Granted Patent
Utility
US 4,904,312 · App. 07/230,429
Method of electrolytically etching linear impressions in electrical steel
Inventors:
Philip Beckley, David Snell
Patented Case
View Patent ↗
Granted: Feb 27, 1990
Filed: Aug 10, 1988
Inventors
Philip Beckley
David Snell
Assignee (at issue)
British Steel plc.
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.