Granted Patent
Utility
US 5,407,172 · App. 08/303,595
Position instrumented blowout preventer
Inventors:
Kenneth D. Young, Kenneth W. Colvin, Joseph L. Frederick
Patented Case
View Patent ↗
Granted: Apr 18, 1995
Filed: Sep 9, 1994
Inventors
Kenneth D. Young
Kenneth W. Colvin
Joseph L. Frederick
Assignee (at issue)
Hydril Company
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.