Patent Publication Number: US-2007094831-A1

Title: All weather windshield wiper system

Description:
TECHNICAL FIELD OF THE INVENTION  
      This invention relates to a windshield wiper system for a vehicle or machine, and, more particularly, to a single windshield wiper system that can be used for all weather and environmental conditions.  
     BACKGROUND OF THE INVENTION  
      Conventional windshield wiper systems employ a single wiper blade attached to a wiper arm assembly for clearing a windshield of water or condensation occurring during rain or fog. That single blade wiper works acceptably when used for clearing falling snow; however, it is ineffective for removing accumulated snow, ice and other debris. For example, when clearing a windshield of mud or dust, water is used causing the windshield to attract additional dust that is smeared on the windshield by the wiper blade. When clearing ice, the blade sometimes buckles or simply glides over patches of ice damaging the wiper blade material.  
      One approach to solving the problem of adequately clearing and cleaning the windshield uses a wiper with a blade that rotates to expose a different windshield contact material. When rain is the problem, a regular rubber or elastomeric blade is used, and when ice is the problem, the blade is rotated to expose a different, harder blade material. A problem with such a rotatable blade wiper system is that is requires the operator to manually rotate the wiper blade. Manual rotation must be accomplished from outside the vehicle requiring the operator to exit the vehicle which is not always possible or even practical. Accordingly, it will be appreciated that it would be highly desirable to have a windshield wiper system that can be easily used in any weather or environmental condition from inside the vehicle or machine.  
     SUMMARY OF THE INVENTION  
      The present invention is directed to overcoming one or more of the problems set forth above. Briefly summarized, according to one aspect of the present the invention, a windshield wiper system comprises a wiper arm; a base member pivotally attached to the wiper arm; a first wiper blade assembly having a first wiper blade and being attached to the base member; a linkage assembly attached to the base member and positioned adjacent the first wiper blade assembly; a second wiper blade assembly having a second wiper blade attached to the linkage assembly; and means for extending and retracting the linkage assembly.  
      The linkage assembly has an upper connecting member, a lower connecting member spaced from the upper connecting member, and one or more intermediate connecting members pivotally connected to the upper and lower connecting members. The upper, lower and intermediate connecting members operate like a bellows moving the lower connecting member toward and from the upper connecting member and thereby moving the second wiper blade toward and from the windshield. A cable operated from inside the vehicle extends and retracts the linkage assembly to move the second wiper blade toward and from the windshield.  
      According to another aspect of the invention, a windshield wiper system comprises a wiper arm; a base member having first and second edge portions and being pivotally attached to the wiper arm; a first wiper blade assembly having a first wiper blade and being attached to the first edge portion of the base member; a second wiper blade assembly having a second wiper blade and being attached to the second edge portion of the base member; a linkage assembly attached to the base member and positioned intermediate the first and second wiper blade assemblies; an intermediate wiper blade assembly having a third wiper blade attached to the linkage assembly; and means for extending and retracting the linkage assembly.  
      The windshield wiper system has multiple blades for clearing the windshield of rainwater, ice, snow, dust and debris. A pair of outer elastomeric squeegee blades remove rainwater while two pairs of inner blades remove ice, snow, dust and other debris. A rigid blade removes ice while a spongy blade takes care of snow, dust and debris. Each pair of inner blades is movable toward and from the windshield, one at a time, while the outer blades remain fixed. An inner blade moves from a normal position out of contact with the windshield to an extended position where it contacts the windshield lifting the fixed exterior blades away from the windshield. Each movable blade is attached to an accordion linkage mechanism and operated from inside the by the driver vehicle via a cable. There is no longer a need to have only one blade option or the need to stop the vehicle to adapt the wipers to environmental conditions.  
      These and other aspects, objects, features and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims, and by reference to the accompanying drawings 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a diagrammatical view of a preferred embodiment of a windshield wiper system having multiple blades according to the present invention.  
       FIG. 2  is a diagrammatic sectional view of the wiper taken along line  2 - 2  of  FIG. 1  further illustrating multiple blades.  
       FIG. 3  is a diagrammatic sectional view similar to  FIG. 1  but illustrating a retractable blade extended to contact a windshield.  
       FIGS. 4-5  are diagrams illustrating operation of the extension linkage to raise and lower a wiper blade.  
       FIG. 6  is diagrammatic exploded view of a squeegee wiper blade.  
       FIG. 7  is a perspective view of an ice scraper wiper blade.  
       FIG. 8  is an end view of the ice scraper wiper blade of  FIG. 7 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Referring to  FIGS. 1-2 , a windshield wiper system  10  for a machine or vehicle  12  clears the windshield  14  of rainwater, ice, snow, dust, mud and debris. Clearing is accomplished by using a plurality of wiper blades on each wiper arm  16  and lowering an appropriate blade for clearing ice, snow, dust, mud and debris while the blade for rainwater is moved out of contact with the windshield  14 .  
      The system  10  includes a base member  18  of metal, plastic or other material that has first and second edge portions and is pivotally attached to wiper arm  16 . An exterior or first wiper blade assembly  20  has a first conventional rubber or elastomeric wiper blade  22 , and is attached to the first edge portion of base member  18 . An exterior or second wiper blade assembly  24  has a second conventional rubber or elastomeric second wiper blade  26 , and is attached to the second edge portion of base member  18 .  
