Patent Publication Number: US-2023148751-A1

Title: Device for guiding a movable furniture part relative to a furniture carcass

Description:
This application claims the benefit under 35 USC § 119(a)-(d) of German Application No. 10 2021 129 646.3 filed Nov. 15, 2021, the entirety of which is incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a device for guiding a movable furniture part relative to a furniture carcass. 
     BACKGROUND OF THE INVENTION 
     There are already known devices with rails for guiding a movable furniture part, such as a drawer, wherein lowering of the movable furniture part relative to the furniture carcass in the open state of the movable furniture part is counteracted. 
     In known devices, the configuration of a carcass rail or a movable rail is changed, for example, by an interruption in the running web of the rails. 
     SUMMARY OF THE INVENTION 
     It is the object of the present invention to provide an improved device for guiding a movable furniture part relative to a furniture carcass, in particular, with regard to a compact and simple construction. 
     The present invention starts from a device for guiding a movable furniture part, in particular, a drawer, wherein the movable furniture part can be received movably on a furniture carcass by means of the device, wherein the device comprises a carcass rail and a movable rail, wherein the carcass rail can be arranged on the furniture carcass, wherein the movably mounted movable rail can be moved in the opening and closing direction relative to the carcass rail, wherein the carcass rail and the movable rail each have a flat running web, wherein load-transmitting rolling elements are each arranged between a running web of the carcass rail and a running web of the movable rail, wherein, during the relative movement between the movable rail and the carcass rail, the load-transmitting rolling elements can be moved along the running webs of the carcass rail and the movable rail. 
     The device is preferably a drawer pull-out guide, in particular, for example, a partial- or full-extension runner. In the case of a partial-extension runner, it is preferable if there is only precisely one movable rail in addition to the carcass rail. In the case of a full-extension runner, there are preferably precisely two movable rails, such as, for example, a central rail and a drawer rail. When the movable furniture part is moved in the opening and closing direction, the movable rail or rails can be moved relative to the carcass rail. Furthermore, during the opening and closing movement of the movable furniture part, a first movable rail, such as, for example, a central rail, can preferably also be moved relative to a second movable rail, such as, for example, a drawer rail. 
     The piece of furniture preferably has two identical devices for each movable furniture part, wherein preferably one device is arranged on, for example, each side wall of the furniture carcass. In the mounted state, the carcass rail is preferably secured on the furniture carcass. The movable rail, such as, for example, the drawer rail, is preferably connected to the movable furniture part, wherein the movable rail is, for example, accommodated in an interior of a side frame of a movable furniture part or is arranged below a base and/or side wall of the movable furniture part. Advantageously, the movable rail together with the movable furniture part can be moved linearly relative to the carcass rail, which is arranged, for example, in a fixed position on a side wall of the furniture carcass, wherein the movable rail can be moved in the opening and closing direction relative to the carcass rail. 
     The carcass rail can preferably have precisely one running web or precisely two running webs. The running webs of the carcass rail are preferably oriented horizontally in the mounted state of the device. The running web preferably has two surfaces, the upper and lower surfaces preferably being arranged on opposite sides of the running web and being separated from one another by the material thickness of the running web. If load-transmitting rolling elements are moved along the surface of the running web, these surfaces are also referred to as running surfaces. If the carcass rail has a single running web, this running web preferably has two running surfaces. If the carcass rail has two running webs, each running web preferably has just one running surface. 
     The movable rail can also preferably have a single running web or two running webs, and, in the case of a single running web, this running web preferably has two running surfaces. In the case of two running webs, each running web preferably has just one running surface or two running surfaces. In this case, the running surfaces of the movable rail are designed to be flat, for example. 
     The load-transmitting rolling elements can preferably be moved in the opening and closing direction along the running surfaces of the running webs of the rails. During the opening and closing movement of the movable furniture part, the rolling elements are moved along the horizontally oriented running web of the carcass rail mounted on the furniture carcass, wherein the movable rail is moved relative to the carcass rail. 
     The essence of the present invention is that the running web of the carcass rail and the running web of the movable rail are uninterrupted, wherein the rolling elements between the carcass rail and the movable rail are configured in such a way that, in the mounted state, the running web of the movable rail is always oriented obliquely relative to the horizontally oriented running web of the carcass rail. 
