| 摘要 |
1308413 Self-tapping screws N L INDUSTRIES Inc 2 July 1971 [14 July 1970] 31127/71 Heading B3N A vibration-resistant, thread-forming screw 10 comprising a shank 14 having a thread 16 and a plurality of lobes 18 distributed circumferentially about said shank and being on a spiral therealong in an angular direction opposite from said thread, said shank having in a plane normal to its axis an inner solid core 20 of circular configuration and said lobes being integral therewith and being uniformly distributed circumferentially, each lobe having in the direction 22 in which the shank is turned when forming a thread, an elongate leading leg 24 which progresses gradually away from the axis and a relatively short trailing leg 26. |
