Granted Patent
Utility
US 5,074,424 · App. 07/574,260
Irreversible tamper indicator for mechanical button cap
Inventors:
Robert J. Heilman, Harry W. Ingersol
Patented Case
View Patent ↗
Granted: Dec 24, 1991
Filed: Aug 30, 1990
Inventors
Robert J. Heilman
Harry W. Ingersol
Assignee (at issue)
Continental White Cap, 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.