     The running webs or the running surfaces of the carcass rail and the movable rail are advantageously designed to be uninterrupted or not interrupted. This means, for example, that there is no space or gaps or a contour which differs from the flat running surfaces in the running web or running surface. This has the advantage that the rolling elements can be moved along the entire running surfaces of the carcass rail and movable rail and that smooth running of the movable rail or of the movable rails in the opening and closing direction is ensured. 
     The oblique position of the running web of the movable rail is preferably not changed during the opening and closing movement of the movable furniture part. The rolling elements which are arranged between the running web of the carcass rail and the running web of the movable rail are advantageously configured in such a way that the movement of the movable rail in the opening and closing direction does not change the orientation of the movable rail unless the movable furniture part acts with a force or a weight on the movable rails in the open state of the movable furniture part. 
     Owing to the oblique position of the running web or running webs of the movable rail, particularly in the open state of the movable furniture part or in the extended state of the movable rail, it is advantageously possible to compensate for lowering of the movable furniture part, in particular, of a fully loaded movable furniture part. This is because, in the case of standard devices for guiding a movable furniture part, the movable furniture part or the drawer rail is deflected downward in the direction of the carcass rail or obliquely with respect to a horizontal in the open state by the weight of the movable furniture part or the contents of the movable furniture part. 
     In the device according to the present invention, the oblique orientation of the running webs of the movable rail ensures that the running webs or running surfaces of the movable rail are pushed or deflected from an oblique position into an approximately horizontal position by the weight of the movable furniture part. As a result, in contrast to the standard devices, the movable furniture part, in particular, a heavy movable furniture part, can advantageously be closed without great expenditure of force. The magnitude of the oblique position of the movable rail is preferably matched to a magnitude of an expected weight of the movable furniture part, ensuring that an approximately horizontal position of the movable furniture part is achieved in the open position. 
     It is advantageous that a rolling element carriage has rolling element rows, each having a plurality of rolling elements. 
     The rolling elements of a rolling element row are preferably of identical configuration or have the same or an identical outer contour and material. 
     The number of rolling elements in a rolling element row can vary for different rolling element rows. For example, one rolling element row can have precisely two, precisely three, precisely four, etc., and another rolling element row can have precisely two, precisely three, precisely four, precisely five, etc., rolling elements. At least two rolling elements are preferably arranged in the rolling element rows. Also conceivable are rolling element rows with precisely three, precisely four, precisely five, precisely six, precisely seven, precisely eight, precisely nine, precisely ten, etc. rolling elements. 
     It is likewise advantageous that the diameter of all the rolling elements of a rolling element row is the same. 
     The rolling elements are preferably cylindrical, wherein the diameter, in particular the diameter of the base surface of the cylinder, of the rolling elements of a rolling element row is preferably the same. Furthermore, the rolling elements can also be designed as balls; in the case of spherical rolling elements too, the diameter of the rolling elements of a rolling element row is preferably the same. 
     It is furthermore conceivable that the diameters of the rolling elements in a rolling element row differ; e.g. the diameters of the rolling elements of the rolling element row can increase or decrease in the opening direction. 
     It is likewise advantageous that there is a single rolling element carriage having four rolling element rows, wherein there are two rolling element rows between the running web of the carcass rail and an upper running web of the movable rail and there are two rolling element rows between the running web of the carcass rail and a lower running web of the movable rail. 
     The movable rail preferably has precisely two running webs. In this case, the horizontally oriented running web of the carcass rail is preferably arranged between the two running webs of the movable rail in the mounted state of the device. Respective rolling elements of the rolling element row are preferably arranged between the running webs of the movable rail and the running web of the carcass rail, and therefore rolling elements are moved along the precisely one running web of the carcass rail on an upper running surface and a lower running surface, the running surfaces of the carcass rail being spaced apart from one another by the thickness of the running web. In the case of the movable rail, as a preferred option, on the upper running web of the movable rail situated above the running web of the carcass rail, it is only possible for rolling elements of the rolling element row to be moved along the lower running surface, which is oriented toward the running web of the carcass rail, and, on the lower running web of the movable rail situated below the running web of the carcass rail, it is only possible for rolling elements of the rolling element rows to be moved along the upper running surface, which is oriented toward the running web of the carcass rail. 
