Granted Patent
Utility
US 4,273,081 · App. 06/057,480
Vent valve for engine cooling systems
Inventors:
Gary L. Cleveland, Clyde O. Taylor
Patented Case
View Patent ↗
Granted: Jun 16, 1981
Filed: Aug 27, 1979
Inventors
Gary L. Cleveland
Clyde O. Taylor
Assignee (at issue)
Caterpillar Tractor Co.
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.