Abstract:
A non-articulated wiper blade ( 10 ), which is constructed of a wiper strip ( 12 ) having a wiper lip ( 14 ), two spring rails ( 30, 32 ) and a connecting device ( 22 ), wherein the spring rails ( 30, 32 ) engage in lateral longitudinal grooves of the wiper strip ( 12 ) that are open towards the outside and are clasped by claw feet ( 28, 68, 76, 108 ) of a sheet metal claw ( 24, 64, 72, 106 ) of the connecting device ( 22 ) from an outer narrow side. The claw feet ( 28, 68, 76, 108 ) are bent around the narrow sides of the spring rails ( 30, 32 ) during the assembly of the sheet metal claws ( 24, 64, 72, 106 ), wherein at least one layer ( 70 ) and/or an intermediate layer ( 48, 84 ) of plastic are provided between the claw feet ( 28, 68, 76, 108 ) on the one hand and the spring rails ( 30, 32 ) on the other hand, which layers are manufactured separately from the wiper strip ( 12 ) and are adapted to the claw feet ( 28, 68, 76, 108 ) as well as have a high coefficient of friction on their surface towards the sheet metal claw ( 24, 64, 72, 106 ) and towards the spring rails ( 30, 32 ).

Description:
BACKGROUND OF THE INVENTION 
     The invention starts with a non-articulated wiper blade. 
     A non-articulated wiper blade is known from DE 101 13 680 A1 whose wiper strip is comprised of an elastomer material and has a spoiler situated on its upper side. This spoiler can be formed on directly and be comprised of the same material as the wiper strip or be a separate component made of another suitable plastic. The spoiler can serve as a supporting element of the wiper blade by itself or together with spring rails, which are inserted into lateral longitudinal grooves of the profile of the wiper strip. Mounted on the ends of the wiper blade are caps, whose guide surfaces run in the longitudinal direction of the wiper blade and are adjacent with a slight shoulder to the guide surface of the spoiler. Because of the guide surfaces of the spoiler and the end caps, the air steam increasingly presses the wiper blade against the vehicle window with increasing vehicle speed if the air stream is flowing towards the wiper blade essentially transverse to the longitudinal direction. 
     In the center region of the wiper blade in a section of the spoiler, a connecting device according to the so-called sidelock system is fastened to the supporting element, in which the wiper arm runs laterally parallel to the wiper blade in the region of the connecting device. It is also known as a so-called overlock system, in which the wiper arm runs above the wiper blade in the region of the connecting device. The connecting device has two claws on each of its side parts, which laterally clasp and hold the spring rails of the supporting element. 
     A non-articulated wiper blade is known from DE 198 35 065 A1, which has a wiper strip with a wiper lip and a top strip. The top strip is connected to the wiper lip in a usual manner via a rocker bridge, which is delimited by two lateral longitudinal grooves. The top strip has a central longitudinal channel, in which a supporting element is embedded in the form a flat, rectangular spring rail. A connecting element in the form of a sheet metal claw is fastened in the central region of the top strip as related to the longitudinal extension. It has a U-shaped profile with a base adjacent to the top strip and adjacent side walls extending towards the outside in the longitudinal direction of the wiper blade so that the U-shaped profile is open towards the side facing away from the wiper strip. The two side walls are connected to each other in their center region by a joint bolt, which serves to couple the wiper blade to a wiper arm according to the top-lock system. In the vicinity of the front sides of the sheet metal claws, two sheet metal tabs are notched out of each the side walls and these tabs are bent around the top strip and partially clasp the spring rails on the longitudinal sides. The claw feet formed by the tabs are pressed together so far perpendicularly against the wide sides of the spring rail until the sheet metal claw sits secure from displacement on the spring rail. In this case, it is advantageous if the intermediate layer between the sheet metal claw and the spring rail, which is formed in the exemplary embodiments by the top strip of the wiper strip, has a greater coefficient of friction than the sheet metal claw and the spring rail. 
     This applies in general to materials from which wiper strips are fabricated. The depicted embodiments show spring rails as supporting elements that are fabricated as one piece of a metal, however, they can also be comprised in principle of several individual parts. During the assembly of the sheet metal claws, difficulties are to be expected, however, in the positioning of the spring rails if two spring rails that run essentially parallel are provided. 
     In addition, a wiper blade with a supporting bracket system is known from DE 43 20 637 A1. A spring rail is provided in a central longitudinal channel. This rail has partial widenings in its end regions, which expand the longitudinal channel towards the outside in a wart-like manner so that the spring rail is secured in the longitudinal direction, particularly when a holding claw of a bow is situated between two wart-like elevations. 