     Precisely two rolling element rows are preferably arranged between the upper running surface of the running web of the carcass rail and the lower running surface of the upper running web of the movable rail. The rolling elements of the two rolling element rows which are arranged between the upper running web of the movable rail and the running web of the central rail preferably have a diameter of 4.5 to 6.5 mm. It is furthermore preferred that precisely two rolling element rows are arranged between the lower running surface of the running web of the carcass rail and the upper running surface of the lower running web of the movable rail. The rolling elements of the two rolling element rows which are arranged between the lower running web of the movable rail and the running web of the central rail preferably have a diameter of 6.2 to 7.7 mm. 
     The rolling elements of the rolling element rows which are arranged between the running web of the carcass rail and the running webs of the movable rail are preferably arranged on a rolling element carriage, with the result that all the rolling elements are moved simultaneously in the opening or closing direction along the running surfaces of the running webs of the movable rail and the carcass rail. 
     It is also advantageous that there is a single rolling element carriage having four rolling element rows, wherein there are two rolling element rows between the running web of the movable rail and an upper running web of the carcass rail and there are two rolling element rows between the running web of the movable rail and a lower running web of the carcass rail. 
     The carcass rail preferably has precisely two running webs. In this case, the running web of the movable rail is preferably arranged between the two horizontally oriented running webs of the carcass rail in the mounted state of the device. Respective rolling elements of the rolling element row are preferably arranged between the running webs of the carcass rail and the running web of the movable rail, and therefore rolling elements are moved along the running web of the movable rail on an upper running surface and a lower running surface, the running surfaces being spaced apart from one another by the thickness of the running web. In the case of the carcass rail, as a preferred option, on the upper running web of the carcass rail situated above the running web of the movable rail, it is only possible for rolling elements of the rolling element row to be moved along the lower running surface, which is oriented toward the running web of the movable rail, and, on the lower running web of the carcass rail situated below the running web of the movable rail, it is only possible for rolling elements of the rolling element rows to be moved along the upper running surface, which is oriented toward the running web of the movable rail. 
     Precisely two rolling element rows are preferably arranged between the upper running surface of the running web of the movable rail and the lower running surface of the upper running web of the carcass rail. It is furthermore preferred if precisely two rolling element rows are arranged between the lower running surface of the running web of the movable rail and the upper running surface of the lower running web of the carcass rail. 
     The rolling elements of the rolling element rows which are arranged between the running web of the movable rail and the running webs of the carcass rail are preferably arranged on a rolling element carriage, with the result that all the rolling elements are moved simultaneously in the opening or closing direction along the running surfaces of the running web of the movable rail and the running webs of the carcass rail. 
     Advantageously, there are two rolling element carriages with in each case two rolling element rows. 
     The two rolling element carriages are preferably spaced apart from one another in the mounted state of the device, in particular, are spaced apart from one another horizontally. 
     The movement of the two rolling element carriages in the opening and closing direction is preferably synchronized. For this purpose, the two rolling element carriages can be connected to one another by a synchronizing rod, for example. 
     Once the precisely one running web of the carcass rail is arranged between the precisely two running webs of the movable rail, then, in the case of each rolling element carriage, one rolling element row is advantageously present between the upper running surface of the running web of the carcass rail and the lower running surface of the upper running web of the movable rail and one rolling element row is present between the lower running surface of the running web of the carcass rail and the upper running surface of the lower running web of the movable rail. 
     Once the precisely one running web of the movable rail is arranged between the precisely two running webs of the carcass rail, then, in the case of each rolling element carriage, one rolling element row is present between the upper running surface of the running web of the movable rail and the lower running surface of the upper running web of the carcass rail and one rolling element row is present between the lower running surface of the running web of the movable rail and the upper running surface of the lower running web of the carcass rail. 
     It is advantageous that the rolling elements of two rolling element rows each have different diameters, wherein one rolling element row is arranged between the running web of the carcass rail and the upper running web of the movable rail and one rolling element row is arranged between the running web of the carcass rail and the lower running web of the movable rail. 
     Preferably, precisely two rolling element rows are arranged at the front of the rolling element carriage in the opening direction, wherein the rolling elements of the rolling element row which are arranged between the upper running web of the movable rail and the running web of the carcass rail have a larger diameter than the rolling elements of a rolling element row which are arranged between the lower running web of the movable rail and the running web of the carcass rail. In this case, the difference in the diameters is preferably from 0.4 mm to 0.95 mm. 
