| 摘要 |
A variable speed ratio multiple sprocket and chain drive, particularly applicable to bicycles, using stacks of resilient sprocket rings (2, 3, 22, 23), each of which is radially split to define resilient sectors (15', 15''). For shifting, the resilient sectors (15', 15'') are axially deflected so that the rows of teeth of adjacent sprocket rings (2, 3, 22, 23) are aligned with one another thereby permitting a roller chain (5) entrained around one sprocket ring (22, 23) to transfer to an adjacent sprocket ring (23, 22) of different pitch diameter, thus changing the drive ratio. A control system (8, 99, 100, 101) is mechanically linked to a resilient sector deflection mechanism (30, 39, 40, 41). The control system (8, 99, 100, 101) tracks which driving sprocket ring (3, 21, 22, 23) and which driven sprocket ring (2, 21, 22, 23) are engaged by the chain (5), and selects either the stack (3) of driving sprocket rings or the stack (2) of driven sprocket rings for shifting so as to allow a rider to change the drive ratio up or down at will.
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