| 摘要 |
This invention is a variable speed transmission member for bicycles for engagement with a positive drive belt. It includes a variable radius sprocket and a means to control its effective radius. The variable radius sprocket is a rotatable disc with a plurality of radial slots therein. A slidable sprocket segment is mounted in each slot. Each segment has a spring biased retaining means to lock it at a particular radial location. The means to control the effective radius of the segments comprises a plurality of pivotal prongs positioned so that they can be pivoted, under manual control, into the path of the segments to push the segments to a different radial location.
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