| 摘要 |
An improved fastener provides axially extending teeth on a narrow shoulder adjacent the fastener head. The teeth bite into sheet material, and are particularly useful in biting into the surface of a thin sheet which is fastened to a thicker sheet material. The teeth extend from a shoulder formed on a medial collar between the head and a threaded shank. The narrow shoulder has a larger diameter than the end of the threaded shank to which the shoulder is joined. The teeth can be formed by cold-flow of the material of the shoulder so that the teeth axially extend from the outer peripheral edge of the shoulder in order to bite into the thin sheet metal proximate the annular periphery of the aperture in which the threaded shank is engaged. Preferably, the teeth axially overlap the threading of the shank which extends entirely to its junction with the shoulder, and the teeth are fabricated after the shank thread in order to enable such overlap by the teeth.
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