Patent Publication Number: US-2019166997-A1

Title: Carriage for a guide system, and method for producing a carriage

Description:
This application claims the benefit under 35 USC § 119(a)-(d) of German Application No. 10 2017 128 752.3 filed Dec. 4, 2017, the entirety of which is incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a carriage for a guide system, and a method for producing a carriage. 
     BACKGROUND OF THE INVENTION 
     A carriage for a guide system, in particular, for a push-in element, for example, for a push-in element of a furniture item or of a domestic appliance or kitchen appliance, is known in different designs. 
     For example, so-called partial-extension mechanisms or full-extension mechanisms with guide rails movable in a mutually telescopic manner are used as guide systems. These guide rails are mounted movably relative to each other by means of carriages. 
     A push-in element, for example, a drawer, a shelf base, a food tray or the like, is generally received in a displaceable manner by way of exactly two separate, identical structural units of a partial-extension mechanism or of a full-extension mechanism. They are preferably received on inner faces of a furniture cabinet or of a housing of a domestic appliance or kitchen appliance. 
     Since a carriage for a guide system has to satisfy stringent demands in terms of technology and economy, further optimizations to previous solutions are necessary to this end. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to further improve the aforementioned carriages for a guide system, particularly in terms of a comparatively high load-bearing capacity and, at the same time, cost-effective production. 
     The present invention proceeds from a carriage for a guide system, in particular, from a carriage for a linear guide system, wherein the carriage has a running cage, wherein the running cage has, in particular, exactly one cage middle element and, in particular, exactly two lateral cage side elements, wherein the cage side elements, lying opposite each other and spaced apart from each other, are each connected to the cage middle element, wherein a plane of extent of a cage side element is at an angle to a plane of extent of the cage middle element. 
     A cage side element and/or the cage middle element advantageously extends in exactly one plane of extent. For example, the cage side element is connected to the cage middle element at a longitudinal side of the cage middle element. The longitudinal side extends, for example, in the longitudinal extent of the cage middle element. Advantageously, the longitudinal side forms an outer face of the cage middle element. In the arranged state on the guide system, the longitudinal extent of the cage middle element is advantageously oriented parallel to a direction of movement of the guide system. 
     The core concept of the present invention is that the plane of extent of a cage side element and the plane of extent of the cage middle element enclose an angle of less than 90°. In this way, the carriage can be arranged on a rail of a guide system in such a way that the carriage is held on the rail perpendicularly with respect to a direction of movement of the rail. The carriage, in particular, the running cage, is advantageously provided in such a way that the plane of extent of a cage side element and the plane of extent of the cage middle element enclose an angle of less than 90° in a state before the carriage is mounted on the guide system. 
     The guide system has, for example, a guide rail, a push-in element rail and a carriage. For example, the guide system is configured as a partial-extension mechanism or as a full-extension mechanism. In the assembled state of the guide system, the carriage is arranged, for example, between the guide rail and the push-in element rail, such that, by means of the carriage, the push-in element rail is mounted on the guide rail in such a way as to be movable relative to the guide rail. A partial-extension mechanism comprises a cabinet rail and a push-in element rail. A full-extension mechanism comprises a cabinet rail, a central rail and a push-in element rail. Advantageously, a carriage is arranged between in each case two rail elements of the guide system. A full-extension mechanism comprises, for example, two carriages. It is conceivable that the full-extension mechanism has two identical carriages. However, it is also conceivable that the full-extension mechanism comprises two different carriages and that, in particular, the two carriages differ exclusively in terms of their length. The guide system is advantageously configured to movably connect a linearly movable push-in element, e.g. a drawer, to a cabinet unit. 
     The guide system is advantageously a linear guide system. For example, the guide system is provided for arrangement on a furniture item or a domestic appliance, for example, a kitchen appliance, for example, as a furniture guide system or as a domestic appliance guide system. Moreover, an orientation of the guide rail in the state of use or state of installation of the guide system in a furniture item or a domestic appliance, for example, a kitchen appliance, is thus defined. 
     In an advantageous embodiment of the present invention, a cage side element is connected to the cage middle element in an articulated manner via a joint. Advantageously, the cage side elements are each connected to the cage middle element in an articulated manner via a joint. This makes production of the carriage easier. 