     In the two rolling element rows which are arranged at the rear of the rolling element carriage in the opening direction, the rolling elements of the rolling element row which are arranged between the upper running web of the movable rail and the running web of the carcass rail have a smaller diameter than the rolling elements of a rolling element row which are arranged between the lower running web of the movable rail and the running web of the carcass rail. In this case, the difference in the diameters is preferably from 1 mm to 2.5 mm. 
     It is advantageous that the rolling elements of two rolling element rows each have different diameters, wherein one rolling element row is arranged between the running web of the movable rail and the upper running web of the carcass rail and one rolling element row is arranged between the running web of the movable rail and the lower running web of the carcass rail. 
     Preferably, precisely two rolling element rows are arranged at the front of the rolling element carriage in the opening direction, wherein the rolling elements of the rolling element row which are arranged between the upper running web of the carcass rail and the running web of the movable rail have a smaller diameter than the rolling elements of a rolling element row which are arranged between the lower running web of the carcass rail and the running web of the movable rail. 
     In the two rolling element rows which are arranged at the rear of the rolling element carriage in the opening direction, the rolling elements of the rolling element row which are arranged between the upper running web of the carcass rail and the running web of the movable rail have a larger diameter than the rolling elements of a rolling element row which are arranged between the lower running web of the carcass rail and the running web of the movable rail. 
     It is also advantageous that the diameter of the rolling elements of the rolling element row which is at the front in the opening direction is different from the diameter of the rolling elements of the rear rolling element rows. 
     In the embodiment in which the precisely one running web of the carcass rail is arranged between precisely two running webs of the movable rail, the diameter of the rolling elements of the rolling element row at the front in the opening direction is preferably smaller than that of the rear rolling element row, in the case of the rolling element rows which are arranged between the running web of the carcass rail and the running surface of the lower running web of the movable rail. In this case, the difference in the diameters is preferably from 0.5 mm to 0.95 mm. Furthermore, the diameter of the rolling elements of the rolling element row which is at the front in the opening direction is advantageously larger than that of the rear rolling element row, in the case of the rolling element rows which are arranged between the running web of the carcass rail and the running surface of the upper running web of the movable rail. Here too, the difference in the diameters is preferably from 0.4 mm to 0.95 mm. For example, the difference in the diameters of the rolling elements of the rolling element row which are at the front in the opening direction with respect to the rear rolling elements of the rolling element row, in the case of the rolling elements which are arranged between the running web of the carcass rail and a running web of the movable rail, is the same. 
     In the embodiment in which the precisely one running web of the movable rail is arranged between precisely two running webs of the carcass rail, the diameter of the rolling elements of the rolling element row at the front in the opening direction is preferably larger than that of the rear rolling element row, in the case of the rolling element rows which are arranged between the running web of the movable rail and the running surface of the lower running web of the carcass rail. Furthermore, the diameter of the rolling elements of the rolling element row which is at the front in the opening direction is advantageously smaller than that of the rear rolling element row, in the case of the rolling element rows which are arranged between the running web of the movable rail and the running surface of the upper running web of the carcass rail. 
     It is advantageous that the sum of the diameters of the rolling elements of the two rolling element rows which are at the front in the opening direction is equal to the sum of the diameters of the rolling elements of the two rear rolling element rows. 
     This advantageously ensures that the oblique position of the two running webs of the movable rail is the same when the running web of the carcass rail is arranged between two running webs of the movable rail. This is because the difference of the diameters of rolling elements of the rolling element row which are at the front in the opening direction with respect to the rear rolling elements of the rolling element row, which are arranged between the upper running web of the movable rail and the running web of the carcass rail, is the same as the difference of the diameter of the rolling elements of the rolling element row which are at the front in the opening direction with respect to the rear rolling elements of a rolling element row, which are arranged between the lower running web of the movable rail and the running web of the carcass rail. 
     In the variant in which the running web of the movable rail is arranged between two running webs of the carcass rail, the fact that the sum of the diameters of the rolling elements of the two front rolling element rows in the opening direction is equal to the sum of the diameters of the rolling elements of the two rear rolling element rows ensures that advantageously only the running web or running webs of the movable rail are oriented obliquely and the running webs of the carcass rail remain horizontally oriented. 
     For example, the diameter of those rolling elements of the rolling element rows which are at the front in the opening direction, which rows are arranged between the running web of the carcass rail and the upper running web of the movable rail, is different from the other rolling elements of the other rolling element rows. The rolling elements of the different rolling element rows preferably each have different diameters from one another. 
