| 摘要 |
A self-drilling fastener for use in a friable material with or without an underlying member at the point of use comprises an elongated body, a threaded exterior, an enlarged head with torque transmitting surfaces, proximal, intermediate, and distal portions, and a drilling tip generally opposite enlarged head. Proximal portion has an axial length, a threaded exterior having root and crest diameters and a thread height, where the crest diameter is about twice the root diameter. Intermediate portion has an axial length, a threaded exterior having a root, a crest diameter substantially smaller than proximal portion crest diameter and a thread height substantially smaller than proximal portion thread height. Distal portion has an axial length, a threaded exterior with a root that tapers toward the drilling tip, a crest diameter substantially smaller than the proximal portion crest diameter, and a thread height substantially smaller than the proximal portion thread height portion. |
