Patent ID: 6637980
Filing Date: 2003-10-28
Classification: E21D

Abstract:
A re-tensionable roof bolt assembly for anchoring a rock strata in an underground mine, comprising:a. a roof plate with an opening formed therein; b. a roof bolt consisting of a head and a shaft, said roof bolt shaft inserted through said opening in said roof plate and inserted into a bore hole in said rock strata along with a quick-setting resin; c. a screw member oriented between said roof plate and the head of said roof bolt, said screw member consisting of an externally threaded portion and a head portion, said screw member further defined to include a central bore having a diameter slightly larger than the diameter of said roof bolt shaft and a slotted first aperture of the same diameter extending radially from said central bore to the exterior of said screw member and extending the full length of both said externally threaded portion and head portion of said screw member thereby effecting a slotted opening; and d. an internally threaded nut having first and second parallel faces and a plurality of outer sides extending between said faces to define a surface for the application of force to turn said nut, further defined to include a central bore through said nut perpendicular to said first and second face and featuring a continuous internal thread adapted and sized to complement the threaded portion of said screw member, and wherein said nut is further defined to include a slotted second aperture approximately identical in size and diameter to said slotted first aperture in said screw member.