Tapping screw

Abstract

Disclosed herein is a tapping screw (1) exerting an excellent anti-loosening effect with regard to a workpiece made of a soft material such as resin and an aluminum alloy. The tapping screw (1) includes a shaft part (3), and a normal thread (10) which is formed on the outer circumferential surface of the shaft part. A clearance groove (20) is formed by cutting out a portion of a ridge of the normal thread, and an engaging protrusion (30) is provided on a bottom of the clearance groove along a portion or an entirety of an edge of the bottom that continuously extends from a flank surface of the normal thread. The tapping screw (1) exerts an excellent anti-loosening effect even when a workpiece expands, contracts or oscillates because the engaging protrusions (30) are embedded into portions of the workpiece which have been embedded into the clearance grooves (20).

Dependencies are inferred from the claim text.