Granted Patent
Utility
US 4,238,188 · App. 06/021,571
Extraoral force-applying orthodontic appliance
Inventor:
Maclay M. Armstrong
Patented Case
View Patent ↗
Granted: Dec 9, 1980
Filed: Mar 19, 1979
Inventor
Maclay M. Armstrong
Assignee (at issue)
Northwest Orthodontics, 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.