     It is also advantageous that the movable rail is a drawer rail. 
     It is likewise advantageous that the movable rail is a central rail. 
     The device preferably has two movable rails, wherein a first movable rail is designed as a central rail and a second movable rail is designed as a drawer rail. 
     The device or the drawer pull-out guide is preferably designed as a full-extension runner, wherein the central rail is preferably arranged between the carcass rail and the drawer rail. As a preferred option, the central rail and the drawer rail can be moved relative to the carcass rail and the drawer rail can be moved relative to the central rail. 
     It is advantageous that two rolling element rows are arranged between a running web of the drawer rail and a running web of the central rail, wherein the rolling elements of one rolling element row have a different diameter than the rolling elements of the other rolling element row. 
     In one variant of the present invention, the precisely one running web of the carcass rail is preferably arranged between precisely two running webs of the central rail, with preferably precisely one running web of the drawer rail being arranged above the upper running web of the central rail. It is furthermore preferred that two rolling element rows are arranged between the upper running web of the central rail and the running web of the drawer rail. The rolling elements of the two rolling element rows preferably have a diameter of 3.5 to 4.5 mm. In this case, the diameters of the rolling elements of the rolling element row which is at the front in the opening direction are advantageously larger than those of the rear rolling element rows. In this case, the difference in the diameters is preferably from 0.1 mm to 0.3 mm. The rolling elements of a rolling element row preferably have the same diameters. In this way, it is advantageously possible to ensure that the running web of the drawer rail is oriented obliquely relative to the running web or running webs of the central rail, wherein the running webs of the central rail are already oriented obliquely relative to the horizontally oriented running web of the carcass rail. As a result, the running web of the drawer rail is preferably oriented obliquely further upward. 
     As a preferred option, in a further variant, a lower running web of the central rail is arranged between precisely two running webs of the carcass rail and an upper running web of the central rail is arranged between precisely two running webs of the drawer rail. As a preferred option, two rolling element rows are arranged between a lower running web of the drawer rail and the upper running web of the central rail and two rolling element rows are arranged between an upper running web of the drawer rail and the upper running web of the central rail. 
     The rolling elements of a rolling element row preferably have the same diameters. The rolling elements of the rolling element row which are arranged between the upper running web of the drawer rail and the upper running web of the central rail preferably have a larger diameter than the rolling elements of a rolling element row which are arranged between the lower running web of the drawer rail and the upper running web of the central rail. In the two rolling element rows which are arranged at the rear of the rolling element carriage in the opening direction, the rolling elements of the rolling element row which are arranged between the upper running web of the drawer rail and the upper running web of the central rail have a smaller diameter than the rolling elements of a rolling element row which are arranged between the lower running web of the drawer rail and the upper running web of the central rail. 
     Moreover, the diameter of the rolling elements of the rolling element row which is at the front in the opening direction is preferably smaller than that of the rear rolling element row, in the case of the rolling element rows which are arranged between the upper running web of the central rail and the lower running web of the drawer rail. Furthermore, the diameter of the rolling elements of the rolling element row which is at the front in the opening direction is advantageously larger than that of the rear rolling element row, in the case of the rolling element rows which are arranged between the upper running web of the central rail and the upper running web of the drawer rail. 
     An advantageous embodiment of the present invention is a piece of furniture having a movable furniture part and a furniture carcass, wherein the movable furniture part can be moved in the opening and closing direction, being guided relative to the furniture carcass, by a device in accordance with one of the above described embodiments. 
     On the piece of furniture, the movable furniture part is designed as a drawer, for example. The piece of furniture preferably has, for example, a plurality of drawers, wherein preferably one or two devices according to one of the above described embodiments are arranged on each drawer, thus enabling the drawers to be moved in the opening and closing direction by the devices. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further features and advantages of the present invention are explained in detail by means of an exemplary embodiment illustrated schematically in the figures. 
