Patent Publication Number: US-10327548-B2

Title: Drawer pull-out guide

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a drawer pull-out guide, including a first rail and at least one second rail which are displaceable relative to one another, and at least one running carriage with at least one rolling body, in which the running carriage is displaceably arranged between the first rail and the second rail over a travelling path. At least one limiting element is arranged on the first rail or on the second rail, and the limiting element limits the travelling path of the running carriage. A damping device is arranged on the running carriage for dampening a movement of the running carriage over a damping path when the running carriage abuts against the limiting element, and a maximum damping path of the damping device is predetermined. 
     The invention further concerns an item of furniture with a furniture carcass and with a drawer displaceably arranged relative to the furniture carcass by a pull-out guide of the type to be described. 
     EP 0 868 866 B1 shows a drawer pull-out guide having a carcass rail and a movably-mounted extension rail, in which a running carriage with load-transmitting rolling bodies is displaceably arranged between the carcass rail and the extension rail. Provided on the rails are stops for limiting the travelling path of the running carriage in the longitudinal direction of the rails. The running carriages, on their frontal faces, have spring buffers for dampening an impact of the running carriage on the stops in the end positions of the running carriage. 
     DE 20 2005 014 127 U1 shows a further pull-out guide, in which a cage for accommodating rolling bodies is displaceably arranged between the carcass rail and the drawer rail. The cage for accommodating the rolling bodies is configured so as to be resilient in a direction of its longitudinal axis by the arrangement of slits, so that the running carriage, when hitting against a stop arranged on the carcass rail, can be decelerated in a noise-absorbing manner. 
     The disadvantage of the above configuration is that the kinetic energy is absorbed almost exclusively by the running carriages when reaching the respective end positions of the extension rail, whereby the running carriages are subjected to considerable strains. These strains can lead to deformations or even to a breakage of the running carriages, in particular when the running carriages, for the reason of a compact design, are formed of plastic having a thin wall thickness. An additional strain of the running carriages occurs when the drawer pull-out guide has a short nominal length, because the extension rail, right after opening, frequently reaches the fully extended position with great momentum and thereby also the spring buffers of the running carriage hit the stops of the rails in a forceful manner. Also in a case of improper use, in which the drawer is being catapulted into the closed position or open position by an excessive manual force, considerable forces act on the running carriage, so that there is the danger of damage of the running carriage. 
     DE 10 2005 019 341 A1 shows, in the embodiment of  FIGS. 15-19 , a drawer pull-out guide in which stops are provided both on the carcass rail and the drawer rail. The stops abut against each other when the drawer rail reaches a maximum extension movement, and a further extension movement is thereby prevented. 
     It is an object of the present invention to propose a drawer pull-out guide mentioned in the introductory part, wherein the danger of a damage of the running carriage is reduced. 
     SUMMARY OF THE INVENTION 
     According to the invention, a stop is arranged on the first rail and a counterstop is arranged on the second rail. At the end of the maximum damping path of the running carriage, the stop of the first rail and the counterstop of the second rail abut against each other and thereby stop a movement of the second rail relative to the first rail. 
     The present invention is thus based on the concept that the running carriage, when abutting the limiting element, is initially dampened over the predetermined maximum damping path of the damping device. When a predetermined force acting on the running carriage is exceeded, the stop and the counterstop abut against each other and stop a further movement of the rails, so that a further force acting on the running carriage is prevented. 
     In this way, the excessive forces are absorbed by the rails of the drawer pull-out guide, so that the running carriage remains unaffected by these additional forces. The running carriage, after the damping hub has been effected, is thus not subjected to additional strains which could lead to a deformation or to a breakage. 
     The damping device can be arranged on a frontal end of the running carriage, wherein the damping device, according to a first embodiment, can include at least one spring tongue arranged on the running carriage. The spring tongue, when the running carriage abuts the limiting element, is configured so as to be reversibly bendable or reversibly deformable against a resilient action of the spring tongue. The maximum damping path is thus predetermined by a maximum compression path of the spring tongue. Without the spring tongue, the running carriage or a further component is damaged. 
     According to a further embodiment, the damping device of the running carriage includes a fluid damper, for example with a piston-cylinder-unit, as shown and described in EP 1 475 014 B1. The maximum damping path, in this case, is predetermined by the maximum admissible damping hub of the piston-cylinder-unit. 
