GB2046827A

GB2046827A - Electronic coded locks

Info

Publication number: GB2046827A
Application number: GB8005859A
Authority: GB
Original assignee: AMCOR Ltd; PAN ENG Ltd
Current assignee: AMCOR Ltd; PAN ENG Ltd
Priority date: 1979-02-21
Filing date: 1980-02-21
Publication date: 1980-11-19
Also published as: DE3005890A1; IL56713A0

Abstract

An electronic coded lock comprises a miniaturized transmitter for transmitting a digital code; a detector 12 for receiving the digital code; and a decoder and amplifier 14 coupled to the detector and operative to provide an enable signal, (e.g. to switch on an ignition coil 20), in response to receipt of a correct code expression; the miniaturized transmitter being associated with a conventional key 10. <IMAGE>

Description

SPECIFICATION Electronic coded locks The present invention relates to electronic coded locks generally and to coded locks for automotive applications.

There are known in the art a great variety of locks. The vast majority of these may be classified as mechanical and are based on the insertion of a suitably configured key into association with a plurality of lock pins. Combination locks are also known in which a combination is sequentially entered into a lock by manual manipulations thereof. Timer operated locks are also known. Electronic locks have also been proposed, but their use seems to be restricted to security installations in which the "key" comprises an electronically passive card which interacts in a predetermined manner with fixed transmitting and receiving apparatus.

It is well known that conventional key locks have not been particularly successful in preventing vehicle thefts. Combination locks are also not suitable, due to the relatively long time it takes to operate them and to the fact that they can be "read" using sensitive listening instruments. Timer operated locks are not practical and electronic locks using a passive key appear to be relatively expensive and unwieldy for vehicle use.

The present invention seeks to overcome disadvantages of prior art locks and to provide an electronic coded lock which is relatively inexpensive, easy of manufacture and use and suitable for vehicle applications.

There is thus provided in accordance with an embodiment of the present invention electronic coded lock apparatus comprising a miniaturized transmitter for transmitting a digital code; a detector for receiving the digital code; and a decoder coupled to the detector and operative to provide an enable signal in response to receipt of a correct code expression; the miniaturized transmitter being associated with a conventional key.

Further in accordance with an embodiment of the present invention communication between the transmitter and the detector is provided by electrooptic means.

The invention will be more fully understood and appreciated from the following detailed description taken in conjunction with the drawings in which: Figure 1 is a schematic block diagram illustration of electronic coded lock apparatus constructed and operative in accordance with an embodiment of the present invention; Figure 2 is a schematic block diagram illustration of code receiving circuitry useful in the apparatus of Fig. 1; Figure 3 is a schematic block diagram illustration of code transmitting circuitry useful in the apparatus of Fig. 1; and Figure 4 is a schematic block diagram illustration of an alternative embodiment of code transmitting circuitry useful in the apparatus of Fig. 1.

Reference is now made to Fig. 1 which illustrates electronic coded lock apparatus constructed and operative in accordance with an embodiment of the present invention, for vehicle use. A key 10, typically comprising a conventional ignition key suitable for mechanically operating a conventional ignition and steering wheel lock, is provided with a miniaturized encoder and code transmitter located at the heat portion of the key. Constructional details of the encoder and transmitter will be described hereinafter in connection with Figs. 3 and 4.

A code detector 12, which may be conveniently located near the entrance opening for a key in a conventional ignition and steering wheel lock, receives the code transmitted by the transmitter and passes it on, via suitable conductors, to amplification and decoding circuitry 1 4.

According to a preferred embodiment of the invention, as will be described in greater detail hereinafter, the communication between the trånsmitter 10 and the detector 1 2 is provided by electrooptic means. Alternatively the transmitter and detector may communicate by means of a direct electrical interconnection.

According to a preferred embodiment of the invention, the amplification and detection circuitry 1 4 are located inside the ignition soil assembly of a vehicle. Thus in order to disable this circuitry, the ignition coil assembly of the vehicle must be broken by a potential thief.

Amplification and decoding circuitry 1 4 comprises an amplifier 1 6 receiving an input signal from detector 1 2 and power from a voltage source Vi, which is coupled to the amplifier via a switch S 1 which is operated as by insertion of key 10 into the ignition lock. Amplifier 1 6 provides an output to a decoder and electrical switch 1 8 which is operative to decode the electrical signals and in response to a predetermined code to close a switch which permits the electrical voltage at source V, to be supplied to the ignition coil 20 to permit operation thereof.