         FIG.  1    shows a piece of furniture in perspective obliquely from above with a drawer in the fully open state on a furniture carcass, wherein the drawer can be moved in the opening and closing direction by a device according to the present invention; 
         FIG.  2    shows a highly schematic sectional illustration of a part of a drawer and a device without rolling elements according to  FIG.  1   ; 
         FIG.  3    shows a side view of a drawer with mounted device according to  FIG.  2    in the closed state of the drawer; 
         FIG.  4    shows a side view of a drawer with mounted device according to  FIG.  3    in the open state of the drawer; 
         FIG.  5    shows a highly schematic sectional illustration of a part of a drawer and an alternative device without rolling elements according to  FIG.  1   ; 
         FIG.  6    shows a side view of a drawer with mounted device according to  FIG.  5    in the closed state of the drawer; and 
         FIG.  7    shows a side view of a drawer with mounted device according to  FIG.  6    in the open state of the drawer. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A piece of furniture  1  having a furniture carcass  2  and a furniture part  3  which can be moved relative to the furniture carcass  2  and which is designed as a drawer is illustrated in  FIG.  1   . The movable furniture part  3  can be moved in the opening direction P 1  and the closing direction P 2  relative to the furniture carcass  2  by means of the device  4  according to the present invention, such as, for example, a drawer pull-out guide. The furniture carcass  2  has a base  5 , an upper panel  6 , a rear wall  7  and two side walls  8 ,  9 . The movable furniture part  3  preferably has a drawer bottom  10 , drawer side walls  11 ,  12 , a drawer front  13  and a drawer rear wall  14 . Furthermore, the movable furniture part  3  can also have a side frame  16 . 
     The device  4  is preferably secured on the side walls  8 ,  9  of the furniture carcass  2 . The device  4 , which here is designed, for example, as a full-extension runner, preferably has a carcass rail  15 , wherein the carcass rail  15  is mounted on the side wall  8 ,  9  of the furniture carcass  2 . The carcass rail  15  preferably has a fastening plate  17  for attachment to the side wall  8 ,  9  of the furniture carcass  2 , wherein the fastening plate  17  can be mounted on the side wall  8 ,  9  by means of fastening mechanisms, such as, for example, screws. Advantageously, a carcass rail  15  is attached to each side wall  8 ,  9  of the furniture carcass  2 , wherein the carcass rails  15  are preferably attached to the side walls  8 ,  9  of the furniture carcass  2  in a mirror-symmetrical manner. 
     The device  4  in  FIGS.  2  to  7    is designed as a full-extension runner and preferably has two movable rails, wherein preferably one movable rail is configured as a central rail  18  and one movable rail is designed as a drawer rail  19 . The central rail  18  is preferably arranged between the carcass rail  15  and the drawer rail  19 , wherein the central rail  18  and the drawer rail  19  are movable relative to the carcass rail  15 . The drawer rail  19  can preferably be moved relative to the central rail  18  in the opening direction P 1  and the closing direction P 2 . 
     The device  4  or the drawer rail  19  of the device  4  is preferably connected to an underside of the drawer bottom  10  and/or an underside of the drawer side wall  11 ,  12  or side surface of the drawer side wall  11 ,  12  (see  FIG.  2   ). Furthermore, it is conceivable that the device  4  is accommodated in a cavity of a side frame  16 , wherein, for example, the drawer rail  19  is connected to the side frame  16  (see  FIG.  5   ). 
     In  FIGS.  2  to  4   , a first variant of the device  4  according to the present invention is shown, wherein a running web  20  of the carcass rail  15  is arranged between two running webs  21 ,  22  of the central rail  18 . The running web  20  of the carcass rail  15  is preferably oriented horizontally in the mounted state on the piece of furniture  1 , and the two running webs  21 ,  22  of the central rail  18  are oriented obliquely relative to the horizontally oriented running web  20  of the carcass rail  15 . The oblique position of the running webs  21 ,  22  of the central rail  18  is achieved in that rolling elements with different diameters are arranged between the running webs  21 ,  22  of the central rail  18  and the running web  20  of the carcass rail  15 . 
     Preferably, two rolling element rows  23 ,  24  are arranged between the running web  20  of the carcass rail  15  and a lower running web  21  of the central rail  18 . The rolling element rows  23 ,  24  preferably each have identical rolling elements  25 ,  26 , wherein the rolling elements  25  in a rolling element row  23  have the same diameters. Two rolling element rows  27 ,  28  with rolling elements  29 ,  30  are also preferably arranged between the running web  20  of the carcass rail  15  and an upper running web  22  of the central rail  18 . In order to obtain an oblique position of the running webs  21 ,  22  of the central rail  18 , the rolling elements  25  of a rolling element row  23  which are arranged at the front in the opening direction P 1  advantageously have a smaller diameter than the rolling elements  26  of a rolling element row  24  which are arranged at the rear in the two rolling element rows  23 ,  24  which are arranged between the lower running web  21  of the central rail  18  and the running web  20  of the carcass rail  15 . In the two rolling element rows  27 ,  28 , in which the rolling elements  29 ,  30  are arranged between an upper running web  22  of the central rail  18  and the running web  20  of the carcass rail  15 , the rolling elements  29  of a rolling element row  27 , which are arranged at the front in the opening direction P 1 , advantageously have a larger diameter than the rolling elements  30  of a rolling element row  28 , which are arranged at the rear. 
