Granted Patent
Utility
US 4,155,161 · App. 05/655,401
Extraoral force-applying orthodontic appliance
Inventor:
Maclay M. Armstrong
Patented Case
View Patent ↗
Granted: May 22, 1979
Filed: Feb 5, 1976
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.