Abstract:
The invention is based on a wiper blade ( 12 ) with an elongate, spring-elastic carrying element ( 36 ) which is precurved in a concave fashion with respect to a vehicle window ( 22 ) and has two spring rails ( 52, 66 ) which run parallel to one another in a plane, and having a wiper strip ( 24 ) which is held with a web ( 34 ) of its head strip ( 30 ) between the spring rails ( 52, 66 ) via the carrier element ( 36 ), said spring rails ( 52, 66 ) being inserted in longitudinal grooves ( 32 ) on both sides of the web ( 34 ), wherein the wiper strip ( 24 ) is secured in the longitudinal direction ( 20 ) relative to the carrier element ( 36 ) at least close to one of the ends of said wiper strip ( 24 ). It is proposed that the spring rails ( 52, 66 ) have, at the longitudinal sides facing one another in their end regions, clips ( 60, 74 ) with cutters ( 62, 76 ) which, in the mounted state, cut into adjoining walls of the longitudinal grooves ( 32 ).

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The invention is based on a wiper blade. 
         [0002]    A wiper blade with an elongate, spring-elastic carrying element which is pre-curved in a concave fashion with respect to a vehicle window is known from the Word Intellectual Property Organization patent WO 2008/020003, said wiper blade having two spring rails and a wiper strip which is received by the carrying element in a manner allowing it to be exchanged. The wiper strip is fixedly connected at one of the ends thereof to a thickened portion, by means of which the wiper strip can be fixed relative to the carrier element. This results from the fact that the thickened portion can be placed in position against an end face of the spring rail or a bridge, which connects the two spring rails to one another. In this position, the wiper strip is fixed relative to the carrying element by means of an end cap. Said end cap can overlap the thickened portion and the bridge and fix them in position by means of detachable latching means. In the case of disassembly of the wiper strip of the wiper blade, the latching means are detached; thus enabling the wiper strip to be pulled out of the carrying element after removal of the end cap. 
         [0003]    The German patent publication DE 10 2004 051 467 A1 discloses a wiper blade of the type in question. The carrying element of said wiper blade comprises two spring rails which run parallel to each other and are connected to each other at their ends by a bridge element. In order to receive a wiper strip, the spring rails form a longitudinal gap, and therefore the wiper strip can be threaded in the longitudinal direction onto the carrying element. Said wiper strip is secured in the longitudinal direction relative to the carrying element by end caps. The latter have an element with a spike which is pressed at the end of installation into a top strip of said wiper strip. In the fitted state, the spike bears against the bridge end face which faces away from the end of the wiper strip. In one exemplary embodiment, the spike is located on a spring tongue which is pressed against the head strip by a flap with an eccentric. The pivot axis of the tongue runs transversely with respect to the longitudinal direction of the wiper blade. In another embodiment, the spike is arranged directly on the flap, with the pivot axis of the flap being provided in the vicinity of the outer end face of the end cap. 
         [0004]    The German patent publication DE 100 25 710 A1 discloses a wiper blade of flat beam construction, which has a rubber elastic wiper strip with a wiping lip. Lateral longitudinal grooves are provided between the wiping lip and a head strip, two spring rails that are pre-curved in a concave fashion with respect to the wiping lip being inserted in said grooves as a carrying element. Said two spring rails are held together by bridge elements on the ends thereof and by a center connecting element. The bridge elements comprise an integrally formed extension as a fixing means, which has on the free end thereof at least one projection directed towards the head strip. During installation, the extension is bent against the head strip so that the projection engages in said head strip and the spring rails are fixed relative to the wiper strip in the longitudinal direction. Finally, the bridge elements are covered with end caps. 
