Granted Patent
Utility
US 4,573,326 · App. 06/698,057
Adaptive defrost control for heat pump system
Inventors:
Louis Sulfstede, Carl Bergt, Robert W. Helt
Patented Case
View Patent ↗
Granted: Mar 4, 1986
Filed: Feb 4, 1985
Inventors
Louis Sulfstede
Carl Bergt
Robert W. Helt
Assignee (at issue)
American Standard 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.