Granted Patent
Utility
US 5,271,426 · App. 07/915,672
Gate valve
Inventors:
Curtis W. Clarkson, Larry F. Koll, Milton E. Jennings, Nicholas J. Williams
Patented Case
View Patent ↗
Granted: Dec 21, 1993
Filed: Jul 21, 1992
Inventors
Curtis W. Clarkson
Larry F. Koll
Milton E. Jennings
Nicholas J. Williams
Assignee (at issue)
The Clarkson Company
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.