         [0005]    The German patent publication DE 102 45 693 A1 discloses a wiper blade, which has, as carrying element, two spring rails which run in parallel and are connected to each other at their ends by a respective transverse clip. Furthermore, retaining means which fix the wiper strip relative to the spring rails are provided. In order to remove the wiper strip, the retaining means can be easily detached. They are connected on one side to the transverse clip and on the other side via a cohesive material joint, a frictional connection and/or via a form-fitting connection to the wiper strip. In one embodiment, a gudgeon reaches through a guide bore of the transverse clip into the wiper strip and is held in the assembly position by an end cap which latches on the transverse clip by means of a spring element. The spring element can be released by an externally operable element, and therefore the end cap and the gudgeon can be released in order to change the wiper strip. In the fitted state, the end cap is supported by a closed end face, which faces the end of the wiper blade, on the associated end face of the transverse clip. A different exemplary embodiment shows a retaining unit which is manufactured from sheet metal and is pressed into the wiper strip by means of a gudgeon bent toward the wiper strip. During the assembly of the spring rails, the retaining unit is pushed under the transverse clip and is latched on said transverse clip between stop surfaces and a spring tongue. After removal of the end cap, the spring tongue can be pressed into a release position and thus the spring rails can be removed. 
       SUMMARY OF THE INVENTION 
       [0006]    According to the invention, the spring rails have clips with cutters at the longitudinal sides facing one another in their end regions. In the mounted state, the cutters cut into the adjoining walls of the longitudinal grooves. By means of the clips with cutters, the spring rails are directly fixed with respect to the wiper strip in the longitudinal direction without substantial effort. An advantageous embodiment results if the spring rails have recesses on the longitudinal sides in the end regions thereof. In the mounted state, the recesses lie opposite to one another and arms branch out from said recesses, which are directed outwardly at a flat angle with respect to the longitudinal direction, wherein the arms of the recesses with the inner longitudinal sides of the spring rails form the clips, which on the end face facing the recess are formed to a cutter. In the mounted state, the cutters are pressed into the web between the longitudinal grooves of the wiper strip. This can advantageously occur, e.g., by means of an end cap that is pushed onto the end of the spring rails and locks with the same. 
         [0007]    According to a further embodiment of the invention, the spring rails likewise have recesses, which lie opposite one another in the mounted state, on the longitudinal sides in the end regions thereof; however, in this case have notches, which form the clips, at least at one delimitation. Said notches are bent up with respect to the spring rails and have cutters on the projecting edges. If the spring rails are pushed laterally into the longitudinal grooves, the cutters catch in the flanks of the longitudinal grooves so that the spring rails are also in this case fixed relative to the wiper strip directly in the longitudinal direction. The longitudinal rails are advantageously held together, e.g., by the end cap. In principle, the clips including the cutters can be provided at both ends of the spring rail. It is normally however sufficient for them to be disposed only at one end and in fact advantageously on the outer end of the wiper blade so that the wiper strip is subjected to pressure by means of centrifugal force during operation. 
         [0008]    According to a further embodiment of the invention, a connecting piece comprising lateral guide profiles is guided on the spring rails and presses the same together. In the mounted state, spring tongues on the guide profiles thereby engage in recesses of the spring rails. In so doing, the cutters can engage in the web or respectively in the flanks of the longitudinal grooves of the wiper strip and hold said strip in position. The spring tongues are advantageously formed by notches from one of the limbs of the guide profiles and extend in each case up to the opposite limb. When disassembling the connecting piece, the spring tongues can be moved from the detent position into a release position by means of openings in the guide profiles. In the assembled position, the guide profiles rest in each case with a hook on the end faces of the spring rails. The hook is formed from an elongated, bent limb on the outer end of the guide profiles. 
         [0009]    In addition to the fixation resulting from the cutters on the clips of the spring rails, provision can be made for a second fixation. For this purpose, a window, into which a clip originating at a delimitation projects, is provided in a top wall, which connects the guide profiles to one another. A claw, which is bent in the direction toward the head strip, is located on the free end of the clip, said clip penetrating the head strip in the mounted state. In order to facilitate the assembly of the connecting piece, the limbs of the guide profiles are bent up towards the outside on the ends facing the spring rails. The connecting piece is advantageously manufactured as a sheet metal bending part. It can however also be manufactured from plastic in an injection molding process. 
         [0010]    This conversely applies to a connecting piece according to a further embodiment. The connecting piece is guided with lateral guide profiles on the spring rails and presses said rails together, wherein centering blocks on the guide profiles engage in the assembled position in recesses on the outer longitudinal sides of the spring rails. The centering blocks rest in the longitudinal direction on the delimitations of the recesses and are therefore secured in both directions relative to the spring rails. 
