Abstract:
A drawer pull-out guide includes a basic-structure rail, which can be fastened on a basic furniture structure, and at least one pull-out rail, which is mounted such that it can be displaced relative to the basic-structure rail between an open position and a closed position. At least one lifting device is provided, by which the pull-out rail can be raised relative to the basic-structure rail towards the end of the closing movement. The lifting device has at least a two-part design, including a raising device, for raising the pull-out rail, and a bearing device, for supporting the pull-out rail in the closed position, and the raising device, in the closed position of the pull-out rail, is relieved of the loading of the pull-out rail.

Description:
BACKGROUND OF THE INVENTION 
     The present invention concerns a drawer extension guide, including a carcass rail which can be fastened to a furniture carcass, at least one extension rail which is supported displaceable relatively to the carcass rail between an open position and a closed position, and at least one lifting device, by way of which the extension rail can be raised relative to the carcass rail towards the end of the closing movement, wherein the lifting device is of at least two-part design, wherein the lifting device has a raising device for raising the extension rail and a bearing device for supporting the extension rail in the closed position. 
     Such drawer extension guides are already known and are mentioned for example in the EP 1 959 794 B1. In conventional drawer extension guides, rolling bodies located between extension rails can be deformed by forces permanently acting on them. For example, these forces result from the weight of a filled drawer. Especially in the closed state of the drawer extension guide, the force effect onto the rolling bodies is higher than during the extension process of the drawer. The deformation of the rolling bodies is expressed by a rattling noise and by an agitated sliding during opening and closing of the drawer. Drawer extension guides which have a bearing device arranged in an anterior end section of at least one extension rail relieve the rolling bodies arranged between the rails and protect them from deformation. Further, this bearing device causes the drawer to be slightly raised in the closed state, and so an adverse lowering of the drawer is prevented. Thus, the horizontally running joints between the front panels of cabinet drawers arranged one upon the other have a constant width so that the joint alignment visible from the outside is visually appealing. Because of the weight of the drawer acting on the bearing device, it is useful that the bearing device is made of a resistant material, for example metal. Even after a long period of use of the drawer, it is guaranteed by the bearing device, for example formed as metallic supporting rolling bodies, that these are fulfilling their purpose for a long runtime of the drawer extension guide. However, there exists a disadvantage. If the load device for example consists of a resistant hard material, for example metal, then the load device generates noises because of its material hardness when interacting with the at least one extension rail. For example: If a supporting rolling body made of metal is used as a load device, then superior rolling noises occur via the also metallic formed rolling bar when retracting the drawer than when using a softer plastic rolling body. These noises are not desired as well as the deformation of the rolling bodies and a non-uniform joint alignment. 
     SUMMARY OF THE INVENTION 
     Therefore, the invention should—while avoiding the previously described disadvantages—show a drawer extension guide which allows a noise-reduced raising of the extension rails by a raising device when retracting in the closed state of a drawer. In the closed state, the extension rails should be supported by a resistant bearing device and the rolling bodies should be relieved. At the same time, a uniform joint alignment of the front panels should be formed. 
     According to the invention, this object is solved in that the raising device is relieved of the extension rail in the closed position of the extension rail. 
     If a lifting device made of softer material—compared with the material hardness of the bearing device—is used, then the lifting device takes over the task of raising the rails noise-reduced. Thereby, the drawer is lifted by the softer lifting device in an area prior to its retracted end position, and the drawer is statically supported by the, for example metallic, supporting rolling body in the end position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further details and advantages of the present invention are described more fully hereinafter by means of the specific description with reference to the embodiments illustrated in the drawings, in which: 
         FIG. 1  shows a piece of furniture formed of a carcass with drawers on drawer extension guides, 
         FIG. 2  shows an embodiment of a drawer extension guide in an exploded view, 
         FIG. 3  shows an anterior end section of a drawer extension guide in a cross section, 
         FIGS. 4 a -4 d    show a schematic illustration of the drawer extension guide with different positions of the extension rail, 
         FIGS. 5 a -5 c    show side views of the drawer extension guide with different positions of the extension rail, 
         FIGS. 6 a  to 6 b    show a schematic illustration of an embodiment of a lifting device formed one-pieced, 
         FIG. 7  shows an anterior area of a drawer extension guide in an extended state in a view from below. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a piece of furniture  40  formed of a carcass  30 . The carcass rail  2  is connected via its mounting area  31  with the carcass  30 , the drawers  21  are laterally mounted at the extension rails  3   a ,  3   b  and are displaceable in the carcass  30 . In the retracted state of the drawers  21 , the front panel  22  is lining up with the carcass  30 . 
