Granted Patent
Utility
US 4,373,697 · App. 06/275,074
Pulse width modulated constant current servo driver
Inventor:
Weldon L. Phelps
Patented Case
View Patent ↗
Granted: Feb 15, 1983
Filed: Dec 29, 1980
Inventor
Weldon L. Phelps
Assignee (at issue)
Caterpillar Tractor Co.
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.