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Electronic lock and key

  • US 4,697,171 A
  • Filed: 01/27/1986
  • Issued: 09/29/1987
  • Est. Priority Date: 03/25/1985
  • Status: Expired due to Fees
First Claim
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1. An electronic lock and key comprising:

  • an electronic key including a key signal generator which generates a predetermined signal when said key is inserted into a keyhole of a key holder disposed within said lock;

    an electronic lock comprising, an unlocking means for unlocking said lock,an alarming circuit,a power source for supplying power to said lock and said key,wherein said alarming circuit becomes actuated when a power voltage which is greater than a predetermined level is applied to said lock,a signal comparing circuit, said signal comparing circuit including a comparator and a lock signal generator for generating a reference signal, wherein said comparator compares said predetermined signal generated by said key signal generator and said reference signal generated by said lock signal generator and wherein said comparator outputs a first control signal when said predetermined signal and said reference signal are substantially identical thereby indicating the insertion of an authorized key into said keyhole and a second control signal when said predetermined signal and said reference signal are substantially different thereby indicating the insertion of an unauthorized key into said keyhole,a delay/switching circuit having a first delay circuit, a second delay circuit, a first relay circuit, and a second relay circuit, wherein where said comparator outputs said first control signal said first delay circuit, coupled between said lock and said power source, becomes actuated a predetermined length of time after receiving said first control signal, thereby actuating said first relay circuit so that said unlocking means actuates to unlock said lock and wherein when said comparator outputs said second control signal said second delay circuit becomes actuated a predetermined length of time after receiving said second control signal thereby actuating said second relay circuit so that said alarming circuit actuates thereby alerting a listener of the insertion of an unauthorized key into said keyhole,and a protecting circuit having a relay circuit which actuates to prevent damage from occuring to said electronic lock when one of a power voltage greater than a predetermined level is applied thereto and a short circuit occurs therein.

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