Granted Patent
Utility
US 4,094,303 · App. 05/769,398
Tympanic membrane vent
Inventor:
Douglas Johnston
Patented Case
View Patent ↗
Granted: Jun 13, 1978
Filed: Feb 16, 1977
Inventor
Douglas Johnston
Assignee (at issue)
Glasrock Products, Inc.
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.