| 摘要 |
<p>The invention aims at obtaining a mechanical lifting jack of minumum height and in which friction on rotation of the rotating parts is low even under high load. The lifting jack comprises a rigid body (17) defining a cylindrical ram passage (41) and a planar base (28). A cylindrical plate (83) rests above the interior surface of base (28) and supports a beveled gear (27). A threaded screw bar (14) is attached to beveled gear (27) and extends upwardly therefrom. A threaded sleeve (21) is received by screw base (14) and supports a ram (16). The latter is movable within ram passage (41) and terminates in a load bearing head (10). A pinion gear (90) is supported in engagement with beveled gear (27) and is coupled to a conventional ratchet drive (92). A siding pad (29) formed of a layer of a fluorine resin material having a low frictional coefficient and self-lubricating property, is interposed between plate (83) and base (28) to act as a bearing for beveled gear (27).</p> |
