Nisshin Steel Co., Ltd.

Hiromichi Shiroma

Masahiro Nakata

Toshiharu Kittaka

Takefumi Nakako

Kenji Ooshima

Takeyuki Yoshida

Tatsurou Iwasaki

Tetsuo Itou

Hiroyuki Tanase

A sleevefor introduction of a pressurized fluid, which is attached to a rockbolt main body, comprises a cylindrical projecting partof a large diameter and a bearing-plate-holding partof a diameter smaller than an aperture of a bearing plate. The projecting partand the bearing-plate-holding partpreferably has the same inner diameter. When the rockbolt main bodyis embedded in a bedrock or ground, the bearing platelocates on an edge of a rockbolt-setting hole of the bedrock or ground, and the bearing-plate-holding partextends through the bearing plateinto the rockbolt-setting hole. Since the projecting partand the bearing plateare disposed on a sprayed concrete layer, a projection height of the rockbolt is remarkably decreased. Consequently, lining concreteis applied onto the sprayed concrete layer with ease, and the bedrock or ground is reinforced with high reliability.

Rockbolts made of steel pipes

Growing community of inventors

Tokyo, Japan

Hiromichi Shiroma