     The joint is preferably configured as a film hinge. Advantageously, each cage side element is connected to the cage middle element via a joint. For example, each cage side element is connected to the cage middle element by means of two or more joints, in particular, film hinges. The film hinge extends advantageously in the longitudinal direction of the carriage. The joint is preferably formed on the longitudinal side of the cage middle element. 
     It also proves advantageous that the cage middle element and the cage side elements comprise attachment means for the movable support of bearing bodies of the carriage, wherein the attachment means are present on the cage middle element along the longitudinal extent of the cage middle element and are present on the cage side element along a longitudinal extent of a cage side element, such that the bearing bodies of the carriage can be arranged in succession on the cage middle element and/or on the cage side element along the longitudinal extent of the cage middle element and/or along the longitudinal extent of the cage side element. This improves the stability of the guide system on which the carriage is present. Advantageously, an attachment means is configured to support exactly one bearing body. 
     Advantageously, the attachment means are present on the cage middle element and/or on the cage side element in a row and/or one after another along the longitudinal extent. It is also conceivable that the attachment means are present on the cage middle element and/or on the cage side element one after another along the longitudinal extent and mutually offset transversely with respect to the longitudinal extent, e.g. are present in a zigzag formation. 
     It also proves advantageous that the bearing bodies are cylinder-shaped and/or roller-like. 
     The bearing bodies can be configured as balls, cylinders and/or rollers. In particular, all the bearing bodies of the running cage are configured as rollers and/or as cylinders. It is also conceivable that cylinder-shaped and/or roller-shaped bearing bodies are present on the cage middle element, and spherical bearing bodies are present on the cage side element, or vice versa. A bearing body is configured, for example, as a bearing roller, roller body and/or antifriction bearing or as a bearing ball and/or ball bearing. 
     Between 2 and 10 attachment means, in particular, between 4 and 6 attachment means, are preferably formed on a cage side element of a running cage. For example, 2, 3, 5, 6, 7 or 8 attachment means, in particular, exactly 4 attachment means, are present on a cage side element of a running cage. Between 2 and 12 attachment means, in particular, between 4 and 6 attachment means, are preferably formed on a cage middle element of a running cage. For example, 2, 3, 4, 6, 7, 8, 9, 10 attachment means, in particular, 5 attachment means, are present on a cage side element of a running cage. For example, between 2 and 10 bearing bodies, in particular, between 4 and 6 bearing bodies, are present on a cage side element of a running cage. For example, 2, 3, 5, 6, 7 or 8 bearing bodies, in particular, exactly 4 bearing bodies, are present on a cage side element of a running cage. For example, between 2 and 12 bearing bodies, in particular, between 4 and 6 bearing bodies, are present on a cage middle element of a running cage. For example, 2, 3, 4, 6, 7, 8, 9, 10 bearing bodies, in particular, exactly 5 bearing bodies, are arranged on a cage side element. 
     It is also advantageous that the running cage has holding means, wherein the holding means are configured in such a way that, in an assembly process, a cage side element is pivotable about a joint of the running cage from a geometric basic shape of the running cage to a functional state, wherein the running cage in the geometric basic shape is located in a basic production state, and wherein the holding means in the functional state determine the angle between the plane of extent of the cage middle element and the plane of extent of the cage side element. This makes production of the carriage easier. 
     Advantageously, the plane of extent of the cage side element encloses, with the plane of extent of the cage middle element, an angle of more than 90° in the production state. In the functional state, the plane of extent of the cage side element encloses, with the plane of extent of the cage middle element, an angle of less than 90°. For example, an underside of the cage side element encloses, with an underside of the cage middle element, the angle in the production state and the angle in the functional state, wherein the underside of the cage side element and the underside of the cage middle element form an outer face of the running cage. Advantageously, an angle between the cage middle element and a cage side element can be altered on the guide system from the production state to the functional state, in particular, the angle between the planes of extent of the two components. 
