Granted Patent
Utility
US 4,617,636 · App. 06/471,333
Protection of electrical power supply systems
Inventors:
Allan T. Johns, Michael A. Martin
Patented Case
View Patent ↗
Granted: Oct 14, 1986
Filed: Mar 2, 1983
Inventors
Allan T. Johns
Michael A. Martin
Assignee (at issue)
NATIONAL RESEARCH DEVELOPMENT CORPORATION
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.