The core advantage of a screw jack is not only its ability to easily lift heavy objects, but also its ability to maintain a stable state after being lifted in place, providing safety guarantees for operators' maintenance work. This key function is the self-locking function, and its absence will greatly reduce the practical value of the jack.

The implementation of self-locking function originates from the special design of the internal threads of the screw jack: relying on the slope between the threads to generate sufficient friction, when the helix angle of the jack is less than the friction angle, the threads can remain stationary on the slope, thereby automatically locking the lifting sleeve and effectively preventing the heavy object from falling back to its initial position under heavy pressure.

This feature provides multiple safety guarantees for the use process: operators do not need to worry about accidents caused by heavy objects slipping off automatically; With the help of the nut self-locking mechanism, the load-bearing safety of heavy objects is greatly improved, and the maximum load weight it can bear can reach 110% of the rated load-bearing capacity of the jack, with a significant transmission safety factor. However, it should be noted that if the equipment is overloaded for a long time or has been in service for too long, the threads will gradually wear out, leading to a decrease in self-locking function and affecting the safety of use.