Spiral jacks, as a common lifting tool, are widely used in mechanical maintenance, construction and other scenarios due to their simple structure and strong load-bearing capacity. But many people have doubts: can a screw jack be used upside down? The answer is no. Using a screw jack in reverse not only affects its effectiveness, but also poses serious safety hazards.

The screw jack achieves lifting and lowering through the meshing transmission of the screw and nut, and its braking depends on the self-locking performance between the threads. When used in a forward direction, the self-locking structure can firmly lock heavy objects and prevent accidental slipping. When reversed, the direction of force on the screw and nut changes, and the original self-locking mechanism is destroyed, which easily leads to the phenomenon of "slipping teeth". Once the self-locking fails, heavy objects may suddenly fall, causing equipment damage or even personal injury.

The base, top, and other components of the screw jack are designed for forward force, and reverse use will cause the key components to withstand unexpected shear forces and torques. Long term or improper use can cause base deformation, screw bending and other faults, shortening the service life of the tool. In addition, in the reverse state, it is difficult for operators to stably control the jack and respond to emergencies in a timely manner, further increasing operational risks.

Therefore, when using a screw jack, it is necessary to strictly follow the operating procedures to ensure positive placement and even force distribution. If special angle operation is required, a dedicated tilting jack should be selected. Do not risk using it for convenience, always prioritize safety.