Patent Publication Number: US-2011073430-A1

Title: Bicycle hub having pawl retaining function

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a bicycle hub having pawl retaining function that can prevent from flexibility fatigue and to prolong service life of the hub body and the ratchet barrel. 
     2. Description of the Prior Art 
     Referring to  FIGS. 1 and 2 , a conventional bicycle hub having pawl retaining function includes a hub body  70 , a ratchet barrel  71 , a plurality of pawl members  72 , a binding member  73 , a shaft  74 , and a bearing  75 , wherein the hub body  70  includes a ratchet face  701  disposed on one side thereof, and the ratchet barrel  71  includes a positioning holder  711  mounted on one end thereof relative to the ratchet face  701  of the hub body  70 , the positioning holder  711  includes a plurality of receiving cavities  712  formed thereon to receive the pawl members  72 , and between the receiving cavities  712  are arranged a number of engaging slots  713  on raised rims thereof, and each pawl member  72  including a groove  720  disposed thereon in response to the retaining slots  713 , such that an open metal member  76  with a notch is used to bind the pawl members  72  to the positioning holder  711  so that the ratchet barrel  71  is engaged to the ratchet face  701  of the hub body  70 , hence as the pawl members  72  engage with each other, some biased pawl members  72  push the other pawl members  72  to extend outward, such that as the ratchet barrel  71  is actuated by a linked member, the pawl members  72  actuate the hub body  70  and a spoke connected on the hub body  70  to rotate forward. In addition, when the hub body  70  and the ratchet barrel  71  rotate relative to each other, the ratchet face  701  of the hub body  70  pushes the pawl members  72  downward, therefore the pawl members  72  do not engage with each other and the hub body  70  and the ratchet barrel  71  rotate idly. 
     Furthermore, although the pawl members  72  of the ratchet barrel  71  are pushed to extend outward (as shown in  FIGS. 3 and 4 ), because the metal member  76  is made of an arcuate metal line, it interferes with the pawl members  72  each other, causing flexibility fatigue. 
     The present invention has arisen to mitigate and/or obviate the afore-described disadvantages. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention is to provide a bicycle hub having pawl retaining function that can prevent from flexibility fatigue and to prolong service life of the hub body and the ratchet barrel. 
     A bicycle hub having pawl retaining function in accordance with a preferred embodiment of the present invention comprises: 
     a hub body including a ratchet face disposed on one end thereof to fit a connecting end of a ratchet barrel, the ratchet barrel including a positioning holder mounted on one end thereof relative to the ratchet face of the hub body, the positioning holder including a number of receiving cavities to receive pawl members, and between the receiving cavities being arranged a number of engaging slots on raised rims thereof, and each pawl member including a retaining groove fixed thereon relative to the engaging slot of the receiving cavity so that the pawl members are positioned in the receiving cavities of the positioning holder by using a binding member and one end of each pawl member extends flexibly, hence the ratchet barrel is engaged to the ratchet face of the hub body securely, characterized in that: 
     the binding member is a closed spring member so that as the pawl members are bound and retained to the positioning holder, the pawl members swing independently from each other by ways of the binding member to prevent from flexibility fatigue and to prolong service life of the hub body and the ratchet barrel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view showing the exploded components of a conventional bicycle hub having pawl retaining function; 
         FIG. 2  is a cross sectional view showing the assembly of a ratchet barrel and a plurality of pawl members of the conventional bicycle hub having pawl retaining function; 
         FIG. 3  is a cross sectional view showing the operation of the pawl members of the conventional bicycle hub having pawl retaining function; 
         FIG. 4  is a partial amplified view of  FIG. 3 ; 
         FIG. 5  is a perspective view showing the exploded components of a bicycle hub having pawl retaining function according to a preferred embodiment of the present invention; 
         FIG. 6  is a perspective view showing the assembly of a ratchet barrel and a plurality of pawl members of the bicycle hub having pawl retaining function according to the preferred embodiment of the present invention; 
         FIG. 7  is a cross sectional view of  FIG. 6 ; 
         FIG. 8  is a cross sectional showing the operation of the pawl members of the bicycle hub having pawl retaining function according to the preferred embodiment of the present invention; 
         FIG. 9  is a partial amplified view of  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will be clearer from the following description when viewed together with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiment in accordance with the present invention. 
     Referring to  FIGS. 5-7 , a bicycle hub having pawl retaining function according to a preferred embodiment of the present invention comprises a hub body  10 , a ratchet barrel  20 , a plurality of pawl members  30 , a binding member  40 , a shaft  50 , and a bearing  60 , wherein 
     the hub body  10  includes a ratchet face  11  disposed on one end thereof to fit a connecting end of the ratchet barrel  20 , the ratchet barrel  20  includes a positioning holder  21  mounted on one end thereof relative to the ratchet face  11  of the hub body  10 , the positioning holder  21  includes a number of receiving cavities  210  to receive the pawl members  30 , and between the receiving cavities  210  are arranged a number of engaging slots  211  on raised rims thereof, and each pawl member  30  includes a retaining groove  31  fixed thereon relative to the engaging slot  211  of the receiving cavity  210  so that the pawl members  30  are positioned in the receiving cavities  210  of the positioning holder  21  by using the binding member  40  and one end of each pawl member  30  extends flexibly, hence the ratchet barrel  20  is engaged to the ratchet face  11  of the hub body  10  securely, an improvement of the present invention comprises: 
     the binding member  40  is a closed spring member so that as the pawl members  30  are bound and retained to the positioning holder  21 , the pawl members  31  swing independently from each other by ways of the binding member  40  to prevent from flexibility fatigue and to prolong service life of the hub body  10  and the ratchet barrel  20 . 
     In operation, as shown in  FIGS. 8 and 9 , when the pawl members  30  are bound and retained to the positioning holder  21  of the ratchet barrel  20  by the binding member  40 , one ends of the pawl members  30  extend out of the receiving cavities  210  of the positioning holder  21  so that as the ratchet barrel  20  engages with the ratchet face  11  of the hub body  10 , the pawl members  30  are retained to the ratchet face  11  to actuate a wheel to rotate forward or idly. Besides, after the pawl members  30  are bound by the binding member  40 , some pawl members  30  are biased against to extend outward so as not to be interfered by other pawl members. 
     Thereby, the pawl members  30  are not interfered by each other to obtain preferred flexibility, prevent from flexibility fatigue and prolong service life of the hub body  10  and the ratchet barrel  20 . 
     It is preferable that the binding member  40  is covered by a flexible film  41  made of rubber material to enhance strength, thus prevent from break. 
     While we have shown and described various embodiments in accordance with the present invention, it is clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.