HOLE DEVICE FOR FORMATION OF DIRECTED FRACTURES Russian patent published in 2002 - IPC

FIELD: mining; applicable in formation of fractures in holes for separation of blocks from rock mass, mining of valuable crystalline materials and building stone. SUBSTANCE: hole device includes outer and inner tubes joined by threaded connection. Tube ends on one side have circular conical stops with vertexes facing each other. Device has sealing bushing made of monolithic material which under effect of outer load is changed into loose state, and screw installed in one of tubes. In this case, inner tube is screwed into end of outer tube having slot on section of internal thread connecting screw with outer tube. EFFECT: higher efficiency of hole device operation. 4 cl, 2 dwg