SCREW DRILL BIT FOR FROZEN SOILS Russian patent published in 2020 - IPC E21B10/44 E21B7/24 E02F5/20 

FIELD: excavation and moving of soil.

SUBSTANCE: invention relates to excavation works, in particular, to devices for formation of wells. Screw drill comprises conical core with helical blade consisting of conical section with constant pitch of blade turns and cylindrical section with pitch of blade turns, which has constant increment relative to step pitch of conical section of blade. Helical blade has the same number of turns on the cylindrical and conical sections, equal to not more than two. Diameter of the turn of the blade on the cylindrical section is more than twice the diameter of the base of the cone described by the edge of the turns of the blade of the conic section. Angle of inclination of generatrix of upper surface of helical blade on cylindrical section of bore to axis of rotation varies from 42° to 90°.

EFFECT: technical result is reduction of power consumption of well drilling in strong and frozen soils, including in frozen sand.

1 cl, 1 dwg