| 摘要 |
A lost motion chain wheel assembly to prevent brake lock up in a bicycle having a pedal crank shaft operated brake, has a chain wheel center or spider fast to a pedal crank and providing an annular channel receiving the inner periphery of an annular chain wheel rim, the rim and the center being coupled by dogs within the channel forming projections into recesses in the internal periphery of the rim, and connected by a bias spring. The recesses have a greater peripheral extent than the projections so as to provide the desired lost motion, and both recesses and projections are inwardly inclined at their ends to provide abutting surfaces which cushion the impacts occurring at the ends of the relative travel of the parts. The center or spider and the rim may readily be adapted from parts of a conventional double chain wheel.
|
