US 4,056,036 AGranted

Borehole anchor

AssigneeBergwerksverband GmbH

InventorsGunther Kamann, Jurgen Krahe, Ulf Zischinsky, Wilhelm Gotze

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Abstract

An anchor assembly or rockbolt for mounting in a borehole in a rock comprises an outer element which is secured proximal to the mouth of the borehole and an inner element which is secured well inside the borehole. The inner and outer elements are connected together in such a manner as to allow mutual limited shifting thereof without disconnection only on stressing of one of the elements relative to the other beyond a predetermined limit. To this end the outer element may be provided with a piston-like inner end that is slidable against a friction coating within a tubular inner element. It is also possible to form the inner and outer elements as separable tube sections interconnected by means of a central rod having a pair of pistons each received in a respective one of the sections and slidable therein on a tight friction lining thereof.

Claims22

Dependent claims

An anchor assembly for mounting in a borehole in a rock, said assembly comprising:

an outer element defining an axis;
means for securing said outer element proximal to the mouth of said borehole;
an inner element limitedly axially displaceable relatively to said outer element through a predetermined axial distance;
means for securing said inner element in said borehole distal from the mouth of said borehole;
a friction surface on one of said elements having a predetermined axial length equal at least to said axial distance;
a friction surface on the other of said elements transversely engageable with said surface of said one element and displaceable axially therealong through said distance;
and
means pressing said surface of said other element transversely against said surface of said one element with a predetermined constant force for interconnecting said inner and outer elements and allowing limited mutual axial shifting thereof through said distance without disconnection only on axial stressing of said elements relative to each other beyond a predetermined limit.

5 more elements

Dependencies are inferred from the claim text.