A screw jack operates by rotating a handle to drive the screw, which in turn engages with the nut through helical threads to produce linear motion. This movement is used to lift or lower heavy objects. The core principle of a screw jack is to leverage the mechanical advantage of screw transmission to convert a relatively small rotational force into a larger lifting force. Screw jacks are common mechanical lifting devices that use the principle of screw transmission to achieve the ascent and descent of heavy loads. They are characterized by simple structure, ease of operation, and strong load-bearing capacity, and are widely used in fields such as automotive repair, construction engineering, and equipment installation.