Abstract:
A wiper blade that cleans panes, in particular of motor vehicles. The wiper blade ( 10 ) comprises a strip-shaped, elongated, elastically resilient support element ( 12 ), the lower strip surface of which faces the pane ( 14 ) and is provided with an elongated, elastic wiper strip ( 24 ) running parallel to the longitudinal axis. The upper strip surface ( 16 ) of the element is provided with a wind deflector strip ( 42 ), which consists of an elastic material, extends in the longitudinal direction of the support element and has an oncoming stream surface ( 54 ) that faces the principal flow direction, (arrow  52 ), of the air stream. A particularly advantageous wiper blade, which is cost-effective to produce, can be achieved if the wind deflector strip, (when viewed in cross-section), comprises two limbs ( 48, 50 ), diverging from a common base ( 46 ) but mutually attached thereto, the free ends of said limbs facing the pane ( 14 ) and being supported on the wiper blade, and if in addition, the oncoming stream surface ( 54 ) is configured on the external face of one limb ( 50 ) and the cross-sectional profile of the wind deflector strip is the same over its entire length.

Description:
RELATED APPLICATION  
       [0001]     This application is a divisional of co-pending U.S. application Ser. No. 10/312,279, filed Jul. 29, 2003, the entire content of which is incorporated herein by reference. 
     
    
     BACKGROUND  
       [0002]     In wiper blades with a spring-action support element, the support element is intended to guarantee as even a distribution of wiper blade pressure onto the windshield issued from the wiper arm as possible, and over the entire wipe field swept by the wiper blade. By appropriately bending the un-loaded support element into shape—the unloaded state being when only the two ends of the wiper blade sit against the windshield—the ends of the wiper strip, which sits completely against the windshield when the wiper blade is in operation, are pushed toward the windshield by the loaded support element, even if the radii of curvature of spherically curved vehicle windshields change with the wiper blade position. The curvature of the wiper blade must therefore be somewhat greater than the maximum curvature measured within the wipe field on the windshield to be wiped. This is because during wiping, the wiper strip, or its wiping lip that sits against the windshield, must be continuously pressed against the windshield with a specific force. The support element thus replaces the expensive stirrup design with two flexible rails located in the wiper strip, as is practiced in conventional wiper blades (DE-OS 15 05 257) since the support element provides the necessary cross-stiffening of the elastic rubber wiper strip in addition to providing a distribution of pressure. Specifically, in the known wiper blade the contact force directed toward the windshield that is exerted by a wiper arm onto a main stirrup is conveyed to two claw-like stirrups and distributed from these onto the elastic rubber wiper strip via four claws. The two flexible rails of this wiper blade mainly provide a cross-stiffening of the wiper strip between the claws when the wiper blade is pushed across the windshield perpendicular to its longitudinal length.  
       SUMMARY OF THE INVENTION  
       [0003]     In a prior art wiper blade of this type (DE 197 36 368.7), the wiper blade is provided with a so-called wind deflection strip in order to produce a force component directed toward the windshield to counteract the tendency of the wiper blade to lift off of the windshield due to the airflow at high vehicle speeds. To this end, the wind deflection strip has a leading edge during the pendulum wiping motion that is mainly impacted by the driving wind, said leading edge being designed as an incident surface. The cross section of the wind deflection strip has approximately the shape of a right triangle, one leg of which directly opposite the support element and the hypotenuse of which represents the incident surface. This makes a sharp angle with the pendulum-like plane of motion of the wiper blade and with the surface of the windshield. The triangle profile used requires a relatively large amount of material to manufacture the wind deflection strip, which is reflected in the costs of the wiper blade. Moreover, the weight of the wiper blade becomes undesirably high. Specifically, the increased mass to be accelerated in the pendulum wiping motion requires a more powerful drive system as well as a more expensive design of pendulum gear attached to it. Furthermore, the action of the support element and of the wiper blade can be adversely affected by the bending stiffness, which depends on its profile, of a wind deflection strip thus formed.  
