Windshield wiper system with tubular member plus internal hose

Abstract

This invention relates to windshield wiper system and method which utilizes a flexible drive arm for withstanding bending loads applied to a wiper. The drive arm may be made of a pull-molded composite material having a relatively low modulus of elasticity and a relatively high elongation factor. The flexible arm twists in the presence a bending load and undergoes rapidly progressing elastic buckling when the bending load exceeds a predetermined amount.

1 - 10 . (canceled)  
   
   
       11 . A windshield wiper system comprising: 
 a drive motor;    a drive arm coupled to said drive motor; and    a wiper blade also coupled to said drive arm for wiping a windshield when said drive motor is energized;    said drive arm being made of a composite material and being generally curved in cross-section and comprising a passageway through which washer fluid may pass.    
   
   
       12 . The windshield wiper system as recited in  claim 11  wherein said generally curved cross-section defines a shape that is elliptical, concave or one side of said arm is generally flat.  
   
   
       13 . The windshield wiper system as recited in  claim 11  wherein said generally curved cross-section defines a width that generally increases when said wiper blade encounters debris on said windshield and said drive arm experiences a bending force that is greater than a predetermined force.  
   
   
       14 . The windshield wiper system as recited in  claim 13  wherein said predetermined force is greater than the blade maximum frictional force.  
   
   
       15 . The windshield wiper system as recited in  claim 11  wherein a leading edge of said generally curved cross-section moves towards said windshield and a trailing edge of said generally curved cross-section moves away from said windshield when said wiper blade encounters debris on said windshield and said drive arm experiences a bending force that is greater than a predetermined force.  
   
   
       16 . The windshield wiper system as recited in  claim 15  wherein said predetermined force is greater than the blade maximum frictional force.  
   
   
       17 . The windshield wiper system as recited in  claim 11  wherein said drive arm twists when said wiper blade encounters debris on said windshield and said drive arm experiences a bending force that is greater than a predetermined force.  
   
   
       18 . The windshield wiper system as recited in  claim 11  wherein said drive arm comprises: 
 a tubular member having a preselected cross-section, and an internal cavity extending along a longitudinal axis, with a curvature extending laterally from said longitudinal axis;    said internal cavity defining said passageway through which washer fluid may pass;    said tubular member defining a wiper axis for connection of a wiper thereto and also defining a motor axis for connection of a drive motor thereto;    said tubular member generally bending about said longitudinal axis when a bending force is applied thereto.    
   
   
       19 . The windshield wiper system according to  claim 18  further comprising an elastomeric hose extending end-to-end through said internal cavity for providing said passageway.  
   
   
       20 . The windshield wiper system according to  claim 19  wherein said tubular member experiences elastic buckling when said bending force exceeds a predetermined amount.  
   
   
       21 . The windshield wiper system according to  claim 19  wherein wiper axis being positioned to cause a bending of said tubular member in a manner which opposes said bending force.  
   
   
       22 . The windshield wiper system according to  claim 19  wherein said cross-section having an off-center shear center.  
   
   
       23 . The windshield wiper system according to  claim 19  Wherein said tubular member being naturally curved in the absence of a bending force on said wiper axis.  
   
   
       24 . The windshield wiper system according to  claim 23 , said tubular member flattens such that at least a portion of said cross-sectional shape is generally flat.  
   
   
       25 . The windshield wiper system according to  claim 24 , further comprising a foam core fitted within said cavity.  
   
   
       26 . The windshield wiper system according to  claim 18  wherein said preselected cross-section is elliptical.  
   
   
       27 . The windshield wiper system according to  claim 18  wherein said preselected cross-section is crescent-shaped.  
   
   
       28 . The windshield wiper system according to  claim 27 , wherein said tubular member being straightened out such that at least a portion of said crescent-shaped cross-section flattens out.  
   
   
       29 . The windshield wiper according to  claim 18 , further comprising a foam core fitted within said cavity.