     SUMMARY OF THE INVENTION 
     According to the invention, the claw feet are bent around the narrow sides of the spring rails during the assembly of the sheet metal claws. In the process, at least one layer and/or an intermediate layer of plastic are provided between the claw feet on the one hand and the spring rails on the other hand, which layers are manufactured separately from the wiper strip and are adapted to the claw feet as well as have a high coefficient of friction on their surface towards the sheet metal claw and towards the spring rails. Because of the measures in accordance with the invention, the sheet metal claw can also be mounted easily and without additional welding or adhesion even with wiper blades with two spring rails. In this case, the spring rails can be grasped by a device and held at a desired distance by a spacer device. Since the intermediate layer is manufactured separately from the wiper strip and allocated and adapted to the claw feet, it can easily be placed on the spring rails before the wiper strip is mounted. As a result, first the sheet metal claw of the connecting device can be fixed on the spring rails and then the wiper strip can be slid between the spring rails. 
     The plastic is selected in such a way that, on the one hand, it has the desired frictional behavior on its surface, and, on the other hand, has sufficient strength to withstand the high stresses in the region of the claw feet. In this case, the possibility exists for the base material of the intermediate layer to obtain the desired surface properties through a suitable surface treatment or coating. Furthermore, it is expedient that the claw feet press the layer or the intermediate layer together against the spring rails. This can be accomplished by the claw feet being pressed together perpendicular to the wide sides of the spring rails or by folding over a leg of the claw feet or by lateral compression. 
     The sheet metal claw can have a wide claw foot on each side of the wiper blade or two narrower claw feet, which are at a distance from one other in the longitudinal direction of the wiper blade and are arranged as a rule in the region of the front sides of the sheet metal claw. The length of the intermediate layers is expediently coordinated with the width of the claw feet. If several claw feet are provided on a longitudinal side of the wiper blade, an intermediate layer can also extend over two or more claw feet. 
     The intermediate layer is advantageously manufactured of an L-shaped, Z-shaped or U-shaped extruded profile, which is cut to the desired length. In a mounted state, the L-shaped or Z-shaped profile with a bent leg is adjacent to an inner longitudinal edge of the associated claw foot. The U-shaped extruded profile is shifted with its open side towards the spring rails between the legs of the claw feet. In another embodiment of the invention, the intermediate layer is formed by a coating of the claw feet at least on their inner surfaces. In this case, a plastic is used that has the same properties as those of the intermediate layer. 
     The sheet metal claw is expediently covered towards the outside by a plastic cap, whose outer contour is adapted to the contour of the adjacent spoilers, so that they are smoothly contiguous to the plastic cap optically and harmoniously in terms of flow technology. The joining gap between the spoiler and the plastic cap is bridged by a projection on the spoiler and the plastic cap, respectively, wherein the projections mutually overlap. In terms of function, it is unimportant which of the projections lies on the outer side of the profile. The sheet metal claw is cast in the plastic cap in an advantageous manner and supports itself with internal counter surfaces on the upper wide sides of the spring rails, in that the counter surfaces protrude a little towards the spring rails relative to the upper legs of the claw feet. In this way, the counter surfaces made of plastic replace a corresponding intermediate layer on this side. 
     As a rule, end caps are mounted and fixed on the ends of the spring rails. The parting line between the end cap and the spoiler is also bridged by a projection on the end cap and on the spoiler, respectively. As a result, it is possible to arrange the spoiler between the end cap and the plastic cap or the sheet metal claw so that it is axially displaceable on the spring rails so that the flexibility of the wiper blade is only negligibly affected in the critical regions by the spoiler. 
     Instead of the intermediate layers or in addition to the intermediate layers, the spring rails can be secured relative to the sheet metal claw in the longitudinal direction by protuberances, which lie between adjacent claw feet and overlap the inner contour of the claw feet upwardly, downwardly and/or laterally. In order to stabilize the claw feet against one another, they are expediently connected to one another via a bridge. This bridge is advantageously arranged on the inner side of the protuberances. 
     According to an embodiment of the invention, the protuberance has at least two elevations. It is possible as a result to shift the elevations near the claw feet without the individual elevation having to be relatively large. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Additional advantages are yielded 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 person skilled in the art will also observe individual features expediently and combine them into additional, meaningful combinations. 
       The drawings show: 
         FIG. 1A  perspective view of an assembled wiper blade from above, 
         FIG. 2  A perspective view of a partially mounted connecting device in accordance with  FIG. 1 . 
         FIG. 3  An enlarged scale of a connecting device in accordance with  FIG. 1 . 
         FIG. 4  A perspective view from below of a connecting device without a supporting element. 
         FIG. 5  A perspective view from below of a connecting device with a supporting element. 
         FIG. 6  A variation of a sheet metal claw according to  FIG. 2 . 