     The holding means are configured, for example, in the form of holding clips. For example, a holding means comprises a holding member and a holding element. For example, the holding member and the holding element are arranged on the bearing cage in such a way that the holding member, during a movement of the cage side element from the production state to the functional state, is pivotable past the holding element relative to the cage middle element, wherein the holding member bears on the holding element in the functional state, such that the cage side element is held in the functional state relative to the cage middle element. For example, the holding means lock the cage side element relative to the cage middle element in the functional state. 
     The holding member is formed, for example, on a longitudinal side of a cage side element. It is also conceivable that the holding member is present on the underside of the cage side element and/or on an upper face of the cage side element, wherein the upper face lies opposite and at a distance from the underside. The holding element is present, for example, on a longitudinal side of the cage side element. It is also conceivable that the holding element is present on the underside of the cage middle element and/or on an upper face of the cage middle element, wherein the upper face lies opposite and at a distance from the underside. The holding member advantageously protrudes from the longitudinal side, the upper face and/or the underside of the cage side element. The holding element advantageously protrudes from the longitudinal side, the upper face and/or the underside of the cage middle element. The holding member and/or the holding element has a wedge-shaped configuration, for example. The holding member is curved, bent and/or chamfered in cross section, for example. The holding member comprises, for example, a radius or a cylindrical surface. 
     It likewise proves advantageous that the carriage has two running cages and a connection element, wherein the connection element connects the running cages to each other, such that the running cages are present at a distance from each other. Two rails of the guide system, between which the carriage is arranged, are thus better supported. 
     The running cages and the connection element of the carriage are advantageously present as separate components. The running cage and the connection element can preferably be produced independently of each other. It is also conceivable that the carriage is formed in one piece. In particular, the running cages are in one piece with the connection element and are connected to each other non-releasably. The connection element is plate-shaped, for example. The connection element is present, for example, as an elongate, flat molding. For example, the connection element is, in particular, connected exclusively to the cage middle elements of the two running cages. 
     It is moreover proposed that the connection element has a connection middle element and a connection side element, wherein a plane of extent of a connection side element is present at an angle to a plane of extent of the connection middle element, wherein the plane of extent of a connection side element and the plane of extent of the connection middle element enclose an angle of less than 90°. 
     Advantageously, the connection element, in particular, comprises exactly two or exactly four connection side elements. A connection side element advantageously extends completely along a longitudinal extent of the connection element. Preferably, at a side region, the connection element preferably comprises two connection side elements lying opposite each other and at a distance from each other. For example, the connection element, in the state when arranged on the carriage, has an angle between a connection side element and the connection middle element identical to the angle between a cage side element and the cage middle element. 
     The connection element preferably has mirror symmetry about a longitudinal plane, wherein the longitudinal plane extends, for example, parallel to a longitudinal axis of the carriage. 
     It is also conceivable that a plurality of connection elements of different length are present, such that a length of the carriage is adaptable. Advantageously, the connection elements differ exclusively in term of their length. The length of a connection element, particularly in the state when arranged on the carriage, extends advantageously parallel to a longitudinal extent of the carriage. The longitudinal extent of the carriage advantageously extends from one end of a first running cage via the connection element to an end of a second running cage lying remote from the end of the first running cage. 
     It is moreover advantageous that the connection element is configured in such a way that, in the state when the connection element is arranged on the carriage, the connection element determines the plane of extent of a cage side element and the plane of extent of the cage middle element of the running cage in an angle of less than 90°. In this way, for example, holding means on the carriage are avoidable, and production of the carriage is thus made easier. 
     Advantageously, an angle between a connection side element and the connection middle element is unalterable. For example, in the state when arranged on the carriage, the connection element fixes the angle between a cage side element and the cage middle element. It is conceivable that, in the state when the connection element is arranged on the carriage, a connection side element is connected to a cage side element and that the connection middle element is connected to the cage middle element. 
     In an advantageous embodiment of the carriage, the carriage has two running cages, wherein a running cage has mirror symmetry about a longitudinal plane, wherein the longitudinal plane extends parallel to a longitudinal axis of the carriage, and wherein the two running cages are present with mirror symmetry to each other on the carriage. In this way, the costs involved in producing the carriage are advantageously reduced. For example, the carriage comprises two identical running cages, which are, in particular, present on the carriage with mirror symmetry to each other. 
