Abstract:
A wiper blade ( 10 ) is proposed, which serves to clean vehicle windows. The wiper blade has an elongated, striplike spring-elastic support element ( 12 ), against one band face ( 48 ) of which, facing away from the window, a connection device ( 16 ) that can be connected to a driven wiper arm ( 18 ) is held, and against whose other band face ( 46 ), facing toward the window, an elongated, rubber-elastic wiper strip ( 14 ) is disposed parallel to the longitudinal axis, wherein the multi-part support element ( 12 ) has two spring rails ( 30, 32 ), disposed in longitudinal grooves ( 38, 40 ) facing one another of the wiper strip ( 14 ), which rails are secured in the longitudinal grooves by at least one holder fitting over their longitudinal edges remote from one another. Simplified and thus economical assembly with improved wiping performance is assured if the holder ( 34  or  36 ) is divided in the longitudinal direction of the wiper blade ( 10 ) into holder parts ( 33, 35 ), and if further the holder parts ( 33, 35 ) are joined together.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a wiper blade for cleaning vehicle windows. 
     In wiper blades the support element is intended to assure the most uniform possible distribution of the wiper blade contact pressure, originating in the wiper arm, on the window over the entire field swept by the wiper blade. 
     By means of a suitable curvature of the unstressed support element—that is, when the wiper blade is not resting on the window—the ends of the wiper strip placed completely against the window while the wiper blade is in operation are stressed by the support element, which is then tensed toward the window even if the radii of curvature of spherically curved vehicle windows change for every wiper blade position. The curvature of the wiper blade must accordingly be somewhat greater than the greatest curvature measured in the wiping field of the window to be wiped. The support element thus replaces the complicated support bracket construction with two spring rails disposed in the wiper strip, of the kind employed in conventional wiper blades (German Published, Non-Examined Patent Application DE-OS 15 05 397). 
     In a known wiper blade of this type (German Patent 10 28 896), the two spring rails, designated as longitudinal springs and belonging to the support element, are secured by one-piece spring clamps in the longitudinal grooves, designated as slits, in the rubber wiper strip. The clamps must be thrust onto the longitudinal springs in the longitudinal direction of the wiper blade, embracing the outer edges of the springs with claws. A rib connecting the claws must be curved to suit the thickness of the spine of the wiper strip, which leads to unfavorable assembly conditions. A middle clamp, disposed in the region of the connection device, must in fact cross this device in an aperture, which entails considerable expense for assembly, since at least one of the two claws cannot be formed until after that. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention in a wiper blade a holder is divided in a longitudinal direction of the wiper blade into holder parts, and the holder parts are joined together. 
     In the wiper blade of the invention, it is possible for the finished holder parts to be brought to the wiper blade crosswise to the longitudinal length of the support element and thus also of the wiper blade and then joined together. This kind of assembly is especially economical, because it can be performed as needed by assembly robots. 
     To improve the wiping performance and quality, a plurality of holders are expediently distributed over the longitudinal length of the support element and spaced apart from one another. 
     With relatively short wiper blades, it can suffice for that purpose to dispose one holder on each end portion of the elongated support element. 
     If the connection device is provided with fastening means that engage the two spring rails; and the connection device is divided in the longitudinal direction of the support element; and the device parts are joined together in their final assembled position, then efficient assembly on the support element for the connection device is obtained as well. 
     The design of a wiper blade that is highly effective, even at high vehicle speeds, is especially advantageous if the region of the wiper strip located on the band face remote from the window is embodied as a wind deflector strip extending essentially away from the window, and each holder is assigned one recess in the wind deflector strip. 
     With regard to the structural height of the wiper blade, it may be favorable if the connection device is assigned a recess in the wind deflector strip. Along with simple assembly, reliable securing of the spring rails in the longitudinal grooves of the wiper strip is attained if the holder parts, in clamplike fashion, grip an exposed portion of the outer edges of the spring rails. 
