Granted Patent
Utility
US 4,337,956 · App. 06/221,425
Double lip seal with pressure compensation
Inventor:
James A. Hopper
Patented Case
View Patent ↗
Granted: Jul 6, 1982
Filed: Dec 30, 1980
Inventor
James A. Hopper
Assignee (at issue)
American Sterilizer Company
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.