Granted Patent
Utility
US 4,540,865 · App. 06/584,626
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Inventor:
John Calder
Patented Case
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Granted: Sep 10, 1985
Filed: Feb 29, 1984
Inventor
John Calder
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.