Granted Patent
Utility
US 4,331,172 · App. 06/187,285
Fire-safe valve structure
Inventor:
John D'Angelo
Patented Case
View Patent ↗
Granted: May 25, 1982
Filed: Sep 15, 1980
Inventor
John D'Angelo
Assignee (at issue)
ACF Industries Incorporated
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.