Granted Patent
Utility
US 4,243,072 · App. 05/972,769
Three position selector valve
Inventors:
Robert K. Hoffman, Mark A. Kavanaugh
Patented Case
View Patent ↗
Granted: Jan 6, 1981
Filed: Dec 26, 1978
Inventors
Robert K. Hoffman
Mark A. Kavanaugh
Assignee (at issue)
Parker-Hannifin 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.