     In an advantageous modification of the carriage, the carriage has two running cages, a connection element and damping means, wherein the connection element connects the running cages to each other, such that the running cages are at a distance from each other, wherein the damping means are configured between a running cage and the connection element in order, in the state with the carriage arranged on the guide system, to damp an opening movement and/or a closing movement of a rail of the guide system relative to a further rail of the guide system. This improves the ease of operation of the guide system comprising the carriage. 
     For example, the damping means are present on the carriage in such a way that, at the end of an opening movement of the push-in element rail relative to the guide rail, the opening movement of the push-in element rail is damped or braked. Advantageously, the damping means comprise a damping element, in particular, two damping elements. The damping element is configured like a spring, for example. 
     The damping element is configured, for example, as a flat element with recesses. The damping element is elastically resilient in the longitudinal direction, for example, on account of the material of the carriage and of the recesses. The recesses on the flat element of the damping element are, in particular, present in the manner of leg springs. The damping element has a meandering structure, for example. 
     It is also advantageous that a respective damping element of the damping means connects the connection element to a respective running cage. In this way, the running cages are advantageously movable toward or away from each other in the opening and/or closing direction of the guide system. Advantageously, a running cage is coupled comparatively flexibly to the connection element by the damping element. The damping element is arranged, for example, on the cage middle element, on the cage side element, on the connection middle element and/or on the connection side element. 
     It is also advantageous that a running cage has, at an end opposite the connection element, damping means in the form of a damping member. 
     A running cage comprises, for example, one, two or three damping members. For example, a damping member is formed on the cage middle element and/or on the cage side element. The damping member is, for example, present as a tab-like spring element. For example, a damping member comprises two e.g. tab-like spring elements. Advantageously, the damping members are comparatively rigid, in particular, with a comparatively high spring strength and/or damping force, such that, in the state when the guide system is arranged on the furniture item or on the domestic appliance, a movement of a push-in element can be damped, in particular, braked, by the damping action and/or spring action of the damping member. For example, when a carriage is in the mounted state, the carriage damps and/or brakes the movement of a push-in element with a mass of between 0 kg and 60 kg, between 0 kg and 50 kg, between 0 kg and 40 kg, between 0 kg and 30 kg, in particular, between 0 kg and 35 kg. 
     It moreover proves advantageous that a running carriage has a coupling element, and the connection element a coupling member, and the running cage is connectable to the connection element by the coupling element and the coupling member, in particular, releasably. A length of the carriage is variable in this way. 
     For example, the connection element is connectable to a running cage via a plug-in connection. For example, the coupling member is configured as a plug-in element, e.g. as a plug, and the coupling element is configured as a socket element, e.g. as a socket, or vice versa. For example, the connection element can be coupled to a carriage in a movement along or transverse to the longitudinal axis of the carriage or of the connection element. It is also conceivable that the connection element is connectable non-releasably to the running cage by means of the coupling member and the coupling element. Advantageously, the coupling member and the coupling element fix the running cage and the connection element in the state when they are arranged on each other. The coupling member is, for example, formed on the connection side element and/or on the connection middle element. The coupling element is, for example, present on the cage middle element and/or on the cage side element. 
     It is moreover advantageous that an attachment means is configured as a recess on which the bearing body can be arranged, wherein the recess has attachment elements via which the bearing body can be supported at running surfaces of the bearing body, such that the bearing body arranged on the carriage is secured on the recess against falling out. 
     For example, the attachment elements are present on the recess in a manner jutting out or protruding. For example, a recess comprises four, five, in particular, six attachment elements. The bearing body can advantageously be arranged between the attachment elements at the recess. For example, the bearing body can be clipped onto the recess by a comparatively slight force. For example, a shortest and/or a longest distance between two attachment elements is smaller than a radius and/or an outer dimension of the bearing body. 
     The recess is formed, for example, as a through-opening, in particular, as an aperture extending advantageously parallel to a normal of the plane of extent of the cage middle element or parallel to a normal of the plane of extent of the cage side element. Advantageously, the through-opening of the recess, or the aperture, extends transversely with respect to the plane of extent of the cage middle element or transversely with respect to the plane of extent of the cage side element. 
