CROWN BIT Russian patent published in 1998 - IPC

FIELD: rock-cutting tools, in particular, diamond crown bits for drilling hard rocks. SUBSTANCE: crown bit has body with fastening thread and diamond-containing matrix with radial water courses and circular concentric grooves at the end made in the form of trapezium in cross-section. Trapezium small base faces bottom hole. Each inlet side of water courses has members installed for crushing of formed rock accumulations. Height of members is less than the depth of grooves and inlet side of each water course is made at an angle 5-45 deg with groove expansion towards flow direction of mud. EFFECT: higher efficiency of drilling. 2 dwg