         [0011]    The guide profiles are connected to one another by a top wall, which has a longitudinal channel for the head strip of the wiper strip, wherein a window is provided in the top wall, in which a spring tongue originating at a delimitation projects. A wedge shaped piece is provided on the free end of said guide profiles, said wedge shaped piece being pressed by the end cap against the head strip in the mounted state. Assembly is also advantageously facilitated in this case if the inner edges on the end face of the guide profiles are in each case chamfered. 
       BACKGROUND OF THE INVENTION 
       [0012]    Further exemplary embodiments and advantages result from the following description of the drawings. Exemplary embodiments of the invention are depicted in the drawings. The drawings, the description and the claims contain numerous features in combination. The specialist in the field will also advantageously consider the features in isolation and integrate them into useful further combinations. 
     
    
     
         [0013]    In the drawings: 
           [0014]      FIG. 1  shows a perspective view of a wiper blade, 
           [0015]      FIG. 2  and  FIG. 3  show in an enlarged scale a top view of the ends of two spring rails which are disposed in a plane parallel to one another and in mirror symmetry, 
           [0016]      FIG. 4  shows a perspective depiction of an end of a wiper blade having a detachable connecting piece for the spring rails during assembly, 
           [0017]      FIG. 5  shows the wiper blade pursuant to  FIG. 4  shortly before completion of the assembly, 
           [0018]      FIG. 6  and  FIG. 7  show a variant to  FIG. 4  and  FIG. 5 , 
           [0019]      FIG. 8  and  FIG. 9  show a further variant to  FIG. 4  and  FIG. 5 , 
           [0020]      FIG. 10  and  FIG. 11  show a wiper strip pursuant to  FIG. 4  and  FIG. 5 , 
           [0021]      FIG. 12  and  FIG. 13  show a further variant pursuant to  FIG. 4  and  FIG. 5 , 
           [0022]      FIG. 14  shows a variant comprising a bracket clip, 
           [0023]      FIG. 15  shows a variant comprising a connecting piece connected to the carrying element in a form-fit manner and 
           [0024]      FIG. 16  shows a variant to  FIG. 15 . 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    A wiper blade  12  comprises a spring-elastic carrying element  36  which is elongated in a ribbon like manner in the form of two spring rails  52 ,  66  which run parallel to and spaced apart from one another in a plane ( FIG. 1  and  FIG. 3 ). Said spring rails are inserted with their inner edge strips, which face each other, into longitudinal grooves  32  of a head strip  30  of a wiper strip  24  while their outer edge strips laterally protrude to some extent out of the longitudinal grooves  32 . A web  34  is located between said longitudinal grooves  32 . 
         [0026]    A wiper lip  26  attaches to the head strip  30  via a rocker web  28  in the direction of a vehicle window  22 , said wiper lip sliding over the vehicle window  22  during a wiping movement in the direction of a double arrow  18 . For this purpose, a wiper arm  10  drives the wiper blade  12  via a connecting device, the component  14  of which on the wiper blade side can be connected in an articulated and detachable manner to the wiper arm  10  whereas said component is fixedly seated in the central region of said wiper blade  12  on the carrying element  36  thereof. At the same time, said wiper arm  10  loads the wiper blade with a contact pressing force  16  in the direction of the vehicle window  22 . Said wiper arm  10  and said vehicle window  22  are indicated by dashed/dotted lines. During operation, the ends  40 ,  42  of the wiper blade  12  describe circular arcs during a pivot movement in the direction of the double arrow  18  about a wiper shaft that is not depicted, wherein the inner end  40  describes an inner circular arc and the outer end  42  an outer circular arc. 
         [0027]    The most pronounced curvature of the vehicle window  22  is less than the curvature of the unloaded wiper blade  12  ( FIG. 1 ) lying with both ends  40 ,  42  thereof on the vehicle window  22 . When subjected to contact pressing force  16 , the wiper blade  12  including the wiper lip  26  thereof is applied to the vehicle window  22  across the entire length thereof. In so doing, a stress develops in the spring-elastic carrying element  36  manufactured from metal or plastic. Said stress provides for a correct application of the wiper strip  24  or respectively the wiper lip  26  to the vehicle window  22  across the entire length of said wiper strip or said wiper lip as well as for an even distribution of the contact pressing force. 
