Granted Patent
Utility
US 4,188,948 · App. 05/844,020
Filter device
Inventor:
John A. Swinton
Patented Case
View Patent ↗
Granted: Feb 19, 1980
Filed: Oct 20, 1977
Inventor
John A. Swinton
Assignee (at issue)
American Hospital Supply Corp.
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.