SCREW DRILL FOR FROZEN SOILS Russian patent published in 2023 - IPC E21B7/26 E21B10/44 E02F5/16 

FIELD: earthworks.

SUBSTANCE: invention relates to earthworks, in particular, to devices for the formation of wells. A screw drill for frozen soils contains a conical core with a screw blade. The screw blade consists of a thrust section with a constant interval of blade turns and a destruction section with an interval of blade turns, having a constant increment relatively to the interval of turns of the thrust section of the blade. The screw blade is made with the same number of turns on destruction and thrust sections, equal to no more than two. An angle of inclination of the generatrix of an upper surface of the screw blade on the destruction section to the axis of rotation changes its value from 42° to 90°. An angle of rotation of a radius of the screw blade, at which its increment occurs, is in the range from 90° to 270°. The ratio of a radius of a screw surface at the end of the destruction section of the screw blade to a radius of the screw surface at the beginning of the destruction section of the screw blade is from 1.5 to 1.7. In a lower part of the drill, there is a borer with a sharpening angle in the range from 30° to 40°, and the ratio of a diameter of the screw surface at the end of the destruction section of the screw blade to a diameter of the borer is from 3.2 to 3.9.

EFFECT: reduction in energy intensity of drilling wells in strong and frozen soils.

1 cl, 1 dwg