         [0028]    Spoiler parts  38 , which are guided on the carrying element  36 , attach in the longitudinal direction  20  to both sides of the connecting element  14  on the wiper blade side. End caps  44  are provided on the ends  40 ,  42  of the wiper blade  12 , are guided on and lock to the carrying element  36  and cover the ends of the spoiler parts  38 . Said spoiler parts  38  have a flow profile  48 , whereas the flow profiles of the end caps are labeled with the reference number  50 . 
         [0029]    The spring rails  52  or  66  are preferably fixed only on one end, advantageously on the outer end  42  of the wiper blade  12 , relative to the wiper strip  24 . For this purpose, said spring rails  52  have recesses on the longitudinal sides in the end regions thereof, said longitudinal sides being opposite to one another in the mounted state. Arms  58 , which are outwardly directed at a flat angle with respect to the longitudinal direction  20 , branch off from these recesses. The arms  58  of the recesses  56  form wings  60  with the inner longitudinal sides of the spring rails  52 , said wings being formed into cutters  62  located on the end faces facing the recesses  56  and adjacent to the web  34  between the longitudinal grooves  32  of the wiper strip  24 . During assembly, the ends of the spring rails  52  are pressed against the web  34  and said web therefore penetrates to a certain extent into the recesses  56  and the cutters  62  catch in said web  34 . Said spring rails  52  are held together by suitable means, e.g. by the end cap  44 , which can lock with detent means, which are not specified in detail, in recesses  54  on the outer longitudinal sides of said spring rails  52 . The sections  64  of said spring rails  52  protruding in the longitudinal direction  20  beyond the recesses  56  or respectively beyond the arms  58  have a reduced width with respect to the central sections of said spring rails  52 . 
         [0030]    The spring rails  66  pursuant to  FIG. 3  are different from the spring rails  52  pursuant to  FIG. 2  in that the recesses lying opposite to one another have a notch  72  in the longitudinal direction on one end thereof, whereby lugs  74  are formed. The lugs  74  of the spring rails  66  are bent up towards a broadside of said spring rails  66 , the protruding edges being formed as cutters  76 . When mounting the spring rails  66  transversely to the longitudinal direction  20  of the wiper strip  24 , the cutters  76  penetrate into the adjoining groove flanks of the longitudinal grooves  32  and interlock with said groove flanks and therefore said spring rails  66  are fixed in the longitudinal direction  20  relative to the wiper strip  24 . Said spring rails are then held together by suitable means, e.g. by the end cap  44 , which lock in the outer recesses  68 . 
         [0031]    According to one embodiment pursuant to  FIG. 4  and  FIG. 5 , a connecting piece  78  holds the spring rails  52  together instead of the end cap  44  and therefore the spring rails are fixed in the longitudinal direction  20  relative to the wiper strip  24 . The connecting piece  78  has guide profiles  80  on the longitudinal sides thereof. Said guide profiles have a U-shaped cross-section which is open to the inside. Said guide profiles  80  are connected to each other by a top wall  82 , which has a longitudinal channel  84  in the central region for receiving the head strip  30 . During assembly, said connecting piece  78  is pushed from the end face onto the spring rails  52  until hooks  96 , which are integrally formed on the ends of the guide profiles  80 , bear against the end faces of said spring rails  52  ( FIG. 5 ). In this position, spring tongues  94  engage in the recesses  54  of said spring rails  52 . The spring tongues  94  are in each case notched from one of the limbs  98 ,  100  of the associated guide profile and bent toward the opposing limb  98 ,  100 . It is advantageous for the guide profile to have an opening  92  in the region of the spring tongue  94  so that the spring tongue  94  can again be detached by a tool. In order to facilitate assembly, the limbs  98 ,  100  are bent open a little bit upwards and downwards in opposite directions to each other so that the connecting piece  78  can easily be pushed over said spring rails  52 . The top wall  82  has a window  86 , into which a clip  88  projects, which has an angled claw  90  on the free end thereof. In the end position of the connecting piece  78 , the claw  90  is pressed into the head strip  30  of the wiper strip  24 . This fixation can additionally or alone secure the relative position of said wiper strip  24  with respect to said spring rails  52 . The connecting part  78  is advantageously manufactured from sheet metal. It can however also be manufactured from plastic. 
