DRILLING DEVICE FOR EXPANDED HOLE Russian patent published in 2001 - IPC

FIELD: drilling of holes with expansion of their lower parts, mainly, of holes for drilling and filled in place piles and also for mining of diamond-bearing ores by drilling. SUBSTANCE: drilling device consists of rotating links with rock-cutting tool which are connected with body by means of axles and cylindrical hole director with wedge-like recesses coming in contact with links. Cylindrical hole director rests on hole bottom. Drilling device body is movable relative to hole director and capable of its accommodation. Telescopic channel for circulation of drilling mud is formed in hole director and drilling device body. Drilling device provides for hole expansion for preset limited height and efficient operation practically in any rocks to expand hole to diameter exceeding its two-fold diameter. EFFECT: higher efficiency of device operation. 5 cl, 4 dwg