Granted Patent
Utility
US 4,369,980 · App. 06/309,235
Fire ring for cylinder head gasket
Inventor:
Robert R. Backlin
Patented Case
View Patent ↗
Granted: Jan 25, 1983
Filed: Oct 7, 1981
Inventor
Robert R. Backlin
Assignee (at issue)
Allis-Chalmers 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.