Abstract:
The invention relates to a wiper blade and to a method for producing a wiper blade, comprising a support element ( 12 ) for receiving a wiper strip ( 14 ), to which support element a connecting device ( 20 ) is attached, which has a wiper blade-side part ( 15 ) having claw-like receptacles ( 32, 34 ) surrounding the support element ( 12 ) at least in some regions. A gap ( 42 ) is provided between the support element ( 12 ) and at least one receptacle ( 32, 34 ). After the support element ( 12 ) is positioned in the receptacles ( 32, 34 ) of the connecting device ( 20 ), a compound ( 44 ) is introduced into the gap ( 42 ), said compound hardening in the gap ( 42 ).

Description:
BACKGROUND OF THE INVENTION 
       [0001]    In wiper blades for wiping panes, in particular vehicle panes, having a carrier element for receiving a wiper strip, to which there is secured a connection device which has a wiper-blade-side portion having claw-like receiving members, which at least partially engage round the carrier element, the carrier element is intended to ensure the most uniform possible distribution of the wiper blade contact pressure applied by the wiper arm to the pane over the entire wiping field which is covered by the wiper blade. As a result of a corresponding curvature of the unloaded carrier element—that is to say, when the wiper blade is not in abutment with the pane—the ends of the wiper strip which is placed fully on the pane during operation of the wiper blade are loaded by the carrier element which is then tensioned with respect to the pane even though the radii of curvature of spherically curved vehicle panes change with each wiper blade position. The curvature of the wiper blade must therefore be slightly greater than the greatest curvature measured in the wiper field on the pane to be wiped. A connection device by means of which the connection to the wiper arm is produced is secured to the carrier element. 
         [0002]    From EP 0914269 B1 it is known to secure the connection device to the carrier element by means of a weld connection. To this end, the wiper-blade-side connection element which comprises either metal or a plastics material is applied or fitted to the carrier element and connected in a materially engaging manner to the carrier element by means of resistance welding in the case of a metal connection element or by means of ultrasound welding in the case of a plastics connection element. This welding connection is subjected to extreme conditions during everyday use and must withstand high levels of torques and vibrations even in differing weather conditions. In particular in the case of wiper blades which are produced in large batch numbers, a weld connection places high quality requirements on the execution of the process and thus makes the wiper blade more expensive, which is intended to be avoided precisely in the case of mass-produced products. 
       SUMMARY OF THE INVENTION 
       [0003]    The wiper blade according to the invention has the advantage that, owing to the additional mass, tolerances between the carrier element and the connection device are completely compensated for and a solid bond is produced. Neither the carrier element, nor the connection device has to be heated up to a liquid state in this instance so that the mechanical properties are not changed. 
         [0004]    The expansion of the mass in the gap can thus effectively be limited when the gap is delimited at least in the direction of the wiper strip. The wiper strip is thus not influenced by the mass. 
         [0005]    In order to nonetheless enable an extensive abutment of the carrier element against the receiving members of the connection device, there may be provision for the gap to extend only over two sides of the carrier element. This may, for example, be a convex upper side or the concave lower side of the carrier element and the narrow longitudinal side thereof. 
         [0006]    A separate opening for introducing the mass is advantageously provided on the at least one receiving member and may be formed at an upper side or a lower side, depending on whether or not an additional covering cap is subsequently used. However, it is also conceivable for the opening to be provided at a narrow longitudinal side. 
         [0007]    In order to be able to readily introduce the mass into the gap, it is advantageous for the mass to be flowable before the introduction operation and to solidify only when in the gap. To this end, the mass may be provided as a liquid or gel. However, it is also possible for the mass to be processed as a powder or granulate. Which administration form is to be selected is dependent on the one hand on the material of the mass itself and on the other hand on the process environment. For example, in a moist environment, a liquid or a gel would be used. 
         [0008]    The mass is preferably a  2 -component adhesive material and/or a resin since these materials can be processed for a defined period of time after the components have been blended, but can be stored for almost an unlimited period of time before the blending. 
         [0009]    If the mass at least partially closes the opening provided for the introduction, during subsequent operation of the wiper blade dirt and water can thereby be prevented from accumulating there in increased quantities. Furthermore, the appearance is improved if the openings remain visible. 