         FIG. 7  A variation of a sheet metal claw according to  FIG. 2 . 
         FIG. 8  A partial view of a sheet metal claw according to  FIG. 7  in the longitudinal direction, whose claw feet press the intermediate layer together perpendicular to the wide sides of the spring rails. 
         FIG. 9  A partial view of a sheet metal claw according to  FIG. 7  in the longitudinal direction, whose claw feet press the intermediate layer together by folding over a claw leg. 
         FIG. 10  A partial view of a sheet metal claw according to  FIG. 7  in the longitudinal direction, whose claw feet press the intermediate layer together via lateral compression. 
         FIG. 11  A perspective representation from below of an end cap. 
         FIG. 12  A perspective representation from above of an end cap in accordance with  FIG. 11 . 
         FIG. 13  A perspective view of an end of an assembled wiper blade. 
         FIG. 14  A perspective partial representation of a spring rail with a protuberance and a sheet metal claw 
         FIGS. 15 to 17  Variations of the embodiment in accordance with  FIG. 14 . 
     
    
    
     DETAILED DESCRIPTION 
     A non-articulated wiper blade  10  has essentially a wiper strip  12  with a wiper lip  14  and spoilers  16 , on which end caps  18  and  20  are attached towards the ends. A connecting device  22  is provided in the center region of the wiper blade  10 , through which the wiper blade  10  can be connected in an articulated manner to a wiper arm (not shown). The connecting device  22  has a sheet metal claw  24  ( FIG. 2 ) and a plastic cap  46  ( FIG. 3 ), which is clipped on the sheet metal claw  24  or on spring rails  30 ,  32 . The spring rails  30 ,  32  form a supporting element for the wiper blade  10 . They are preliminarily bent in such a way that in an unstressed state the wiper blade  10  has a considerably stronger curvature than a vehicle window for which it is intended. If the wiper blade  10  is pressed against the vehicle window by the wiper arm, a distribution of pressure that is suitable for the wiping process is produced over the length of the wiper blade  10 . 
     The sheet metal claw  24  is formed from a sheet metal strip, which is folded by 180 degrees in a center part  36 , wherein the fold runs in the longitudinal direction of the wiper blade  10  and the sheet metal walls abut one another in the area of the fold. The free ends of the sheet metal strip are bent to the outside, overlap the upper side of the spring rails  30  and  32  and form a free space  38  for a top strip  34  of the wiper strip  12 . 
     During assembly the parts of the sheet metal strip that project laterally over the spring rails  30 ,  32  are bent twice towards the wiper strip  12  so that claw feet  28 , each with a upper leg  40 , a side part  44  and a lower leg  42 , are formed. The lower leg  42  clasps the spring rails  30 ,  32  from below ( FIG. 5 ) and is pressed against the upper leg  40  so that the spring rails ( 30 ,  32 ) are clamped between the legs  40 ,  42 . 
     Applied between the claw feet  28  and the spring rails  30 ,  32  is an intermediate layer  48  made of a plastic ( FIG. 4 ) whose coefficient of friction vis-à-vis the spring rails  30 ,  32  is greater than that of the material of the sheet metal claw  24 . However, the plastic must also be suitable to absorb the very high stresses and surface pressures in the region of the claw feet  28 . The claw feet  28  can be dimensioned to be sufficiently large in the longitudinal direction, thereby enlarging the contact surfaces and therefore reducing the surface pressures. 
     During the folding over of the claw feet  28  and the pressing process approximately perpendicular to the wider surfaces of the spring rails  30 ,  32 , they are fixed vis-à-vis one another at a prescribed distance via a spacer device  58 . In doing so, the intermediate layer  48  is pressed together somewhat against the spring rails  30 ,  32 . An intermediate space  56  is formed between the spring rails  30 ,  32 , into which the wiper strip  12  will later be inserted, wherein the top strip  34  lies on the side of the spring rails  30 ,  32  facing the connecting device  22 . There is also the possibility of pressing the claw feet  28 ,  76  against the spring rails  30 ,  32  by folding over the lower leg  42  of said claw feet ( FIG. 9 ) or by lateral compression of the claw feet  76  ( FIG. 10 ). 
