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 elongated channel member for supporting the surface of an underground rock formation includes a base portion with a bearing surface for contacting the rock strata and an opposite surface having a longitudinally extending central rib and flanged edges for resisting deflection and bending of the channel member under the load of the rock strata. A plurality of openings spaced a preselected distance apart extend through the central rib. A bearing plate is positioned in overlying abutting relation with each opening in the channel member. The bearing plate includes embossed areas and longitudinally flanged edges that are complementary in shape with the central rib and flanges on the channel to securely engage the bearing plate on the channel member. Thus, the bearing plate engages the channel member to restrain longitudinal and lateral movement of the bearing plate on the channel member and stiffen the channel member to resist bending.

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: A tapered camming plug positioned within an expansion shell is threaded onto an upper end portion of an elongated bolt advanced behind a resin cartridge system into a bore hole drilled in a rock formation. A bearing plate is carried on the opposite end of the bolt and abuts the rock formation surrounding the bore hole. The cartridge is ruptured by upward thrust and rotation of the bolt to release the resin components for mixing. The mixed resin flows downwardly in the bore hole into surrounding relation with the camming plug and expansion shell. The expansion shell includes a plurality of expansion fingers each formed integral at one end portion with a ring end portion of the shell and extending upwardly to a free end portion for outward expansion into engagement with the wall of the bore hole as the camming plug advances downwardly on the bolt after the resin is mixed.

Abstract: An improved expansion assembly for a mine roof bolt adapted for use in a 11/2" diameter bore hole with a 1" roof bolt. The expansion assembly has a plug with tapered surfaces, an expansion shell with leaves extending axially upwardly from a support ring into contact with the tapered surfaces of the plug and a support washer. The inner surface of the expansion leaves are spaced inwardly from the surface of the support ring. The expansion leaves have serrations on their outer surfaces such that the serrations are formed by the intersection of a planar surface perpendicular to the axis of the mine bolt and a frusto-conical surface. The end of the leaves on the expansion shell have vertical serrations parallel to the longitudinal axis of the leaf. The tapered plug has channels running longitudinally between the surfaces on the plug for facilitating use of the expansion assembly with resin. The improved expansion assembly may be utilized with or without resin bonding.

Abstract: A delay stopper for use in a mine roof anchor is provided. A mine roof anchor has a threaded roof bolt and a threaded receiving member for the roof bolt whereby the roof bolt and the receiving member initially rotate as a unit to mix resin components that are placed in the bore hole in a destructible capsule above the roof anchor. When the roof anchor is placed in the bore hole, the destructible capsule is ruptured, and the components within the capsule are mixed to form resin which at least partially secures the mine roof anchor within the bore hole. The delay stopper causes the roof bolt and the threaded receiving member to rotate as a unit to mix the resin after the capsule ruptures. The delay stopper has a cylindrical body portion interfitting into the threads of the threaded receiving member and a conical end portion formed on the cylindrical body portion and extending axially from the body portion in a direction toward the end of the roof bolt. The delay stopper is preferably formed of an epoxy resin.

Abstract: An improved expansion assembly for a mine roof bolt for use in a nominal one inch diameter bore hole with a nominal 5/8" diameter roof bolt is provided. The expansion assembly has a tapered plug with four tapered surfaces, an expansion shell that has four leaves extending axially upwardly from a support ring and into contact with the four tapered surfaces on the tapered plug, and a threaded support washer to support the expansion shell on the threaded end of a mine roof bolt. The tapered plug has a threaded bore therethrough for threading onto the mine roof bolt. The tapered plug tapered surfaces have an angle of taper of at least 6.5.degree. to the axis of the mine roof bolt. The expansion leaves each have seven serrations formed on the surface such that the serrations are formed by the intersection of a planar surface perpendicular to the axis of the mine roof bolt and a frusto-conical surface. The frusto-conical surface is at an angle of 72.3.degree. to the planar surface.

Abstract: A roof support for an underground mine or the like is disclosed. The roof support is comprised of two roof anchors that are secured in bore holes formed in the mine roof with a cross member tensioned between the roof anchors. The roof anchors have eye-bolt heads formed on the ends which protrude from the roof and to which the cross member is readily secured. A tensioning means is provided to tension the cross member and the major portion of the cross member may be either a rigid metal rod or a flexible wire rope cable. The present invention also provides for a roof anchor that is formed from concrete reinforcing bar which has an eye-bolt head that is hot forged onto the reinforcing bar.

Abstract: An improved expansion assembly for a mine roof bolt for use in a nominal one inch diameter bore hole with a nominal 5/8" diameter roof bolt is provided. The expansion assembly has a tapered plug with four tapered surfaces, an expansion shell that has four leaves extending axially upwardly from a support ring and into contact with the four tapered surfaces on the tapered plug, and a threaded support washer to support the expansion shell on the threaded end of a mine roof bolt. The tapered plug has a threaded bore therethrough for threading onto the mine roof bolt. The tapered plug tapered surfaces have an angle of taper of at least 6.5.degree. to the axis of the mine roof bolt. The expansion leaves each have seven serrations formed on the surface such that the serrations are formed by the intersection of a planar surface perpendicular to the axis of the mine roof bolt and a frusto-conical surface. The frusto-conical surface is at an angle of 72.3.degree. to the planar surface.

