BORING BIT FOR ROTARY DRILLING Russian patent published in 2001 - IPC

FIELD: drilling of holes accommodating roof bolting. SUBSTANCE: boring bit includes body with tail part and two points carrying two hard-alloy plates anchored asymmetrically relative to rotation axis which form core-starting section together with internal surfaces of point. Each plate has major cutting edge in the form of polygonal line composed of two unequal sections with point of bend in vertex of point. Relation of projection of larger section of major cutting edge of each plate on to plane parallel to longitudinal axis of boring bit to corresponding projection of lesser section is 2.6-3.0. Relation of projection of larger section of major cutting edge on to longitudinal axis of boring bit to corresponding projection of lesser section is also 2.6-3.0 and relation of height of point to distance between two extreme internal points of major cutting edges of both points amounts to 1.4-1.7. EFFECT: enhanced drilling speed, reduced energy consumption for rock drilling. 1 dwg