Patent ID: 8888415
Filing Date: 2014-11-18
Classification: E21D,F16B

Abstract:
1. An anchor, comprising: an anchor bolt having a shaft comprised of a first shaft part and a second shaft part, the second shaft part being coaxial with said first shaft part and smaller in diameter than said first shaft part, a step is formed between said first shaft part and said second shaft part, the second shaft part is provided with a male screw thread, and a bolt head is provided at the first shaft part and a tip portion is provided at the second shaft part; a spreading sleeve having a tubular body and spreading parts provided at a tip portion of the tubular body, the spreading sleeve being capable of being fitted on the tip portion of said shaft so as to receive the tip portion of the shaft therein, the spreading parts being formed by a longitudinally cut slot so as to spread outwardly; and a cone nut provided at its inner side with a threaded hole to threadedly engage with said male screw thread formed on said shaft, the cone nut having an outer diameter that gradually increases in the axial direction of said threaded hole from a first end of the cone nut to a second end of the cone nut, the cone nut being attached to the tip portion of said shaft while the first end of the cone nut is fitted in the tip portion of said spreading sleeve, wherein said first shaft part is provided with a rupture portion, the rupture portion being provided at a position spaced by a predetermined length from said step, the rupture portion rupturing if torque of a predetermined value or more acts on said bolt head, wherein the first shaft part includes a screw thread between the rupture portion and said step, said spreading sleeve can be fitted on said second shaft part of said shaft so as to receive said second shaft part therein, and when said shaft of said anchor bolt is inserted into a hole formed in a surface with the bolt head and a portion of the first shaft projecting from the surface and then rotated in response to rotation of said bolt head of said anchor bolt, said cone nut travels into said spreading sleeve, thereby making said spreading parts spread outwardly, and when torque of said predetermined value or more acts on said bolt head, said rupture portion ruptures to separate said bolt head from said first shaft which projects from the surface.