Windshield wiper system with tubular drive arm and cavity

Abstract

This invention relates to windshield wiper system 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 - 8 . (canceled)  
   
   
       9 . 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 an internal cavity extending along its length.    
   
   
       10 . The windshield wiper system as recited in  claim 9  wherein said generally curved cross-section defines a shape that is elliptical, concave or one side of said arm is generally flat.  
   
   
       11 . The windshield wiper system as recited in  claim 10  wherein the cross-section defines a concave shape.  
   
   
       12 - 16 . (canceled)  
   
   
       17 . The windshield wiper system as recited in  claim 9  wherein said drive arm comprises: 
 a tubular member defining said cross-section and said cavity comprising an internal cavity extending initially forward along a longitudinal axis; and    said tubular member comprising a wiper axis for connection of a wiper thereto and a motor axis for connection of a drive motor thereto;    said wiper axis being selected to cause a bending of said tubular member about said longitudinal axis when said bending force is applied thereto.    
   
   
       18 . The windshield wiper system according to  claim 17  wherein said tubular member experiences an elastic buckling when said bending force exceeds a predetermined amount.  
   
   
       19 - 20 . (canceled)  
   
   
       21 . The windshield wiper system according to  claim 17  wherein said tubular member being naturally curved in the absence of a bending force on said wiper axis.  
   
   
       22 . The windshield wiper system according to  claim 21 , said tubular member flattens out such that at least a portion of said cross-sectional shape becomes generally flat.