ROLLER-CUTTER CORE DRILL BIT Russian patent published in 1994 - IPC

FIELD: drilling equipment. SUBSTANCE: axis of one end of spindle 4 is displaced relative to place of fitting of roller cutters 5 and 6. Both ends may be displaced to one side and through same distance from axis of place of fitting for roller cutters 5 and 6. Diameter of one end of spindle 4 is smaller, and diameter of the other end of spindle 4 is larger than the diameter of place of fitting for roller cutters. EFFECT: higher efficiency due to uniform action of core- forming roller cutters on core. 2 cl, 2 dwg