| 摘要 |
The hoist comprises at least one jack (1) controlled by a screw (6) and from which the load is suspended by connectors. The jack is suspended from a support (2) so that the load (9) can be raised by rotating the screw in one direction and lowered by rotating it in the other. The jack's screw is engaged with a nut forming one of its pivots, and it can have ball bearings on either side of the pivot at the opposite end of the screw.In a variant of the design, the hoist can incorporate two parallel overhead rails, with the jack mounted on rollers running in the rails, which can be of U-section and fixed to a ceiling. The jack's screw can be operated by a reversible ratchet mechanism (10). ADVANTAGE - More convenient to use, allowing load to be raised and lowered without shocks.
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