Granted Patent
Utility
US 4,299,510 · App. 05/967,274
Drill steel and method of fabrication
Inventors:
Kenneth C. Emmerich, Donald K. Chrise
Patented Case
View Patent ↗
Granted: Nov 10, 1981
Filed: Dec 7, 1978
Inventors
Kenneth C. Emmerich
Donald K. Chrise
Assignee (at issue)
Fansteel 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.