ROTATION BIT Russian patent published in 2002 - IPC

FIELD: hole drilling equipment. SUBSTANCE: rotation bit has body with core-receiving cavity, augers secured to bit body, core-trimming and borehole forming cutters side window in bit body between augers for communication of core-receiving cavity with space between augers, core breaker located in core-receiving cavity opposite to window upper part. Working surface of core breaker is inclined towards bit axis. Side window is made in the form of spiral cutout whose helix angle equals or exceeds to auger helix angle. Ratio of distance between ends of core-trimming cutters and core breaker center to bit inner diameter formed by core-trimming cutters equals to 1.6-4.0. Auger is made of hard polymer material and has comb-shaped profile of its internal side. Internal surface of core-receiving cavity has curved spiral grooves with increasing diameter towards side window. Core-trimming and borehole forming cutters are different lengths, short and long. EFFECT: higher efficiency of rock drilling. 4 dwg