Jennmar Corporation

Paul A Yacisin

John C Stankus

Frank Calandra, Jr

Mike Cokus

John G Oldsen

Brian R Castle

Kendal L Taylor

Ken Barish

James J Scott, Deceased

A tensionable mine roof cable bolt having a resin grouted upper portion and a mechanically anchored lower portion. The lower portion includes a shaft which is swaged to the cable and accepts a mechanical anchor. The cable bolt is rotated during installation in a mine roof to mix resin and simultaneously engage the mechanical anchor with the rock. A drivehead attached to the lower end of the cable fails upon tensioning of the bolt to a predetermined load.

Tensionable cable bolt with mixing assembly

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. The shell ring end portion has a circular opening for receiving the bolt and an outer, non-circular surface forming a wall having areas of non-uniform thickness to increase the area of the annulus between the ring end portion and the wall of the bore hole. The increased area around the ring end portion facilitates the insertion of the expansion shell assembly into the resin by permitting the resin to flow past the shell and the ring end portion and bond the expansion shell and a portion of the bolt to the rock formation within the bore hole.

Expansion shell assembly

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. The serrations are equally spaced from each other and have a peak to peak distance of 0.186'. The expansion shell has a maximum length of 2.35 inches. The tapered plug has a rounded upper surface and channels running longitudinally between the tapered 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.

Expansion assembly for mine roof bolts utilized in small diameter bore

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. The serrations are equally spaced from each other and have a peak to peak distance of 1.86'. The expansion shell has a maximum length of 2.35 inches. The tapered plug has a rounded upper surface and channels running longitudinally between the tapered 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.

An elongated rod with an expansion shell assembly positioned on the upper end thereof is advanced into a bore hole drilled in rock formation behind a resin cartridge system. The lower end of the rod is connected by a coupling to the upper end of a bolt having a bearing plate positioned on a lower end of the bolt emerging from the bore hole. Unitary rotation of the rod and bolt in a preselected direction while maintaining the shell assembly in an unexpanded condition effects mixing of the resin components in the bore hole. Continued rotation of the rod and bolt 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. Continued rotation applied to the bolt after setting of the shell shears a pin in the coupling to permit the bolt to rotate relative to the anchored rod and move the bearing plate on the end of the bolt upwardly into compressive relation with the rock formation to put the bolt and the rod under tension without interrupting the rotation to allow the mixed resin to cure.

Roof bolt apparatus with expansion shell and coupling

An improved roof support system for a mine or the like is of the type which includes a pair of plates secured to the roof of the mine at opposite sides thereof adjacent opposing ribs of the mine and a horizontal, transverse reinforcing member extending between the pair of plates. The improvement includes the reinforcing member having a first rod with a first end thereof secured to a first of the plates and a second end extending toward the second plate. The second plate includes a vertical portion with a transversely extending opening therethrough. The reinforcing member also includes a second rod in the form of a bolt which has a bolt head located against the vertical portion of the second plate with the threaded second end thereof extending through the opening toward the first plate. The second end of the first rod includes a sleeve mounted thereon having a threaded bore therethrough for receipt of the threaded end of the bolt. The bolt and the first rod are coupled together by insertion of the threaded end of the bolt into the threaded bore to form the reinforcing member. The reinforcing member is capable of producing tension between the first and second plate which tension may be varied by rotation of the bolt head of the bolt relative to the first rod. The invention also includes the method of supporting the roof of a mine and a tool for providing the same.

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Patton, PA, United States of America

Paul A Yacisin