Screw thread structure of rounded square-shaped attachment element used in e.g. automobile, has flattened hole that is provided in intervention unit by applying high clamping force in intervention direction and in opposite direction

摘要

The screw thread structure has a fixing element that is made of metal or plastic or other appropriate material. A flattened hole is provided in a less resistant intervention unit, by applying a high clamping force against loosening in intervention direction and in opposite direction. A shaft (5) of attachment element (2) is provided with threads (13-21). Independent claims are included for the following: (1) a rounded square-shaped attachment element; (2) a special rolling object; and (3) a manufacturing method of screw thread structure of rounded square-shaped attachment element.