Granted Patent
Utility
US 4,468,321 · App. 06/465,899
Filter device with magnetic filter clamp
Inventor:
Gerald D. St. John
Patented Case
View Patent ↗
Granted: Aug 28, 1984
Filed: Feb 17, 1983
Inventor
Gerald D. St. John
Assignee (at issue)
Gelman Sciences
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.