      The present invention differs from conventional wiper blade assemblies by providing at least a first, and preferably a second, interior or intermediate wiper blade assembly  28 ,  30  positioned between exterior wiper blade assemblies  20 ,  24 .  
      A first linkage assembly  32  is attached to base member  18  and is positioned intermediate the first and second wiper blade assemblies  20 ,  24 . First linkage assembly  32  comprises an upper connecting member  34 , a lower connecting member  36 , and at least one intermediate connecting member  38  pivotally connected to the upper and lower connecting members  34 ,  36 . The upper, lower and intermediate connecting members form an extension device that operate like an accordion or bellows moving lower connecting member  36  toward and from upper connecting member  34  which is fastened to base member  18 .  
      Intermediate wiper blade assembly  28  has a wiper blade  40  attached to the lower connecting member  36  of the linkage assembly  32 . Also attached to the lower connecting member  36  of the linkage assembly  32  is a cable  42 . The other end of cable  42  terminates inside the vehicle where it attaches to a knob, panel or other lever for operation. Cable  42  provides a means for extending and retracting linkage assembly  32  and thereby wiper blade  40 .  
      A second linkage assembly  44  is attached to base member  18  and is positioned intermediate the first and second wiper blade assemblies  20 ,  24  adjacent intermediate wiper blade assembly  28 . Linkage assembly  44  comprises an upper connecting member  46 , a lower connecting member  48 , and at least one intermediate connecting member  50  pivotally connected to the upper and lower connecting members  46 ,  48 . The upper, lower and intermediate connecting members form an extension mechanism that operates like an accordion or bellows moving lower connecting member  48  toward and from upper connecting member  46  which is fastened to base member  18 .  
      Intermediate wiper blade assembly  30  has a wiper blade  52  attached to the lower connecting member  48  of the linkage assembly  44 . Also attached to the lower connecting member  48  of the linkage assembly  44  is a cable  54 . The other end of cable  54  terminates inside the vehicle where it attaches to a knob, panel or other lever for operation. Cable  54  provides a means for extending and retracting linkage assembly  32  and thereby wiper blade  40 .  
       FIG. 6  illustrates a squeegee wiper blade  56  that has a spongy cover member  58  for absorbing and then dispersing cleaning fluid. Water or cleaning fluid is routed from a fluid reservoir in the vehicle through tubing  60  and a plurality of openings  62  to spongy cover  58 . Tubing  60  preferably terminates in a fluid holding chamber prior to dispersal to the spongy cover  58 .  
       FIGS. 7-8  illustrate an intermediate blade  64  for removing ice. Blade  64  has an upper attaching portion  66  and a lower working portion  68 . Working portion  68  is displaced from upper portion  66  at an angle of about forty-five degrees. A distal portion of lower portion  68  is preferably bifurcated forming a scraper  70  and serrations or teeth  72 . Teeth  72  may be shallow, fine and narrow like the teeth of a crosscut saw blade as illustrated or may be squarer like the teeth on dental molding. On a forward (or reverse) pass of the wiper, scraper  70  removes ice by scraping loose ice off the windshield. On a reverse (or forward) pass of the wiper, teeth  72  break the ice so that it can be removed by scraping on the next pass.  
      It can now be appreciated that a windshield wiper system for a machine or a vehicle has been presented that changes wiper blades according to the type of material to be removed from the windshield. Normally, the exterior wiper blades are common squeegee blades constructed of rubber or elastomeric material for moving water. Intermediate wiper blade  40  can be used for snow, dust and mud. Blade  40  may have a deformable surface for contacting the windshield and hugging to it so that it actually removes material rather than simply gliding over the material. A spongy material has the advantage of absorbing moisture that is helpful where there is dust or mud. When a spongy material is used, the cleaning fluid that is normally lost is captured for cleaning. Intermediate blade  52  removes ice. It is formed of a hard plastic material or metal with a pointed working surface so that it is useful for scrapping ice from the windshield and pushing sheets of melting ice off the windshield. Either or both intermediate wiper blades may be used in a wiper assembly, although only one of the blades contacts the windshield at a time.  
      While the invention has been described with particular reference to the preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements of the preferred embodiments without departing from invention. For example, instead of operating the cables by manually pulling a knob or lever, a cable may be connected to a motor operated by a push button.  
      As is evident from the foregoing description, certain aspects of the invention are not limited to the particular details of the examples illustrated, and it is therefore contemplated that other modifications and applications will occur to those skilled in the art. For example, a wiper blade for scraping ice may have a sharp edge on a front working surface and a serrated rear working surface like a manual ice scraper. It is accordingly intended that the claims shall cover all such modifications and applications as do not depart from the true spirit and scope of the invention.  
     ELEMENT LIST  
     
         
           10  windshield wiper system  
           12  machine or vehicle  
           14  windshield  
           16  wiper arm  
           18  base member  
           20  exterior or first wiper blade assembly  
           22  wiper blade  
           24  exterior or second wiper blade assembly  
           26  wiper blade  
           28  interior or intermediate wiper blade assembly  
           30  interior or intermediate wiper blade assembly  
           32  linkage assembly  
           34  upper connecting member  
           36  lower connecting member  
           38  intermediate connecting member  
           40  wiper blade  
           42  cable  
           44  linkage assembly  
           46  upper connecting member  
           48  lower connecting member  
           50  intermediate connecting members  
           52  wiper blade  
           54  cable  
           56  squeegee wiper blade  
           58  spongy cover member  
           60  tubing  
           62  plurality of openings  
           64  intermediate wiper blade  
           66  upper attaching portion  
           68  lower working portion  
           70  scraper  
           72  teeth