BORING UNIT FOR MACHINES WITH SCREW WORKING TOOL Russian patent published in 2004 - IPC

FIELD: mining industry. SUBSTANCE: boring unit includes gripping blocks of saddle form, levers of turn, drive of these levers, centering rollers. Bar-like turn limiter of gripping block is put on at least one lever on one side with reference to anchoring axle of gripping block, perpendicular to internal and external surfaces of lever of turn. Working end of limiter protrudes above internal surface of lever for interaction with gripping block with its butt. Limiter is mobile relative to internal and external surfaces of lever and is fitted with device changing length of its working end. Opposite end of limiter is positioned with its butt in plane of external surface of lever of turn. EFFECT: enhanced drilling efficiency with screw working tool with partial wear of spirals along diameter. 4 cl, 4 dwg