Granted Patent
Utility
US 4,042,864 · App. 05/585,210
AC-DC Traction drive control system
Inventor:
Melvin Norris
Patented Case
View Patent ↗
Granted: Aug 16, 1977
Filed: Jun 9, 1975
Inventor
Melvin Norris
Assignee (at issue)
Joy Manufacturing 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.