Granted Patent
Utility
US 4,620,309 · App. 06/717,939
Electric furnace construction
Inventors:
Stephen J. Schultz, John F. Huebner, Duane E. Wiedor, Dennis S. Pribish
Patented Case
View Patent ↗
Granted: Oct 28, 1986
Filed: Mar 29, 1985
Inventors
Stephen J. Schultz
John F. Huebner
Duane E. Wiedor
Dennis S. Pribish
Assignee (at issue)
PPG Industries, 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.