| 摘要 |
An enclosed bicycle drivetrain is provided that produces a range of drive ratios suitable for any riding purpose. The enclosure of substantially the entire drivetrain is made practical by the synergistic cooperation of a planetary drive system using a single chain ring and a streamlined rear derailleur system that separates the tensioning and chain guiding functions of a conventional rear derailleur, allowing the rear derailleur components to remain substantially within the shadow of the outer perimeter of the bicycle frame. The planetary drive system is provided with a unique compound pawl that may be easily disengaged from a planetary ratchet member under full riding loads by the application of a small force to destabilize the pawl. A unique shift buffer mechanism cooperates with the rear derailleur system to buffer and store up to the full range of available shift commands.
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