     A production method is also proposed for producing a running cage and/or for producing a carriage with a running cage according to one of the aforementioned variants, wherein, in a first production step, a geometric basic shape of the running cage and/or a geometric basic shape of the carriage is produced by means of a deformation process, and, in a further production step, a cage side element of a running cage is pivoted from the geometric basic shape to a functional state about a joint of the running cage. 
     Advantageously, the cage side element is pivoted, in particular, about a joint axis of the joint, for example, about a hinge axis of the film hinge. For example, the cage side element is kinked, bent and/or pivoted relative to the cage middle element. 
     In a further embodiment of the production method, it is proposed that, in one production step, the running cage is fitted with bearing bodies, in particular, cylinder-shaped bearing bodies. 
     It is conceivable that the carriage is fitted with bearing bodies after the production of the geometric basic shape and that at a later time the running cages are deformed. However, it is also conceivable that the carriage is fitted with bearing bodies at a time after the deformation of the running cages. 
     It also proves advantageous that, in one production step, a running cage is connected to a connection element. For example, the running cage is produced together with the connection element, in particular, in one piece in one production step, e.g. in an injection molding process. It is also conceivable that the running cage and the connection element are two separate components which are generated in preceding production steps and are then connected to each other in a further production step, e.g. by machine and/or manually. 
     A guide system with a carriage according to one of the modifications discussed above is also proposed. The present invention also covers a furniture item or domestic appliance, in particular, kitchen appliance, comprising a cabinet and a push-in element, wherein the push-in element is received movably on the cabinet by way of a guide system, wherein the guide system for the push-in element is present with a carriage according to one of the configurations discussed above. The advantages set out can thus be achieved for the furniture item or domestic appliance. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Further features and advantages of the invention are explained in more detail on the basis of the illustrative embodiments of the present invention shown in the figures, in which: 
         FIG. 1  shows a schematically depicted furniture item according to the present invention in a perspective view obliquely from above, with a drawer received displaceably thereon; 
         FIG. 2  shows in cross section a perspective detail of a furniture item according to the present invention, in the region of a drawer side adjacent to a furniture cabinet wall and a furniture cabinet base; 
         FIG. 3  shows the detail according to  FIG. 2  in a front view; 
         FIG. 4  shows an exploded view of a structural unit of a guide system according to the present invention; 
         FIG. 5  shows a perspective view of an end portion of a central rail of the guide system according to  FIG. 4 ; 
         FIG. 6  shows a perspective view, obliquely from above, of a carriage according to the present invention in a basic production state; 
         FIG. 7  shows a front view of the carriage according to  FIG. 6 , with bearing bodies arranged thereon; 
         FIG. 8  shows an enlarged perspective view of part of a running cage of the carriage according to  FIG. 6 , 
         FIG. 9  shows, in a perspective view obliquely from above, a running cage according to  FIG. 6  in a functional state; 
         FIG. 10  shows a front view of the carriage according to  FIG. 9  with bearing bodies arranged thereon; and 
         FIG. 11  shows an enlarged perspective view of part of a running cage of the carriage according to  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     For corresponding elements of different illustrative embodiments, the same reference signs are used below in part. 
       FIG. 1  shows a highly schematic depiction of a furniture item  1  according to the present invention in a state of use, with a hollow cuboid furniture cabinet  2  and a push-in element configured as a drawer  3 , wherein the drawer  3  is received displaceably on the furniture cabinet  2 . The furniture cabinet  2  comprises two opposite vertical side walls  4  and  5  between which the drawer  3 , starting from a state of accommodation in the interior of the furniture cabinet  2 , can be pulled out in a horizontal direction according to P 1  and then pushed in in an opposite direction according to P 2  via a guide system according to the invention with telescopic guide means, e.g. in an undermount configuration, or a first full-extension rail  6  and a second full-extension rail  7 . The drawer  3  is shown in  FIG. 1  in the state when moved out to the maximum extent or completely from the interior of the furniture cabinet  2 . The storage volume of the drawer  3  can thus be accessed virtually unimpeded from above. 
