Granted Patent
Utility
US 4,386,973 · App. 06/261,761
Vacuum carburizing steel
Inventors:
Richard J. Kawka, Daniel H. Herring, Philip Roth, Richard J. Sitko
Patented Case
View Patent ↗
Granted: Jun 7, 1983
Filed: May 8, 1981
Inventors
Richard J. Kawka
Daniel H. Herring
Philip Roth
Richard J. Sitko
Assignee (at issue)
Federal Signal Corporation
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.