         [0010]    The bond between the carrier element and connection device can be improved if the carrier element has a recess through which the mass extends. If a portion of the mass also remains in the opening provided for the introduction, a connection is produced which positions the connection device in a positive-locking manner on the carrier element. 
         [0011]    With the method according to the invention for producing a wiper blade, it is possible in a simple manner and without excessive supply of heat to secure the connection device to the carrier element. This is particularly effective when the mass which is introduced through an opening is distributed along the gap. This can be achieved in a particularly simple manner when the mass is pressed in by means of a piston or a stamp. 
         [0012]    Flow behavior and solidification can be improved when the mass is heated before being introduced and is cooled after being introduced. Depending on the material of the mass, it is also possible to heat the mass only in the gap and then to solidify it, for example, by means of chemical reactions. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    In the drawings: 
           [0014]      FIG. 1  is a perspective view of a wiper blade according to the invention, with a wiper arm which is indicated with dot-dash lines, and a surface of a windscreen which is indicated with dot-dash lines; 
           [0015]      FIG. 2  is a view according to II-II in  FIG. 1 ; 
           [0016]      FIG. 3  is a schematic illustration of the view according to  FIG. 2  with only one resilient strip; 
           [0017]      FIG. 4  is a schematic view in the viewing direction IV in  FIG. 1  with only one end cap, and 
           [0018]      FIGS. 5 and 9  are sectioned views of a receiving member in respect of various embodiments, respectively. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    A wiper blade  10  shown in  FIG. 1  has a resilient carrier element  12  ( FIGS. 1 and 2 ) which is elongate in a strip-like manner and to whose lower strip side  13  facing the pane an elongate resilient wiper strip  14  is secured in a manner parallel with the longitudinal axis. At the upper strip side  11  of the carrier element  12  which can also be referred to as the resilient strip, facing away from the pane, there is arranged in the central portion thereof the wiper-blade-side portion  15  of a connection device by means of which the wiper blade  10  can be releasably connected in an articulated manner to a wiper arm  16  indicated with dot-dash lines in  FIG. 1 . The wiper arm  16  which is driven in an oscillating manner in the direction of a double-headed arrow  18  in  FIG. 1  is loaded in the direction of an arrow  24  with respect to the pane to be wiped—for example, with respect to the windscreen of a motor vehicle—whose surface is indicated in  FIG. 1  with a dot-dash line  22 . Since the line  22  is intended to constitute the highest level of curvature of the pane surface, it can clearly be seen that the curvature of the wiper blade which abuts the pane with both ends thereof and which is not yet loaded is greater than the maximum pane curvature ( FIG. 1 ). Under the contact pressure (arrow  24 ), the wiper blade  10  is in abutment with the pane surface  22  with the wiper lip  26  thereof over the entire length thereof. A tension is built up in the resilient carrier element  12  which is produced from metal and ensures correct abutment of the wiper strip  14  or the wiper lip  26  over the entire length thereof on the pane surface  22  and uniform distribution of the contact pressure (arrow  24 ). 
         [0020]    The specific configuration of the wiper blade according to the invention will now be explained in greater detail below. 
         [0021]    In  FIG. 2 , it can be seen that the carrier element  12  is constructed from two mutually separate resilient strips  28  and  30  which are spaced apart from each other and which form a gap  32 . The connection device  15  has in a lower region two U-shaped receiving members  34  and  36 , in which the resilient strips  28  and  30  are received. The receiving members  34  and  36  surround the resilient strips  28  and  30  over a relatively large portion of the cross-section thereof, the portion of the connection device  15  which corresponds to the wiper arm  16  being arranged at the convex side  29  of the carrier element  12  whilst the concave side  31  is opposite it. 
         [0022]      FIG. 3  is a schematic illustration of the connection device  15 , the corresponding resilient strip  28  being drawn in the receiving member  34 , whilst the resilient strip  30  is not in the corresponding receiving member  36 . It can be seen that the receiving members  34  and  36  engage around the resilient strips  28  and  30  in a close-fitting manner. In the region above the resilient strips  28  and  30  and above the gap  32 , the connection device  15  has a recess  40  in which, when the wiper blade  10  is assembled, an upper portion of a wiper strip comes to rest. 
