| 摘要 |
A self-tailing capstan for use in pulling and/or hoisting heavy loads or for tensioning lines, etc., includes a frame upon which first and second drums are rotatably mounted with their axes parallel. The first drum is rotatable in only one direction with reverse rotation being prevented typically by a ratchet and pawl assembly, while the second drum is freely rotatable in either direction. A detachable turning means such as a lever is provided the preferred embodiment of the invention to turn either drum as desired. In operation of the preferred embodiment, a flexible line is wrapped at least once around each drum. The length of line winding onto the two drums during hauling is defined as the "leading segment," and the length of line unwinding from the second drum is defined as the "tailing segment." The tailing segment always passes through a block attached either to the load or to a fixed anchor. The leading end of the line is attached to either the load or the anchor, except when the frame itself is anchored, in which case the leading end passes through a block and then is attached to a block or blocks through which one or more parts of the tailing segment is passed. The frictional grasp of the line wraps around the second drum is greater than that of the wraps around the first drum so that reverse rotation of the second drum may release line tension or lower the load without disengagement of the first drum's ratchet and pawl assembly.
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