Granted Patent
Utility
US 4,581,727 · App. 06/444,365
Finding the direction of a sound
Inventors:
Philip G. Harper, Stuart I. Jardine, Andrew J. Quinn, David M. Treherne
Patented Case
View Patent ↗
Granted: Apr 8, 1986
Filed: Nov 26, 1982
Inventors
Philip G. Harper
Stuart I. Jardine
Andrew J. Quinn
David M. Treherne
Assignee (at issue)
NATIONAL RESEARCH DEVELOPMENT CORPORATION
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.