Abstract: A washer insert is made preferably of plastic for use with a bearing plate and a mine roof bolt. The bearing plate includes an upper surface, lower surface and a hole passing therethrough. The roof bolt includes a shaft having a head attached to the shaft. The outer diameter of the head is greater than the outer diameter of the shaft. The washer insert includes a hollow first section having a first end and an inner diameter equal to or greater than the outer diameter of the roof bolt shaft and less than the outer diameter of the roof bolt head. A flange attaches to the first end of the first section extending outwardly from the first section and coaxial with the first section.

Abstract: The anchor bolt assembly is of the type used in mine roofs where the anchor bolt is assembled and positioned in a drill hole in a rock formation and in which quick-setting adhesives secure the assembly to the rock formation. The assembly includes an elongated reinforcing rod, an elongated bolt, and a coupling internally threaded at each end and connected to the rod and bolt. A cylindrical plug of aluminum is positioned within the bore of the coupling and frictionally engaged by the threads so as to permit the entire assembly to turn in a first position and to disengage from its frictional engagement to permit turning of only the elongated bolt in a second position.