Granted Patent
Utility
US 4,405,680 · App. 06/452,595
Roofing shingle
Inventor:
David R. Hansen
Patented Case
View Patent ↗
Granted: Sep 20, 1983
Filed: Dec 23, 1982
Inventor
David R. Hansen
Assignee (at issue)
SHELL OIL COMPANY
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.