Granted Patent
Utility
US 4,304,822 · App. 06/156,378
Coated metal tubing
Inventor:
Russell G. Heyl
Patented Case
View Patent ↗
Granted: Dec 8, 1981
Filed: Jun 4, 1980
Inventor
Russell G. Heyl
Assignee (at issue)
International Telephone and Telegraph 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.