Granted Patent
Utility
US 4,332,553 · App. 06/229,956
Vacuum firing porcelain furnace
Inventors:
Roger Earle, William J. Walsh
Patented Case
View Patent ↗
Granted: Jun 1, 1982
Filed: Jan 30, 1981
Inventors
Roger Earle
William J. Walsh
Assignee (at issue)
Sybron Corporation
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.