Granted Patent
Utility
US 4,763,880 · App. 07/033,971
Rotary hearth multi-chamber, multi-purpose furnace system
Inventors:
John W. Smith, Gary D. Keil
Patented Case
View Patent ↗
Granted: Aug 16, 1988
Filed: Apr 3, 1987
Inventors
John W. Smith
Gary D. Keil
Assignee (at issue)
Holcroft/Loftus, 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.