Patent Publication Number: US-9421948-B2

Title: Wiper blade

Description:
BACKGROUND OF THE INVENTION 
     The invention is based on a wiper blade. 
     DE 85 15 052 U1 discloses a wiper blade of the type in question. The supporting bracket system has a main bracket as the superordinate bracket, which is connected in an articulated manner to an intermediate bracket as the subordinate bracket. On the other hand, the intermediate bracket likewise serves as a superordinate bracket with respect to a claw bracket which is connected in an articulated manner to the intermediate bracket and constitutes a subordinate bracket thereto. In this case, the superordinate bracket and the subordinate bracket are manufactured from sheet metal. They are connected to each other in an articulated manner by a plastic connecting piece. For this purpose, the side walls of the connecting piece have spring tongues, the outer sides of which have projecting sections with which said spring tongues latch in openings in the side walls of the superordinate bracket during installation. Bearing pins are arranged on the insides, lying opposite the projecting sections, said bearing pins latching into openings in the side walls of the subordinate bracket during the installation of the subordinate bracket. To simplify the installation, the bearing pins have installation slopes toward the open side of the U-shaped cross sectional profile. The connecting piece furthermore has, lying on the inside and integrally formed on its top wall, a curved bead which serves as a rolling bearing for the subordinate bracket, and on which the latter is supported. Via the rolling bearing, the main contact pressure forces of the wiper blade are transmitted by the wiper arm to the wiper strip while the bearing pins absorb the smaller forces in the opposite direction. The diversity of components results in high production costs. Furthermore, the openings in the side walls of the superordinate profile interfere with the visual impression of the wiper blade. 
     Furthermore, EP 0 578 563 B1 discloses a wiper blade with a supporting bracket system which has, as the superordinate bracket, a main bracket, the ends of which are each connected in an articulated manner to a claw bracket as the subordinate bracket. The main bracket and the claw brackets are produced from plastic by compression molding. At the ends, the main bracket has projecting spring tongues with bearing bores, the spring tongues engaging in a cavity of the claw bracket. During the installation, corresponding bearing pins of the claw bracket latch into the bearing bores. The bearing pins are arranged on the inside of a cutout of the claw bracket and have installation slopes in order to simplify the installation. For lateral guidance of the claw brackets, transverse webs which run transversely with respect to the longitudinal direction of the main bracket are provided on both sides of the bearing bores. In addition, a pin is arranged in the longitudinal direction in a manner offset with respect to the center of the main bracket, the pin engaging in a cavity of the claw bracket and serving for additional guidance in particular transversely with respect to the longitudinal direction of the main bracket. 
     SUMMARY OF THE INVENTION 
     According to the invention, the pair of brackets which is interconnected in an articulated manner in this way is manufactured from plastic by injection molding, with the pivots being integrally cast on the insides of the side walls of the superordinate bracket. The design according to the invention means that no annoying functional elements, for example cutouts for bearing openings or clip connections, are visible on the outsides in the region of the joints. Furthermore, the diversity of components and the manufacturing costs are reduced. At the same time, a stable joint which can transmit large contact pressure forces via a bearing bridge designed as a rolling bearing is produced. 
     To simplify the manufacturing, the subordinate bracket has a demolding cutout joining the clip cutout toward the open side of the U-shaped cross sectional profile of the superordinate bracket. This results overall in an elongated cutout which is closed on one side in the region of the clip cutout while it is open on the opposite side. For the lateral guidance of the subordinate bracket, the clip cutout and the demolding cutout are bordered by guide surfaces which can also be part of guide ribs and are supported on the inner surfaces of the side walls of the superordinate bracket. 
     To improve the lateral guidance of the subordinate bracket, it may furthermore be expedient for the superordinate bracket to have an additional bearing, for example in the form of a pin or a rib, which is integrally formed on the inside of its top wall. The additional bearing engages in a depression in the subordinate bracket, as a result of which the latter is guided precisely in particular transversely with respect to the longitudinal direction of the wiper blade. For better demolding of the superordinate bracket from the injection mold, demolding holes are provided in the region of its pivots in its top wall. 
     To facilitate the installation, it is expedient for the edges of the subordinate bracket, which edges face the top wall of the superordinate bracket, to have installation slopes. It accordingly holds true for the pivots of the superordinate brackets that they likewise have installation slopes toward the open side of the U-shaped cross sectional profile. 
     In order to optimize the dimensional stability of the entire wiper blade with little material being used, it may be advantageous, in the case of a wiper blade with a main bracket, two intermediate brackets and two claw brackets, to manufacture the main bracket from sheet metal while the intermediate brackets and the claw brackets are manufactured from plastic by injection molding. 
     The articulated connection according to the invention of the brackets of a supporting bracket system to one another can also be used for the articulated connection between the wiper blade and a wiper arm to which the wiper blade is connected in an articulated manner. For this purpose, the wiper blade has a cross sectional profile of a subordinate bracket in the region of the mounting box, and, at its associated end, the associated wiper arm has the matching cross sectional profile of a superordinate bracket. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages emerge from the description below of the drawing. The drawing illustrates exemplary embodiments of the invention. The drawing, the description and the claims contain numerous features in combination. A person skilled in the art will expediently also consider the features individually and put them together to form meaningful further combinations. 
