CROWN BIT Russian patent published in 2013 - IPC E21B10/46 

FIELD: mining.

SUBSTANCE: crown bit comprises a body with a diamond-bearing matrix fixed on it, which is separated with washing slots into sectors reinforced with rock-breaking elements in the form of wear-resistant inserts from synthetic diamonds placed in a central, well-forming and core-forming part of sections according to an overlapping diagram. Hardness of the central part of each of rock-breaking elements is 3.5÷3.9 times, and hardness of their peripheral part is 1.1÷1.3 times higher than hardness of the matrix material. The overlapping value "b" between rock-breaking elements arranged in a well-forming or core-forming part of sections and rock-breaking elements placed in the central part of sectors may be found according to a certain dependence. The number of rock-breaking elements, which are in the central part of sectors to the same extent exceeds the number of rock-breaking elements, which are both in the well-forming and core-forming part of sectors, the number of which is identical, at the same time the total quantity of the rock-breaking elements in the crown may be found according to a certain dependence.

EFFECT: high resistance, maximum breaking capability, elimination of disastrous wear and sludging-up, resulting in burns of a crown bit matrix.

3 cl, 2 dwg