Granted Patent
Utility
US 4,484,578 · App. 06/535,018
Respirator apparatus and method
Inventor:
Gerald Durkan
Patented Case
View Patent ↗
Granted: Nov 27, 1984
Filed: Sep 23, 1983
Inventor
Gerald Durkan
Assignee (at issue)
Kircaldie, Randall and McNab (As Trustee)
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.