e ). The interaction between the tab  19 , the opening  50  and the rocker  17  is ideal. No correction of the running carriage  3  is performed. In other words, there is no correction of the position of the running carriage  3  in relation to the rails  1 ,  2 . 
     FIGS. 14   a  to  14   e  also show a movement sequence with no running carriage errors, in which the pull-out rail  2  is moved to the left. The rocker  17  of the running carriage  3  once again comes up against the tab  19 , and the rocker  17  is turned counterclockwise as viewed in the drawing, with the upper (second) part  21  of the rocker  17  turned to move into the opening  50  of the pull-out rail  2 . The interaction of the tab  19 , the opening  50  and the rocker  17  is once again ideal. No correction of the movement of the running carriage  3  is performed. The running carriage  3  runs precisely differentially between the pull-out rail  2  and the support rail  1 . 
     FIGS. 15   a  to  15   e  show a movement sequence with a carriage running error, in which the pull-out rail  2  is moved to the right (the first direction). As shown in  FIG. 15   a , the edge  26  of the opening  50  comes up against the stop face  22  of the rocker  17  at a first predetermined point. The rocker  17  cannot, however, tilt away downward because of the tab  19  on the support rail  1 . This has the result that the running carriage  3  is fixed (locked) to the pull-out rail  2  and moves with the pull-out rail  2  at the same speed until the rocker  17  can tilt down over the end of the tab  19  at a second predetermined point ( FIG. 15   c ).  FIGS. 15   d  and  15   e  show the running carriage  3  in the corrected position, and show how the running carriage  3  can continue to move in the first direction after the locking device (edge  26 , rocker  17 , and tab  19 ) releases the running carriage  3  from being locked to pull-out rail  2 . 
     FIGS. 16   a  to  16   e  show a movement sequence with a carriage running error, in which the pull-out rail  2  is moved to the left. 
   In  FIG. 16   b , the rocker  17  is in contact with the tab  19  forming the stop of the support rail  1 , and the rocker  17  begins to turn counterclockwise. This rotation is possible, despite the incorrect position of the running carriage  3 , since the rocker  17  is constructed in two parts and the upper (second) part  21  of the rocker  17  can tilt with respect to the lower (first) part  20  of the rocker  17 . There is no correction of the movement of the running carriage  3 . 
   With this construction, it is possible to choose whether a correction of the running position of the carriage  3 , when a carriage running error occurs (error in the position of the running carriage  3  in relation to the rails  1 ,  2 ), is to be performed only when the drawer is opened or only when the drawer is closed. Generally, it is desirable for the correction of the running carriage  3  to be performed when the drawer is opened, since upon opening, the drawer is moved manually at full force and the resistance of the running carriage  3  when the correction is made is not noticeable. 
     FIGS. 17   a  to  17   e  show a one-part rocker  17  that is constructed in one piece and is not acted upon by a spring. In the example embodiment shown, the pull-out rail  2  moves to the left. A movement sequence with a running carriage  3  error is shown. 
   The rocker  17  meets the tab  19  ( FIG. 17   b ). Because it is rigid and cannot fold together, and because it abuts against the horizontal web  2 ′ of the pull-out rail  2 , the rocker  17  cannot rotate. The running carriage  3  is therefore coupled to the support rail  1  and remains stationary until the pull-out rail  2  has been moved far enough to the left for the opening  50  to make it possible for the rocker  17  to pivot. This happens at the moment when the running carriage  3  is in the correct running position in relation to the rails  1 ,  2 . 
   It is an essential part of the invention that the position of the running carriage  3  in relation to the rails  1 ,  2  is always corrected between the two end positions of the pull-out rail  2  (in other words, not directly as the drawer is finally closed), and the pull-out rail  2  is pulled into the furniture carcass by a pull-in device. 
     FIGS. 18 and 19  show an embodiment where a central rail  27  is provided between the pull-out rail  2  and the support rail  1 . A first running carriage  3  is positioned between the pull-out rail  2  and the central rail  27 , and a second running carriage  3  is positioned between the central rail  27  and the support rail  1 . Correction of the position of the running carriages  3  is achieved in the same way as in the embodiments described before. The only difference is that the interaction takes place between the pull-out rail  2  and the central rail  27 , and the central rail  27  and the support rail  1  respectively and not between the pull-out rail  2  and the support rail  1 .