ROTARY-PERCUSSION DRILLING BIT Russian patent published in 2002 - IPC

FIELD: mining industry. SUBSTANCE: rotary-percussion drilling bit has a body with central air course and conical hollow in center of the body working end face with conical hollow small base diameter equal to that of air course, and hard-alloy inserts located on the body working end face with inserts forming core-receiving cavity by their internal end faces. Diameter of large base of conical hollow is equal to diameter of core-receiving cavity, and height of conical hollow equals to diameters difference of its large and small bases. Hard-alloy inserts are made in the form of bent blades and in a number at least eight which coming in contact with rock and whose end faces form cutting edges. Frontal surface of blades has semispiral grooves with cutting edges. Conical hollow is made in the form of revolution hyperboloid of one napper whose saddle is coated with flexible member. EFFECT: higher drilling rate stability and efficiency. 4 dwg