| 摘要 |
A relatively simple jack which can be manually operated using a wrench or mechanically operated using a driven socket wrench includes an elongated, upwardly tapering, square cross section casing, with a slot extending longitudinally of one side wall thereof, an endless chain mounted on sprockets at the top and bottom ends of the casing, and an off-the-shelf slack adjuster mounted on an upper side wall of the casing for driving the chain, which is engaged by a pawl having a load support arm extending outwardly through the slot in the front wall of the casing. By rotating the worm gear drive of the slack adjuster, the load support arm can be caused to move vertically in the slot to raise or lower a load.
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