A screw jack is a common mechanical lifting device. It has a simple structure and high reliability. The screw jack mainly consists of a screw, nut, and housing, with a compact structure, few components, low failure rate, and convenient maintenance. Due to the use of mechanical transmission, it does not require hydraulic or pneumatic systems, avoiding issues such as oil leaks and air leaks, ensuring stable and reliable operation. The screw jack utilizes the self-locking characteristic of threads (the thread angle of rise is less than the friction angle), allowing it to automatically lock in position under load without the need for additional braking devices, providing high safety. Even when operation stops, the load will not slide down on its own, making it suitable for supporting heavy objects over extended periods. The screws and nuts of the screw jack are usually made of high-strength alloy steel, capable of bearing large loads (common models can reach several tons to tens of tons). They are suitable for heavy-duty applications, such as automotive repairs, bridge construction, equipment installation, etc.