     This embodiment is advantageous, with the same advantages, for the disposition of the connection device as well. Moreover, the installed connection device can contribute to seating the spring rails, as prescribed, in their middle portion in the longitudinal grooves. 
     An especially simple, stable and easily installed connection device is obtained if the connection device has two device parts, and each device part has a flangelike protrusion, extending into the longitudinal direction of the support element and standing upright on the window and extending away from it, on which protrusion connection means for the wiper arm are seated. 
     Further simplifications in assembly both for the holders and for the connection device are obtained if the holder parts and/or the connection devices can be interlocked with one another. 
    
    
     Further advantageous refinements and features of the invention are disclosed in the ensuing description of exemplary embodiments shown in the associated drawing. 
     BRIEF DESCRIPTION OF THE DRAWING 
     Shown in the drawing are: 
     FIG. 1, a side view of a wiper blade according to the invention; 
     FIG. 2, a perspective view of the wiper blade of FIG. 1, not to scale; 
     FIG. 3, a plan view on the wiper blade of FIG. 1; 
     FIG. 4, a fragmentary section taken along the line IV—IV through the support element, provided with a connection device, of the wiper blade of FIG. 3; 
     FIG. 5, a section taken along the line V—V through the arrangement of FIG. 4; 
     FIG. 6, a fragmentary section taken along the line VI—VI through the support element of the wiper blade of FIG. 3; 
     FIG. 7, a section taken along the line VII—VII through the support element of FIG. 3, rotated by 90°; 
     FIG. 8, a fragmentary section taken along the line VIII—VIII through the support element of the wiper blade of FIG. 3; 
     FIG. 9, a section taken along the line IX—IX through the support element of FIG. 3, rotated by 90°; 
     FIG. 10, a section through FIG. 5 through a wiper blade equipped with a different connection device, with the parts of the wiper blade and the connection device shown in the position prior to assembly; 
     FIG. 11, an arrangement according to FIG. 10 for a differently embodied wiper blade, with the parts of the wiper blade and connection device shown in their operating position; 
     FIG. 12, a section as in FIG. 9 through a wiper blade in the region of a holder for the spring rails, the two parts of which are interlocked with one another, on a larger scale; and 
     FIG. 13, a plan view on a support element of the wiper blade of FIG.  2 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A wiper blade  10  shown in FIGS. 1-3 has a multipart, elongated, spring-elastic support element  12 , which is shown separately in FIG.  13 . On the top side of the support element, facing away from the window to be wiped, a connection device  16  is provided, with the aid of which the wiper blade  10  can be separably joined to a driven wiper arm  18  guided in the body of a motor vehicle. On the underside of the support element  12 , facing toward the window, an elongated, rubber-elastic wiper strip  14  is disposed, parallel to the longitudinal axis. On the free end  20  of the wiper arm  18 , a hook acting as a counterpart connection means is formed on; it grips a pivot pin  22  that belongs to the connection device  16  of the wiper blade  10 . Securing between the wiper arm  18  and the wiper blade  10  is performed by securing means, not shown in further detail but known per se and embodied as an adapter. The wiper arm  18  and thus also the hook on the end  20  of the arm is urged in the direction of the arrow  24  toward the window to be wiped, whose surface to be wiped is suggested in FIG. 1 by a dot-dashed line  26 . Since the dot-dashed line  26  is intended to represent the greatest curvature of the window surface, it is clear that the curvature of the wiper blade  10 , which contacts the window with its two ends, is greater than the maximum curvature of the window. Under the contact pressure (arrow  24 ), the wiper blade presses with its wiper lip  28  over its entire length against the window surface  26 . In the process, a tension builds up in the striplike spring-elastic support element  12 , and this tension assures proper contact of the wiper strip  14  or wiper lip  28 , over its entire length, with the motor vehicle window. 
