Granted Patent
Utility
US 4,444,404 · App. 06/435,346
Variable bore ram packing element and blowout preventer
Inventor:
Glenn C. Parks, Jr.
Patented Case
View Patent ↗
Granted: Apr 24, 1984
Filed: Oct 19, 1982
Inventor
Glenn C. Parks, Jr.
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.