       FIG. 2  shows a drawer extension guide in an exploded view with its individual assembly groups. The extension rails  3   a —formed of a drawer rail  13  which can be connected to the drawer—and the extension rails  3   b —a center rail  14  located between drawer rail  13  and carcass rail  30 —are supported lengthwise displaceably via the carriages  18  relative to the carcass rail  2  and relative to each other. A plurality of rolling bodies  17  is arranged in the carriages  18 , and the rolling bodies  17  are rolling along the rolling track  8  of the carcass rail  2  and of the extension rail  3   a ,  3   b . The lifting device  4  interacts with this rolling track  8  and with the elevation  7  as soon as the drawer extension guide  1  closes. In this embodiment, the elevation  7  is formed by an embossing of the extension rail  3   a . In a further embodiment, the elevation  7  can also be located on the carcass rail  2  or can be built by the carcass rail  2 . 
       FIG. 3  shows an anterior end section of a drawer extension guide  1  on which the extension rails  3   a ,  3   b , for example comprising a center rail  14  and a drawer rail  13 , are supported lengthwise displaceably. In addition to the rolling bodies  17 , the lifting device  4  is also arranged between the rails  2 ,  3   a ,  3   b  of the drawer extension guide  1 . The lifting device  4  comprises the raising device  5  with the lifting rolling body  15  and the bearing device  6  with the supporting rolling body  16 . An elevation  7  similar to a ramp is located on the drawer rail  13 , and the elevation  7  contacts the raising device  6  or the bearing device  6  towards the end of the retracting motion of the extension rails  3   a ,  3   b  in relation to each other and to the carcass rail  2 . 
       FIG. 4 a    shows a drawer extension guide  1  comprising a carcass rail  2  and the extension guides  3   a ,  3   b , between which the rolling bodies  17  and the lifting device  4  are located. In this embodiment, the lifting device  4  comprises a raising device  5  and a bearing device  6  which are formed as lifting rolling body  15  and supporting rolling body  16 . The center rail  14  and the drawer rail  13  are only supported on the rolling bodies  17  in the shown position of the drawer rail  12  relative to the carcass rail  2 . The lifting device  4  has no contact to the extension guide  3 . Thus, the whole load of the drawer  21  rests on the rolling bodies  17 . 
       FIG. 4 b    schematically shows a drawer extension guide  1  in an area directed in the retracted state of the drawer  21 , wherein now the raising device  5  interacts with the elevation  7 . Because of the schematic illustration of the drawer extension guide  1 , in each case only two rolling bodies  17  are indicated in  FIG. 4 a    to  FIG. 4 b   . As can be seen in  FIG. 1 , the drawer extension guide  1  not only comprises two rolling bodies  17  but a plurality of rolling bodies  17 . The rolling bodies  17  are successively relieved from the weight of the drawer  21  by the lifting of the extension guides  3   a ,  3   b  when now further retracting the drawer  21 . The lifting of the drawer rail  13  and the center rail  14  is effected by the interaction of the raising device  5  and the elevation  7 . 
       FIG. 4 c    shows in a schematic illustration the drawer extension guide  1 , wherein the extension rail  3   a ,  3   b  is still further retracted in the direction of the end position than shown in  FIG. 4 b   . In this position of the extension rails  3   a ,  3   b  relative to the carcass rail  2 , the raising device  5  and the bearing device  6  in cooperation with the elevation  7  take on a large part of the weight of the drawer. The rolling bodies  17  are now substantially completely relieved from the weight of the drawer  21 . Drawers  21  are often top-heavy because of their construction, filling and the front panels  22  and put a higher load to the anterior end section of the drawer extension guide  1  than to the posterior. Thus, the rolling bodies  17  arranged rearward are generally loaded less than those arranged forward. 
