Granted Patent
Utility
US 4,646,537 · App. 06/793,365
Hot water heating and defrost in a heat pump circuit
Inventor:
James Crawford
Patented Case
View Patent ↗
Granted: Mar 3, 1987
Filed: Oct 31, 1985
Inventor
James Crawford
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.