     The particular design of the wiper blade of the invention will now be described in further detail. In FIG. 13, the support element  12  is shown separately. It is clear from this that the support element  12  has two spring rails  30  and  32 , which are spaced apart from one another. Besides the two spring rails  30  and  32 , the support element  12  in the embodiment of FIGS. 1-3 and  13  also includes holders  34  and  36 , whose purpose will be explained later. It is also suggested in FIG. 13 that the connection device  16 , shown in dot-dashed lines there, is seated in the middle region of the support element  12 . The disposition and fastening of the connection device  16  to the support element  12 , or to its spring rails  30  and  32 , can best be seen from FIGS. 4 and 6. FIG. 12 in particular shows the disposition of the support element parts (spring rails  30  and  32 ) with respect to the wiper strip  14 . In conjunction with FIGS. 2 and 3, it can be seen that the spring rails  30  and  32  rest in two opposed longitudinal grooves  38  and  40  of the wiper strip  14 , which are located in the same plane and between which a longitudinal slit  42  remains in the support element  12  (FIG.  13 ). Extending through this longitudinal slit  42  is a riblike constriction  44  of the wiper strip  14 . It can also be seen from FIGS. 12 and 13 that the support element  12  has two band faces, of which one band face  46  faces toward the window to be wiped, while the other band face  48  points away from window. It can also be seen that at least in some portions, the two spring rails  30  and  32  protrude out of the longitudinal grooves  38 ,  40  of the wiper strip  14  with their longitudinal edges  50  and  52  pointing away from one another. To secure the two spring rails  30  and  32  in their longitudinal grooves  38  and  40 , two holders are used in this exemplary embodiment, of which one is located on each end portion of the spring rails  30  and  32 . The two holders  38 ,  40  are thus spaced apart. The holders themselves extend crosswise to the longitudinal length of the wiper blade  10  and grip the outer longitudinal edges  50  and  52 , which are remote from one another, of the two spring rails  30  and  32  with clawlike protrusions  54 . It can also be seen that the holders  34  and  36  are divided longitudinally of the wiper blade  10 , which is suggested in FIGS. 2,  3  and  13  by a longitudinal seam  50 . In actual practice, however, this longitudinal seam  56  will not necessarily be embodied as shown in FIGS. 2,  3  and  13 . In order for the holders to perform their securing function with regard to the spring rails  30  and  32 , the holder parts  33  and  35 , formed by the parting seam  56 , must be firmly joined together after assembly. This can be done for instance by welding, adhesive bonding, or some similar production or assembly technique, regardless of whether the holders are made from a plastic or from metal. 
     One of a plurality of suitable ways in practice to join the two holder parts  33  and  35  to one another will now be explained in conjunction with FIG.  12 . It can be seen there that the holder parts  33  and  35  of the holder  36  are seated with clawlike protrusions  54  on their spring rails  30  and  32 , respectively. Their placement is made such that the protrusions  54  grip the outer edges  50 ,  52  of the spring rails in an exposed portion of the spring rails  30 ,  32 . The holder part  33  grips the wiper strip  14  with a protrusion  58  oriented crosswise to the longitudinal length of the wiper blade. A U-shaped extension  60  of the holder part  35  in turn fits over the protrusion  58  of the holder part  33 . The free end portion of the U-shaped extension  60  located on the side of the holder part  33  fits with its suitably embodied leg  62  of the U under an undercut  64  of the holder part  33 , so that an unintended separation of the holder parts  33  and  35  from one another is not possible. To mount the two holder parts, that is, to put them in the designated operating position, they must be pressed against one another in the direction of the two arrows  65  and  66 , which can be done by utilizing the elasticity of the wiper strip  14 . Once the interlocking has been effected in accordance with FIG. 12, the two holder parts  33  and  35  are seated with a residual tension of the wiper strip  14  in their prescribed position as shown in FIG.  12 . The holders may for instance be embodied according to FIG. 5, where with a caplike end wall  68  they cover the end edges of the spring rails  30  and  32 . As a result, a lessening in the risk of injury