| 摘要 |
1508619 Self-drilling screws TEXTRON Inc 24 Sept 1975 [27 Sept 1974] 39111/75 Heading F2H [Also in Division B3] A composite drill screw 10 has a threaded section 14, a cutting end section 16 with a drill point 20 and a head section 12, at least one of the sections being of one metal and the remainder of a different metal, the portions being joined by a friction inertia weld. As shown the head 12 is joined to the threaded section 14 by a weld W but in other embodiments the weld may be between sections 14 and 16 or midway along the threaded section 14. |