     If the drawer  3  uses, instead of the full-extension rails  6 ,  7 , in each case a partial-extension rail, the drawer  3 , in the state of maximum extraction, cannot be moved so far out of the interior of the furniture cabinet  2  in direction P 1  as is possible with the full-extension rails  6 ,  7  according to the depiction in  FIG. 1 . The front element  12  is then nearer to the open front face of the furniture cabinet  2  than is shown for the drawer  3  according to  FIG. 1 . 
     The full-extension rail  6  screwed onto the inner face of the side wall  4  is located opposite, and at the same height as, the full-extension rail  7  screwed onto the side wall  5 . The full-extension rail  7  is concealed in  FIG. 1  and is indicated by broken lines. 
     A further drawer (not shown in  FIG. 1 ), guided correspondingly by way of full-extension rails  8  and  9 , can be accommodated in the furniture cabinet  2  above the drawer  3 . 
     The drawer  3  has mutually opposite drawer side walls  10 ,  11 , each of which comprises a structured hollow-chamber drawer side. Moreover, the drawer  3  comprises a front element  12 , a rear wall  13  lying horizontally opposite the latter, and a horizontally extending drawer base  14 , which reaches as far as and is connected to the drawer side walls  10 ,  11 , the front element  12  and the rear wall  13 . 
       FIGS. 2 and 3  show, in the region of a cabinet side wall  5 , a detail of a drawer  3  which in this case has hollow-chamber drawer sides, with a drawer base  14 , a drawer side wall  11  designed as a hollow-chamber drawer side  15 , and a rear wall  13 . The drawer  3  is received on the furniture cabinet  2  via two structural units of a guide system according to the present invention, i.e. on the side wall  5  via a full-extension rail  16  according to the present invention and in the same way on the side wall  4  (not visible in  FIG. 2 ) via a further hollow-chamber drawer side of the drawer  3 . It is received on the side wall  4  via a further structural unit or a further full-extension mechanism according to the present invention, as a result of which the drawer  3  is linearly displaceable horizontally in the directions P 1  and P 2 . 
     The hollow-chamber drawer side  15 , preferably made of bent sheet-metal material, has an outer housing  15   a  and an inner structure  15   b , such that the full-extension mechanism  16  can be accommodated in a recessed manner in the internal volume of the hollow-chamber side wall  15 . On an inner face of the hollow-chamber side wall  15  in the lower portion of the latter, it is designed to receive a longitudinal edge of the drawer base  14 . 
     The full-extension mechanism  16  according to the present invention, formed as a structural unit of the guide system, comprises three mutually telescopic guide rails, namely a cabinet rail  17 , a central rail  18  and a push-in element rail  19 . 
     The central rail  18  is configured as a hollow profile according to the present invention. 
     A push-in element to be moved, for example, the drawer  3 , is coupled or connected to the push-in element rail  19 , for example, fixed to the hollow-chamber drawer side  15 , whereas the cabinet rail is connected to the stationary part of the item of furniture. If the full-extension mechanism  16  is used as an undermount slide, an underside of a push-in element, or the base thereof, bears on an upper face  19   a  of the push-in element rail  19 . An upwardly protruding hook element  19   b  at the rear end of the push-in element rail  19  forms a stop for a portion of a rear outer face of the push-in element, wherein, in order to achieve precise positioning, a portion of the hook element  19   b  angled parallel to the upper face  19   a  engages in a suitably prepared depression in the rear outer face of the push-in element. 
     Moreover, the full-extension mechanism  16  comprises a first or lower carriage  20  with bearing bodies  37  arranged thereon, wherein the carriage  20  between the cabinet rail  17  and the central rail  18  ensures a load-transmitting relative movement of the rails  17 ,  18 . 
     Moreover, the full-extension mechanism  16  comprises a second or upper carriage  21  with bearing bodies  38  arranged thereon, wherein the carriage  21  between the central rail  18  and the push-in element rail  19  ensures a load-transmitting relative movement of the rails  18 ,  19 . 
     Pins  32  are present on a vertical, inwardly facing narrow side of a rail body  31  of the cabinet rail  17 , by way of which pins  32  a movement mechanism  22  of the full-extension mechanism  16  can be attached, for example, for ejection and/or retraction of the drawer  3 . 
