Roy A Mathers

US Patent:

47639377, Aug 16, 1988

Filed:

Sep 11, 1986

Appl. No.:

6/906168

Inventors:

Ralph A. Sittnick - Southington CT
Roy A. Mathers - Farmington CT

International Classification:

E05C 1756

US Classification:

2922515

Abstract:

An electromagnetic door lock system employs an electromagnetic lock which magnetically bonds with an armature plate. An acoustical sensor generates a detection beam. The detection beam is directed toward the doorknob. Reflected energy is received and electronically processed to detect the presence of a foreign object in the vicinity of the doorknob. The lock automatically deactuates when a foreign object is detected in the vicinity of the knob. The electromagnetic lock, sensor and processing circuitry are mounted in a housing which is located near the top of a doorway. An audio alarm and status light indicators are mounted at the housing to indicate the status of the lock.