Granted Patent
Utility
US 4,336,692 · App. 06/140,706
Dual source heat pump
Inventors:
Amir L. Ecker, Joseph A. Pietsch
Patented Case
View Patent ↗
Granted: Jun 29, 1982
Filed: Apr 16, 1980
Inventors
Amir L. Ecker
Joseph A. Pietsch
Assignee (at issue)
Atlantic Richfield Company
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.