US 3196440 A
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Description (OCR text may contain errors)
July 20, 1965 R. WEINSTEIN 3,196,440
RADIO CONTROL SYSTEM FOR OPERATING A DISTANT ELECTROMECHANICAL TRANSDUCER DOOR LOCK UTILIZING A CAPACITY-SENSITIVE CIRCUIT AT THE DISTANT LOCATION AND AN OPERATOR-CARRIED TRANSCEIVER Filed Nov. 7, 1962 F/G. 2 a
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United States Patent 3,196,440 RADIQ QQNTRQL SYSTEM FUR @PERATENG A DHSTANT LEQITRQll/KECHANECAL TRANSDUQ- ER DGQR ILK UTELEZENG A CAFAQliTY-SENSI- THVE QERQUKT AT THE DiSTANT LUCATIQN ANS AN @FERATURQZARRIED TRANSCEIVER Richard Weinstein, Westbury, N.Y., assignor, by mesne assignments, to tlommercial Factors, Ltd, Montreal, Quebec, Canada Filed Nov. '7, 1962, Ser. No. 235,971 '7 Claims. (Cl. 343-225) This invention relates to an electronic lock for operating the locks applied to doors, safes, or other confined areas which are desired to be secured against unauthorized entry. The invention has particular reference to a convenient means for opening locks without the use of a key or a combination which must be applied to a combination lock.
Many types of locks and other door opening devices have been designed and used for the opening of doors Some of these devices have employed supersonic signals generated by a portable unit for opening garage doors. Other door openers have employed signals generated by head lamps on an automobile and high frequency radio signals generated by a portable oscillator. All of these prior art devices have been limited because unauthorized entry is possible by anyone using a signal generator which can be varied in frequency to produce the code required to open the lock. The present invention differs from all prior art devices in two specific classifications First, it does not require a portable unit having a power means necessary to its operation. Second, an unauthorized person cannot gain entry because the opening of the lock requires the knowledge of two predetermined frequencies, one a low frequency within the range of 10,000 to 309,000 cycles per second or radio frequency which lies within the range of 1 to 50 megacycles per second. An ordinary signal generator cannot operate such a device even though the range of frequency includes all the above named variations. The only way to open the lock hereinafter described is to use two frequencies which coincide exactly with the frequencies of the circuits included in the device.
One of the objects of this invention is to provide an improved electronic lock which provides one or more of the disadvantages and limitations of prior art arrangements.
Another object of the invention is to provide a lock which is secure and tamper proof but is opened without use of a mechanical key.
Another object of the invention is to increase the speed or response of electronic locks to signal controls.
Another object of the invention is to increase the security afforded by a signal controlled lock.
Another object of the invention is to reduce the size of the portable unit or transceiver necessary to open the lock.
Another object of the invention is to conserve the power required to operate a signal controlled lock.
The invention comprises a power operated circuit which is established at or adjacent to the door to be opened. A portable transceiver, light in weight and small enough to be carried in a pocket is carried by all those who are authorized to open the door. The transceiver has no vpower supply of its own. That portion of the mechanism which is mounted adjacent to the door includes a transceiver includes a means for receiving and rectifying alternating current power transmitted by the transmitter and an oscillator with a tuned antenna which generates and transmits radio frequency power.
For a better understanding of the present invention, together with other and further objects thereof, reference is made to the following description taken in connection with the accompanying drawings.
FlGURE 1 is a circuit diagram of the lock system with the components shown in block form.
FIGURE 2 is the capacity switch with circuit connections which is operated Whenever an operator touches a selected door knob related to the door to be opened.
FIGURE 3 is a schematic diagram of connections showing the low frequency transmitter which generates a low frequency signal and thereby supplies power to the receiver portion of a transceiver.
FIGURE 4 is a schematic diagram of connections showing a radio frequency receiver having a resonant circuit tuned to a radio frequency and a coupling circuit tuned to a modulating frequency for operating a lock solenoid.
FIGURE 5 is a schematic diagram of connections of the transceiver which receives a first frequency from the transmitter and uses this frequency to power an oscillator which radiates radio waves at a second frequency by means of a small resonant circuit.
FIGURE 6 is a chart showing some of the currents and voltages that are generated in the above described circuits.
