| 摘要 |
The gear drive from the hand wheel to the chain drum includes a worm wheel coaxial with the chain drum. An idler shaft parallel to the plane of the worm wheel carries a worm engaging the worm wheel and a bevel gear. The hand wheel shaft is parallel to the chain drum shaft and carries a bevel gear engaging the bevel gear on the idler shaft. Between the worm wheel and the chain drum is a release mechanism which includes a release ring which when rotated about the axis of the chain drum is cammed to push a release plate into disengagement position. This release ring has a gear segment thereon which is engaged by a gear segment on a release actuating lever. In a modified embodiment this release lever also carries a cam which urges a brake shoe against a brake drum on the chain drum to apply a restraining force to the chain drum when the release mechanism is released. There is also described a similar type of brake for chain drum drag on a conventional hand brake mechanism which utilizes only spur gears rather than a worm gear drive.
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