Abstract: A mechanical anchor including an expansion shell and an expansion plug positioned in the shell is engaged with the end of a bar having helically extending rib segments formed on the outer surface of the bar. The expansion plug has an internal bore defining a wall having a configuration to receive and mate with the helically extending rib segments formed on the outer surface of the bar. The mechanical anchor and a portion of the bar are inserted in a bore hole drilled in a rock formation and, upon rotation of the bar in a preselected direction, the expansion plug nonrotatably moves down the bar to expand the shell into engagement with the bore hole wall. As the shell engages the bore hole wall, the bar is mechanically anchored within the bore hole by the mechanical anchor.

Abstract: A bendable roof bolt is provided for use in a mine at locations where it is desired to utilize a roof bolt having an overall length greater than the available vertical working distance between a mine floor and mine roof. The bendable roof bolt is made from a rebar material and has a preselected length greater than the available vertical working distance between the mine floor and mine roof. The rebar has a uniform cross section over its entire length. Prior to inserting the bendable roof bolt in a bore hole drilled in the mine roof, the roof bolt is bent by suitable means at a predetermined location along the rebar preselected length to allow the end of the bendable roof bolt to be inserted in the bore hole. After the roof bolt is bent and the roof bolt end inserted in the bore hole, the roof bolt is rebent to partially straighten the roof bolt and allow the remainder of the roof bolt to be advanced in the bore hole.

Abstract: An elongated rod with an expansion shell assembly positioned on the upper end portion thereof is advanced behind a resin cartridge system into a bore hole drilled in a rock formation. A bearing plate and a stop nut are positioned on the end of the rod emerging from the bore hole. Unitary rotation of the nut and rod in a preselected direction while maintaining the shell assembly in an unexpanded condition effects mixing of the resin components. Continued rotation of the nut and rod after the resin components are mixed effects expansion of the shell into engagement with the wall of the bore hole to anchor the rod in the bore hole. The rotation applied to the nut after setting of the shell permits the nut to advance on the lower end of the rod to urge the bearing plate into compressive relation with the rock formation to put the rod under tension without interrupting rotation to allow the mixed resin to cure.

Abstract: A mechanical anchor including an expansion shell and a camming plug positioned in the shell is threaded onto the end of a mine roof bolt. A roof support plate is carried on the opposite end of the bolt. The mechanical anchor is inserted in a bore hole drilled in a rock formation with one or more resin cartridges advanced by upward movement of the bolt to the end of the bore hole. The cartridge is ruptured by upward thrust and rotation of the bolt to release the resin components for mixing. A stop device extending through the plug abuts the end of the bolt to prevent axial movement of the plug on the bolt when the bolt is rotated in a preselected direction to mix the resin components before the shell is expanded. Rotation of the bolt continues without expansion of the shell for a period of time to permit formation of a curable resin mixture.

Abstract: A mechanical anchor including an expansion shell and a camming plug positioned in the shell is threaded onto the end of a mine roof bolt. A roof support plate is carried on the opposite end of the bolt. The mechanical anchor is inserted in a bore hole drilled in a rock formation with one or more resin cartridges advanced by upward movement of the bolt to the end of the bore hole. The cartridge is ruptured by upward thrust and rotation of the bolt to release the resin components for mixing. A stop device extending through the plug abuts the end of the bolt to prevent axial movement of the plug on the bolt when the bolt is rotated in a preselected direction to mix the resin components before the shell is expanded. Rotation of the bolt continues without expansion of the shell for a period of time to permit formation of a curable resin mixture.

Abstract: A mechanical anchor including an expansion shell and a camming plug positioned in the shell is threaded onto the end of a mine roof bolt. A roof support plate is carried on the opposite end of the bolt. The mechanical anchor is inserted in a bore hole drilled in a rock formation with one or more resin cartridges advanced by upward movement of the bolt to the end of the bore hole. The cartridge is ruptured by upward thrust and rotation of the bolt to release the resin components for mixing. A stop device extending through the plug abuts the end of the bolt to prevent axial movement of the plug on the bolt when the bolt is rotated in a preselected direction to mix the resin components before the shell is expanded. Rotation of the bolt continues without expansion of the shell for a period of time to permit formation of a curable resin mixture.

Abstract: A mechanical anchor including an expansion shell and a camming plug positioned in the shell is threaded onto the end of a mine roof bolt. A roof support plate is carried on the opposite end of the bolt. The mechanical anchor is inserted in a bore hole drilled in a rock formation with one or more resin cartridges advanced by upward movement of the bolt to the end of the bore hole. The cartridge is ruptured by upward thrust and rotation of the bolt to release the resin components for mixing. A stop device extending through the plug abuts a tapered end of the bolt to prevent axial movement of the plug on the bolt when the bolt is rotated in a preselected direction to mix the resin components before the shell is expanded. Rotation of the bolt continues without expansion of the shell for a period of time to permit formation of a curable resin mixture.