Granted Patent
Utility
US 4,658,121 · App. 06/771,384
Self regulating heating device employing positive temperature coefficient of resistance compositions
Inventors:
David A. Horsma, Teddy J. Hammack
Patented Case
View Patent ↗
Granted: Apr 14, 1987
Filed: Aug 29, 1985
Inventors
David A. Horsma
Teddy J. Hammack
Assignee (at issue)
Raychem Limited
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.