THREAD FORMING FASTENER

摘要

The present invention envisions a fastener and a blank for forming a fastener. Threads are formed on the fastener blank of the present invention to achieve the fastener of the present invention. The fastener and blank include a shank which defines a central axis of the fastener. A head is provided on one end of the shank and a leading end is provided on an opposite end of the shank distal the head. A plurality of lobes are provided on the shank and are generally axially aligned with the central axis. Flutes are defined between neighboring lobes. The plurality of lobes include at least three major lobes and three minor lobes. The major lobes are defined by a major arc which is struck by a major radius. The minor lobes are defined by a minor arc struck by a minor radius. The major and minor radii extend from different radial points of origin. An inner circle of origin is positioned outwardly from the central axis and an outer circle of origin is positioned outwardly from the central axis and said inner circle of origin. The minor radii extend from a point on the inner circle and the major radii extend from a point on the outer circle. Threads are formed on the outside surface of the fastener blank as described hereinabove to produce the threaded fastener of the present invention.