Electric door lock with time delay

Abstract

Abstract AN ELECTRIC LOCK DEVICE FOR OPENING AN ELECTRICALLY RELEASABLE LATCH MEANS UPON INSERTION OF A KEY INTO A KEY SLOT IN THE LOCK CYLINDER. A TIME DELAY INCLUDING A SILICON CONTROLLED RECTIFIER AND A CAPACITOR-RESISTANCE SERIES IS USED TO PREVENT PICKING OF THE LOCK. THE CYLINDER ARRANGEMENT COMPRISES ELECTRICALLY CONDUCTING PINS HAVING INSULATIVE BANDS SUCH THAT WHEN NO KEY IS IN THE LOCK, A CIRCUIT IS COMPLETED THROUGH THE PINS AND THERE IS NOT SUFFICIENT CURRENT THROUGH THE TIME DELAY CIRCUIT TO ACTIVATE THE LATCH. WHEN THE KEY IS INSERTED, THE INSULATIVE BANDS INTERRUPT THE LOCK CIRCUIT SO THAT CURRENT FLOWS THROUGH THE SCR, CAPACITOR-RESISTANCE CIRCUIT OF THE TIME DELAY, THUS WHEN THE SCR IS TRIGGERED, SUFFICIENT CURRENT PASSES THROUGH THE LATCH TO OPEN THE LATCH. A MODIFICATION PROVIDES A VARIABLE TIME DELAY AND UTILIZES RESISTORS CONNECTED IN PARALLEL COMBINATIONS BY DIFFERENT LOCATION OF THE PINS. DIFFERENT KEYS DISCONNECT DIFFERENT PINS AND THUS CAUSE DIFFERENT TIME DELAYS TO OCCUR BEFORE THE CHARGE ON THE CAPACITOR TRIGGERS THE SCR AND OPENS THE LATCH. THIS TIME DELAY DEPENDS ON THE NUMBER OF RESISTORS CONNECTED INTO THE CIRCUIT BY THE INSERTION OF A PARTICULAR KEY. A SECOND SCR IS USED IN THE CIRCUIT TO FORM A PULSATING OUTPUT. THIS CICRUIT IS TERMED A RELAXATION OSCILLATOR. A CIRCUIT IS ALSO USED TO IDENTIFY DIFFERENT KEYS BY USE OF AN IDENTIFICATION CIRCUIT INCLUDING WHEATSTONE BRIDGE CIRCUITS, HAVING RESISTORS PROPORTIONAL IN VALUE AS THOSE USED IN THE LOCK CYLINDER ASSEMBLY, TO CONTROL A NEON READOUT DEVICE.

Inventors

• 👤 Jonathon H Katz

Bibliographic Details