ROCK CRUSHER Russian patent published in 2015 - IPC E21B10/43 

FIELD: mining.

SUBSTANCE: rock crusher comprises the body with studded cutters. Note here that said cutters feature cylindrical shape and chisel-shaped working surface. Central cutter is fitted at two-blade body and shifted to the drill rotational axis and two rows of cutters, one in a row per every blade, one of them being arranged at larger height cutters. Cutters pitch in one row equals that between cutters of the other row with the shift by the pitch magnitude. Cutters in rows and central cutter feature identical diameter while two extreme cutters and central cutter feature smaller height. Note here that said central cutters are fitted in place with cutting edge forward inclination toward the drill spinning direction.

EFFECT: higher efficiency, lower power input, higher rate of well drilling.

4 dwg