| 摘要 |
In a multi-speed sprocket assembly for a bicycle having at least one large sprocket with teeth and one small sprocket with teeth disposed adjacent each other and selectively engageable with a drive chain of the bicycle consisting of a series of pivotably connected link plates, the improvement includes a chain receiving portion formed on a reference tooth of the large sprocket so as to receive a connecting portion of the link plates with diametrical clearance from a tooth space bottom of the large sprocket. The teeth of the small sprocket have such phase relationship relative to the chain receiving portion of the large sprocket that a tooth of the small sprocket positioned downstream relative to the reference tooth engages with the chain when the connecting portion of the chain is received by the chain receiving portion of the reference tooth. A cutout portion for preventing interference with the link plates is provided to a tooth of the small sprocket positioned within a path of the link plates of a chain portion positioned more upstream than a chain portion engaging the small sprocket and moving to the chain receiving portion. With the improvement, the chain shifting operation from small to large sprockets can be effected smoothly yet reliably.
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