Bicycle crank and method for manufacturing the same

Abstract

A bicycle crank and a method of making a bicycle crank is provided. The bicycle crank has an elongated core with first and second ends, first and second inserts arranged on the ends of the core, and a high-resistance fibre coating incorporated in a plastic material matrix which forms a casing incorporating the core and the inserts. The core is a rigid element and each insert is equipped with a connecting portion inserted into a respective end of the core to establish a shape coupling therewith.

1 . A bicycle crank comprising: 
 an elongated core having open first and second ends;    first and second inserts that are tapered and matingly engagable with said first and second ends, with the first insert positioned adjacent to the first end of the core and the second insert positioned adjacent the second end of the core; and    an outer casing comprised of a fibrous plastic material which encases the core and the inserts.    
   
   
       2 . The bicycle crank of  claim 1 , further comprising a third insert arranged in an intermediate area of said crank.  
   
   
       3 . The bicycle crank of  claim 1 , wherein said structural fibers are chosen from a group comprising: carbon fibers, glass fibers, aramidic fibers, boron, fibers, ceramic fibers or a combination thereof.  
   
   
       4 . The bicycle crank of  claim 1 , wherein said inserts are metallic.  
   
   
       5 . The bicycle crank of  claim 4 , wherein said inserts are made of an aluminum alloy.  
   
   
       6 . The bicycle crank of  claim 4 , wherein said inserts are made of fiber-reinforced plastic material.  
   
   
       7 . The bicycle crank of  claim 1 , wherein said elongated core is rigid.  
   
   
       8 . The bicycle crank of  claim 1 , wherein said elongated core provides little or no structural resistance.  
   
   
       9 . The bicycle crank of  claim 7 , wherein said elongated core is made of plastic.  
   
   
       10 . The bicycle crank of  claim 7 , wherein said elongated core is made of metal.  
   
   
       11 . The bicycle crank of  claim 7 , wherein said elongated core is made of fiber-reinforced plastic material.  
   
   
       12 . The bicycle crank of  claim 1 , wherein said elongated core comprises end portions in which said inserts are connected to establish a shape coupling.  
   
   
       13 . A bicycle crank, comprising: 
 an elongated core having open first and second ends;    a first and a second insert arranged at the ends of said casing for connecting the bicycle crank to a pedal and to a bottom bracket spindle, wherein said first and second inserts are tapered to matingly engage said first and second ends of the core, said inserts and core are enclosed within a single structural unit casing of structural fibers incorporated in a plastic material matrix, that substantially structurally connects the said inserts to said casing.    
   
   
       14 . The bicycle crank of  claim 13 , further comprising a third insert arranged in an intermediate area of said crank.  
   
   
       15 . The bicycle crank of  claim 13 , wherein said structural fibers are chosen from a group comprising: carbon fibers, glass fibers, aramidic fibers, boron fibers, ceramic fibers or a combination thereof.  
   
   
       16 . The bicycle crank of  claim 13 , wherein said inserts are metallic.  
   
   
       17 . The bicycle crank of  claim 16 , wherein said inserts are made of an aluminum alloy.  
   
   
       18 . The bicycle crank of  claim 16 , wherein said inserts are made of fiber-reinforced plastic material.  
   
   
       19 . The bicycle crank of  claim 13 , wherein said elongated core is rigid.  
   
   
       20 . The bicycle crank of  claim 13 , wherein said elongated core provides little or no structural resistance.  
   
   
       21 . The bicycle crank of  claim 19 , wherein said elongated core is made of plastic.  
   
   
       22 . The bicycle crank of  claim 19 , wherein said elongated core is made of metal.  
   
   
       23 . The bicycle crank of  claim 19 , wherein said elongated core is made of fiber-reinforced plastic material.  
   
   
       24 . The bicycle crank of  claim 13 , wherein said elongated core comprises end portions in which said inserts are connected to establish a shape coupling.  
   
   
       25 . Method of manufacturing a bicycle crank, comprising the following steps: 
 a) forming an elongated rigid core;    b) applying a pair of inserts to the opposite ends of said elongated core;    c) surrounding the core and inserts with a coating of structural fibres incorporated in a plastic material matrix; and    d) hardening said plastic material matrix to form a high resistance rigid casing enclosing said elongated core and said inserts.    
   
   
       26 . Method of manufacturing a bicycle crank comprising the following steps: 
 a) providing an elongated core having first and second ends;    b) positioning at least one insert adjacent to at least one end of the core;    c) applying a fibrous structural plastic material to the core and the insert; and    d) hardening the plastic material to form a structural casing enclosing the core and the insert to provide substantially all of the structural connection to the insert.