Granted Patent
Utility
US 4,418,921 · App. 06/261,870
Mechanical seal
Inventors:
Winfred J. Wiese, Joseph A. Marsi
Patented Case
View Patent ↗
Granted: Dec 6, 1983
Filed: May 8, 1981
Inventors
Winfred J. Wiese
Joseph A. Marsi
Assignee (at issue)
BorgWarner 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.