ROLLER-TYPE DRILLING BIT Russian patent published in 1999 - IPC

FIELD: mining industry. SUBSTANCE: this drilling bit is used for secondary opening of productive beds with going out of producing pipe strings of earlier drilled bore-holes, and it also used for acquiring curvature at drilling slant bore-holes. Roller-type drilling bit has rock-crushing teeth. Cutting edge of teeth 15 in peripheral rim of main cone of rolling cutter protrudes in radial direction above surface of inverted cone 10 of rolling cutters by value lying within interval of l₁ = 0.01-0.03 of drilling bit diameter D. Edge of teeth 15 protrudes above cutting edge of teeth of inverted cone by value of l₃ = 0.01-0.03 D. Edge of teeth 15 protrudes above lip 2 of lug by value of l_q = 0.02-0.05 D. Axes of teeth 15 at moment of contact with rock create angle with bit axis within interval of α = 45-75 deg. Aforesaid embodiment of roller-type drilling bit improves efficiency of bit operation in initiating drilling of bore-holes from earlier drilled bore-holes and at acquiring curvature in drilling slant bore-holes. EFFECT: higher efficiency. 1 dwg