     In the embodiment according to  FIG. 4 , the sheet metal claw  24  is cast in the plastic cap  46 , but the sheet metal parts of the claw feet  28  remain free so that they can be bent in the course of subsequent assembly. The plastic cap  46  with the sheet metal claw  24  is mounted on the spring rails  30 ,  32  ( FIG. 5 ), wherein guide strips  60  of the plastic cap  46  grasp the spring rails  30 ,  32  from below. On the upper side of the spring rails  30 ,  32 , the plastic cap  46  supports itself via counter surfaces  50  on the spring rails  30 ,  32 . The counter surfaces  50  project somewhat relative to the upper leg  40  of the claw foot  28  so that on this side there is no metallic contact between the claw foot  28  and the spring rail  30 ,  32 . When bending the lower leg  42  of the claw foot  28 , an intermediate layer  48  of plastic is inserted between the lower leg  42  and the associated spring rail. Its length corresponds to the width of the claw foot  28 . It is cut expediently from an extruded profile with an L-shaped or Z-shaped cross-sectional profile. A leg of the extruded profile is adjacent to the inner edge of the claw foot  28  ( FIGS. 4 and 5 ). The sheet metal claw  24  is provided for the articulated connection to the wiper arm according to the so-called sidelock principle. As a result, it has a bearing bore hole  26 , which runs coaxial to a bearing opening  62  of the plastic cap  46 . 
     The sheet metal claw  64  with a bearing bore hole  66  has claw feet  68 , which are coated at least on their inner surfaces with a layer  70  of plastic. The plastic of the layer  70  has the same properties as the plastic of the intermediate layer  48 . It adheres firmly to the sheet metal parts so that the layer  70  does not detach when folding over the claw feet  68 . 
     The sheet metal claw  72  according to the embodiment in  FIG. 7  is embodied for connection to the wiper arm in accordance with the so-called overlock principle. As a result, it has a bearing pin  74  in its center part. Moreover, it differs from the sheet metal claw  24  by the fact that it has two claw feet  76  on each side of the wiper blade  10 . Allocated to said claw feet is an intermediate layer  84  of plastic, which extends between the outer front sides  78  of the claw feet  76 . It has a U-shaped extruded profile. The claw feet  76  are formed of sheet metal parts of the sheet metal claw  72 , in that they are bent around the outer longitudinal side of the spring rails  30 ,  32  and then pressed against one another in a pressing direction  90 . In doing so, the intermediate layer  84  or the layer  70  yields elastically a little. In order to facilitate the bending process and avoid fissures in the hollow channels, predetermined bending points  80  with a rounded out cross section are provided in the hollow channels of the claw foot  76 . Located between said predetermined bending points approximately in the center of the side part is another predetermined bending point  82 , via which controlled shaping of the claw foot  76  is guaranteed. 
     After assembly of the wiper strip  12 , the end caps  18 ,  20  are mounted and fastened on the ends of the spring rails  30 ,  32 , e.g., by gluing, clipping, welding or the like. For this purpose the spring rails  30 ,  32  have guide profiles  92 , into whose guide slot  94  the spring rails  30 ,  32  are inserted. A wedge-shaped projecting part  96  on the closed end of the end caps  18 ,  20  extends into the intermediate space  56  and presses the spring rails  30 ,  32  apart. The lateral guide profiles  92  can protrude vis-à-vis a front wall  98  towards the spoiler  16  and have a hole  100  in the projecting part transverse to the guide slot  94 . The hole  100  can be used to pin the end caps  18 ,  20  together with the spring rails  30 ,  32 . The end caps  18 ,  20  have the same outer profile as the spoilers towards the spoilers  16  so that like the plastic cap  46  they are smoothly contiguous to the spoiler  16 . 
     The joining gaps between the spoiler  16  and the plastic cap  46  are bridged by projections  52  on the spoilers and projections  54  on the plastic cap  46 , which mutually overlap. In this case, it is unimportant which of the projections  52 ,  54  is arranged towards the outside. Between the end caps  18 ,  20  and the spoilers  16 , the joining gap is also bridged in the same way by projections  102  on the end caps  18 ,  20  and projections  104  on the spoilers  16 . In this case, projections  104  on the spoilers  16  can cover the projecting parts of the guide profiles  92  with the holes  100  to the outside. The projections  102 ,  104  make an axial displacement of the spoilers  16  possible between the end caps  18 ,  20  on the one hand and the plastic cap  46  on the other. 
     The spring rails  30  according to the embodiments in  FIGS. 14 through 15  have protuberances  110 ,  112 ,  114  and  116 , which lie in the area of the outer longitudinal sides of the spring rails  30 ,  32  between two adjacent claw feet  108  of a sheet metal claw  106 . In this case, the embodiment according to  FIG. 14  shows a protuberance  110  upwards towards the center part of the sheet metal claw  106 . 
     The free legs of the claw feet  108  are connected to one another via a bridge  118  on the under side of the spring rail  30 . 
     The protuberance  112  according to  FIG. 15  extends towards the side and upwards, while the protuberance  114  according to  FIG. 16  only extends towards the side. The protuberance  116  has two elevations in the longitudinal direction so that the side surface of the spring rail  30  runs in an undulated way.