DRILLING TOOLS Russian patent published in 2016 - IPC E21B10/56 E21B10/58 

FIELD: drilling of soil or rock.

SUBSTANCE: drilling tool comprises a housing with openings in which are fixed cutters insert comprising a shank and a working head portion of a torus. Working head inserts in the frontal plane is made of at least one recess arranged asymmetrically relative to the longitudinal axis of the shank, and the shank in cross section is formed as an asymmetric ring segment greater radius greater than the radius of the holes in the housing under the insert.

EFFECT: technical result is to increase the efficiency of the drilling tool.

1 cl, 2 dwg