Granted Patent
Utility
US 6,629,476 · App. 09/969,444
Bi-center bit adapted to drill casing shoe
Inventors:
Coy M. Fielder, Rogerio H. Silva
Patented Case
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Granted: Oct 7, 2003
Filed: Oct 2, 2001
Inventors
Coy M. Fielder
Rogerio H. Silva
Assignee (at issue)
Diamond Products International, Inc.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.