Granted Patent
Utility
US 4,258,743 · App. 06/045,379
Expanding gate valve having mechanically secured seats
Inventors:
Roy R. Dare, Robert C. Houlgrave, William S. Shelton
Patented Case
View Patent ↗
Granted: Mar 31, 1981
Filed: Jun 4, 1979
Inventors
Roy R. Dare
Robert C. Houlgrave
William S. Shelton
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.