Granted Patent
Utility
US 5,871,640 · App. 08/823,868
Filter and housing
Inventor:
Norman W. Gavin
Patented Case
View Patent ↗
Granted: Feb 16, 1999
Filed: Mar 25, 1997
Inventor
Norman W. Gavin
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.