Granted Patent
Utility
US 4,457,333 · App. 06/264,457
Check valve with relief-valve feature
Inventor:
Donald L. Sharp
Patented Case
View Patent ↗
Granted: Jul 3, 1984
Filed: May 18, 1981
Inventor
Donald L. Sharp
Assignee (at issue)
Transamerica DeLaval 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.