Granted Patent
Utility
US 4,415,378 · App. 06/370,719
Case hardening method for steel parts
Inventors:
Joe R. McKinney, Roy G. Swagger
Patented Case
View Patent ↗
Granted: Nov 15, 1983
Filed: Apr 22, 1982
Inventors
Joe R. McKinney
Roy G. Swagger
Assignee (at issue)
DANA LIMITED
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.