DRILLING BIT Russian patent published in 1996 - IPC

FIELD: rock crushing tools for drilling deep and super-deep holes. SUBSTANCE: in drilling bit, butt end cutters of pads 22 are made in the form of cylinders 31. Frontal head is formed as cylinder 18. Pad 22 has recess 29 and through hole in its butt part which communicate with holes in cylinders 31. Rim 4 has protrusion 30 which can be located in recess 29. Cylinder 18 can be installed eccentrically relative to axis of bit rotation. Several passages 19 can be made in butt end part of cylinder 18 which match with passages 20. EFFECT: high efficiency. 2 cl, 1 dwg