Granted Patent
Utility
US 6,478,898 · App. 09/664,766
Method of producing tool steels
Inventors:
Tomoaki Sera, Masahide Umino, Yasutaka Okada, Kunio Kondo
Patented Case
View Patent ↗
Granted: Nov 12, 2002
Filed: Sep 19, 2000
Inventors
Tomoaki Sera
Masahide Umino
Yasutaka Okada
Kunio Kondo
Assignee (at issue)
SUMITOMO METAL INDUSTRIES, LTD.
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.