Pull cap

The pull nut is a fastener and also a special nut. Its English name is Rivet Nut. Simply put, it is a nut with riveting function. Some people also call it rivet nut. The pull nut was initially used on the skin of the wings and fuselage of large aircraft. Since the aircraft will continue to withstand high-frequency vibrations during flight, metal materials are prone to fatigue. The aluminum alloy structure is combined with welding. Since the welding points have poor vibration resistance, it is easy to cause structural fracture. Therefore, the external parts of the aircraft are almost all riveted and fixed. The pull nut is mainly divided into three parts: the thread section, the deformation section and the flange. As long as the pull nut is pulled or compressed, the necessary section in the middle will bulge to form an annular structure. This annular structure will tightly clamp the plate part and will not fall off easily. It also has considerable anti-rotation force. A single pull nut can support hundreds to thousands of kilograms of weight.