Granted Patent
Utility
US 4,648,418 · App. 06/836,543
Fireproof valve assembly and valve element for use therein
Inventors:
William B. Scobie, Michael L. Wagberg
Patented Case
View Patent ↗
Granted: Mar 10, 1987
Filed: Mar 5, 1986
Inventors
William B. Scobie
Michael L. Wagberg
Assignee (at issue)
Keystone International
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.