Granted Patent
Utility
US 4,381,821 · App. 06/238,988
Blast joint and protection element therefor
Inventor:
George J. Greene, Jr.
Patented Case
View Patent ↗
Granted: May 3, 1983
Filed: Feb 27, 1981
Inventor
George J. Greene, Jr.
Assignee (at issue)
Weatherford, Stonebor, 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.