CROWN BIT FOR ROTARY-PERCUSSION DRILLING Russian patent published in 2003 - IPC

FIELD: rock-cutting tools, particularly, crown bits for rotary-percussion drilling; applicable in mining industry. SUBSTANCE: crown bit for rotary-percussion drilling consists of body with working surface separated in its end part by diametrical dissection into wings. Body is monolithic, and its end part has semitoroidal surface passing into side cylindrical surface. Wings are made with internal and external cutting edges. Internal cutting edges are formed by diametrical dissection made of acute angle in direction of crown bit rotation. External cutting edges are formed by acute angle in cross-section and directed to side of crown bit rotation. EFFECT: higher efficiency of drilling of louse and medium hard rocks and decreased cost of crown bit manufacture. 3 dwg