Granted Patent
Utility
US 4,827,247 · App. 07/037,731
Self-compensating projected-beam smoke detector
Inventor:
Ralph Giffone
Patented Case
View Patent ↗
Granted: May 2, 1989
Filed: Apr 13, 1987
Inventor
Ralph Giffone
Assignee (at issue)
ADT Holdings, 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.