| 摘要 |
A lift frame adapted to be pivotally mounted on a hoist include a tubular sleeve guide that guides a lift slide. The lift slide carries a lift frame for supporting a load such as a beam or truss to be lifted, and is spring loaded in an upward direction by a spring extending between a slider tube and the lift frame. The spring keeps the bracket seated on the load for a limited distance along the lift path. The lift slide has a stop that limits the amount of downward movement of the lift slide relative to the guide as the load is lifted. Specifically, a pair of frames are mounted at opposite ends of a spreader bar for lifting an elongated beam. A bracket on each lift slide engages one end of the beam and supports it under spring load for a selected amount of vertical travel, and thereafter the beam or load is directly lifted mechanically by having the stop on the lift slide engaging the sleeve guide.
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