     Two L-shaped fastening elements  33  and  34  belong to the cabinet rail  17 , wherein the fastening elements  33  and  34  serve to fasten or fix the full-extension mechanism  16  on an inner face of the side wall of a cabinet, for example, the inner face  5   a  of the side wall  5  of the furniture cabinet  2  of the furniture item  1 . 
     The guide rails  17 ,  18 ,  19  are preferably made of a sheet metal material which, starting from the flat sheet metal material, is shaped, for example, by a punching and bending process, in order to give the end product of the respective guide rail. 
       FIG. 5  shows the front end portion of the central rail  18  with respect to the state of use of the full-extension mechanism  16 . According to the illustrative embodiment shown, the central rail  18  has an upper flat horizontal wall portion  23 , a lower flat horizontal wall portion  24 , two flat upper side wall portions  25 ,  26 , two lower flat side wall portions  27 ,  28  and middle wall portions  29  and  30 . 
     The horizontal wall portion  23  forms a distal wall or upper face of the central rail  18  or of the corresponding hollow profile. Accordingly, the horizontal wall portion  24  forms a distal wall or underside of the central rail  18  or of the hollow profile. 
     The terms upper and lower pertain to the orientation of the full-extension mechanism  16  in the state of use or in the state when mounted on the furniture item, especially as shown in  FIGS. 2 and 3 . The planes respectively spanned by the mutually parallel horizontal wall portions  23  and  24  and their exterior or distal sides are at least almost horizontally oriented. 
     In order to limit a relative movement of the lower carriage  20  and the upper carriage  21  with respect to the central rail  18  in the longitudinal extent of the central rail  18  along a central longitudinal axis L (see  FIG. 5 ), upper stops  35  and lower stops  36  are provided on the central rail  18 . 
     With the full-extension mechanism  16  assembled, the bearing bodies received on the carriages  20 ,  21  run on the outwardly directed sides of the central rail  18  or on the horizontal wall portions  23 ,  24  and the side wall portions  25 - 28 . With its portions  20   a  and  20   b  that carry the bearing bodies, the lower carriage  20  engages externally around the horizontal wall portion  24  and the side wall portions  27 ,  28 . 
     With its portions  21   a  and  21   b  that carry the bearing bodies, the upper carriage  21  engages externally around the horizontal wall portion  23  and the side wall portions  25 ,  26 . 
     A carriage  20 ,  21  according to the invention comprises two running cages  20   a ,  20   b  and  21   a ,  21   b , respectively, and a respective connection element  39 ,  40 . In the following ( FIGS. 6 to 11 ), the design of the carriage  20  is explained below, and this, for example, also applies accordingly to the carriage  21 . 
       FIG. 6  shows the carriage  20  in the basic production state. The running cages  20   a  and  20   b  are connected to the connection element  39  by a damping means  41 ,  42 . The connection element  39  comprises an elongate, plate-shaped connection middle element  43  which, in the state when arranged on the full-extension mechanism  16 , extends along, and, in particular, at a distance from, a horizontal wall portion  23 ,  24  of the central rail  18 . The damping means  41 ,  42  are advantageously identical or have mirror symmetry. The damping means  41 ,  42  comprise a meandering structure, e.g. with annular recesses  44 , such that the damping means  41 ,  42  are flexible, in particular, compressible and/or extensible or stretchable, in the longitudinal extent L of the carriage  20 . 
     The following description given for the running cage  20   b  of the carriage  20  also applies to the further running cage of the carriage  20 ,  21 . The running cage  20   b  comprises a cage middle element  45  and two cage side element  46 ,  47 . The cage side elements  46 ,  47  are each connected to the cage middle element  45  in an articulated manner via joints in the form of film hinges  48   a - 48   d . In the basic production state, a plane of extent M 1  of the cage middle element  45  encloses, with a respective plane of extent S 1 , S 2  of a cage side element  46 ,  47 , an angle α or β, respectively, which is greater than or equal to 90°. For example, an underside  51  of the cage side element  47  or an underside  52  of the cage side element  46  encloses the angle α or β with an underside  53  of the cage middle element. 
