| 摘要 |
<p>A derailleur 12 for a bicycle 10 is provided that is easy to operate. The derailleur 12 basically has a mounting member 40, a chain guide 42 and a chain guide positioning mechanism 48. The mounting member 40 is adapted to be coupled to a portion of the bicycle 10. The chain guide 42 is movably coupled to the mounting member 40. The chain guide 42 is adapted to shift a chain 20 of a bicycle 10 in a transverse direction. The chain guide positioning mechanism 48 has an actuating cam 71 operatively coupled to the chain guide 42. The actuating cam 71 is adapted to be coupled to a control element 18 such as a cable. The actuating cam 71 is arranged to rotate only in one direction in response to movement of the control element 18 to move the chain guide 42 from a first position to a second position. In the preferred embodiment, the chain guide positioning mechanism 48 includes one-way clutch coupled to the actuating cam 71, and an indexing mechanism 74 with an indexing element 90 that is arranged to operatively apply a retaining force to the actuating cam 71. The one-way clutch has a ratchet 70 fixedly coupled to the actuating cam 71 and an actuating element 80 with a pawl 81 engaging the ratchet 70. The actuating element 80 is adapted to be coupled to the control element 18 such that the control element 18 rotates the actuating element 80, which in turn engages the ratchet 70 to rotate the actuating cam 71 and moves the chain guide 42. <IMAGE></p> |
