Granted Patent
Utility
US 4,369,889 · App. 06/271,775
Tamperproof closure
Inventor:
Efrem M. Ostrowsky
Patented Case
View Patent ↗
Granted: Jan 25, 1983
Filed: Jun 8, 1981
Inventor
Efrem M. Ostrowsky
Assignee (at issue)
Ethyl Products 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.