         [0032]    In the exemplary embodiment pursuant to  FIG. 6  and  FIG. 7 , a similar connecting piece  102  is provided, which is advantageously manufactured from plastic. It has guide profiles  104  on the longitudinal sides thereof, said guide profiles being connected to each other by a top wall  108 . A window  110  is provided in said top wall, wherein a spring tongue  112  from a delimitation of the window  110  projects into said window  110 . A wedge shaped piece  114 , which runs to the end  42  of the wiper blade  12  while being inclined toward the spring tongue  112 , is integrally formed on the free end of the spring tongue  112 . The connecting piece  102  has centering blocks  106  in the region of the guide profiles  104  thereof, said centering blocks fitting into the recesses  54  on the outer longitudinal sides of the spring rails  52 . During assembly, the connecting piece  102  is pushed frontally onto the spring rails  52 , wherein the guide profiles  104  laterally widen until the guide blocks  106  engage in the recesses  56 . If the end cap  44  is pushed onto the end of the wiper blade  12 , inner locking elements, which are not visible, press on the wedge shaped piece  114  and press the spring tongue  112  onto the head strip  30 , and therefore the carrying element  36  in the form of spring rails  5  is additionally or alone secured to the fixation described above relative to the wiper strip  24 . The connecting piece  102  is advantageously manufactured from plastic. 
         [0033]    In the embodiment pursuant to  FIG. 8  and  FIG. 9 , the spring rails  52  are braced together by a bracket  116 , which laterally encompasses said spring rails  52  with claws  118 , which rest against the delimitations in the longitudinal direction of the recesses  54 . In so doing, noses  122 , which are oriented in the longitudinal direction  20  and are integrally formed on the claws  118 , grip said spring rails  52  from below. Further claws  118  on the top side of the bracket  116  grip in the mounted state into the head strip  30  of the wiper strip  24  from above and therefore constitute a further fixation between the wiper strip  24  and said spring rails  52 . 
         [0034]    The exemplary embodiment pursuant to  FIG. 10  and  FIG. 11  distinguishes itself from the preceding exemplary embodiment by virtue of the fact that a brace  124  made of thin sheet metal is stretched over the head strip  30 , wherein the limbs  126  of the brace  124  are bent around the outer longitudinal sides of the spring rails  52 . During assembly, a gudgeon  128 , which is notched from the center part of the brace  127  and is bent towards the head strip  30 , penetrates said head strip  30 . 
         [0035]    The exemplary embodiment pursuant to  FIG. 12  and  FIG. 13  distinguishes itself from the exemplary embodiment pursuant to  FIG. 10  and  FIG. 11  by virtue of the fact that the spring rails  52  have apertures  130  between the recesses  54  thereof and the outer end  42 , through which the limbs  126  of the holding clip  124  are guided; and after passing through the apertures  130 , said limbs are preferably bent outwards. 
         [0036]    The exemplary embodiment according to  FIG. 14  shows a connecting piece in the form of a bracket clip  134 , the limbs  136  of which have a fir tree shaped profile  138  in the mounting direction. Said limbs  136  are inserted through the apertures  130  and secured in their position by means of the profile  138 . In the embodiments pursuant to  FIG. 15  and  FIG. 16 , the spring rails  52  are held together by connecting parts  140  or  148  by said spring rails being connected transversely with respect to the longitudinal direction  20  via a cohesive material joint that is subjected to a preload in the plane of the spring rails  52 . The connecting part  140  (Figure  15 ) is manufactured from thin sheet metal in the shape of a bridge and is preferably connected at the feet  144  thereof to said spring rails  52  by welding. In the mounted state, noses  146  press against the head strip  30  and therefore additionally secure the wiper strip  24  relative to said spring rails  52 . 
         [0037]    The connecting part  148  pursuant to  FIG. 16  is configured arrow-shaped and preferably has a thin wall thickness. It is pushed through the web  34  between the back of the head strip  30  and the top surfaces of the spring rails  52  and therefore secures the relative position of the wiper strip  24  with respect to said spring rails  52 .