What is the principle of self-locking nut?

Self-locking nuts generally rely on friction. The principle is to press the embossed teeth into the preset holes of the sheet metal. Generally, the diameter of the square preset holes is slightly smaller than that of the rivet nut. The nut is connected with the locking mechanism. When the nut is tightened, the locking mechanism locks the ruler body, and the ruler frame cannot move freely to achieve the purpose of locking; when the nut is loosened, the locking mechanism disengages the ruler body, and the ruler frame edge The ruler moves.