| 摘要 |
PURPOSE: To attain precise alignment to a pilot hole by forming a conical-shaped tip end part so that an axis may form an oblique angle against the axis of a shank part, at the shank part, thereby minimizing driving effort in the clamp of a thread-forming fastener. CONSTITUTION: A fastener clamp 20 consists of a shank part 22 and a conical- shaped tip end part 24. An oblique angle 30 is formed by the axis 28 of the tip end part 24 against the axis 26 of the shank part 22. The tip end part 24 and the end part of the shank part 22 are jointed at an oblique boundary 34, a dummy conical shape 32 is cut so that the end surface 36 of the tip end part 24 may form a right angle to the axis 26 of the shank part 22, and the tip end part 24 is formed in a truncated cone. A short side 38 and a long side 40 are formed so as to oppose each other to form the point of intersection 49 of the shaft part axis 26 and the tip end part axis 28. This structure forms a thread 50 on the clamp 20 to manufacture a thread-forming fastener. The thread 58 of the tip end part 24 is formed on only the short side 38, and the opposite side become an unthreaded surface 60. It is thus possible to conduct precise alignment on a pilot surface. |
