CROWN FOR PERCUSSIVE-ROTARY WELL DRILLING Russian patent published in 2007 - IPC E21B10/36 

FIELD: drilling equipment, particularly rock-cutting tool for percussive-rotary drilling of rock having high or medium hardness.

SUBSTANCE: crown has body with stem, hard-alloy ball-shaped inserts arranged on peripheral crown part, prismatic inserts arranged in collar installed in central crown part so that the collar may rotate about crown axis and fix the crow position with respect to ball position. Crown has central flushing channel communicated with two inclined channels and additional prismatic inserts mutually arranged between two inclined channels so that T-shaped structure is created.

EFFECT: increased drilling speed due to improved well bottom cutting efficiency.

3 dwg