Granted Patent
Utility
US 4,893,852 · App. 07/297,700
Dual sensor electromagnetic door lock system
Inventors:
Daniel J. Harris, Richard W. Gladych
Patented Case
View Patent ↗
Granted: Jan 16, 1990
Filed: Jan 17, 1989
Inventors
Daniel J. Harris
Richard W. Gladych
Assignee (at issue)
Harrow Products LLC
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.