Granted Patent
Utility
US 4,849,004 · App. 07/264,750
Pulsed pressure method for vacuum refining of glassy materials
Inventors:
Ronald L. Schwenninger, David A. Hanekamp, Jr., Homer R. Foster
Patented Case
View Patent ↗
Granted: Jul 18, 1989
Filed: Oct 31, 1988
Inventors
Ronald L. Schwenninger
David A. Hanekamp, Jr.
Homer R. Foster
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.