Nitto Seiko Co., Ltd.

Shinichi Hamano

Shingo Torii

Toshimasa Toyooka

A locking screw including a male screw and a female screw, the male screw being screwed into the female screw, the male screw including male threads and the female screw comprising female threads, wherein a male thread comprises a crest side flank surface and a root side flank surface connecting the crest side flank surface and a root of the male thread, a slope of the crest side flank surface is smaller than a slope of a female flank surface of the female thread, a slope of the root side flank surface is larger than the slope of the female flank surface, a connected portion of the crest side flank surface and the root side flank surface interferes with the female thread, and a clearance is formed between the root side flank surface and the female screw when the connected portion interferes with the female thread.

Locking screw

The present invention provides a screw, comprising a screw head having a drive recess and a screw shank having threads and being integrally formed with the screw head, wherein the drive recess includes a plurality of engaging grooves equiangularly radiating from an axis of the screw in plan view, a bottom face of each engaging groove having a steep slope, which is near to the screw shank, and a gentle slope, which is far from the screw shank, for enlarging the engaging area of the engaging grooves.

Growing community of inventors

Ayabe, Japan

Shinichi Hamano