Self-locking cap nut made by welding - with formation of corner butt weld between cap and nut

摘要

Mfr. of a self-locking cap nut comprises electrically welding a cap, which is drawn from sheet metal and provided with a bevelled outer edge, and which is pressed against a metal nut to form a corner butt weld on the inside. The welding process is divided into pre-pressing, welding and holding stages. The metal nut is subjected to cold deformation in the region of its thread to form an annular attachment which is compressed concentrically to provide the required locking force. Then the cap, which engages over the conical attachment with a slight clearance is uniformly welded to the nut to form an intermediate corner butt weld.