The screw jack, also known as a helical drive mechanism, is primarily used to convert rotational motion into linear motion or vice versa. It includes types that are mainly for transmitting motion, such as the feed screw of machine tool tables, as well as those for adjusting the relative positions of parts. Screw jacks are divided into sliding friction and rolling friction mechanisms. The sliding screw and nut mechanism is simple in structure, easy to process, and has a low manufacturing cost, featuring an automatic locking function, but it has a large friction torque and low transmission efficiency. The ball screw and nut mechanism, although more complex in structure and higher in manufacturing cost, lacks the automatic locking feature, but it boasts small friction torque, high transmission efficiency, high precision, good system stiffness, reversible motion, and a long service life. The screw jack consists of a worm gear reducer and a screw, with the减速 part being the worm drive that uses the worm to drive the worm gear for减速. The worm gear acts as the nut for the lifting screw, matching it perfectly.