DIAMOND CROWN BIT Russian patent published in 2001 - IPC

FIELD: rock-cutting tools, particularly, crown bits for rotary drilling of geological exploration wells in hard rocks. SUBSTANCE: diamond crown bit has body and diamond-containing matrix with protruding rock-cutting members. To provide for uniform wear of rock-cutting members of varying width, increasing from periphery to center, equality of cutting structures of rock-cutting members is ensured by varying diamond concentration in diamond-bearing layer, in each row of rock-cutting members in compliance with relation ship K1•S1 = K2•S2 = ...Ki•Si, where K1,K2,Ki are concentrations of diamonds in diamond-bearing layer of the 1st, 2nd, ith rows of rock-cutting members, respectively, vol.%; S1,S2,Si are areas of the 1st, 2nd, ith rows of rock-cutting members, sq. cm. EFFECT: increased service life of crown bit and reduced footage cost. 1 dwg, 1 tbl