Granted Patent
Utility
US 4,889,318 · App. 07/279,718
Molded hopper tee
Inventor:
David E. Sisk
Patented Case
View Patent ↗
Granted: Dec 26, 1989
Filed: Dec 5, 1988
Inventor
David E. Sisk
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.