| 摘要 |
1,142,175. Self-tapping screws. EATON YALE & TOWNE Inc. 10 May, 1967 [10 May, 1966], No. 21679/67. Heading B3N. A self-tapping screw is produced by rolling a thread on a screw blank 16, so that a portion H has a conventional thread, portion T is of lobular form for swaging, and portion P provides a pilot portion. The crests 26, Fig. 5, on portion T which are situated between flat areas 22, Fig. 3, are concave. |
