| 摘要 |
<p>A pierce nut (10) having a central pilot (15), a cylindrical flange portion (29) surrounding the pilot (15) and a groove (16) in the flange portion having at least one inclined side wall (22) and a bottom wall having a convex annular protuberance preferably comprising spaced arcuate protuberances (24a,24b,24c,24d) extending around the pilot (15) which deforms panel metal beneath the inclined side wall and providing anti-rotation means when the nut is attached to a metal panel. The outer groove side wall includes radial notches or grooves (30a,30b,30c,30d) which receive panel metal to provide anti-torque means. The improved die button (52) includes an annular lip (53) having an inside piercing edge (58) spaced from the end to pierce a smaller slug and an annular convex fillet (57) which deforms more panel metal into the nut groove to form a secure mechanical interlock between the nut and panel. <IMAGE></p> |
