Granted Patent
Utility
US 4,376,464 · App. 06/214,041
Well safety valve
Inventor:
Robert W. Crow
Patented Case
View Patent ↗
Granted: Mar 15, 1983
Filed: Dec 8, 1980
Inventor
Robert W. Crow
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.