| 摘要 |
A multi-speed bicycle transmission located in the pedal hub and actuable through the drive pedals. Drive gears (92, 94, 96) are rotatable about the pedal shaft (32) and can be selectively brought into driving engagement with the shaft by means of a mechanism including a shiftcollar (312), the axial position of the collar along the pedal shaft determining which drive gear is engaged. A shift pin (308) extends into the hub from a tubular frame member and is displaceable radially against a spring (310). Inclined camming channels (320,322) in the shift collar (312) cooperate with the shift pin and are shaped to effect longitudinal displacement of the collar upon reverse rotation of the pedal shaft. On forward rotation of the pedal shaft, the shift pin (308) is forced radially outwardly and no longitudinal displacement of the collar is effected. |
