Granted Patent
Utility
US 4,862,907 · App. 07/242,467
Check valve
Inventors:
Marvin L. Ledtje, Aubrey D. Long, Jr.
Patented Case
View Patent ↗
Granted: Sep 5, 1989
Filed: Sep 7, 1988
Inventors
Marvin L. Ledtje
Aubrey D. Long, Jr.
Assignee (at issue)
Spectra-Physics, 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.