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

Stressed relieved bit leg for an earth boring bit

Patent ·
OSTI ID:6633440
An earth boring bit has features to reduce stress concentration. The earth boring bit is of the type having three bit legs, each bit leg having a depending bearing pin for rotatably carrying a cutter. An annular fillet is formed at the junction of the bearing pin and the bit leg for receiving a seal ring. To relieve stress above the fillet and on the inside surface of the bit leg, a depression is formed. The depression is formed in the inside surface of the bit leg with a lower edge commencing at the top of the fillet. The depression is curved in vertical cross-section and is located behind the backface of the cutter.
Assignee:
Hughes Tool Company
Patent Number(s):
US 4431066
OSTI ID:
6633440
Country of Publication:
United States
Language:
English