Granted Patent
Utility
US 4,988,421 · App. 07/296,469
Method of toughening diamond coated tools
Inventors:
William R. Drawl, Robert Corbly McCune
Patented Case
View Patent ↗
Granted: Jan 29, 1991
Filed: Jan 12, 1989
Inventors
William R. Drawl
Robert Corbly McCune
Assignee (at issue)
Ford Motor Company
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.