Granted Patent
Utility
US 5,118,335 · App. 07/590,713
Tempering ring design
Inventors:
George R. Claassen, Robert G. Frank, Rudolph A. Karlo, John J. Ewing
Patented Case
View Patent ↗
Granted: Jun 2, 1992
Filed: Oct 1, 1990
Inventors
George R. Claassen
Robert G. Frank
Rudolph A. Karlo
John J. Ewing
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.