DRILL HEAD FOR EXPANDING A PILOT BORE IN ORDER TO CREATE A BOREHOLE Russian patent published in 2018 - IPC E21B10/28 

FIELD: drilling soil or rock.

SUBSTANCE: invention relates to a drill head for expanding a pilot bore in order to create a borehole having a borehole wall, by removing rock surrounding the pilot bore in the region of a working face extending substantially at a right angle to the pilot bore. Drilling head comprises a main body, on which a connecting element for a pilot drill string is provided. On the main body, at least one tool retainer for at least one drilling tool being provided. At least one tool retainer is radially spaced from the main body further than the at least one other tool retainer, such that at least one outer and one inner drilling tool are present. At least one inner drilling tool and the at least one outer drilling tool are each arranged in an offset manner at an angle to the working face. There is provided at least one gripping tool having a bottom engaging area in which the drilling tool is located and adapted to grip the drill bit separated at the bottom and its withdrawal from the drilling area. At least one gripping tool is provided for capturing a drilling bit located at the bottom of the well and having a gripping surface that is inclined relative to the line of sight of the well at an angle <20°.

EFFECT: technical result consists in reducing the wear of the cutting rollers.

14 cl, 11 dwg