| 摘要 |
<p>PURPOSE:To re-engage a chain with a sprocket on the large diameter side by providing a mechanism wherein a chain support step part lifts a chain toward a part with which a chain is re-engaged and arranging a chain support part to the side of a spot where the chain is lifted to a target of chain engagement. CONSTITUTION:When a sprocket is placed in its rotation while a derailer is operated, chain support parts 9, 10, and 11 are rotated around a spot below a chain located closer to a sprocket S1 on the large diameter side and perform support operation. When rotation further progresses, the sprocket S1 on the large diameter side lifts a chain 4 through the working of the chain support parts 9, 10, and 11. Along with lifting of the chain 4 toward target parts 15, 16, and 17 for chain engagement, the chain 4 is lifted to the target parts 15, 16, and 17, for chain engagement, through operation of the derailer. As noted above, since the chain support parts 9, 10, and 11 perform support operation in a state to be non-engaged with the chain 4, re-engaging operation is reliably carried out through a light operation force regardless of the increase and the change of a running load.</p> |