Referring now to FIGURE 1, the permanent installation adjacent to the door lock includes a capacity switch circuit ill, a transmitter circuit ill, a receiver circuit 12, and a door lock circuit 13 which operates a bolt 14. The complete system also includes one or more portable transceiver circuits 15 which can be carried in the pocket and which operate to open the door whenever one of transceivers is brought within operating distance of the transmitter circuit 11 and the receiver circuit 12. The capacity switch circuit 10 operates to supply biasing voltages to other circuits when the capacity of a door knob 16 is altered by placing the hand or some other conductive object in contact with it. The capacity switch circuit is shown in detail in FIGURE 2 where a door knob 16 is connected by means of a resonant concentric line to the control electrode 18 and cathode 20 of an electron discharge device 21. The discharge device 21 includes an anode connected through a relay winding 22 and a source of potential 23. The relay winding 22. is arranged to actuate an armature having contacts 24 and 2 5 so that when the relay is actuated the direct current power from source 23 is available over conductors 26 and 27.
The operation of such a circuit is well known and has been described in prior publications. The resonant con centric line 1'7 can be adjusted to maintain the discharge device 21 in oscillating condition. When a hand or other conducting material is placed on the knob 16 the additional resistance and capacity causes the circuit to stop oscillating and increases the current through the anode cathode circuit which includes relay winding 22. When this happens, the relay is actuated and contacts 24 and 25 are closed, thereby applying the potential of the direct current source 23 to wires 26 and 27.
FIGURE 3 shows the connections of a low frequency oscillator which includes a resonant circuit having an inductance 3t and a capacitor 33 Oscillation of this circuit is provided for by a feed-back coil 32 which is connected in series between conductor 26 and an anode 33 in an electronic discharge device 34 which also includes a control electrode and a cathode 35. This type of oscillating circuit is quite old in the art and has been described in many prior publications. Its frequency of oscillation depends upon the resonant frequency of inductor 30 and capacitor 31. For this transmitter the frequency may i If, vary anywhere from 10,000'cycles per second to 30,000 cycles per second. In this application inductor 35) is constructed with only a few turns but with each turn including a large area so that the frequency'of oscillation gencrates a large magnetic field which extends over a corisiderable distance, at least. for 801' 9 feet. This'transrnitter circuit may be permanently mounted adjacent -to the capacity switch and the door to be opened.
quency. These high frequency pulsesiare'picked up by receiver circuit 12, amplified and rectified by vacuum tube 55 and applied to the resonant circuit composed of capacitor 61 and winding 59. The anode circuit current has a form as indicated by curve 66 in FIGURE 6. When sufiicient energy is received by receiver 12,, the bolt 14 is Transceiver 15 is a portable circuit designed to be carried V by the operator who operates the door lock. There may be many such transceivers, each carried by a personwith authorized access. The transceiver circuit is quite small and contains no power source of its own, thereby elimi nating a considerable portion of the weight which would otherwise be necessary for its operation. Because it has no batteries, the transceiver will last almost indefinitely The transceiver circuit includes.
and needs no servicing. V a a receiving loop 38 which is bridged across a capacitor 4%, these two circuit elements designed for resonance 'at the first frequency generated by the transmitter 11.
One terminal of the loop 38 is connected in'series with a rectifying semi-conductor diode 41 which permits only" current pulses ofone polarity to be transmitted; A zener diode 42 may be connected across the output terminals of the receiving loop and its rectifier in order to stabilize the voltage but this is not necessary and may be omitted. The loop terminals are also connected to an oscillating circuit 43 containing a transistor 44 whose collector is.
connected to the negative terminal of the loop power supply in series with'a resistor 45. The emitter of transistor'dd is connected tov the positive terminal of the loop supply circuit througha high resistor 46. The oscillating portion of this circuit includes two capacitors 47 and 48 and an inductor 50 with its terminals coupled to the 'capacitors and the transistor 44; The inductor maybe wound on a ferrite core 51.. This type of oscillating- 'transmitting circuit is conventional and is well known in the art and has been employed for transmitting radio Waves in the 10 megacycle region. V a a The receiver circuit 12 is shown in 1516.4 and includes Theinductor 52 is connected to a capacitor 54 thereby forming a resonant circuit' tuned to receive the'same frequency as that transmitted by oscillator 43. The resonant circuit 52, 54 is coupled to a vacuum tubetriode detector 55 through a grid capacitor 56 and resistor leak 57. The other side of. the resonant circuit is coupled to the'triode' cathode. This type of circuitis also old in the art and has been described in prior publications. The anode potentialis supplied through terminal 58 by contacts and conductor .27
and the current from power supply 23 to the anode fiows through the primary winding 59 of an output transformer 6%. A capacitor otis bridged'acro'ss the terminals of winding 59 and the values of these two circuit components are adjusted so that they are in resonance at the first frequency generated by transmitter 11. The secondary wind-' ing 62 is connected directly to theusual solenoid door lock 7 13 which operates bolt 14 to open the door. g I The operation of this circuit will now be described in -.distance; a capacity-sensitive circuit including a relay an inductor 52 on a ferrite core 53 having the same dimensicn as the inductor 50.
