Patent ID: 8794891
Filing Date: 2014-08-05
Classification: B21D,B25B,F16B

Abstract:
1. A screw comprising: a first section having a shape of substantially a cylinder having a threaded side surface, at least part of which is for use for engagement with a nut; a second section for wrenching drive, the second section formed contiguously and concentrically to the first section and having a shape of substantially a polygonal prism; and a third section formed contiguously and concentrically to the second section, the third section having a cylindrical portion and a round top having a convex shape, the edge of which contiguously connects to a side surface of the cylindrical portion, wherein a diagonal of a horizontal cross-sectional shape of the polygonal prism is larger than a diameter of the cylindrical portion, and a diameter of the first section is larger than the diagonal of the horizontal cross-sectional shape of the polygonal prism.