| 摘要 |
<p>A self drilling fastener (1) for use in a friable material mounted on a member comprises an elongated body (12) having an axis, an enlarged head (14) having torque transmitting surfaces (15) therein, a proximal portion (18) , an intermediate portion (20) , a distal portion, (22) , and a drilling tip (16) generally opposite the enlarged head. The proximal portion has a threaded exterior (19) having a root (26) , a crest diameter (27) , and a thread height (DH) . The intermediate portion has a threaded exterior (21) having a root (28) , a crest diameter (TC) substantially smaller than the crest diameter (DC) of the proximal portion, and a thread height substantially (MH) smaller than the thread height of the proximal portion. The distal portion (22) has a threaded exterior (23) with a root (30) that tapers toward the drilling tip (16) , a crest diameter substantially smaller than the crest diameter of the proximal portion, and a thread height substantially smaller than the thread height of the proximal portion.</p> |