       FIG. 4 d    shows schematically a drawer extension guide  1 , wherein the drawer is in a retracted state. It can be recognized that the bearing device  6  consisting of the supporting rolling body  16  now carries the extension rail together with the elevation  7  and a part of the rolling body  17  which is slightly loaded with weight. The raising device  5  does not have contact to the elevation  7  anymore and is non-effective in the shown position. Thus, the whole load of the drawer is spread to the bearing device  6  (in other words the supporting rolling body  16 ), and to a small part of the rolling bodies  17 . The large part of the rolling bodies  17  and also the raising device  5  are in the relieved state and, therefore, protected from deformation. 
       FIG. 5 a    shows a part of a drawer extension guide  1  in a side view. There, the elevation  7  can be clearly recognized. In this drawing, it is recognizable that neither the raising device  5  nor the bearing device  6  are interacting with the elevation  7 . 
       FIG. 5 b    shows an embodiment of a drawer extension guide  1  in the side view, wherein one of the extension rails  3   a —the drawer rail  13 —is located in an area prior to the end position of the drawer  21 . The raising device  5 , formed as a lifting rolling body  15 , contacts the elevation  7  and raises the drawer rail  13  preparatory for the bearing by the bearing device  6 . The bearing device  6 , formed as a supporting rolling body  16 , does not yet contact the elevation  7  in this position and is, therefore, relieved from the weight of the drawer  21 . 
       FIG. 5 c    shows how the bearing device  6 , formed as a supporting rolling body  16 , is located on the elevation  7  and shows how the raising device  5 , formed as a lifting rolling body  15 , is relieved. 
       FIG. 6 a    shows schematically the lifting device  4 , comprising a first area  4   a  and a second area  4   b . The first area  4   a  is the operating area of the raising device  5 ; the second area  4   b  is the operating area of the bearing device  6 . As already shown in the previous drawing descriptions, the elevation  7 —not shown in this figure—first interacts with the raising device  5  when retracting the drawer  21  and interacts with the bearing device  6  when further retracting the drawer. If now the area  4   a  is made of a softer material, for example a soft plastic, then noises of the drawer extension guide  1  can be reduced. From a static point of view, more resistant material, for example metal, is more suitable for supporting the drawer  21  than the soft plastic of the area  4   a . The area  4   b  comprises the bearing device  6  which is—compared with the soft plastic—made of a harder and more resistant material. Here, for example, a metal is used which is characterized by a higher wear resistance and form stability than the plastic of the area  4   a . Thus, the drawer is supported by the area  4   b  (in other words, the bearing device  6 ) in the retracted state of the drawer. The area  4   a  is relieved in this case. A soft and quiet driving and lifting of the drawer  21  is guaranteed by the area  4   a  and a long-term stable and resistant supporting of the drawer  21  is guaranteed by the area  4   b.    
       FIG. 6 b    shows a lifting device  4  with the two areas  4   a  and  4   b . In this embodiment, the two areas are formed as a lifting rolling body  15  and a supporting rolling body  16 . The lifting device  4  is seesawing connected to the at least one extension guide  3   a ,  3   b  by a bearing  9 . The arrangement comprising the lifting device  4  with the lifting rolling body  15  and the supporting rolling body  16  can thus be adapted to the rolling track  8  and the elevation  7  by the seesawing bearing  9 . 
       FIG. 7  shows a partial area of a drawer extension guide  1 , comprising a carcass rail  2  and the extension rails  3   a ,  3   b , for example the center rail  14  and the drawer rail  13 . When the lifting device  4  and the elevation  7  are cooperating in the retracted state of the drawer  21 , the center rail  14  is supported by the bearing  9 , while the drawer rail  13  is raised by the lifting rolling body  15  and the supporting rolling body  16 . Therefore, the rolling bodies  17 —which are not shown in  FIG. 6 —below and above the center rail  14  are relieved because the weight force is directly released from the drawer rail  13  via the dotted illustrated supporting rolling body  16  to the carcass rail  2 .