CODED ELECTRICAL LOCKING DEVICE

• US 3,796,889 A
• Filed: 09/18/1972
• Issued: 03/12/1974
• Est. Priority Date: 09/18/1972
• Status: Expired due to Term

• Current Assignee: Carl Frederick Wolcott, Neil E. Fradkin
• Original Assignee: Carl Frederick Wolcott, Neil E. Fradkin
• Inventors: Fradkin, Neil E., Wolcott, Carl Frederick
• Primary Examiner(s): Hohauser, Herman J.
• Application Number:
  US05/289,889
• Time in Patent Office: 540 Days
• Field of Search: 317/134 307/40,1AT 180/114 340/63,64
• US Class Current: 361/172
• CPC Class Codes: B60R 25/04 operating on the propulsion system, e.g. engine or drive motor
• CPC Class Codes: G07C 9/0069 actuated in a predetermined sequence

Abstract

An electrical circuit for restricting the application of electrical power to an automobile ignition circuit or for controlling other electro-mechanical locking devices wherein a plurality of switches are actuated by a numbered keyboard according to a preselected code so that they must be actuated in proper sequence to unlock the mechanism. The primary code sequence can be changed using the same keyboard to set up a simpler, alternate sequence without the necessity for any electrical or mechanical variations in the device, so that access is permitted by others for limited purposes without the necessity of disclosing the entire code to anyone. The circuit also includes a time delay mechanism which disables the circuit if the proper code sequence is not followed or is not performed within a predetermined period of time.

Claims

1. A combination-coded electrical locking system which enables an external circuit when at least one of a series of digits selected from two or more sequences of digits are entered into the system, comprising:

code selector means having a plurality of input means, each of said input means having a characteristic digit assigned thereto;

a primary code circuit coupled to said code selector means whereby preselected ones of said input means establish a first sequence of primary code digits, said prim ry code circuit including output means responsive to said preselected input means to provide an output signal only when the digits of said primary code are entered according to said first sequence;

an alternate code circuit coupled to said code selector means, said alternate circuit including means coupled to additional ones of said input means to establish a second sequence of alternate code digits, said alternate code circuit including output means responsive to said additional input means to provide an output signal only when the digits of said alternate code are entered according to said sequence;

code latching means coupled to said primary and said alternate code circuits, said code latching means including means for selectively disabling said primary code circuit and simultaneously enabling said alternate code circuit; and

external circuit enabling means coupled to the outputs of said primary and said alternate code circuit means, said external circuit enabling means having means responsive to an output of either of said code circuit means to provide an output for controlling an external circuit.

2. The system set forth in claim 1 wherein said alternate code circuit is coupled to preselected ones of said input means thereby establishing a fixed alternate code sequence.

3. The system set forth in claim 1 wherein said alternate code circuit is coupled to a plurality of said input means one of which is also coupled to said primary code circuit such that said primary and alternate code sequences share at least one digit in common.

4. The system set forth in claim 1 wherein said primary code circuit and said alternate code circuit are each coupled to two or more of said input means whereby each code sequence comprises at least two digits.

5. The system set forth in claim 1 wherein said alternate code circuit includes selector circuit means coupled to said input means for selecting the digits comprising said alternate code sequence, said selector circuit means being enabled by said latching means whereby said selector circuit means becomes responsive to the actuation of selected Ones of said input means to couple the same into said alternate code circuit according to a selected sequence.

6. The system set forth in claim 3 wherein said primary code circuit and said alternate code circuit are each coupled to two or more of said input means whereby each code sequence comprises at least two digits.

7. The system set forth in claim 1 further including disabling means coupled to said primary code circuit, said disabling means responsive to the input means coupled to said primary circuit to disable said circuit whenever an input is actuated having a characteristic digit not an element of said primary code sequence or not in the correct sequence, time delay means coupled to said disabling means to establish a time interval during which said disabling means is maintained in an inoperative state, and said latching means coupled to said time delay means to render the same inoperative when said latching means is in the state disabling said primary code circuit.

8. The system set forth in claim 1 further including disabling means coupled to said primary code circuit, said disabling means responsive to the input means coupled to said primary circuit to disable said circuit whenever an input is actuated having a characteristic digit not an element of said primary code sequence or not in the correct sequence, time delay means coupled to said disabling means for establishing a time interval during which said primary circuit is held in the disabled state in response to an improper digit entry, said latching means being coupled to said time delay means to disable said delay means when said latching means is in the state disabling said primary code circuit.

9. The system set forth in claim 1 wherein said primary code circuit comprises:

a plurality of silicon controlled rectifiers coupled in series circuit relationship, means coupling said selected input means of said primary code to each rectifier to sequentially initiate conduction therein according to said primary code sequence, the last one of said selected input means being coupled to the output of said primary code circuit.

10. The system set forth in claim 9 wherein said latching means comprises:

means for supplying electrical potential to said selected input means of said primary code circuit, said alternate code circuit comprising switching means coupled between the output of said primary code circuit said source of electrical potential and said external circuit enabling means whereby electrical power is supplied to said enabling circuit through said alternate circuit means when said primary circuit means is conducting.

11. The system set forth in claim 9 wherein said latching means comprises:

means for supplying electrical potential to said selective input means of said primary code circuit, said alternate code circuit including switching means coupled intermediate two of said series connected silicon controlled rectifiers of said primary code circuit, input means coupled to said switching means of said alternate code circuit to actuate the same.

12. The system set forth in claim 11 wherein said alternate code circuit comprises:

second circuit means comprising one or more silicon controlled rectifiers each coupled to ones of said input means other than those of said primary code circuit, said input means coupled to said rectifiers to initiate conduction therein when said primary code circuit is conducting.

13. The system set forth in claim 11 further including time delay means coupled to said primary code circuit, said time dealy means operative to disable said primary code circuit for a preselected period of time, and wherein said latching means further includes means coupled to said time delay means for disabling said delay means when said latching means disables said primary code circuit.

14. The system set forth in claim 9 wherein said primary circuit means comprises silicon controlled rectifiers coupled in series and with each of said selected inpuT means, each of said input means comprising switch means having a normally closed first position and a momentary closed second position;

the first controlled rectifier coupled to the switch means corresponding to the first digit of said primary code sequence having the cathode thereof connected to ground, the anode thereof coupled to said switch means in the first position thereof and to a source of electrical potential, the gate electrode of said controlled rectifier coupled to said source of electrical potential through said switch means when the same is in said second position, whereby movement of said switch to said second position initiates conduction in said controlled rectifier which conduction continues after said switch is returned to said first position;

the second controlled rectifier coupled to second switch means corresponding to the second element of said primary code sequence, said second controlled rectifier having the cathode thereof coupled to the anode of said first controlled rectifier when said first switch means is in said first position, the anode of said second controlled rectifier coupled to said source of electrical potential through said second switch means when in the second position thereof, whereby movement of said second switch to said second position after movement of said first switch to the second position thereof initiates conduction of current through said second controlled rectifier and said first rectifier to ground which conduction continues after said second switch is returned to said first position.