| 摘要 |
An inexpensive, self-locking, high-lift jack constructed of high strength materials. The jack comprises a rail having spaced apart parallel rows of offset notches and a base support stand in which the rail is vertically mounted. A rider member reciprocates on the rail. The rider includes a crankshaft having two diametrically offset pinions projecting out from opposite faces of a central support surface thereof. Each pinion is positioned to engage the notches of one of the pair of parallel rows of notches on the rail. The crankshaft is fixed to and projects from the rider housing which encloses both the pinions and the section of rail engaged thereby. The rider has an L-shaped lifting members extending therefrom which functions as a load platform. A handle is attached to the crankshaft and turning of the handle rotates the crankshaft to sequentially move the pinions into and out of the notches in the rail which has the effect of raising or lowering the rider and any load applied to the L-shaped lifting members. The crankshaft turns in a central guide of the housing which travels in a space between parallel rails during movement of the rider with respect to the rail.
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