Granted Patent
Utility
US 5,890,700 · App. 08/902,298
Gate valve
Inventors:
Curtis W. Clarkson, Nicholas J. Williams
Patented Case
View Patent ↗
Granted: Apr 6, 1999
Filed: Jul 29, 1997
Inventors
Curtis W. Clarkson
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.