Granted Patent
Utility
US 4,319,950 · App. 06/135,565
Mandrel for making a coupling for rigid pressure pipe
Inventors:
John L. Sznopek, Charles Lostak, Robert W. Heisler, Joseph P. Ferraro, Henry J. Kazienko
Patented Case
View Patent ↗
Granted: Mar 16, 1982
Filed: Mar 31, 1980
Inventors
John L. Sznopek
Charles Lostak
Robert W. Heisler
Joseph P. Ferraro
Henry J. Kazienko
Assignee (at issue)
Manville Service Corporation
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.