Granted Patent
Utility
US 4,330,876 · App. 06/185,739
Sonar systems
Inventor:
Phillip Johnson
Patented Case
View Patent ↗
Granted: May 18, 1982
Filed: Sep 10, 1980
Inventor
Phillip Johnson
Assignee (at issue)
Plessey Overseas Limited
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.