Granted Patent
Utility
US 4,455,553 · App. 06/378,400
Smoke detector of the ionization type
Inventor:
Robert Johnson
Patented Case
View Patent ↗
Granted: Jun 19, 1984
Filed: May 17, 1982
Inventor
Robert Johnson
Assignee (at issue)
Pyrotector, Inc.
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.