Granted Patent
Utility
US 4,392,657 · App. 06/151,841
Belleville spring loaded seal
Inventor:
Robert D. Roley
Patented Case
View Patent ↗
Granted: Jul 12, 1983
Filed: Feb 19, 1980
Inventor
Robert D. Roley
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.