         [0004]     In the wiper blade according to the invention, the weight of the wind deflection strip is considerably reduced due to the cross sectional structure of an angular profile. Moreover, in addition to the material savings, there is a reduction in the moving mass along with the advantages with respect to the design of the drive system and the pendulum gear as a result. Also, the bending stiffness of the wind deflection strip is reduced, thus considerably reducing its influence on the bending and spring behavior of the wiper blade support element. For more detailed shapes, this wind deflection strip can be manufactured both as an injection molded part as well as using the simple, and thus cost effective, extrusion process.  
         [0005]     In a further development of the invention, at least one support means is placed between the two sides of the wind deflection strip at a distance from their common base point, said support means stabilizing the sides. This provides a certain degree of stiffening even when using a relatively soft material for the manufacture of the wind deflection strip, which provides the necessary form stability of the wind deflection strip even at a high wind loads.  
         [0006]     What is helpful here is that the support means is made up of a wall that extends in the longitudinal direction of the wind deflection strip that is connected to both sides, said wall extending along the entire length of the wind deflection strip, if necessary.  
         [0007]     If the support element is made up of two flexible rails, each of which sits in a longitudinal notch associated with it, respectively, said longitudinal notches being open toward the opposite lateral sides of the wiper strip, and if the outer strip edges of each of said flexible rails extend out of these notches, the support means are positioned at a distance from the support element. This results in a space between the wiper strip and the support means into which the area of the wiper strip located above the support element can extend. By correspondingly dimensioning this space, undesired friction between the wiper strip and the wind deflection strip is prevented.  
         [0008]     In another embodiment of the concept of the invention, the free ends of the sides of the wind deflection strip are provided, respectively, with claw-like extensions that grip tightly around these exterior strip edges of the support element at least in sections. This provides the ability to snap the wind deflection strip onto the exterior edge or to push it onto this edge in the longitudinal direction. This makes it possible to do away with a glued connection between the wind deflection strip and the support element. A glued connection of this type can limit the flexibility of the support element needed to attain a satisfactory wipe result due to its stiffness.  
         [0009]     In the process, it can be advantageous if the wind deflection strip is designed as a binary component whose longitudinal area provided with the claw-like extensions is made of a harder material than the longitudinal area lying closer to the base. In this way, the longitudinal area of the wind deflection strip provided with the extensions can be manufactured from a material that is well suited for the purposes of securing the wind deflection strip to the support element, whereas the area of the wind deflection strip provided with the incident surface can be made of a material that accounts for the further requirements on the wind deflection strip.  
         [0010]     In a wiper blade designed in this way, it can be advantageous if the transition from the harder longitudinal area to the softer longitudinal area occurs near the wall.  
         [0011]     According to another embodiment of the invention, it can be advantageous in certain applications if the wind deflection strip and the wiper strip form a one-piece component that is penetrated by a longitudinal channel in which the support element sits that is designed as a one-piece flexible belt. It is further advantageous for the channel wall facing the upper belt surface of the support element to constitute the support means located between the two sides of the wind deflection strip. Designing the wiper blade according to the invention in this way is especially cost-effective to install since the wind deflection strip is made in one piece together with the wiper strip and thus some installation steps can be eliminated.  
         [0012]     If the wall surfaces of the longitudinal channel facing the two belt surfaces of the support element are provided with longitudinal ribs that sit against the belt surfaces, this makes it considerably easier to insert the support element into the longitudinal channel as a result of the reduced friction surfaces.  
         [0013]     In a wiper blade with a one-piece component encompassing the wind deflection strip and the wiper strip, the component has three longitudinal strip areas that are permanently connected to one another as seen in cross section, of which the wiper strip can be pressed against the windshield. The wiper strip is located on the side of the base strip, which contains the longitudinal channel, that is opposite the wind deflection strip. The three strip areas thus resulting must be designed to meet the requirements placed on them individually.  
         [0014]     Thus, it can be very helpful if at least one of the strip areas of the component is made of a material whose hardness differs from the hardness of the other strip areas. In this way, it is possible to optimize the materials to be used with respect to the associated tasks of the individual strip areas.  
