Granted Patent
Utility
US 4,959,867 · App. 07/231,115
Audiometer attenuation method and apparatus
Inventor:
William Lutz
Patented Case
View Patent ↗
Granted: Sep 25, 1990
Filed: Aug 11, 1988
Inventor
William Lutz
Assignee (at issue)
Nicolet Instrument 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.