       In the drawing: 
         FIG. 1  shows a perspective view of a wiper blade, 
         FIG. 2  shows a perspective view of an intermediate bracket with a claw bracket, 
         FIG. 3  shows a perspective view of an intermediate bracket, 
         FIG. 4  to  FIG. 5  show perspective views of a claw bracket, 
         FIG. 6  shows a cross section corresponding to the line VI-VI in  FIG. 2 , and 
         FIG. 7  to  FIG. 9  show variants to  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION 
     A wiper blade  10  comprises a main bracket  12 , two intermediate brackets  24  and two claw brackets  28 . The intermediate brackets  24  act as subordinate brackets in relation to the main bracket  12  while they should be regarded as superordinate brackets in relation to the claw brackets  28 . Accordingly, the main bracket  12  is a superordinate bracket to the intermediate brackets  24  while the claw brackets  28  constitute subordinate brackets to the intermediate brackets  24 . Joints  20  connect the main bracket  12  in an articulated manner to the intermediate brackets  24  while joints  26  connect the intermediate brackets  24  in an articulated manner to the claw brackets  28 . 
     In the embodiment according to  FIG. 1 , the main bracket  12  is manufactured from sheet metal while the intermediate brackets  24  and the claw brackets  28  are plastic parts. In this case, the joints  20  and  26  differ. The joint  20  is formed by bearing openings  22  in the side walls  18  of the main bracket  12  and by pivots  38  which latch into the bearing openings  22  during the installation. To facilitate the installation, the pivots  38  have installation slopes  40  in the installation direction. A mounting box  14 , in the side walls of which eyelets  16  for a bearing pin (not illustrated) are arranged, is provided in the central region of the main bracket  12 . 
     In principle, the main bracket  12  can also be produced from plastic by injection molding. In this case, the joint  20  is designed in the same manner as the joint  26 . 
     In the region of the pivot  38 , the intermediate bracket  24  is designed as a bearing bridge  34  with bearing ribs  36  running in the longitudinal direction. Adjoining the bearing bridge  34  toward the end wall  32 , a stop surface  42 , which is formed by a border, limits the pivoting movement of the intermediate bracket  24 . The bearing ribs  36  form a rolling bearing and are supported under load on a top wall of the main bracket  12  while the forces in the opposite direction are absorbed by the pivots  38 . For the transverse guidance of the intermediate bracket  24 , guide surfaces  46  which may be part of guide ribs are arranged to the side of the bearing pins  38 . 
     The end walls  32  of the intermediate brackets  24 , which end walls face the inner and outer ends of the wiper blade  10 , are closed and fix a wiper strip  68  in the longitudinal direction. The intermediate brackets  24  have, offset inward with respect to the end walls  32 , claws  30  with which they hold the wiper strips  60  transversely with respect to the longitudinal direction. In addition, the wiper strip  68  is held on the claw brackets  28  by claws  30 . 
     At the ends of the intermediate brackets  24  opposite the end walls  32 , said intermediate brackets have a cross sectionally U-shaped cross sectional profile which is formed by side walls  44  and a top wall  58 . The joint  26  is located within said U-shaped profile. It is firstly formed by pivots  50  which latch into clip cutouts  54  of the side surfaces of the claw bracket  28  and secondly by a bearing bridge  66  which is designed as a rolling bearing and is supported on the inside of the top wall  58  of the intermediate bracket  24 . The bearing play at the pivots  50  is dimensioned in such a manner that, under the contact pressure force exerted by a wiper arm, the forces are transmitted via the bearing bridge  66  while the claw bracket  28  is supported in the opposite direction on the pivots  50 . 
     The pivots  50  are integrally formed on the insides of the side walls  44  of the intermediate bracket  24  such that the visible surfaces  52  on the outer sides of the side walls can be formed smoothly and free from functional features. For better demolding of the claw brackets  28 , they have demolding cutouts  56  as an extension of the clip cutouts  54  toward the open side of the U-shaped cross sectional profile. For the same purpose, demolding holes  48 , which are provided in the region of the pivots  50  in the top wall  58 , are used for better demolding of the intermediate bracket  24 . In the direct vicinity of the clip cutouts  54  and the demolding cutouts  56  there are guide surfaces  64  which can be part of guide ribs and serve for guiding the claw bracket  28 . 
     In the embodiment according to  FIG. 6 , the intermediate bracket  28  has an additional bearing  60  which is integrally formed on the top wall  58  and engages in a depression  62  in the claw bracket  28 . The additional bearing  60 , which can be designed as a pin or as a rib, guides the claw bracket  28  in particular transversely with respect to the longitudinal direction of the wiper blade  10 . In the embodiment according to  FIG. 7 , the demolding holes  48  have been omitted. This is possible inter alia if the additional bearing  60  is offset with respect to the pivots  50  in the longitudinal direction of the intermediate bracket. 
     The additional bearing  60  has been omitted in the embodiment according to  FIG. 8 , and the demolding cutouts  56  have been omitted in the embodiment according to  FIG. 9 . These measures simplify the construction of the joint  26 , and smaller manufacturing tolerances have to be taken into consideration.