     Moreover, holding means in the form of holding members  49   a - 49   d  are advantageously formed on the cage side elements  46 ,  47  and holding elements  50   a - 50   d  are advantageously formed on the cage middle element  45 . For example, the holding members  49   a - 49   d  are bent in a cross section transverse to the longitudinal extent of the running cage  20   b , such that, during a pivoting of the cage side elements  46 ,  47 , they are able to be pivoted or pressed past the holding elements  50   a - 50   d , with application of a relatively low force, from the basic production state according to  FIGS. 6 to 8  to the functional state according to  FIGS. 9 to 11 . In the functional state, the holding members  49   a - 49   d  bear on the holding elements  50   a - 50   d , such that the angle α or β cannot be enlarged. In the functional state of the running cage  20   b , the carriage  20  can be pushed onto the central rail  18 , such that the carriage  20 , in the state when pushed onto the central rail  18 , is fixed on the central rail  18  in a direction transverse to the longitudinal extent of the central rail  18  or of the carriage  20 . 
     At one end  54  of the running cage  20   b , the carriage  20  comprises damping members  55 - 57 , which are present, for example, in the form of tabs or springs, in order to damp a movement of the carriage  20 . Advantageously, each cage side element  46 ,  47  and/or the cage middle element  45  comprises a damping member  55 - 57 . 
     Moreover, the running cage comprises attachment means  58  on the cage middle element  45  and attachment means  59 ,  60  on the cage side elements  46 ,  47  for the purpose of arranging the bearing bodies  37 ,  38 . The attachment means  59 ,  60  of the cage side element  46 ,  47  are advantageously present as recesses and comprise attachment elements  62  in order to support the bearing body  38  movably at front faces of the bearing body  38  and to secure it against falling out of the recess. The attachment means  58  of the cage middle element  45  in turn are advantageously likewise present as recesses, wherein a recess of the attachment means  58  has, on inner recess side faces  63 , attachment elements  61  which are present protruding from the recess side faces  63 . The recess of the attachment means  58  advantageously comprises two recess side faces  63 , at which the attachment elements  61  are formed. The two recess side faces  63  of the attachment means  58  are advantageously oriented transversely with respect to a longitudinal extent of the running cage  20   b  and are present at a distance from each other. An attachment element  61  is present in the shape of a triangle, for example, wherein a beveled surface  65  of the attachment element  61 , starting from an upper face  64  or starting from the underside  53  of the cage middle element  45 , tapers in the direction of the surface of the recess side face  63  in the direction of the recess interior. A bearing body  63 , which can be arranged on the cage middle element  45 , is advantageously pressed, with comparatively little force, past the attachment elements  61  of the recess in the direction of the recess interior, such that the bearing body  66  is held on the recess between the attachment elements  61 , wherein the running face of the bearing body  66  can come to bear on the beveled faces  65  of the attachment elements  61 , as a result of which the bearing body  66  is held movably. 
     LIST OF REFERENCE SIGNS 
     
         
           1  furniture item 
           2  furniture cabinet 
           3  drawer 
           4 - 5  side wall 
           6 - 9  full-extension rail 
           10 - 11  drawer side wall 
           12  front element 
           13  rear wall 
           14  drawer base 
           15  hollow-chamber drawer side 
           15   a  housing 
           15   b  inner structure 
           16  full-extension mechanism 
           17  cabinet rail 
           18  central rail 
           19  push-in element rail 
           19   a  upper face 
           19   b  hook element 
           20  carriage 
           20   a - 20   b  running cage 
           21  carriage 
           21   a - 21   b  running cage 
           22  movement mechanism 
           23 - 24  horizontal wall portion 
           25 - 28  side wall portion 
           29 - 30  middle wall portion 
           31  rail body 
           32  pin 
           33 - 34  fastening element 
           35 - 36  stop 
           37 - 38  bearing body 
           39 - 40  connection element 
           41 - 42  damping means 
           43  connecting middle element 
           44  recess 
           45  cage middle element 
           46 - 47  cage side element 
           48   a - 48   d  film hinge 
           49   a - 49   d  holding member 
           50   a - 50   d  holding element 
           51 - 53  underside 
           54  end 
           55 - 57  damping member 
           58 - 60  attachment means 
           61  attachment element 
           62  attachment element 
           63  recess side face 
           64  upper face 
           65  surface 
           66  bearing body