and to terminal-58 in the receiver circuit, and energizing both these circuits to respectively transmit a first frequency wave and to receive a second high frequency radio wave.
The first frequency wave sent out by transmitter ll is.
shown as curve 64 in FIG. 6. This power is receivedby loop 33 and applied to oscillator circuit 43 which generates high frequency waves 7 65 modulated at the lower fre- 'its own rectifiers and'itsown' amplifier means.
withdrawn and-the door or gate may be opened. It is to be understood that the door lock circuit 13 may contain I It is also understood that any of the vacuum tubes shown in the drawings'maybe replaced by'transistors which require no heater current and are available for instant operation.
If an unauthorized person'tries to open the look by using a signal generator. and varying its frequency over a wide range, the doorcannot be opened because the unniodulated radio waves received by dipole 52 will only increase the direct current through winding 53 and will not affect the door lock circuit 13. In order to open the door, the operator must match the frequency generated by transmitter, 11 and also the frequency generated by 7 Having thus fully described the invention, what is claimed as new and desired .to be secured by Letters Patent of the United States is: g
1. A'radio control system for operating a distant electromechanical transducer door lock comprising; a transrnitter circuit for generating alternating current power at 'a first frequency; said transmitter circuit having a power supply and an oscillator which includes a first inductor forcreatlng an alternating magnetic fieldfat a coupled to a conductor for actuation'of the relay by a change of capacity applied to the conductor means connected to said capacity-sensitive circuit to initiateoperation' thereof; contacts on the relay connected in series with said power supply for actuating the oscillator; at
. least one portable transceiver circuit for receiving power from said magnetic field. at essentiallythesarne time as sa d operation of the. capacity sensitive circuit is initiated and; for transmitting a radio signal having a second frequency, modulated by said first frequency; said transceiver including a's'ec'ond inductor and. a rectifier connected in series for producing pulsating current power; an oscillator .c1rcurt' connected to said second. inductor for generating modulated alternating current power at said second frequency, and an antenna tuned to said second frequency for broadcasting said radio power; a radio receiver for receiving the modulated radio waves from any one of said transceivers at the second frequency and for rectifying the received currents to. produce a series ofv current pulses at said first frequency; said receiver including an antenna tuned to said second frequency, a rectifying means connected to said antenna, a resonant'circuit connected to said rectifying means and tuned to said first frequency,
and circuit means coupled to said resonant circuit for applying said series of current pulses to said electromechanical transducer for mechanical actuation thereby.
I 2. A radio control system as claimedin claim 1 wherein said transceiver circuit also includes a capacitor for creating resonance at said first frequency.
3. A radio control system as claimed in claim 2 wherein said inductor and rectifier means is bridged across a z ener diode, for stabilizing the current'pulses produced 4. A radio control-system as claimed in claim 2 wherein said. oscillator includes a transistor, a dipole coupled to the transiston'and aquartz crystal coupled to the dipole. V
5. A radio control system as claimed in claim 1 wherein' said radiore eiver antenna is adipole having a quartz crystal coupled to thedipole terminals.
6. A radio control. system as claimed in claim 5 wherein thereceiver resonant circuit includes a; capacitor and the primary winding of an output transformer, ,the sec- 5 ondary winding of the transformer connected to a solenoid for operation of a door bolt.
7. A radio control system as claimed in claim 1 wherein said first frequency is Within the range of 10,000 cycles per second to 300,000 cycles per second and said second frequency is within the range of 1 megaeycle per second to 50 megacycles per second.
2,851,592 9/58 Webster NEIL C. READ, Primary Examiner.
11/57 Magondeaux 343-225 XR