GB2051208A

GB2051208A - An Electronic Lock

Info

Publication number: GB2051208A
Application number: GB7919739A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-06-06
Filing date: 1979-06-06
Publication date: 1981-01-14
Also published as: GB2051208B

Abstract

An electronic lock for remotely locking and/or unlocking comprises a transmitter system comprising an oscillator circuit (10) for producing pulses, a modulator circuit (12) for modulating the frequency of the pulses from the oscillator circuit, and a transmitter antenna (13) for transmitting the frequency-modulated pulses from the modulator circuit, and a receiver system includes a receiver antenna (14) for receiving the frequency-modulated pulses from the transmitter antenna, a detector circuit (15) for detecting only carrier waves out of the received pulses, a decoder circuit (16) for reproducing only received waves, a plurality of thyristors (20) adapted to selectively operate with the output from the decoder circuit and turn on in a predetermined order, and a solenoid (21) operable when the thyristors turn on to thereby lock or unlock at (22). <IMAGE>

Description

SPECIFICATION An Electronic Lock This invention relates to an electronic lock for locking and unlocking a machine or other apparatus (hereinafter referred to simply as a machine) positioned at a remote location.

There have been proposed and also used a variety of electronic locks for locking and unlocking a machine positioned at a remote location, and these prior art electronic locks are generally classified into a first type wherein solenoids are arranged in various ways and a second type wherein a high frequency and more than one low frequencies are combined in various ways. However, both these types of prior electronic locks have the disadvantage that erroneous operation may occur due to noise caused by pulses, and they are complicated in construction, easily vulnerable to trouble, and high in production costs.

Therefore, one major object of the present invention is to provide an electronic lock which can effectively eliminate or at least reduce the disadvantages inherent in the prior art electronic locks referred to above.

Another object of the present invention is to provide an electronic lock for locking and unlocking a remotely located machine, having a novel and improved construction which is substantially unaffected by noise, which can employ unlocking numerals in virtually countless combinations, and which is simple in construction, substantially free of trouble, and relatively inexpensive to produce.

According to the invention, there is provided an electronic lock for locking and/or unlocking a remotely located machine, cdmprising a transmitter system which include an oscillator circuit for producing pulses and a transmitter having a modulator circuit incorporated therein for modulating said pulses; and a receiver system which includes a detector circuit for selecting only carrier waves of said pulses from transmitter system by the heterodyne system, a decoder circuit for reproducing only received waves out of said detected pulses, a plurality of thyristors adapted to turn on with the output from said decoder circuit in a predetermined order, and actuating means operable only when said thyristors turn on in said predetermined order to thereby lock or unlock said machine.

Preferably, said actuating means comprise a solenoid.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic view of the transmitter system of an electronic lock constructed in accordance with the present invention; Figure 2 is a table showing various combinations of unlocking numerals and frequencies in said electronic lock; Figure 3 is a schematic view of the receiver system of said electronic lock; and, Figure 4 is a diagram of the electronic circuit leading from the decoder circuit to the solenoid in said electronic lock.

Referring to the accompanying drawings, which show one preferred embodiment of the electronic lock constructed in accordance with the principle of the present invention, it will be assumed that the unlocking combination is numerals 1, 3 and 5.

First, referring to Figure 1 of the drawings which shows the unlocking signal wave transmitter system of the electronic lock of the invention, reference numeral 10 denotes an oscillator circuit in which a crystal oscillator or the like (not shown) is incorporated and which is adapted to produce pulse signals which correspond to the selected unlocking numerals, respectively, when the switches of the transmitter which are associated with the selected unlocking numerals are turned on. In the illustrated embodiment, it is only necessary to turn on the switches associated with the unlocking numerals 1, 3 and 5, respectively, in a desired or predetermined sequence.

As more clearly shown in Figure 2, each of the unlocking numerals can be represented by a combination of two different frequencies. For example, the unlocking numeral 1 is represented by the combination of frequencies F, and F4.

Pulses produced in the oscillator circuit 10 are passed to and through an oscillator circuit 11 for producing pulses in the form of a combination of two different frequencies corresponding to the selected unlocking numeral. The oscillator circuit 11 produces a pulse having a carrier frequency upon the receipt of a pulse in the form of the combination of frequencies, and the pulse from the oscillator circuit 11 is passed to and through a modulator circuit 12 adapted to modulate the carrier frequency of the pulse. The frequency modulated pulse is passed to and through a transmitter system antenna 1 3 which transmits the frequency-modulated pulse to the receiver system.

When the frequency-modulated pulse is transmitted to the receiver system, as more clearly shown in Figure 3, a receiver system antenna 14 receives the pulse and passes the received pulse to and through a detector circuit 1 5 which is adapted to provide a beat with the oscillator output and the received frequencymodulated pulse in accordance with the heterodyne system, and then passes the pulse to a decoding circuit 16.

