Granted Patent
Utility
US 4,751,439 · App. 06/495,284
Multiple chopper speed control system for compound motor
Inventors:
Frank S. Buchwald, William Pickering
Patented Case
View Patent ↗
Granted: Jun 14, 1988
Filed: May 16, 1983
Inventors
Frank S. Buchwald
William Pickering
Assignee (at issue)
Caterpillar Industrial Inc.
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.