| 摘要 |
This invention relates to a screw threaded insert or member cutting its own thread in a workpiece, adapted to be fitted in a workpiece of soft material, such as for instance aluminum, plastics, wood, or the like, wherein the thread has flanks differentially inclined relative to a plane normal to the axis of the thread at angles predetermined in accordance with specific mathematical relationships so as to be self-locking against rotation due to axial loading of the insert in the direction of pull-out while permitting installation of the insert under axial loading in the opposite direction.
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