from the sharp end edges of the spring rails  30 ,  32  is achieved. Moreover, by means of these caplike end holders  34 , the risk of damage to the vehicle paint or to the wiper blade itself can be reduced. However, it is also possible to embody the holders as shown in FIG. 8, where this end wall is missing and the holder  36  is flush with the end edges of the spring rails  30 ,  32 . The connection device  16  has a design similar to the holders  34  and  36 . As FIG. 2,  3  and  5  show, the connection device is also divided in the longitudinal direction of the wiper blade. This is represented by a seam line  72 . This seam line  72  extends through both a plate part  74  (FIG.  5 ), which contacts the support element  12  and grips the spring rails  30  and  32  with its claws  70 , and the pivot pin  22 . The claws  70  thus form fastening means for retaining the connection device  16  on the support element  12 . In an embodiment of the connection device shown in FIGS. 2-5, this device has flangelike walls  75 , which are disposed on the plate part  74  and are spaced apart from one another and on each of which half of the also divided pivot pin  22  is disposed. The flangelike walls  75  belong to two device or base parts  73 , which can be joined together along the seam line  72  and of which each has a flangelike protrusion (wall  75 ), extending longitudinally of the support element and standing upright from the window and extending away from it, on which protrusion the connection means for the wiper arm  18 , which are formed by the pivot pin  22 , are seated. The two parts  73  of the connection device  16 , with their claws  70 , grip an exposed middle portion of the outer edges of the spring rails in clamplike fashion. Just as has already been explained for the holders  34  and  36 , the two device parts  73  of the connection device  16  can be joined together by means not shown in further detail. Interlocking of the two device parts with one another is just as conceivable as welding or adhesive bonding, for instance. 
     Another design of a connection device  116  can be seen from FIG.  10 . There, flangelike protrusions  175  are again provided on the two base parts  174 , extending longitudinally of the support element and standing relative to the window and extending away from it, but these protrusions can be joined together in direct contact with one another. In addition, in this embodiment as well, the base parts  174  grip the outer longitudinal edges of the spring rails  30  and  32  with clawlike protrusions  154 , as has already been described for the preceding exemplary embodiment of the connection device  16 . The fastening of these two base parts  174  can be achieved by a screw connection. To that end, the two protrusions  175  each have a bore  176 , and in the installed state of the connection device  116  these bores are aligned with one another. A screw  177  passes through the protrusions  175  through the bores  176  and cooperates with a nut part  178  of a pivot pin  180 , on which in a manner known per se the suitably designed free end of a wiper arm can be connected. However, it is also conceivable—in a manner known per se—to join the pivot pin fixedly to the wiper arm and to secure the pin receptacle, belonging to it, to the protrusions  175 . Then at the same time a fixed connection of the two base parts  174  can be realized. 
     A further embodiment, highly similar to the embodiment of FIG. 10, is shown in FIG.  11 . The essential difference from the embodiment of FIG. 10 is that the two spring rails  230  and  232  are of unequal width. A corresponding embodiment therefore also has the clawlike protrusions  254  of this further connection device  217 . 
     A special feature of the wiper blade of the invention will now also be explained in conjunction with FIGS. 1-3 and  11 . As can be seen from these drawings, the wiper strip  14 , on the band face  48  of the support element  12  remote from the window, has an extension, which is embodied as a wind deflector strip  200  extending essentially away from the window. So that in a wiper blade embodied in this way it is possible to place the holders  34 ,  36  and also the connection device  16  appropriately, recesses are assigned to these parts in the wind deflector strip  200 . 
     A common feature of all the exemplary embodiments of the holders  34 ,  36  is that in a wiper blade of this type the holders are divided longitudinally of the wiper blade, and that the holder parts  33 ,  35  are joined to one another. 
     A corresponding embodiment is also provided for the various connection devices  16 ,  116  and  216  described.