Granted Patent
Utility
US 4,242,564 · App. 05/956,639
Frost plug immersion heater and improved clamping structure
Inventor:
Willard E. Kendall
Patented Case
View Patent ↗
Granted: Dec 30, 1980
Filed: Nov 1, 1978
Inventor
Willard E. Kendall
Assignee (at issue)
Budd Canada, 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.