BLADE DRILLING BIT Russian patent published in 2001 - IPC

FIELD: rock-cutting tools, particularly, blade drilling bits. SUBSTANCE: blade drilling bit has body and stepped cutting head made of separate sectors and reinforced with rock-cutting members. Jet nozzles are located between sectors. Each sector step is made with, at least, two concentric surfaces. Protruding surface carries rock-cutting members, and internal surface deepens into body. Projecting and deepened surfaces alternate by sectors and by length of bit circumference. Nozzles are installed at different levels, and their center of opening is located on middle radius of surface deepened into body. EFFECT: higher penetration rate and operating stability of bit cutting members due to improved their washing, cooling and quality cleaning from cuttings. 3 dwg