         [0023]    The wiper blade  10  which is illustrated from below in  FIG. 4  and which is drawn without the wiper strip  14  or wiper lip  26  has the resilient strips  28  and  30 , the gap  32  and the receiving members  34  and  36  of the connection device  15 . It can be seen that, in this embodiment of the wiper blade  10 , the resilient strips  28  and  30  are completely separate from each other and are held together only by the connection device  15  or by means of end caps  38 , of which only one is drawn at one end in  FIG. 4 . 
         [0024]      FIG. 5  is a sectioned view of the receiving member  34  in which a resilient strip  28  of the carrier element  12  is located. Between the receiving member  34  and the resilient strip  28  of the carrier element  12  there is a small gap  42  which extends in this embodiment at the convex upper side  29  and at the lateral longitudinal side  46 . The concave lower side  31  rests directly in the receiving member  34 . At a side facing the wiper strip  14  (not illustrated in  FIG. 5 ), the gap  42  is delimited by a collar  52 . Such a collar  52  may also be located in the region of the lower side if the gap  42  also extends at that location. 
         [0025]    In an upper region of the receiving member  34 , there is an opening  48  through which a mass  44  can be introduced. To this end, there is located in the opening  48  above the mass  44  a stamp  50  which can be moved downwards in the direction of the arrow indicated. 
         [0026]    In  FIGS. 6 ,  7  and  8 , it is indicated how the mass  44  is distributed in the gap  42  by means of the stamp  50 . To this end, as indicated in  FIG. 5 , the mass is first introduced into the opening, for example, sprinkled or blown in as powder or directly pushed in with the stamp  50  in compressed tablet form. It is also conceivable to introduce the mass with a liquid or gel-like consistency. 
         [0027]    The stamp  50  is then moved in the direction of the arrow  54  so that, as can be seen in  FIGS. 6 and 7 , the mass  44  expands along the gap  42  and fills the gap  42 . If, as illustrated in  FIGS. 6 to 8 , no collar  52  is provided, the quantity of the mass  44  must be provided in such a manner that an overflow is prevented. If the mass  44  is completely pressed in ( FIG. 8 ), the stamp  50  is then pulled out when the solidification of the mass  44  has at least begun. Depending on the material of the mass  44 , the solidification can be accelerated by heat  58  or ultraviolet light being supplied to the region of the gap. 
         [0028]    Another embodiment is illustrated in  FIG. 9 , in which the introduction of the mass  44  is already complete and the stamp  50  has been removed. In this variant, the resilient strip  28  has a recess  56 , through which the mass  44  has penetrated completely. Furthermore, a portion of the mass  44  remains in the opening  48 . In this manner, after the solidification of the mass  44 , a positive-locking bond is produced between the resilient strip  28  and the receiving member  34 . In order to further reinforce the bond, the opening  48  can also be at least partially continued into a lower region of the receiving member  34 . The recess  56  can also be produced at the edge of the resilient strip  28 ,  30 . It is further possible to provide a plurality of recesses  56 . 
         [0029]    A wiper blade  10  according to the invention is produced as follows: 
         [0030]    The resilient strips  28 ,  30  of the carrier element  12  are introduced into the receiving members  34 ,  36  of the connection device  20  so that a gap  44  is produced between the receiving members  34 ,  36  and the resilient strips  28 ,  30 . The resilient strips  28 ,  30  are fixed relative to the connection device  20 . The mass  44  is introduced into the openings  48  and pressed into the gap  44  by means of the stamp  50 . After the mass  44  has solidified, the stamps  50  are removed and the wiper strip  14  is introduced. After the subsequent application of the end caps  38 , a covering cap can also be placed over the connection device  20  if it is provided. 
         [0031]    As the mass  44 , it is possible to provide, for example, meltable polymers which are introduced in heated form into the openings  48  and cool and harden in the gaps  42 . However, it is also possible to provide as the mass  44  thermosetting plastics which vulcanize and harden in the gaps  42 . In order to accelerate the reaction, there may be provision for this region to be heated or to be irradiated with ultraviolet light. 
         [0032]    It is also possible to provide the mass  44  as part of the wiper-blade-side portion  15 , which is then melted in a first step by means of the sonotrodes and is pressed into the gap. A separate handling operation involving powder, gel or liquid is thereby dispensed with. The mass  44  would then be provided in a similar manner to  FIG. 6  as a type of base in the opening  48 .