Granted Patent
Utility
US 4,325,534 · App. 06/195,995
Manually operated blowout preventer and hydraulic operator therefor
Inventors:
James T. Roark, Steven R. Hayter
Patented Case
View Patent ↗
Granted: Apr 20, 1982
Filed: Oct 10, 1980
Inventors
James T. Roark
Steven R. Hayter
Assignee (at issue)
Otis Engineering Corporation
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.