Granted Patent
Utility
US 4,452,421 · App. 06/337,063
Well blowout preventer, and packing element
Inventors:
Wai J. Huey, Fernando Murman, Eugene Matsuda
Patented Case
View Patent ↗
Granted: Jun 5, 1984
Filed: Jan 4, 1982
Inventors
Wai J. Huey
Fernando Murman
Eugene Matsuda
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.