     Because of the fact that the closing movement of an extendable rail of the drawer pull-out guide is frequently decelerated by a self-closing retraction device having a damping function, a stop member of the rails, in the closed position of the drawer pull-out guide, is not necessarily required. Thus, it can be sufficient when the first rail and the second rail are displaceably arranged between a closed position and an open position, and the stop of the first rail and the counterstop of the second rail abut against each other in the open position and therewith prevent a further extension movement of the second rail towards the opening direction. 
     A first embodiment of an inventive item of furniture is characterized in that the item of furniture has a furniture carcass and a drawer displaceably arranged relative to the furniture carcass by a drawer pull-out guide of the type described. The first rail is configured as a carcass rail to be fixed to a furniture carcass, and the second rail is a drawer rail fixed to the drawer. The running carriage is displaceably arranged between the carcass rail and the drawer rail. 
     A second embodiment of an inventive item of furniture is characterized in that the item of furniture has a furniture carcass and a drawer displaceably arranged relative to the furniture carcass by a drawer pull-out guide of the type described. The first rail is a carcass rail fixed to the furniture carcass, and the second rail is a central rail displaceably arranged between the carcass rail and a drawer rail fixed to the drawer, and the running carriage is displaceably arranged between the carcass rail and the central rail. 
     A third embodiment of an inventive item of furniture is characterized in that the item of furniture has a furniture carcass and a drawer displaceably arranged relative to the furniture carcass by a drawer pull-out guide of the type described. The second rail is a drawer rail fixed to the drawer and the first rail is a central rail displaceably arranged between a carcass rail fixed to the furniture carcass and the drawer rail, and the running carriage is displaceably arranged between the central rail and the drawer rail. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further details and advantages of the present invention will be explained with the aid of the following description of figures, in which: 
         FIG. 1  is a perspective view of an item of furniture with a furniture carcass and drawers displaceably mounted thereto, 
         FIG. 2 a , 2 b    is a partially broken away perspective view of the drawer pull-out guide and an enlarged detail view thereof, 
         FIG. 3 a , 3 b    show continued extension movements of the second rail with a running carriage abutting the limiting element, and 
         FIG. 4 a -4 c    show the cooperation of the damping device with the limiting element and the cooperation of the stop with the counterstop in temporal sequences. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows an item of furniture  1  with a cupboard-shaped furniture carcass  2 , wherein drawers  3  are displaceably arranged relative to the furniture carcass  2  by drawer pull-out guides  4 . The drawers  3  each have a front panel  5 , a drawer bottom  6 , drawer side walls  7  and a rear wall  8 . The drawer pull-out guides  4  each have a rail  9  (carcass rail) to be stationarily fixed to the furniture carcass  2  by fastening portions  12   a ,  12   b , a second rail  10  (drawer rail) which is displaceably arranged relative to the carcass rail  9  and which is connected or which is adapted to be connected to the drawer side wall  7 , and a first rail  11  (central rail) displaceably arranged between the rail  9  and the second rail  10  so as to allow the drawer  3  to be fully extended. In the present description, for the sake of simplicity, the central rail is denoted as the first rail  11  and the drawer rail is denoted as the second rail  10 . Naturally, it is also clear that the carcass rail  9  can be seen as the first rail and the central rail as the second rail. 
       FIG. 2 a    shows a partially broken away view of drawer pull-out guide  4  in an open position, with the rail  9  (carcass rail) to be fixed to the furniture carcass  2 , wherein a first rail  11  (central rail) is displaceably arranged between the rail  9  and the second rail  10  for enlarging the extension movement of the drawer  3 . Connected to the rail  9  are fastening portions  12   a ,  12   b  by which the drawer pull-out guide  4  can be mounted to the furniture carcass  2 . 
       FIG. 2 b    shows the region framed in  FIG. 2 a    in an enlarged view. The fastening portion  12   a  has a plurality of holes  13  for the passage of screws by which fastening to the furniture carcass  2  is effected. The second rail  10  is depicted partially broken away so that the running carriage  16  with the rolling bodies  17  arranged therein is visible. Arranged on a frontal end of the running carriage  16  is a damping device  18  which, in the shown embodiment, is configured as a spring buffer having at least one spring tongue  18   a . Preferably, the spring tongue  18   a , together with the running carriage  16 , has a one-piece configuration formed by a molded plastic portion. Arranged on a rear end region of the second rail  10  is a limiting element  15  for limiting a travelling path of the running carriage  16  in the extension direction  19 . In the shown figure, the limiting element  15 , together with the second rail  10 , has a one-piece configuration and can be formed by a tab bent away from the second rail  10 . The spring tongue  18   a  is configured so as to be reversibly bendable or reversibly deformable against a resilient action of the spring tongue  18   a  when the running carriage  16  abuts against the limiting element  15  and thereby dampens an impact of the running carriage  16  when hitting against the limiting element  15 . Instead of one or a plurality of spring tongues  18   a , the damping device  18  can also be configured as a linear damper, for example with a piston-cylinder-unit, arranged in or on the running carriage  16 . Arranged on the rear end of the second rail  10  is a pin  14  which is spaced from an upper side of the second rail  10  and which extends in a horizontal and in a longitudinal direction of the second rail  10 . The pin  14 , in the mounted position, engages into a bore arranged in the rear wall  8  (see  FIG. 1 ) and thereby prevents an undesired change in position of the rear end region of the drawer  2  relative to the second rail  10 . 