The ignition coil in turn provides a high voltage output to a distributor 22 and thence to spark plugs 24.

A more detailed explanation of the detector and decoding apparatus will now be presented in connection with Fig. 2. A photodetector 30 sense the optical outputs of the transmitter and supplies in response to receipt thereof, electrical signals to an amplifier 32. The output of amplifier 32 is supplied to a pulse shaper 34, whose output is in turn supplied to a pulse demodulator 36. The output of pulse demodulator 36 is supplied to a code analyzer 38. Code analyzer 38 is typically operative to provide an enable signal to an electronic switch 40, such as an SCR in response to a received correct code. In response to a received incorrect code, the code analyzer may be operative to interrupt detection for a predetermined time in order to prevent the possible use of a device for transmitting a multiplicity of codes in a rapid sequence as by a potential thief.In response to a predetermined number of received incorrect codes, an alarm may be activated to indicate a theft attempt.

Reference is now made to Fig. 3 which illustrates a self powered transmitter key constructed and operative in accordance with an embodiment of the invention. The transmitter comprises a modulator 50 which receives electrical current as from a battery 52. The modulator 50 provides an electrical signal to a current pulse generator 54 which in turn powers an electrooptical transducer 55, such as an LED, a Gallium Arsenic laser or any other suitable light source. The battery 50 may also be coupled to a control and status display 56 to indicate sufficient battery capacity.

Reference is now made to Fig. 4 which shows transmitting apparatus constructed and operative in accordance with an alternative embodiment of the present invention.

In the illustrated embodiment, a power supply 60 and a clock 62 are associated with the vehicle and located in a secure location. Through suitable plug-in connectors they supply an operating voltage and a clock input to a code modulator 64 in the key. The code modulator operates a current pulse generator 66 which in turn operates an electrooptic transducer 68 of a type described hereinabove and which also receives operating current from the power supply via the connectors.

It is appreciated that coding of the modulator can be readily accomplished even after manufacture as by fusing of portions of a conductive or other circuit. Coding may also be accomplished by selective masking of portions of circuitry as during manufacture.

It is noted that multiple codes may be employed in apparatus of the type described herein for carrying out various commands and functions.

The coding may be of various types. The information may be contained, for example, in the time separation between adjacent pulses or in the number of pulses transmitted within a given time frame. The decoder or code analyzer may, for example, contain a shift register whose contents may be compared with the contents of a preset memory or of another preset shift register.

In one preferred embodiment of the invention, the various components may be as follows: The transmitter: Modulator: A shift register (e.g. 4014B) the code being fed thereto in parallel via fuses, and having a serial output generating a burst of pulses.

Current pulser: Switching transistor such as 2N2222.

The receiver: Pulse shaper: 4093B Quad 2 input NAND Schmitt trigger.

Pulse demodulator: Monostable: 4528 Code analyzer: A shift register (e.g. 4034 8 bit universal bus register) having a serial input and a parallel output connected to a digital comparator (two bit 4585).

Claims

1. Electronic coded lock apparatus comprising: a minaturized transmitter for transmitting a digital code; a detector for receiving said digital code; and a decoder coupled to said detector and operative to provide an enable signal in response to receipt of a correct code expression; said miniaturized transmitter being associated with a conventional key.

2. Apparatus according to Claim 1 and wherein said transmitter comprises an electrooptic transducer for providing optically sensible pulses and said detector comprises an electrooptic transducer for detecting said optically sensible pulses and converting them into electrical signals.

3. Apparatus according to Claim 2 and wherein said detector is integrally formed with a vehicle ignition coil for selectable operation thereof.

4. Apparatus according to Claim 3 and wherein said transmitter is formed with its own power supply.

5. Apparatus according to Claim 3 and wherein a power supply and clock pulse generator are associated with said detector and supply power and clock pulses to said transmitter.

6. Apparatus according to Claim 3 and wherein a power supply is associated with said detector and supplies power to said transmitter via an electrical connector.

7. Apparatus according to Claim 3 and wherein a clock pulse generator is associated with said detector and supplies clock pulses to said transmitter via an electrical connector when said transmitter is operated.

8. Apparatus according to Claim 3 and wherein said detector is associated with the ignition lock of a vehicle.

9. Apparatus according to Claim 3 and also comprising a power supply and a switch governing supply of electrical current from said power supply to said decoder in response to physical mating engagement between said conventional key and a key socket.

10. Electronic coded lock apparatus substantially as hereinbefore described with reference to Figs. 1 to 3 or Figs. 1 and 4 of the accompanying drawings.