Variable stiffness bellows

Abstract

This invention relates to a flexible tube that includes a bellows having a plurality of convolutes formed in the wall of said tube and extending above the top surface of the tube, said convolutes being spaced from one another in the axial direction of the tube, wherein at least one of said convolutes comprises two opposing bending sections and two restrained elongation sections positioned between the bending sections, and wherein the height of the bending sections above the top surface of the tube is greater that the height of the restrained elongation sections above the top surface of the tube.

1 . A flexible tube having a bellows comprising a plurality of convolutes formed in the wall of said tube and extending above the top surface of the tube, said convolutes being spaced from one another in the axial direction of the tube, 
 wherein at least one of said convolutes comprises two opposing bending sections and two restrained elongation sections positioned between the bending sections, and    wherein the height of the bending sections above the top surface of the tube is greater that the height of the restrained elongation sections above the top surface of the tube.    
     
     
         2 . The tube of  claim 1 , further comprising a transition section position between a bending section and a restrained elongation section.  
     
     
         3 . The tube of  claim 1 , wherein the width in the axial direction of the restrained elongation section is less than the width in the axial direction of the bending section.  
     
     
         4 . The tube of  claim 1 , wherein the restrained elongation section includes second convolutes radially spaced apart that connect a restrained elongation section to a bending section.  
     
     
         5 . The tube of  claim 1 , wherein at least two of said convolutes comprises two opposing bending sections and two restrained elongation sections positioned between the bending sections, and 
 wherein the length in the radial direction of the elongation sections decreases from a first convolute to a second convolute.    
     
     
         6 . The tube of  claim 1 , wherein said tube comprises a thermoplastic resin.  
     
     
         7 . An air duct that includes the tube of  claim 1 .  
     
     
         8 . A coolant pipe that includes the tube of  claim 1 .  
     
     
         9 . A fuel tube that includes the tube of  claim 1 .  
     
     
         10 . A filler neck that includes the tube of  claim 1 .  
     
     
         11 . The use of a flexible tube according to  claim 1  for air-conduction parts and liquid lines in automobiles or as water lines for washing machines.