Living hinge member and suspension

Abstract

A structural member ( 38, 40 ) is designed to have a first portion having a first composite layup, a second portion having a second composite layup, and at least one center portion having at least a third composite layup such that it can flex near a desired point of the structural member. The structural member may be used as a chain stay ( 26 ) in a bicycle frame ( 10 ). The chain stays are designed to have a geometry that will allow for flexing or bending at or in the vicinity of a desired point. They may be pre-loaded for flex in both a positive and negative direction. The chain stays are designed having a varying cross sectional area. The bending or flexing location of the chain stays has a narrower height from the side view than the ends of the chain stay allowing the chain stay to flex. Additionally, the bending or flexing location has a wider width from the top view than the ends of the chain stay for additional torsional and lateral stiffness.

What is claimed:  
     
         1 . A structural member having a longitudinal axis comprising: 
 a first portion having a first composite layup;    a second portion having a second composite layup; and    at least one center portion having at least a third composite layup and disposed between the first portion and the second portion;    wherein the first, second, and center portions are formed integrally into the structural member and are configured and dimensioned to flex at or in the vicinity of at least one desired point along a length of the structural member allowing displacement relative to a longitudinal axis of the structural member.    
     
     
         2 . The structural member of  claim 1 , wherein at least one of the first composite layup, the second composite layup or the third composite layup includes at least one layer of carbon braid.  
     
     
         3 . The structural member of  claim 1 , wherein at least one of the first composite layup, the second composite layup or the third composite layup includes at least one layer of glass fibers.  
     
     
         4 . The structural member of  claim 1 , wherein at least one of the first composite layup, the second composite layup or the third composite layup includes a matrix of at least a plurality of fibers and a binder.  
     
     
         5 . The structural member of  claim 4 , wherein the binder is a resin, and the plurality of fibers is at least one of glass or carbon.  
     
     
         6 . The structural member of  claim 5 , wherein the plurality of fibers of glass are aligned parallel to the longitudinal axis of the structural member.  
     
     
         7 . The structural member of  claim 5 , wherein the plurality of fibers of carbon are braided in strands at a ±45° angle relative to the longitudinal axis of the structural member.  
     
     
         8 . The structural member of  claim 1 , wherein at least one of the first composite layup, the second composite layup or the third composite layup is formed of at least two layers of material.  
     
     
         9 . The structural member of  claim 8 , wherein a plurality of layers of materials are provided in each portion and at least some of the plurality of layers of material overlap between the portions.  
     
     
         10 . The structural member of  claim 8 , wherein at least one layer of material has a different longitudinal length than the other layers of material.  
     
     
         11 . The structural member of  claim 1 , wherein the first composite layup, the second composite layup and the third composite layup are substantially the same.  
     
     
         12 . The structural member of  claim 1 , wherein the first composite layup and the second composite layup are substantially the same.  
     
     
         13 . The structural member of  claim 1 , wherein the structural member is a chain stay.  
     
     
         14 . The structural member of  claim 1 , wherein at least one of the center portion, the first portion, or the second portion has a cross-sectional area different from the other portions.  
     
     
         15 . The structural member of  claim 1 , further comprising a first section, a second section, and at least one center section connecting the first and second sections such that at least one of the center section, the first section, or the second section has a cross-sectional area different from the other sections.  
     
     
         16 . The structural member of  claim 1 , further comprising a reinforcement associated with the structural member.  
     
     
         17 . The structural member of  claim 16 , wherein the reinforcement is provided inside the structural member.  
     
     
         18 . The structural member of  claim 16 , wherein the reinforcement is at least one of aluminum, balsam wood, plastic and structural foam and is positioned inside the structural member.  
     
     
         19 . The structural member of  claim 16 , wherein the reinforcement is associated with at least the first, second or center portions.  
     
     
         20 . A frame comprising: 
 a front portion for locating a steering assembly, a seat assembly and a pedal assembly in spacial relation to each other;    a rear portion connected to the front portion, comprising, 
 a bottom bracket for operatively connecting the pedal assembly,  
 a pair of dropouts spaced from the bottom bracket  
 a pair of seat stay tubes coupled adjacent to the seat assembly and extending generally rearwardly and downwardly to the associated dropout, and  
   a pair of chain stay tubes spaced from one another and extending generally rearwardly from the bottom bracket to the associated dropout,    wherein each chain stay tube is a structural member according to  claim 1 .    
     
     
         21 . A structural member comprising: 
 a tubular member configured and dimensioned by at least one of its geometry, cross-sectional geometry, thickness, and material variations to flex at or in the vicinity of at least one desired point along a length of the structural member allowing bending displacement relative to a longitudinal axis of the structural member.    
     
