| 摘要 |
The derailleur includes a relatively long, torsion-resisting bar extending below and generally along one of the two rear wheel-supporting bicycle frame members. The front end of said bar is held by a fastener secured to the bicycle frame adjacent the housing of the pedalling axle. The holder prevents the bar from rotating about its long axis. The rear end of the bar is movable transversely of the frame member by a remote control actuator. The rear end of said bar carries a drive chain idle transfer and a chain take-up device which serve to transfer the drive chain from one to another rear drive sprocket, while taking up the slack in the chain. The chain take-up device preferably comprises an elongated member supported by and extending alongside the bar, movable longitudinally along said bar and carrying at its rear end a drive chain engaging idle sprocket. The elongated member is biased rearwardly. The rear end of the bar carries a hook selectively engaging anyone of several positioning recesses made in a plate fixed to the frame member, whereby the bar can be positioned transversely of the frame member to maintain the drive chain transfer member in alignment with the selected drive sprocket socket. The invention is also directed to two types of derailleurs for the front crank sprockets and to combined front and rear derailleurs.
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