The decoding circuit 16 comprises a plurality of filters 17, 1 7 . . . associated with the frequencies F, ... F7, respectively, and a greater number of NOR circuits 1 8 adapted to be setectively turned on depending upon which filters 17 are operated. For example, the unlocking numeral 1 signal is passed to and through the filters 1 7 associated with the frequencies F, and F4 and the outputs of the filters are passed to the NOR circuit 1 8 associated with the above-mentioned filters 1 7. The NOR circuits 18 provide negative theoretical outputs.

The negative theoretical outputs of the NOR circuits 1 8 drive one of a plurality of monostable multivibrators 19, 19 ... associated with the above-mentioned NOR circuits 18, andthe output of the driven monostable multivibrator 19 is passed to and through one of a plurality of thyristors 20, 20 ... associated with the driven monostable multivibrators 1 9 to thereby turn on the thyristor 20.

In the illustrated embodiment, the unlocking numerals 1, 3 and 5 are transmitted and received in that order, and the three thyristors 20 are operated in succession in the order corresponding to the order of the unlocking numerals. When all the three thyristors 20 are turned on, electric current is allowed to flow through the solenoid 21 which in turn locks or unlocks the machine 22 (Figure 3) with which the electronic lock of the invention is employed.

The three thyristors 20 are so designed that when the outputs of the monostable multivibrators 19 are passed to and through the thyristors in any order other than the predetermined or desired order, the thyristors will not allow electric current to flow through the solenoid 21 whereby the electronic lock will not operate.

If the transmitter system erroneously transmits (or in any order other than the predetermined order) signals to the receiver system, a reset switch 23 (Figure 4) will be actuated to cause the transmitter system to restart the signal transmission in the predetermined or correct order. With the above-described construction and arrangement of the components of the electronic lock of the present invention, each of the unlocking numerals is represented by a combination of two different frequencies and the electronic lock is actuated only when the pulses are received by the receiver system in the same order as to that in which the transmitter system transmits the pulses. Therefore, although there may be high noise in the operation of the electronic lock, there is no possibility of erroneous operation of the electronic lock. Also, since the unlocking numerals can be combined in various different ways, the electronic lock of the present invention is substantially theft-proof.

Furthermore, the electronic lock of the present invention is simpler in construction, more precise in operation and substantially less expensive, in comparison with prior electronic locks of corresponding type. The electronic lock of the present invention finds its application in control locks for various machines, engine starters, etc., and can also be operated with acoustic waves instead of radio waves. Thus, the electronic lock of the present invention has a wide range of applications.

Claims

1. An electronic lock for locking and/or unlocking a remotely located machine, comprising a transmitter system which includes an oscillator circuit for producing pulses and a transmitter having a moduiator circuit incorporated therein for modulating said pulses; and a receiver system which includes a detector circuit for selecting only carrier waves of said pulses from said transmitter system by the heterodyne system, a decoder circuit for reproducing only received waves out of said detected pulses, a plurality of thyristors adapted to turn on with the output from said decoder circuit in a predetermined order, and actuating means operable only when said thyristors turn on in said predetermined order to thereby lock or unlock said machine.

2. An electronic lock as claimed in Claim 1, in which said oscillator circuit has a crystal oscillator incorporated therein and said transmitting system further includes a transmitter antenna for receiving said modulated pulses from said modulator circuit and transmitting the modulated pulses to said receiver system.

3. An electronic lock as claimed in Claim 2, in which said receiver system further includes a receiver antenna for receiving said modulated pulses from said transmitter antenna.

4. An electronic lock as claimed in any preceding Claim, in which said decoder circuit comprises a plurality of filters associated with a plurality of frequencies, and a greater number of NOR circuits adapted to selectively turn on when the associated filters turn on.

5. An electronic lock as claimed in Claim 4, in which monostable vibrators are included in the circuit leading from said NOR circuits, and said thyristors are each adapted to be driven by the outputs from the associated NOR circuits.

6. An electronic lock as claimed in any preceding Claim, in which, when said thyristors turn on in any order other than said predetermined order, said actuating means are rendered inoperative.

7. An electronic lock as claimed in any preceding Claim, in which said receiver system further includes a reset switch adapted to operate when said thyristors turn on in any order other than said predetermined order, thereby to cause said transmitter system to restart the transmission.

8. An electronic lock as claimed in any preceding Claim, in which said actuating means comprises a solenoid.

9. An electronic lock, substantially as hereinbefore described with reference to the accompanying drawings.

10. The features herein described, or their equivalents, in any novel selection.