Granted Patent
Utility
US 4,393,644 · App. 06/289,869
Two-speed drive apparatus for blower fans
Inventor:
Wayne B. Martenas
Patented Case
View Patent ↗
Granted: Jul 19, 1983
Filed: Aug 4, 1981
Inventor
Wayne B. Martenas
Assignee (at issue)
Sperry Corp.
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.