CONE DRILL BIT Russian patent published in 1997 - IPC

FIELD: hole drilling. SUBSTANCE: cone drill bit includes body, feet, cones, rinsing ducts made in body between cones, attachments with central axial duct and hole in bottom part set in rinsing ducts. Bottom part of attachment is spherical and has hole in the form of slit directed counter to rotation of drill under coming cone and expanding towards periphery of drill bit in proportion to increase of diameter of cone. Edges limiting length of slit form angle embracing radius of drill bit. Internal surface of central axial duct of attachment has longitudinal grooves. Side surfaces of partitions separating grooves are located in radial-axial planes. Depth of grooves, mean width of grooves and thickness of partitions separating grooves are equal to size of abrasive particles of drilling fluid. Butts of partitions are rounded. EFFECT: enhanced hole drilling efficiency. 1 dwg