| 摘要 |
A self-drilling expansion fastener (20) is integrally formed of a sheet metal material for locking two or more sheet workpieces together, and includes an expansion structure (21) and a drill structure (30). The expansion structure (21) has a plurality of internal threads (24) and force-distributing bars (25). The drill structure (30) has a chip guard (31) for covering a head of the expansion structure (21), and a drill (32) forward projected from the chip guar (31) for self-drilling a hole. When an externally threaded element is screwed into the expansion structure (21) to mesh with the internal threads (24), the force-distributing bars (25) are brought to expand outward and are finally compressed into a folded state to thereby tightly lock the sheet workpieces to one another. A method of forming the self-drilling expansion fastener (20) is also disclosed. |
