| 摘要 |
A derailleur for a bicycle, which is adapted to shift a driving chain to a selected one of two or more sprocket wheels by pushing or pulling a push-pull control wire. The derailleur is provided with at least one arm oscillating independently from a movable member in shifting one of the push-pull wire and an outer cable for the wire. The wire is secured to the arm and a spring is secured to the arm so that when the movable member is, in changing speed, loaded above a predetermined value, the arm is oscillated to prevent the wire from buckling. On the other hand, when the resistance is removed the energy stored in the spring by the oscillation of the arm allows the movable member to shift so that the driving chain may be shifted to a desired speed-changing stage.
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