US 4,664,561 AGranted

Combined resin-mechanical mine roof bolt anchor

AssigneeThe Eastern Company

InventorJerry Frease

Life of this patent

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Abstract

A system is disclosed for anchoring a tensioned bolt in a drill hole in the roof of a mine, or other such location. The bolt is threaded from one end and has a head on the other end which carries a standard bearing plate. The bolt passes through a hollow tube having an outer diameter slightly (e.g., 1/8") smaller than the bore hole diameter. The threaded end of the bolt engages a nut affixed to the upper end of the tube and extends through the nut to the end of the threads. A standard, mechanical, expansion anchor is carried on the threaded end of the bolt extending through the tube and is inserted into the drill hole behind a conventional, two-compartment resin package. As the bolt is pushed into the hole, the package is broken and the resin components are forced into the annular space around the hollow tube, as well as around the threaded end of the bolt and expansion shell. Rotation of the bolt to expand the anchor also rotates the hollow tube, mixing the resin components and forcing the mixture into voids in the wall of the drill hole. The hollow tube is tapered inwardly toward its lower end providing a wedge effect resisting downward movement in the drill hole.

Claims6

Dependent claims

A combined mechanical-chemical mine roof anchoring and stabilizing system for insertion into a drill hole of predetermined depth and diameter following a standard, two-compartment resin cartridge, said system comprising:

(a) an elongated rod having a head at one end and threaded from the opposite end for a portion of its length;
(b) a mechanical expansion anchor including a radially expansible shell and an internally threaded camming plug engaged with the threads of said rod for movement of said plug into said shell to effect expansion thereof into engagement with the wall of said drill hole in response to rotation of said rod in a predetermined direction;
(c) means for maintaining said plug and shell in assembled relation on said rod prior to expansion of said shell;
(d) a hollow tube carried by said rod and rotatable in response to rotation of said rod, said rod extending axially through said tube between first and second ends of the latter, adjacent to and remote from said expansion anchor, respectively;
and
(e) means closing at least said first end of said tube about said rod, said rod having a length so related to said predetermined depth that said resin cartridge is broken and components carried thereby released by forcing said rod into said hole behind said cartridge, and a diameter less than the internal diameter of said tube, the outside diameter of said tube being only slightly less than the diameter of said hole to provide a relatively thin annular space surrounding said tube into which said resin components flow and are mixed as said bolt and tube are rotated.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/895,705Filed 12 Aug 1986
Granted: 12 May 1987
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

E21D 20/025
With provisions for grouting: grouting with organic components, e.g. resin
E21D 21/0033
Characterised by constructional features of the bolts: having a jacket or outer tube
E21D 21/008
Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection: anchoring or tensioning means
F16B 2013/148
Fixing plugs in holes by the use of settable material: means for inhibiting adhesion between dowel or anchor bolt parts and the surrounding…