PLANETARY DRILL Russian patent published in 2001 - IPC

FIELD: drilling equipment to drill large-diameter holes. SUBSTANCE: planetary drill includes turbo-drill anchored in upper and lower cross- pieces whose axis is displaced relative to axis of hole. Turbo-drill is coupled to drill pipe string with the aid of central shaft. Longitudinal axis of turbo-drill is inclined towards axis of central shaft at angle from 30 min to 7 degrees. For stabilization and centering of planetary drill along axis of hole it is fitted with drilled barrel which lower end carries rotary bit satellite-runner. EFFECT: increased productivity of drilling thanks to growth of axial load on drill bit and reduced vibration of planetary drill. 2 cl, 3 dwg