DRILL BIT Russian patent published in 1994 - IPC

FIELD: mining industry. SUBSTANCE: drill bit has flexible collar 10 with radial protrusions 11. Collar is connected to body 1 with capability of overlapping of nonworking face of roller bit 6. The latter has radial recessions 9 with through holes communicating with face zone and with space above roller bit. Pin 3 has conical central duct 4 narrowing to its end and duct 15 communicating along tangent line with broad part of duct 14 and duct 2 in body 1. Protrusions 1 of collar 10 are located for interaction with protrusions 9 of roller bit 6. EFFECT: improved operational characteristics. 4 dwg