Granted Patent
Utility
US 4,394,147 · App. 06/325,756
Internally supported filter
Inventors:
John A. Caddy, William A. Putman
Patented Case
View Patent ↗
Granted: Jul 19, 1983
Filed: Nov 30, 1981
Inventors
John A. Caddy
William A. Putman
Assignee (at issue)
Allis-Chalmers Corporation
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.