Patent Publication Number: US-2003235356-A1

Title: Bottom bracket assembly for bicycles

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates to a bottom bracket assembly for bicycles wherein two bearings are mounted close to one end of the axle and positioned by two flanges and the other end of the axle has one bearing. The arrangement of the bearings ensures that axle to rotate smoothly.  
       BACKGROUND OF THE INVENTION  
       [0002] A conventional bottom bracket assembly for bicycles generally includes an axle with two bearings mounted thereto and two cranks are connected to two ends of the axle. The bottom bracket assembly is too heavy so that many efforts have made to reduce the weight of the conventional bottom bracket assembly. A hollow axle is used to replace the conventional solid axle and in order to install the two bearings to two ends of the axle, each end of the axle has an enlarged cup in which the bearing is received. However, the single bearing on each end of the axle does not provide sufficient support to the load on the axle so that the axle could be deformed after being used for a period of time. Besides, a gap could be formed when installing the bearings to the enlarged cups and noise generates when the bottom bracket assembly is operated.  
       [0003] The present invention intends to provide a bottom bracket assembly wherein the axle is supported by three sets of bearing.  
       SUMMARY OF THE INVENTION  
       [0004] In accordance with one aspect of the present invention, there is provided a bottom bracket assembly which comprises an axle received in a bottom bracket and has two first flanges extending radially outward from an outer periphery of the axle and located close to a first end of the axle. A second flange extends radially outward from the outer periphery of the axle and located close to a second end of the axle.  
       [0005] Two first bearings are mounted to the axle and engaged with the two first flanges respectively. Two first retaining rings are respectively mounted to the two first bearings. A second bearing is mounted to the axle and engaged with the second flange. A second retaining ring is mounted to the second bearing.  
       [0006] An outer tube is mounted to the axle and engaged between one of the first retaining rings and the second retaining ring. Two locking members are respectively connected to two ends of a bottom bracket so as to position the axle.  
       [0007] The primary object of the present invention is to provide a bottom bracket assembly that has bearings mounted on the axle such that the axle is rotated smoothly.  
       [0008] The present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.  
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0009]FIG. 1 is an exploded view to show a bottom bracket assembly of the present invention;  
     [0010]FIG. 2 is a cross sectional view to show the bottom bracket assembly of the present invention;  
     [0011]FIG. 3 is a perspective view to show the bottom bracket assembly of the present invention with a part of the bottom bracket removed, and  
     [0012]FIG. 4 is a perspective view to show the bottom bracket assembly of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
     [0013] Referring to FIGS.  1  to  4 , the bottom bracket assembly of the present invention comprises an axle  10  which is received in a bottom bracket  50  of a bicycle and each end of the axle  10  has a connection end  111 ,  112  for cranks (not shown) connected to the two connection ends  111 ,  112  respectively. Two first flanges  101 ,  102  extend radially outward from an outer periphery of the axle  10  and are located close to a first end of the axle  10 . A second flange  103  extends radially outward from the outer periphery of the axle  10  and the second flange  103  is located close to a second end of the axle  10 .  
     [0014] Two first bearings  301 ,  302  are mounted to the axle  10  and engaged with the two first flanges  101 ,  102  respectively. A second bearing  303  is mounted to the axle  10  and engaged with the second flange  103 .  
     [0015] Two first retaining rings  401 ,  402  are respectively mounted to the two first bearings  301 ,  302 , and a second retaining ring  403  is mounted to the second bearing  303 . An outer tube  20  is mounted to the axle  10  and engaged between one of the first retaining rings  401 ,  402  and the second retaining ring  403  as shown.  
     [0016] Two locking members  51 ,  52  each have a threaded section which is threadedly connected to an inner periphery of the two ends of the bottom bracket  50 . The adapted to be connected to two ends of a bottom bracket so as to position the axle  10 .  
     [0017] The  10  is well supported by the bearings  301 ,  302  and  303 , and each bearing  301 / 302 / 303  is retained by respective retaining ring  401 / 402 / 403  so that the axle  10  is rotated smoothly and the structural strength of the whole bottom bracket assembly is reinforced.  
     [0018] While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.