Granted Patent
Utility
US 4,228,340 · App. 05/900,666
Voltage regulated capacitive discharge welding power supply
Inventor:
Gerald Dufrenne
Patented Case
View Patent ↗
Granted: Oct 14, 1980
Filed: Apr 27, 1978
Inventor
Gerald Dufrenne
Assignee (at issue)
Unitek
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.