The bevel gear screw jack, also known as the umbrella gear screw jack, is equipped with a nut sleeve, screw, and umbrella gear transmission mechanism inside its casing. Compared with the screw jack, its screw part only rotates without lifting. There is a directional keyway milled on the sleeve, and the sleeve only lifts without rotating. Therefore, when working, the handle is turned to rotate the umbrella gear, causing the screw to rotate. When the screw rotates, the sleeve lifts and lowers along the directional key on the upper part of the shell.

The bevel gear spiral jack breaks the traditional way of using screws for spiral motion and nuts for fixation in spiral mechanical jacks. When working, the handle or handwheel rotates, and through a pair of bevel gears, the nut rotates horizontally, driving the screw to move up and down. Due to the positioning limitation of the nut in the vertical direction by the base, the handwheel or handle always rotates in the vertical plane, and the rotation center position does not change with the screw up and down, thus ensuring the stability of the system.

A thrust bearing is installed between the bottom and base of the bevel gear screw jack to reduce friction at the bottom of the gear. The lifting capacity of this screw jack is about 8-50 tons, and the lifting height can reach 250-400 millimeters.