| 摘要 |
<p>Nail-type fastener, comprising an elongated shank with a head at one end, and a point at the other end. The nail shank has three equally spaced longitudinal grooves separated by longitudinal ridges with a cross-sectionally arcuate outer side. The grooves have flat, concave or cross-sectionally V-shaped bottom surface and usually side flank surfaces arranged obliquely thereto which connect to the bottom surface via individual corners of small radius of curvature. The cross-sectional shape selected provides a nail with high flexural rigidity and high pull grip with comparatively low weight. The fastener or nail is produced starting from a cross-sectionally circular nail wire stock which is profiled in two cold-rolling steps. In the first step, the nail wire passes through a first roller trio, the rollers of which roll guide grooves of arcuate cross-section into the nail blank wire. In the second step, the nail wire passes through a second roller trio, the rollers of which engage the guide grooves centrally thereto and produce a deepening of these grooves into deep grooves. The head is then upset on one end of the shank, and a point is made at the other end of the shank, as the finished nail is thereby separated.</p> |
