Granted Patent
Utility
US 4,400,474 · App. 06/371,864
Basic refractory cementitious material and components thereof
Inventors:
Martin Copperthwaite, Michael Roberts
Patented Case
View Patent ↗
Granted: Aug 23, 1983
Filed: Apr 26, 1982
Inventors
Martin Copperthwaite
Michael Roberts
Assignee (at issue)
USS Engineers and Consultants, Inc.
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.