     The four rolling element rows  23 ,  24 ,  27 ,  28  are preferably arranged on a rolling element carriage  31 . Furthermore, it is conceivable that two rolling element rows  23 ,  27  are arranged on a first rolling element carriage and the other two rolling element rows  24 ,  28  are arranged on a second rolling element carriage. 
     The rolling elements  25 ,  26 ,  29 ,  30  advantageously all have different diameters, wherein the rolling elements of an associated rolling element row have the same diameter. 
     A running web  32  of the drawer rail  19  is preferably arranged above the upper running web  22  of the central rail  18 . It is furthermore preferred that two rolling element rows  33 ,  34  with rolling elements  35 ,  36  are arranged between the running web  32  of the drawer rail  19  and the upper running web  22  of the central rail  18 , wherein the rolling elements  35  of a rolling element row  33  which are at the front in the opening direction P 1  have a larger diameter than the rolling elements  36  of a rolling element row  34  which are arranged further toward the rear. The rolling element rows  33 ,  34  are preferably arranged on a further rolling element carriage  37 . For example, the movement of the rolling element carriages  31 ,  37  can be synchronized with one another, with the result that, during the opening movement of the movable furniture part  3  in the opening direction P 1 , both the central rail  18  and the drawer rail  19  are moved simultaneously in the opening direction P 1 . 
     As a result of the configuration or the different diameters of the rolling elements  25 ,  26 ,  29 ,  30 ,  35 ,  36 , the running webs  21 ,  22  of the central rail  18  and the running web  32  of the drawer rail  19  are already oriented obliquely relative to the horizontally oriented running web  20  of the carcass rail  15  in the closed state of the drawer (see  FIG.  3   ). Furthermore, the running web  32  of the drawer rail  19 , on which the movable furniture part  3  preferably rests, is preferably oriented obliquely relative to the upper running web  22  of the central rail  18 . During the opening of the movable furniture part  3  in the opening direction, this oblique position of the running webs  21 ,  22  of the central rail  18  and the running web  32  of the drawer rail  19  is not changed (see  FIG.  4   ). This ensures that lowering of the movable furniture part  3  is prevented since the weight of the heavy movable furniture part  3  acts on the drawer rail  19 , above all in the open state of the movable furniture part  3 , as a result of which the oblique position of the running web  32  of the drawer rail  19  is compensated by the weight of the movable furniture part  3 . 
     A further variant of the device  4  is shown in  FIGS.  5  to  7   , in which a lower running web  38  of the central rail  18  is arranged between precisely two horizontally aligned running webs  39 ,  40  of the carcass rail  15  and an upper running web  41  of the central rail  18  is arranged between precisely two running webs  42 ,  43  of the drawer rail  19 . 
     Preferably, two rolling element rows  44 ,  45  are arranged between the lower running web  38  of the central rail  18  and the lower running web  29  of the carcass rail  15 ; the rolling element rows  44 ,  45  preferably each have rolling elements  46 ,  47  of the same type. Two rolling element rows  48 ,  49  with rolling elements  50 ,  51  are also preferably arranged between the lower running web  38  of the central rail  18  and the upper running web  40  of the carcass rail  15 . In order to obtain an oblique position of the running web  38  of the central rail  18 , the rolling elements  46  of the rolling element row  44  which are arranged at the front in the opening direction P 1  advantageously have a larger diameter than the rolling elements  47  of the rolling element row  45  which are arranged at the rear, in the two rolling element rows  44 ,  45  which are arranged between the lower running web  38  of the central rail  18  and the lower running web  39  of the carcass rail  15 . In the two rolling element rows  48 ,  49 , in which the rolling elements  50 ,  51  are arranged between an upper running web  40  of the carcass rail  15  and the lower running web  38  of the central rail  18 , the rolling elements  50  of a rolling element row  48 , which are arranged at the front in the opening direction P 1 , advantageously have a smaller diameter than the rolling elements  51  of a rolling element row  49 , which are arranged at the rear. 
