| 摘要 |
<p>The punched nut (1) has a shaft (13) arranged opposite to a head (11), where the shaft has a non-circular mantle surface tapered towards the head for forming an undercut. The shaft has a cutting ring (16) arranged at a front surface, where the cutting ring has a sharper cutting edge (17) whose external diameter is smaller than a diameter of the shaft. The head has a collar (12) that is inclined for forming the undercut, and a ratio of the external diameter of the cutting ring to the diameter of the mantle surface is between 0.9 and 0.98.</p> |
