1. spring washer locking: the spring washer is made of spring steel. After assembly, the washer is flattened, and its resilience can maintain the pressing force and friction between threads, thus achieving locking.

2. Locking of jacking nut: Bolt type bears extra tension and extra friction by using jacking nut.

3. Locking of the self-locking nut: one end of the nut is slotted and made into a non-circular convergent or radial convergent. When the nut is tightened, the closure expands and the thread is pressed by the elastic force of the closure. This locking structure is simple and reliable, and can be disassembled and assembled many times without reducing the locking performance.