Granted Patent
Utility
US 5,180,137 · App. 07/770,181
Ram type blowout preventer having improved ram front packings
Inventors:
Douglas W. Carlson, Stephen P. Simons
Patented Case
View Patent ↗
Granted: Jan 19, 1993
Filed: Oct 2, 1991
Inventors
Douglas W. Carlson
Stephen P. Simons
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.