Patent ID: 6698980
Filing Date: 2004-03-02
Classification: E21D,F16B

Abstract:
A rock bolting apparatus for use with adhesive material for insertion into a drilled hole penetrating the face of the rock formation, said hole transversing unstable rock strata and penetrating into stable rock strata in underground mines, said apparatus comprising:a. a tensionable reinforcing member inserted into the drilled hole the member having a threaded portion at one end extending out of the borehole; and an opposite end placed totally within the drill hole and adapted to be embedded in adhesive material placed within the drill hole; wherein said member threaded portion includes at least one bore intermediate thereof and positionable anywhere along the length thereof b. at least one square nut threadably receivable by the member threaded portion said nut having at least one bore positioned there within and intermediate thereof equal in diameter with the at least one bore through the member threaded portion and extending transversely through the nut, the nut being sufficiently dimensioned so that said at least one bore does not degrade the strength thereof; wherein said at least one nut has a first temporary operation position located at the top of the member threaded portion and wherein the nut and member are rotatable together for mixing adhesive material in the drill hole and a second permanent operation position located at the bottom of the member threaded portion so that the bearing plate is in abutting contact with the rock face; c. at least one bearing plate retained on the rod threaded portion by the nut; d. at least one shearing element inserted into the axially aligned nut and member threaded portion bores for fixing said nut in said first operating position and subsequently, upon shearing, permitting the nut to rotate freely on the member threaded portion so that it can advance to said second permanent operating position wherein the at least one shearing element fits within the length of the axially aligned nut and member threaded portion bores and wherein the at least one shearing element comprises a member having a compressible diameter having a compressible gap along its length.