       FIG. 3 a    shows, in relation to  FIG. 2 b   , a continued movement of the second rail  10  in the extension direction  19 , in which the spring tongue  18   a  of the damping device  18  abuts against the limiting element  15 . In  FIG. 3 b   , the maximum damping path  23  (see  FIG. 4 b   ) of the damping device  18  has been reached, and the free end of the spring tongue  18   a  abuts against the limiting element  15  and is therewith maximally deformed or bent. In this position of the running carriage  16 , a stop  20  of the second rail  10  and a counterstop  21  of the first rail  11  abut against each other and stop a movement of the second rail  10  relative to the first rail  11 , as shown and described in the following figures (of course, the names “stop” and “counterstop” are interchangeable such that the first rail  11  can be identified as having a “stop”  21 , while the second rail  10  has a “counterstop”  20 ). 
       FIG. 4 a -4 c    show the cooperation of the damping device  18  of the running carriage  16  with the limiting element  15  of the second rail  10  as well as the cooperation of the stop  20  of the second rail  10  with the counterstop  21  of the first rail  11  in temporal sequences. The limiting element  15  and the stop  20  are firmly connected to the second rail  10 , while the counterstop  21  is firmly connected to the first rail  11 . The second rail  10  is moved in the extension direction  19  until the spring tongue  18   a  of the damping device  18  arranged on the running carriage  16  abuts against the limiting element  15  of the second rail  10  (see  FIG. 4 b   ). At this point, the stop  20  protruding transversely from the second rail  10  and the counterstop  21  protruding transversely from the first rail  11  are still spaced from each other. By bending or by deforming the spring tongue  18   a , a movement of the running carriage  16  can be dampened over a predetermined damping path  23 , namely as long as the free end of the spring tongue  18   a  is maximally deformed or bent until abutting against another portion of the running carriage  16 . When the maximum damping hub of the damping device  18  has been reached (i.e., at a position corresponding to the end of the maximum damping path  23  of the running carriage  16 ), the stop  20  of the second rail  10  and the counterstop  21  of the first rail  11  abut against each other (see  FIG. 4 c   ) and thereby prevent a further movement of the second rail  10  relative to the first rail  11 . By the cooperation of the stop  20  with the counterstop  21 , the running carriage  16  is relieved from additional forces, so that the danger of an undesired deformation or a breakage of the running carriage  16  is prevented. The cooperation of the spring tongue  18   a  with the limiting element  15  and the cooperation of the stop  20  with the counterstop  21  cause two different sounds perceptible by a person. The stop for the rails, formed by the stop  20  and the counterstop  21 , is namely configured so as to be harder than the stop for the running carriage  16 , formed by the damping device  18  and the limiting element  15 . For example, this can be realized such that the stop  20  and the counterstop  21  are each formed by a metallic material and thereby cause an acustically hard warning sound. Accordingly, the majority of the energy is dissipated by these “hard stops” and not by the running carriage  16 . 
     The drawer pull-out guide  4  further includes a forced control device  22  for controlling a movement of the running carriage  16  relative to a further (second) running carriage  16   a  which is displaceably arranged between the rail  9  to be fixed to the furniture carcass  2  and the first rail  11 , and/or for controlling at least a movement of the running carriage  16  relative to the first rail  11  and second rail  10  according to a predetermined movement pattern. In the shown embodiment, the forced control device  22  includes a gear pivotally arranged on the first rail  11 . The gear cooperates, on the one hand, with a tooth arrangement of the upper running carriage  16  and, on the other hand, with a tooth arrangement of the lower running carriage  16   a . Alternatively, the forced control device  22  can include, as commonly known, a friction wheel cooperating, on the one hand, with a first running surface of the rail  9  and, on the other hand, with a second running surface of the second rail  10 .