Planetary gear mechanism for a bicycle

Abstract

A planetary gear mechanism for a bicycle, and more particularly to a planetary gear mechanism comprising a first planetary mechanism connected coaxially in series to a second planetary mechanism, which second planetary mechanism is connected coaxially in series to a third planetary mechanism, the second planetary mechanism output is a step up in speed from the first planetary mechanism output, the third planetary mechanism output is a step up in speed from the second planetary mechanism output.

We claim: 
     
         1 . A bicycle comprising:
 a frame ( 30 );   a planetary gear transmission comprising an input member ( 22 ), a first planetary mechanism, a second planetary mechanism and a third planetary mechanism, and an output member ( 44 );   the first planetary mechanism, second planetary mechanism and third planetary mechanism are each connected in series; and   a flexible drive member ( 50 ) drivingly engaged between the output member ( 44 ) and a wheel ( 34 ).   
     
     
         2 . The bicycle as in  claim 1 , wherein:
 the input member is connected to the first planetary mechanism;   the second planetary mechanism rotary output is a step up in speed from the first planetary mechanism rotary output, the third planetary mechanism rotary output is a step up in speed from the second planetary mechanism rotary output; and   the third planetary mechanism is connected to the output member.   
     
     
         3 . A bicycle comprising:
 a frame having a bottom bracket;   a planetary gear transmission comprising an input member, a first planetary mechanism, a second planetary mechanism and a third planetary mechanism, and an output member, the first planetary mechanism, second planetary mechanism and third planetary mechanism are each connected in series;   the planetary gear transmission disposed in the bottom bracket; and   a flexible drive member drivingly engaged between the output member and a rear wheel.   
     
     
         4 . The bicycle as in  claim 3 , wherein the planetary gear transmission comprises twelve output gear ratios. 
     
     
         5 . The bicycle as in  claim 3 , wherein the flexible drive member comprises a belt. 
     
     
         6 . The bicycle as in  claim 3 , wherein the input member comprises a crank. 
     
     
         7 . The bicycle as in  claim 5 , wherein the output member comprises a sprocket, the sprocket having a plurality of holes, each hole being engagable by a belt tooth.