Granted Patent
Utility
US 4,314,688 · App. 06/071,996
Gate valve
Inventor:
A. Louis Leman, Jr.
Patented Case
View Patent ↗
Granted: Feb 9, 1982
Filed: Sep 4, 1979
Inventor
A. Louis Leman, Jr.
Assignee (at issue)
SOUTHWEST OILFIELD PRODUCTS, 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.