Granted Patent
Utility
US 4,313,458 · App. 06/209,180
Restricted movement valve seats for an expanding gate valve
Inventors:
Ivan A. Burns, William R. Hochmuth
Patented Case
View Patent ↗
Granted: Feb 2, 1982
Filed: Nov 21, 1980
Inventors
Ivan A. Burns
William R. Hochmuth
Assignee (at issue)
ACF Industries Incorporated
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.