         [0015]     Based on the requirements placed on the base strip, it is practical to make it out of a harder material than the wind deflection strip. It can also be advantageous if the transition from harder material to softer material occurs near the wall of the longitudinal channel that faces the upper belt surface of the support element.  
         [0016]     In order to attain a satisfactory wipe result, it is practical to make the wiper strip out of a softer material than the base strip.  
         [0017]     In the process, manufacturing advantages result if the transition from softer material to harder material occurs near the root of the wiper strip.  
         [0018]     In order to avoid material such as snow, ice, etc. that is pushed away during the wiping process from getting jammed between the base strip and the windshield, the base strip becomes narrower as seen in cross section as it approaches the wiper strip.  
         [0019]     To fasten a connector to the wiper blade, by means of which it can be attached to a driven wiper arm, a recess is provided in the center section of the wind deflection strip to which to attach this equipment. This recess can be produced by subsequently removing a central section of the wind deflection strip. However, in a wiper blade with a separate wind deflection strip, it is also conceivable to design this in two parts as seen in the longitudinal direction, so that one half of the wind deflection strip can be attached to the support element on both sides of the connector.  
         [0020]     Other advantages of the further developments and configurations of the invention are given in the following description of exemplary embodiments illustrated in the associated drawing. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0021]      FIG. 1 a  wiper blade according to the invention in a perspective representation with the wiper arm shown as a dot-dashed outline,  
         [0022]      FIG. 2 a  cross section through the wiper blade along the line II-II in  FIG. 1  in an enlarged representation and  
         [0023]      FIG. 3  the arrangement according to  FIG. 2  for another embodiment of the wiper blade according to the invention.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]     A wiper blade  10  shown in  FIG. 1  has an elongated belt-shaped, flexible spring, one or more part support element  12  that is curved in the longitudinal direction in the un-loaded state. Located on the convex upper, or exterior, side of the belt  16  ( FIGS. 1 and 2 ) of the support element facing away from the windshield  14  to be wiped there is a connector  18  attached to the center section of the support element, for example flat. By means of this connector, the wiper blade  10  can be removably connected to a driven wiper arm  20  that leads to the body of an automobile. Located on the concave lower, or inner, side of the belt  22  of the curved support element  12  that directly faces the windshield is an elongated elastic rubber wiper strip  24  that extends parallel to the longitudinal axis of the support element  12 . At the free end of the wiper arm are mating connectors, which are not illustrated in more detail, that cooperate with the connector  18  of the wiper blade to form a hinge. The wiper arm  20 , and thus the wiper blade  10 , is forced in the direction of the arrow  26  toward the windshield to be wiped whose surface to be wiped is indicated in  FIG. 1  by the dot-dashed line  14 . Since the dot-dashed line indicates the greatest amount of curvature of the windshield surface, it can be clearly seen that the curvature of the as yet unloaded wiper blade  10 , whose ends  10  sit against the windshield  14 , is greater than the maximum windshield curvature. The wiper blade thus has—in the unloaded state—a concave shape in comparison to the windshield. Under pressure (arrow  26 ) the wiping lip  28  of the wiper blade  10  that performs the wiping presses its entire length against the windshield surface  14  and assumes its working position approximating the stretched position. In the process, tension builds up in the belt-shaped flexible spring support element  12 , ensuring proper seating of the wiper strip  24  and its wiping lip  28  along its entire length against the automobile windshield  14 . Since the generally spherically curved windshield is not in fact a section of a spherical surface, the wiper blade  10  in conjunction with the wiper arm  20  must be able to constantly adjust itself according to its respective position and to the shape of the windshield surface  14  during its wiping motion (double arrow  30 ). This necessitates a hinged connection between the wiper arm  20  and the wiper blade  10 , which enables a tilting motion (double arrow  32 ) about the hinge axis of the connection, if necessary.  
         [0025]     Below, more detail is provided on the special configuration of the wiper blade  10  according to the invention with the help of a first embodiment of the wiper blade shown in  FIG. 2 .  
