BIT FOR ROTARY DRILLING Russian patent published in 1996 - IPC

FIELD: tools for rotary drilling of holes in coal industry in driving of mine workings by drilling and blasting. SUBSTANCE: bit for rotary drilling has working surfaces of diamond- hard alloy inserts 7 and 8 which are made of two-layer metal material 9. Inner layer 10 is made of metal adhesively apt to diamond polycrystalline material. Outer layer 11 is made of metal with high ductility and impact strength. Total thickness of layers 10 and 11 is 0.03-0.15 of the thickness of diamond layer 12. All outer surface of working head 3 with wings 4 and 5 may be made of two-layer metal material. Outer surface of wings 4 may be made of molybdenum or titanium, and that of wings 4, of two-layer metal material 9. Inner surface of recesses 6 may be made of metal adhesively apt to diamond polycrystalline material. EFFECT: higher efficiency. 4 cl, 4 dwg