     
         22 . The structural member of  claim 21 , further comprising: 
 a first section;    a second section; and    at least one center section connecting the first and second sections such that the center section has a cross-sectional geometry different from the first and second sections.    
     
     
         23 . The structural member of  claim 22 , wherein the structural member is a chain stay of a bicycle frame.  
     
     
         24 . The structural member of  claim 22 , wherein the center section further includes: 
 an arc having a length;    wherein the structural member has an overall length and a ratio of the overall length of the arc to the length of the structural member is at most 0.3.    
     
     
         25 . The structural member of  claim 22 , wherein the structural member further includes: 
 a first height of the center section; and    a second height of the first or second sections,    wherein the ratio of the height of the center section to the height of the first or second sections is at least 0.3.    
     
     
         26 . The structural member of  claim 22 , wherein the structural member further includes: 
 a first width of the center section; and    a second width of the first or second sections,    wherein the ratio of the width of the center section to the width of the first or second sections is at least 1.3.    
     
     
         27 . A bicycle frame comprising: 
 a front portion for locating a steering assembly, a seat assembly and a pedal assembly in spacial relation to each other;    a rear portion connected to the front portion, comprising, 
 a bottom bracket for operatively connecting the pedal assembly,  
 a pair of dropouts spaced from the bottom bracket  
 a pair of seat stay tubes coupled adjacent to the seat assembly and extending generally rearwardly and downwardly to the associated dropout, and  
   a pair of chain stay tubes according to  claim 22 , said chain stay tubes being spaced from one another and extending generally rearwardly from the bottom bracket to the associated dropout.    
     
     
         28 . The frame of  claim 27 , wherein each chain stay tube is pre-loaded for flex in a positive and negative direction such that a total travel of each chain stay tube is greater than the displacement in either the positive or negative direction from the longitudinal axis.  
     
     
         29 . The frame of  claim 28 , wherein each chain stay tube is pre-loaded at least one-quarter inch in the negative direction relative to the longitudinal axis.  
     
     
         30 . The frame of  claim 27 , further comprising 
 a link connecting the seat stay tubes to the seat tube; and    a seat stay bridge member connecting the seat stay tubes and the link.    
     
     
         31 . The frame of  claim 27 , wherein each chain stay tube further includes: 
 a first section;    a second section; and    at least one center section connecting the first and second sections such that at least one of the center section, the first section, or the second section has a cross-sectional area different from the other sections.    
     
     
         32 . The frame of  claim 27 , wherein each chain stay tube further includes: 
 a first portion having a first composite layup;    a second portion having a second composite layup; and    at least one center portion having a third composite layup and disposed between the first and second portions.    
     
     
         33 . The frame of  claim 32 , wherein at least one of the first composite layup, the second composite layup or the third composite layup includes at least one layer of carbon braid or uniglass.  
     
     
         34 . The frame of  claim 32 , wherein a plurality of layers of materials are provided in each of the first, second and center portions and at least some of the plurality of layers of material overlap between the portions.  
     
     
         35 . A chain stay for a bicycle frame comprising: 
 a composite tubular member having a length and being formed from a plurality of layers of material, said layers including: 
 a first inner layer extending along a predetermined length;  
 at least one second layer positioned over the first layer and formed as two second portions spaced apart from one another and positioned substantially at the ends of the tubular member;  
 at least one third layer positioned over the at least one second layer and formed as two third portions spaced apart from one another and positioned substantially at the ends of the tubular member;  
 at least one fourth layer positioned over the at least one third layer and centered on the first member and extending partially along the predetermined length of the first layer; and  
 at least one fifth layer positioned over the at least one fourth layer and centered on the first layer.  
   
     
     
         36 . The chain stay of  claim 35 , wherein at least the first inner layer, the at least one fourth layer, and the at least one fifth layer, is made of at least carbon fibers.  
     
     
         37 . The chain stay of  claim 35 , wherein at least the at least one second layer and the at least one third layer is made of at least glass fibers.  
     
     
         38 . The chain stay of  claim 35 , wherein the at least fifth layer extends the length of the tubular member to substantially cover the first inner, the at least one second, the at one least third and the at least one fourth layers.  
     
     
         39 . The chain stay of  claim 38 , wherein the at least one fifth layer includes a total of three layers, each of which has a length equal to or greater than the length of the tubular member.  
     
     
         40 . The chain stay of  claim 35 , wherein the two second portions and the two third portions have different lengths.  
     
     
         41 . The chain stay of  claim 35 , wherein at least one of the at least one second layer, the at least one third layer, and the at least one fourth layer overlap.