Granted Patent
Utility
US 4,332,367 · App. 06/146,077
Blowout preventer having a variable ram seal
Inventor:
Norman A. Nelson
Patented Case
View Patent ↗
Granted: Jun 1, 1982
Filed: May 2, 1980
Inventor
Norman A. Nelson
Assignee (at issue)
NL Industries, 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.