Granted Patent
Utility
US 4,448,216 · App. 06/358,313
Subsurface safety valve
Inventors:
Steven C. Speegle, Kenneth L. Schwendemann, Michael B. Vinzant, Robert W. Crow, Cary Gorten Mondon
Patented Case
View Patent ↗
Granted: May 15, 1984
Filed: Mar 15, 1982
Inventors
Steven C. Speegle
Kenneth L. Schwendemann
Michael B. Vinzant
Robert W. Crow
Cary Gorten Mondon
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.