| 摘要 |
A drive mechanism for a driven member having a hub (15) and rim (2) coaxial with and supported by the hub (15) comprises at least two transmission cables (12) which extend between the hub (15) and the rim (2). One end of each transmission cable (12) is secured to the hub (15) and extends from the hub (15) over a guiding sheave journalled within a pulley block (13) fastened to the rim (2) and then extends from the pulley block (13) to the next contiguous, pulley block (13) in a direction opposite to that in which the driven member is to be rotated. The distal end of the transmission cable is attached to this next contiguous pulley block (13). Tensioners (17) are provided for pre-tensioning each cable (12). The driven member can be the rear wheel of a bicycle whereby the extension of the cables (12) can provide a lag between the turning of the hub (15) and the rim (2) thereby effectively providing a variable ratio gearing.
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