| 摘要 |
A dual derailleur bicycle gearshift comprises a first cable pull member pivotally secured to a support for rotation about a first axis and a second cable pull member pivotally secured to the first cable pull member for rotation about a second axis perpendicular to the first axis, wherein the second cable pull member defines a single actuator that is centered on both axes for pivotal movability within a first arc located within a first plane that extends axially of and contains the first axis to rotate the second cable pull member about the second axis and pivotal movability within a second arc located within a second plane that extends axially of and contains the second axis to rotate the first cable pull member about the first axis. In a handlebar mounted embodiment the first cable pull member rotates about a longitudinal axis of the bicycle's handlebar and the actuator is a yoke centered on both axes and having one end defining the second cable pull member. In a handlebar stem mounted embodiment the actuator is a lever and the first cable pull member is notched for centering the lever on both axes. In each embodiment a first bracket member stationary with the support provides anchorage for a casing associated with a cable pulled by the first cable pull member, and a second bracket member rotatable with the first cable pull member provides anchorage for a casing associated with a cable pulled by the second cable pull member.
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