Granted Patent
Utility
US 4,435,794 · App. 06/280,749
Wall-driven oval ring transducer
Inventors:
William J. Marshall, Gerald A. Brigham
Patented Case
View Patent ↗
Granted: Mar 6, 1984
Filed: Jul 6, 1981
Inventors
William J. Marshall
Gerald A. Brigham
Assignee (at issue)
Sanders GmbH
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.