Abstract: A mechanical truss wrench for use with a mine roof bolting machine. The wrench includes a casing having a locking bracket pivotably secured to the exterior. An input shaft extends into the casing and is positioned at a right angle to an output shaft extending out of the casing. The lower end of the input shaft is secured to the torquing member of the mine roof bolting machine. In operation, a socket on the output shaft is engaged with a head of a horizontally extending torquing bolt or similar tensioning mechanism of a truss-type mine roof utilizing U-bolts. The input shaft is rotated about a vertical axis to operate a gear train to rotate the output shaft and the socket to torque the bolt. A locking member with tabs coacts with the legs of a U-bolt or similar tensioning mechanism to prevent the casing from rotating about the axis of the input shaft and a guiding member is provided to assist in guiding the torquing bolt into the socket.

Abstract: A pair of truss brackets are secured to the roof of an underground passage adjacent to opposing ribs of the passage. The truss brackets each include a roof engaging surface and a truss supporting arm member extending from the roof engaging surface. A pair of U-bolts are supported by the arm members of the truss brackets. Each arm member extends horizontally from the truss bracket to an enlarged end portion of the arm member. The U-bolt is horizontally movable in a vertically hanging position on the arm member and is restrained by the enlarged end portion from disengagement from the arm member. The U-bolts are pivoted on the truss brackets to a horizontal position for connection to truss members which are connected to each other and tensioned to apply an uplifting force to the roof. As the truss members are connected and tensioned, the U-bolts are retained for a range of horizontal movement on the arm members to facilitate adjustments in the position of the U-bolts on the truss brackets.

Abstract: A pair of truss brackets are secured to the roof of an underground passage adjacent to opposing ribs of the passage. The truss brackets each include a roof engaging surface and a truss supporting arm member extending from the roof engaging surface. A pair of U-bolts are supported by the arm members of the truss brackets. Each arm member extends horizontally from the truss bracket to an enlarged end portion of the arm member. The U-bolt is horizontally movable in a vertically hanging position on the arm member and is restrained by the enlarged end portion from disengagement from the arm member. The U-bolts are pivoted on the truss brackets to a horizontal position for connection to truss members which are connected to each other and tensioned to apply an uplifting force to the roof. As the truss members are connected and tensioned, the U-bolts are retained for a range of horizontal movement on the arm members to facilitate adjustments in the position of the U-bolts on the truss brackets.

Abstract: An expansion assembly for use with resin on a mine roof bolt includes an expandable shell and a camming plug having a first end wall spaced from a second end wall by a tapered body portion. Four equidistantly spaced grooves extend longitudinally in the tapered body portion. Pairs of grooves are connected across the second end wall by transverse grooves that form resin flow channels. A rib formation extends outwardly from the side wall adjacent to and removed from a groove. The rib formation defines the edge of the groove and abuts an edge of one of the fingers of the expandable shell to align the grooves of the plug with the respective slots formed between the shell fingers. This alignment assures unobstructed flow of the mixed resin downwardly through the plug grooves and shell slots into surrounding relation with the expansion assembly for secure bonding of the assembly with the walls of a bore hole.

Abstract: The mine roof anchor includes a roof bolt assembly with an expansion shell assembly secured at the end of the bolt inserted into the bore hole. The expansion shell assembly includes a friction reducing means to increase the horizontal force on the leaves and the bolt assembly includes an adjustable resin retaining washer to compress the resin in the bore hole.

Abstract: A mechanical expansion shell assembly has an expansion shell with a plurality of leaves and a plug with a plurality of sloped surfaces. The inner surfaces of the leaves are positioned in overlying relation with the sloped surfaces of the plug. A friction reducing material is positioned between the overlying surfaces and is arranged to reduce the torque applied to the roof bolt connected to the expansion shell assembly to obtain a preselected lateral force on the expansion shell leaves. In another embodiment, a friction reducing material is positioned between a nut threaded on the roof bolt and the underside of the expansion shell ring portion.