Granted Patent
Utility
US 4,520,868 · App. 06/443,811
Heat exchanger
Inventor:
Charles E. Grawey
Patented Case
View Patent ↗
Granted: Jun 4, 1985
Filed: Nov 22, 1982
Inventor
Charles E. Grawey
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.