| 摘要 |
<p>A fastening element (10,20,30,40,50,60) has a shank (11,21,31,41,51,61) formed on a bottom end thereof and a head (12,22,32,42,52,62) formed on a top end thereof. The shank (11,21,31,41,51,61) has a thread (111,211,411,511) helically formed around the shank (11,21,31,41,51,61), and at least one auxiliary thread (112,212,412,512) helically formed between each two adjacent tooth segments of the shank (11,21,31,41,51,61), and a drilling portion (114,214,415,515) connected with the thread (111,211,411,511). A pitch diameter of the thread (111,211,411,511) is greater than that of the multiple auxiliary threads (112, 212, 412, 512). An arc shaped surface (113,213,414,514) formed between each tooth segment of the thread (111,211,411,511) and one of each two adjacent tooth segments of the auxiliary thread (112,212,412,512) is recessed inwardly. Accordingly, a contact area between the shank and the hard pavement increases, an object to be fastened can be securely locked, and chips cut by the fastening element can be easily removed. There can also be an additional thread between the head and the shank providing a nut fixing. The multiple auxiliary threads when compared to each other can be of varying pitch depth.</p> |
