ANNULAR DRILLING BIT Russian patent published in 2008 - IPC E21B10/02 

FIELD: drilling equipment, particularly drilling bits adapted to drill rock with continuous core removal.

SUBSTANCE: drilling bit comprises body with longitudinal grooves on outer surface thereof. The longitudinal grooves connect radial body channels and grooves made in working end thereof. The working end is reinforced with well-forming and core-forming cutters displaced relatively diametrical planes, which are parallel to cutting edges thereof, in direction opposite to drilling bit rotation direction. Drilling bit comprises guiding bush arranged on outer body surface and restricted from rotation relatively the body. Inner surface of guiding bush has longitudinal grooves communicated with radial channels of the body and radial grooves of working end. Guiding bush is fixed from rotation relatively the body with splined connection and is provided with sealing unit made as several rings or spring arranged on outer bush surface.

EFFECT: increased operational efficiency.

3 cl, 3 dwg