Granted Patent
Utility
US 4,338,962 · App. 06/177,928
Control and relief valves
Inventors:
John D. Turko, John D. Petro
Patented Case
View Patent ↗
Granted: Jul 13, 1982
Filed: Aug 13, 1980
Inventors
John D. Turko
John D. Petro
Assignee (at issue)
Commercial Shearing, Inc.
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.