| 摘要 |
<p>A derailleur for use with a multi-stage sprocket assembly of a cycle, said derailleur comprising; a fixing member (1) and a derailleur body having a parallelogram linkage comprising a support member (2), a pair of link members (3, 4) each pivotally connected to said support member (2) and to a movable member (5), which mounts a chain shift means (14), said derailleur body including a return spring (27) arranged for biasing said movable member (5) unidirectionally, said derailleur body being pivotally mounted (6) on said fixing member (1) via said support member (2), said chain shift means (14) being pivotally movable relative to said movable member (5), which along with the chain shift means (14) has a tension spring (31) disposed for acting therebetween and biasing said derailleur body counterclockwise relative to said fixing member (1), one of the members (3 to 5) of the derailleur body having a control wire (W) secured thereto, so that displacement thereof will transform the parallelogram linkage against the biasing force of said return spring (31) and swing said derailleur body relative to said fixing member (1) against the biasing force of said tension spring (27).</p><p>According to this invention there is provided a step-wise feed means (21, 23) disposed for acting between said fixing member (1) and said derailleur body, said feed means (21, 23) being operable, in use, by said wire (W) to swing said derailleur body step-wise in correspondence with speed changes between different sprockets of said multi-stage sprocket assembly, relative to said fixing member (1) and to subsequently transform said derailleur body, when changing from one speed to another corresponding to shifting of the drive chain from a higher speed sprocket to a lower speed sprocket of the multi-stage sprocket assembly in use of the derailleur.</p> |
