| 摘要 |
The screw fastener (1) has a threaded shank (2) having a thread (12) defined by two flanks (15,16) along a shank core (10). The thread has niches (24) in the wave trough regions (22) of a thread edge (14). The thread has apex angle from 30 to 35 degrees between the flanks in the wave crest regions (20) of the thread edge, and apex angle from 30 to 58 degrees in the deepest wave trough regions of the thread edge. |
