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U.S. Department of Energy
Office of Scientific and Technical Information

Rock bit with improved shirttail ventilation

Patent ·
OSTI ID:6460805
An earth boring bit of the air cooled bearing type has features to improve cleaning of the borehole. The bit has 3 bit legs, each with a depending bearing pin that receives a rotatable cutter. Bearings are located between the bearing pin and the cutter. Passages communicate drilling fluid from the drill string to the bearings. A slot between the bit leg and the backface of the cutter enables air to be discharged from the bearing pin into the borehole. The portion of the slot on the lower side of the bearing pin is greater in cross-sectional flow area than the portion on the upper side. The portion of the slot on the lower side exposes the outer ends of the roller bearings to the borehole. 5 claims.
Assignee:
Hughes Tool Co.
Patent Number(s):
US 4421184
OSTI ID:
6460805
Country of Publication:
United States
Language:
English