Apertured sleeve-shaped members for use in carrying out roof-bolting by means of bolts fastened in bore holes

Claim 1

In a roof bolt emplaced in a bore-hole, comprising a sleeveshaped member disposed in the bore-hole and having a plurality of apertures therethrough, a bolt extending lengthwise the interior of said sleeve-shaped member, and a quantity of cement mortar surrounding the bolt and extending through said apertures and filling the space between said sleeve-shaped member and the side walls of the bore-hole; the improvement in which the sleeveshaped member consists of a relatively rigid by resilient material, the circumferential surface of said member being interrupted by a longitudinal and relatively wide slit which allows the introduction of the cement mortar into the interior of said member and which under the influence of a radial pressure on said member on both sides of the said slit allows a variation of the diameter of the member while maintaining a desired, substantially circular cross-section and an adaptation thereof to bore holes of different sizes, and fixing means surrounding the sleeve-shaped member and maintaining said member compressed to a smaller diameter than when said member is uncompressed.