Granted Patent
Utility
US 5,036,921 · App. 07/544,910
Underreamer with sequentially expandable cutter blades
Inventors:
Fred J. Pittard, Jimmy Fultz
Patented Case
View Patent ↗
Granted: Aug 6, 1991
Filed: Jun 28, 1990
Inventors
Fred J. Pittard
Jimmy Fultz
Assignee (at issue)
Slimdril 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.