         [0026]     The embodiment according to  FIG. 2  of the wiper blade according to the invention has a wiper strip  24  whose two lateral sides opposite one another are each provided with a longitudinal notch  34 , said notches being opposite one another, that is open toward the lateral side. Placed into each of the longitudinal notches  34  is a flexible rail  36  whose width is larger than the depth of the longitudinal notches  34 . The two flexible rails  36  are part of the support element  12 . Their outer longitudinal edges or strip edges  38  extend out from the longitudinal notches  34 . The two flexible rails  36  are properly secured in their longitudinal notches  34  by end caps  40  ( FIG. 1 ). Moreover, the connector  18  ( FIG. 1 ) can also contribute to the securing of the flexible rails  36  in their longitudinal notches  34 . At the side of the belt of the support element opposite the wiping lip  28 , the wiper blade  10  is provided with a wind deflection strip  42  that is made of two pieces  41 , between which the connector  18  for the wiper arm  20  sits on the support element  12  in a gap  65 . The effective area of the wind deflection strip  42  extends from each end cap  40  to the connector  18  ( FIG. 1 ). The wind deflection strip  42  is made of an elastic material, for example a plastic. It has an essentially triangular cross section with a cavity  44  that extends in the longitudinal direction of the wind deflection strip so that—as seen in the cross section—two side  48 ,  50  result that diverge from a common base point  46  and are connected to one another at the base point. Of these, side  50  is provided with a sloped incident surface  54  at its exterior that faces the main flow direction of the wind during driving ( FIG. 2 ). The free ends of the two sides  48  and  50 , which extend toward the windshield  14 , are supported at the wiper blade, i.e. at the longitudinal edges  38  of the support element  12 . To this end, they grip around the longitudinal edges  38  with tightly fitting claw-like extensions  56 , at least in sections. Thus, on one side they sit against the upper side of the belt  16  of the support element  12  and grip under the lower side of the belt  22  via the extensions  56 . To install the wind deflection strip  42 , it is pushed onto the flexible rails  36  of the support element  12  in the longitudinal direction, said flexible rails having the wiper strip  24  installed on it, so that the longitudinal edges  38  are wrapped tightly by the claw-like extensions  56  of the wind deflection strip  42 . So that the wind deflection strip  42 , which is made of an elastic material, also has the necessary form stability at high rates of speed and thus at high wind pressures, a support means is placed between the two sides  48 ,  50  of the wind deflection strip  42  at a distance from their common base point  46 , said support means stabilizing these sides. In the exemplary embodiment, this support means is made up of a wall  58  that is connected to the two sides  48 ,  50 .  
         [0027]     Furthermore,  FIG. 2  shows that the wind deflection strip  42  has two longitudinal areas  62  and  64  that are made of different materials. The materials have different hardnesses. In the exemplary embodiment, the longitudinal area  64 —which assumes the main tasks of the wind deflection strip by means of its incident surface  54 —is made of a softer material than longitudinal area  62 , which has in particular the claw-like extensions  56  that serves to secure the wind deflection strip  42  to the support element  12 . In the process, the transition from harder longitudinal area  42  to the softer longitudinal area  64  occurs near the wall  58 . In general, the wall  58  is placed at a distance from the claw-like extensions  56  and the support element  12  between it and the common base point  46  of the two sides  48 ,  50 , so that an recess  60  results between the support element and the wall  58  that provides space for the strip flaps  25  of the wiper strip  24  located above the support element. This prevents the wiper strip  28  and the wind deflection strip  42 , i.e. its wall  58  from touching one another, which disrupts the wiping process. The binary wind deflection strip  42  described has an even profile along its entire length. Thus it can be manufactured in an especially cost-effective manner by means of the so-called complex extrusion process.  
