Patent Publication Number: US-2006010772-A1

Title: Path-controlled window lifter for motor vehicles

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
      This application claims priority of German Utility Model Application Number 20 2004 010 955.7, filed on Jul. 13, 2004.  
     BACKGROUND  
      The invention relates to a path-controlled window lifter for a motor vehicle.  
      Path-controlled cable window lifters have two or more guideways stamped into a sheet metal plate and each holding a follower which is capable of sliding movement. The followers support the window pane which is to be raised and lowered through a retaining rail. A window lifter of this kind is shown in DE 202 12 774 U1.  
      With this known window lifter three guideways are provided in a guide plate wherein each guideway has two guide webs running parallel to each other through the stamping process. The multi-part follower consists of an upper and a lower slide element which are connected together through a bolt and spring element (plate spring). The slide elements interact with the upper and lower side of the guide plate and thus produce the guide for the follower perpendicular to the plane of the guide plate—this direction is designated the Y-direction in the case of a window lifter of a side window (vehicle door).  
      The guidance of the follower in the plane of the guideway, thus perpendicular to its direction of movement—the X-direction is undertaken by a further slide element in the form of a slide block which fits with precision between the guide webs and which interacts by its two outer sides with the flanks of the guide webs.  
      In the case of a window lifter having three guideways the situation is over-defined. As a result of manufacturing tolerances there is always a forced action—the slide block which produces the defined fit is subject to increased friction which produces heavy going and heavier wear. Thus in time play occurs which prevents precision guiding and positioning of the window pane.  
      Even with path-controlled window lifters with two guideways tolerances mean increased friction and wear-inducing forces in the region of the slide block and guideway.  
     BRIEF DESCRIPTION  
      The object of the present invention is therefore to further develop a path-guided window lifter with a view to improving its functioning.  
      It is proposed that the slide block has elasticity on the sides interacting with the flanks of the guide webs. This elasticity compensates position tolerances of the guideways—increased wear is counteracted.  
      According to an embodiment of the invention it is proposed that the slide block is made from a wear-resistance material having good sliding properties, preferably plastics. The regions of the outer sides of the slide block which interact with the guide webs of the guideway are filled with a material producing elasticity. Thus a pliability is produced with sliding properties which are as good as if the slide block were made only of this material.  
      The elasticity of the slide block in the proposed regions can also be achieved through shaping the slide block body. Thus it is possible to design the regions underneath the sides of the slide block interacting with the guide webs to be hollow and thus to provide elasticity in the manner of a leaf spring.  
      The slide element can also be made up in many pieces instead of as a one-piece slide block. Thus slide elements interacting with the guide webs can be provided which are supported through spring elements. Even with such a design of the invention tolerance compensation is produced through the pliability which is achieved. Running defects of the window lifter are lower and the system has an overall easy action. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The invention will now be explained in further detail with reference to an embodiment illustrated in the drawings.  
       FIG. 1  shows a view of the follower;  
       FIG. 2  shows a perspective view of the slide block;  
       FIG. 3  shows a section through the follower and slide block;  
       FIG. 4  shows a section on an enlarged scale through the slide block;  
       FIG. 5  shows a plan view of the slide block and  
       FIG. 6  shows a window lifter having three guideways. 
    
    
     DETAILED DESCRIPTION  
       FIG. 1  shows a follower in a view towards the guideway (Z-direction). The follower consists of an upper and lower slide element  1 ,  2  which interact with the upper and lower side of a guide plate  3  which is made from a stamped sheet metal plate. In the region of the guideway two guide webs  4 , 5  are shaped round perpendicular to the guide plate  3  (through a stamping process) and thus produce a guide channel with two opposite parallel flanks.  
      Between the slide elements  1 ,  2  which are made from a slidable plastics or are coated with a slideable plastics is inserted a slide block  6  which is in play-free contact by its two outer sides forming its slide faces  7 ,  8  with the flanks of the guide webs  4 ,  5 . The two slide elements  1 ,  2  as well as the slide block  6  are connected to a bolt  9  and a plate spring  11 . The two slide elements  1 ,  2  can compensate for any irregularities/thickness tolerances in the guide plate  3  through the plate spring  11 . At one end of the bolt  9  is a fixed retaining rail  10  which supports a window pane (not shown).  
       FIG. 3  shows in a sectional view the follower according to the invention next to the slide block  6 . The bolt  9  engages through the two slide elements  1 ,  2  which are designed as moulded parts, as well as through the slide block  6 . The elastic coupling between the upper and lower slide element  1 ,  2  is produced through the plate spring  11 .  
       FIG. 4  shows in an enlarged sectional view the slide block  6  according to  FIG. 3 . The through opening for the bolt is shaped tapering conically from its two sides and surrounds the bolt  9  in the region of the smallest diameter without play—thus allowing the bolt  9  to tilt relative to the slide block  6 . The bolt  8  is thus mounted movable within a maximum angle about a point in the centre of the through opening (of the slide block  6 ).  
      The slide faces  7 ,  8  of the slide block which interact with the guide webs  4 ,  5  which are not shown in  FIGS. 4 and 5  are designed elastically pliable. According to this embodiment this is achieved in that the region of the slide block  6  lying underneath the slide faces  7 ,  8  is filled with an elastically pliable material—soft region  13 ,  14 . The slide block  6  itself consists of a hard plastics material with good sliding properties—hard region  12 .  FIG. 5  shows the slide block  6  in a view from above— FIG. 2  in a perspective view.  
       FIG. 6  shows a path-controlled window lifter which is known per se. This consists of a guide plate  3  in which three guideways  15 ,  16 ,  17  are stamped. A follower  18 ,  19 ,  20  constructed in principle as described above runs in each of these guideways  15 ,  16 ,  17 . These followers are of identical construction whereby only one of the followers  18 ,  19 ,  20  has the elastic slide block  6 —the other followers  18 ,  19 ,  20  are fitted with a non-flexible slide block of hard sliding material. The centre follower  19  can be driven by an electric motor  22  through a cable pulley system  21 . The two other followers  18 ,  20  are moved along through the retaining rail which is not shown.