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US 4,305,687 AGranted
Anchoring system for rock bolts
OwnerJack Parkerinventor
Life of this patent
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OwnerJack Parkerinventor
Estimating the term…
An anchoring system for rock bolts which support and reinforce rock structures, primarily roof structures in underground mines. The anchoring system involves the coaction of: (1) a hardenable grout such as a synthetic resin; and (2) a simple but specially designed rock bolt which has a frustum or wedge portion or element at its inner end. In this system, the wedge is secured to or forms a part of the rock bolt and the bolt is anchored by the direct mechanical action of the wedge against the hardened grout, with the wedge causing the grout to be placed under compression as the wedge slides through the grout. The anchoring is accomplished without changing the position of movable mechanical parts and without grouting along the entire length of the rock bolt. The rock bolt anchoring system is used by drilling a hole in a rock formation, introducing into the hole an anchoring amount of a hardenable grout in an amount which is sufficient to fill the hole in the zone occupied by the anchoring wedge but which is substantially less than the amount of grout required to grout the entire rock bolt, simultaneously or subsequently inserting the specially designed rock bolt into the hole, permitting or causing the grout to harden in the hole while the grout is in contact with the wedge shaped portion of the rock bolt, and then imparting tensile forces to the rock bolt by tightening the rock bolt against a suitable bearing plate or other restraining device located at or near the outer end of the rock bolt.
A non-expanding, grout-activated anchor, said anchor comprising at least one wedge-shaped portion which has a head, an angle of taper of 2.degree.-22.degree. from said head relative to the longitudinal axis of the anchor, and sufficient tapered surface area to secure the anchor in a hole when the anchor is restrained against pull-out by a grout which fills the hole proximate the anchor;
A one piece rock bolt anchor suitable for use with and connection to a rock bolt, said anchor consisting essentially of:
A rock bolt suitable for insertion into a pre-formed drill hole which is located in an exposed rock formation wherein the rock bolt can be anchored against tensile forces by wedging action between an anchoring portion of the rock bolt and a grout which is hardened around the anchoring portion of said rock bolt within said hole, said rock bolt consisting essentially of:
Dependencies are inferred from the claim text.