     The four rolling element rows  44 ,  45 ,  48 ,  49  are preferably arranged on a rolling element carriage  52 . 
     Preferably, two rolling element rows  53 ,  54  are arranged between the upper running web  41  of the central rail  18  and the lower running web  42  of the drawer rail  19 ; the rolling element rows  53 ,  54  preferably each have rolling elements  55 ,  56  of the same type. Two rolling element rows  57 ,  58  with rolling elements  59 ,  60  are also preferably arranged between the upper running web  41  of the central rail  18  and the upper running web  43  of the drawer rail  19 . The rolling elements  55  of the rolling element row  53  which are arranged at the front in the opening direction P 1  advantageously have a smaller diameter than the rolling elements  56  of the rolling element row  54  which are arranged at the rear, in the two rolling element rows  53 ,  54  which are arranged between the upper running web  41  of the central rail  18  and the lower running web  42  of the drawer rail  19 . In the two rolling element rows  57 ,  58 , in which the rolling elements  59 ,  60  are arranged between an upper running web  41  of the central rail  18  and the upper running web  43  of the drawer rail  19 , the rolling elements  59  of a rolling element row  57 , which are arranged at the front in the opening direction P 1 , advantageously have a larger diameter than the rolling elements  60  of a rolling element row  58 , which are arranged at the rear. 
     The four rolling element rows  53 ,  54 ,  57 ,  58  are preferably arranged on a rolling element carriage  61 . For example, the movement of the rolling element carriages  52 ,  61  can be synchronized with one another, with the result that, during the opening movement of the movable furniture part  3  in the opening direction P 1 , both the central rail  18  and the drawer rail  19  are moved simultaneously in the opening direction P 1 . 
     As a result of the configuration or the different diameters of the rolling elements  46 ,  47 ,  50 ,  51 ,  55 ,  56 ,  59 ,  60 , the running webs  38 ,  41  of the central rail  18  and the running webs  42 ,  43  of the drawer rail  19  are already oriented obliquely relative to the running webs  39 ,  40  of the carcass rail  15  in the closed state of the drawer (see  FIG.  6   ). 
     Furthermore, the running webs  42 ,  43  of the drawer rail  19  are preferably oriented obliquely relative to the running webs  38 ,  41  of the central rail  18 . During the opening of the movable furniture part  3  in the opening direction P 1 , this oblique position of the running webs  38 ,  41  of the central rail  18  and the running webs  42 ,  43  of the drawer rail  19  is not changed (see  FIG.  7   ). This ensures that lowering of the movable furniture part  3  is prevented since the weight of the heavy movable furniture part  3  acts on the drawer rail  19 , above all in the open state of the movable furniture part  3 , as a result of which the oblique position of the running web  42 ,  43  of the drawer rail  19  is compensated by the weight of the movable furniture part  3 . 
     LIST OF REFERENCE SIGNS 
       1  piece of furniture 
       2  furniture carcass 
       3  furniture part 
       4  device 
       5  base 
       6  upper panel 
       7  rear wall 
       8  side wall 
       9  side wall 
       10  drawer bottom 
       11  drawer side wall 
       12  drawer side wall 
       13  drawer front 
       14  drawer rear wall 
       15  carcass rail 
       16  side frame 
       17  fastening plate 
       18  central rail 
       19  drawer rail 
       20  running web 
       21  running web 
       22  running web 
       23  rolling element row 
       24  rolling element row 
       25  rolling element 
       26  rolling element 
       27  rolling element row 
       28  rolling element row 
       29  rolling element 
       30  rolling element 
       31  rolling element carriage 
       32  running web 
       33  rolling element row 
       34  rolling element row 
       35  rolling element 
       36  rolling element 
       37  rolling element carriage 
       38  running web 
       39  running web 
       40  running web 
       41  running web 
       42  running web 
       43  running web 
       44  rolling element row 
       45  rolling element row 
       46  rolling element 
       47  rolling element 
       48  rolling element row 
       49  rolling element row 
       50  rolling element 
       51  rolling element 
       52  rolling element carriage 
       53  rolling element row 
       54  rolling element row 
       55  rolling element 
       56  rolling element 
       57  rolling element row 
       58  rolling element row 
       59  rolling element 
       60  rolling element 
       61  rolling element carriage