         [0028]     The embodiment of the wiper blade  110  according to the invention corresponding to  FIG. 3  differs from the wiper blade according to  FIG. 2  especially in that the wind deflection strip  112  and the wiper strip  114  are permanently connected to a base strip  130 . This results in a single strip-shaped component  116  whose base strip area is penetrated by a longitudinal channel  118  into which a support element  120  is placed that is designed as a one-piece flexible spring belt. This longitudinal channel wraps around both the two belt surfaces  122  as well as the two lateral edges  123  of the support element  120 . The channel walls directly facing the belt surfaces are provided with a number of longitudinal recesses  124  so that longitudinal ribs  126  form between the recesses that sit against the belt surfaces  122 . This facilitates the insertion of the support element  120  into the longitudinal channel  118 . At the bottom of the base strip  130  facing the windshield  114  is the wiper strip  114  with its wiping lip  128 , said wiper strip sitting against the windshield. The base strip becomes narrower—as seen in cross section—in the direction toward the wiper strip  114  so that walls result that slope toward the windshield  14 , which is particularly advantageous when wiping iced windshields or windshields covered with wet snow. On the upper side of the base strip  130  that is opposite the wiper strip  114  is the wind deflection strip  112  with its incident surface  140 . It also has a longitudinal cavity  142  that is placed such that between it and the longitudinal channel  118  a wall  144  remains that connects the sides  136 ,  138 , which result from the cavity, that diverge from a common base point  134  toward the windshield  14 . The wall stabilizes the two side  136 ,  138  of the wind deflection strip  112 . Some of the longitudinal ribs  126  are located on the bottom. Further, each of the three strip areas  112 ,  128  and  130  of the component  116  is made of a different material. This makes it possible to select the appropriate material characteristics to account for the different requirements placed on the respective areas. For example, the hardness values of a strip area can differ from the hardness values of the others. It is especially advantageous if the base strip  130  is made of a harder material than the wind deflection strip  112  and/or the wiper strip  114 . The transition from harder material to softer material then is intended to occur near the stabilizing wall  144  or in the root  146  of the wiper strip  114  where it transitions to the base strip  130 . This results in transition regions between two directly adjacent strip areas  112  and  130  or  130  and  114 . The exact position of these transition regions is established on a case-by-case basis by one trained in the art—taking into consideration the appropriate special requirements placed on the wiper blade.  
         [0029]     In the embodiment of the wiper blade  110  according to  FIG. 3 , component  116  first of all has the same length as the support element  120 . To secure component  116  to the support element in its longitudinal direction, it is provided at both ends with a recess so that the two end areas of the support element  120  are exposed and accessible to snap on end caps  40 . Further, the wind deflection strip  112  is provided with a gap or recess at its center section that in principle corresponds to the gap  65  in  FIG. 1 . This recess can be designed deep enough that in this embodiment the support element  120  is exposed and thus ready for the installation of the connector  18 . In this embodiment, it has been shown to be especially helpful if this gap  65  is attached by means of a process known as “water jet cutting”.  
         [0030]     Both the wind deflection strip  42  and the wiper strip  24  as well as the component  116  have an even profile along their entire length and can thus be manufactured in an especially cost-effective manner in one piece by means of the so-called extrusion process. In the process, it is quite helpful to manufacture these parts using the so-called complex extrusion process. The necessary sections can then be cut to length as needed—as well in the embodiment according to  FIG. 2 .  
         [0031]     All exemplary embodiments share the characteristic that the wind deflection strip  42  or  112  has two sides  48 ,  50  or  136 ,  138  that diverge from a common base point  46  or  134  as seen in cross section and that are connected to it. The free ends of the sides that face the windshield  14  are supported at the wiper blade. What is also common is that the incident surface  54  or  140  is designed at the exterior of one side  50  or  138  and that the profile of the cross section of the wind deflection strip is the same along its entire length. Further, both exemplary embodiments have at least one support means located between the two sides  48 ,  50  of the wind deflection strip  42  or  112  at a distance from their common base point  46  or  134 . This support means is made up of a wall  58  or  144  that is connected to both sides and extends in the longitudinal direction of the wind deflection strip, said wall extending along the entire length of the wind deflection strip, if necessary.