US3056951A - Safe alarm system - Google Patents

Description

'ogn 2; i962 Filed May e. 1953 INVEN ma; l

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This invention relates to an alarm system and more particularly to providing a completely metal or partially metal enclosure with 'an alarm system for safeguarding it from theft or tampering. l

It has always been a problem to design a container p in which valuables can be kept without fear of having them stolen. Topsolvef this problem metal enclosures, or safes, have been buil'. As a precautonaryrneasure, these safes are usually constructed with thick walls and doors andfor are provided with ingenious locking devices. Even with the added precaution taken., of building more structurally sound enclosure;` andvin making their locking devices so-ealied burglar prooff safes still continue to be burgled. ln many instances 4the carefully designed enclosure isblown open by an er'tplosive.` charge. Frequently, the safe is removed from its taken to a piace where it can be opened by the thief without fear 'of interference or'detcction.

'United sores'efemorf original surroundings and lf the safe is provided with an alarm system, the alarm v system furnishes an added measure of security since it can perform the `functions of frightening the Would-be thier' and also notifying the police of an attempted theft. Such alarm systems have been utilized in the past. However, many of these prior systems use wires or cables connecting externally of the enclosure Orl-safe. These 'external connections would warnthe would-be'thief that,

the safe is provided with an alarm and thereby afford himthe opportunity of disabling it. Other alarm systems are actuated only by shorting or opening up the ciicuitsof the system actuator within the safe, usually by means o cutting or crossing wire contacts. Such alarm systems would not be eective if the safe were removed to :t remote location and opened there..

The present invention overcomes these disadvantages `by providing an alarm system where no external wires, cables,- connectors, etc. are required. 'Ihe alarm system actuating device is. enclosed entirely inside the safe and is enabled by any vibration f the safe such as would occur if the safe' were' moved or jostled. The alarm itself is at a point remote from the safe and is energized when the actuating ce, which controls a radio-transmitter, iS enabled. Since there are no external connections aperson Y attempting to tamper with or burgle the enclosure would I not be aware of the presence of .the alarm system.

It is therefore an obect of this invention to provide a. novel alarm 'system wherein the actuating mechanism forA the alarm s 'stern is entirely" selffcontainedwithin the I enclozure.

which cannot gizing an alarm. t

it is also ein -obiect of this invention to providea safe ,equipped r lt is a fu be' moved or tampered withwithout enered person attempts to force entry into the ts of this invention can be more fully as-y eierrlrtg to the drawings, in which:

. shows a schematic diagram of the alarm- 'trs one form of a switch which' g device; and

er object of thisinvention to provide a 'safe can be modification of thefswitchf of .f

n an alarmsystem which'isactuated 'when 4hinges 4.'

ceiven The recerangeoi thetrar Paten'tedoct. 2, 1952.V

a vibration sensitive switch which controls a radiofrequency transmitter, both the switch and the transmitter being entirely enclosed within the safe. The actuating device, which is enabled when an attempt isk made to move or iostle the safe, energizes the transmitter which produces a radio-frequency signal. The output signal from the transmitter is coupled to the walls of the safe, which are used as the ltransmitter antenna, and the signal is thereby radiated to space. The transmitted signal is picked up by an'antenna -coupled to aradio receiver tuned to the frequency of the transmitted radio signal. Aftersuitable amplification, the received signal is utilized to energize an alarm. In this manner, a totally hidden alarm system is provided.

Referring to FIGURE 1 of the drawings, an enclosure or safe 1, has' a top wall (shown partially broken away) 2. The safe 1 is also titted with a door 3 which swings on The construction of the enclosure 1 is usually solid metal, although a portion of it; may be constructed ,of some non-metallic material such as concrete cr granite, and the usual locking device (notshown) is always provided.

A transmitter, generally shown within dotted lines 6, in the form of a radio frequency oscillator, is suitably v typ'e of suitable oscillator circuit may be used, for example, tuned-plate-tuned-grid, Hartley, or any other type i capable of generating radiofrr quency energy. Connected to the plate of triode 7 is a tuned output circuit S, which may-be adjustable, and which will determine the frequency at which the triodc 7 will oscillate and thereby determine the frequency of the output signal.

A coil A9 is inductively coupled to the tuned output I circuit 8 and the ends of the coil are fastened to the metal side walls of the sate at points 10. lt should be noted that the ends of coil 9 can be connected to any suitable place on the safe from whence oscillations may be transmitterl When the transmitter 6 is energized, energy will be induced into coil 9 from the output circuit 8 and tne'outer walls of the safe I will function as the transmitter antenna.` InV this manner, energyY can` be radiated into space from the transmitter 6 contained inside the door 3 open or utilizing an external antenna. v The transmitter 6 is energized from a suitable source of B+ voltage of a switch 1 2 is enabled. The B+ source J1 can be any battery-or other suitable voltage supply. lnthis particular instance, a battery is usually more suitable since it also can be self-conta.' en within the safe. Switch l2, which detail, is shownschematically in FIG- device 12, which is designed to' will bedescribed URE l. The' actuating be enabled only n nects the plate oA age. The whole n the safel 1 is moved or jcstled, contrznsmitter unit including'the power supply source Hand the .switch 12 is designed for easy in order to facilitate servicing'and radio frequency the walls of safer'l. and delivers t'ne a tuned resonant circuit t6 ofthe re 'located at any p in the form ofV the safe 1, without having'` 1I when an actuating device in the form l rode 7 to the sourcefll of B+' volt- Y s eovlfn within the dotted lines 14,

"- unit 14 and the antenna ltmalfbe.: y within the 'radi us of the transmitting, :er ti.'l Since 'oniya single, frequency' is used, the components of the receiver 14, for example,

antenna 15, andthe tuned circuits such as 16, may be designed specitically forthe single frequency. -It should also be noted that as the frequency of transmission is increased, the physicai size of the components used decreases. I Y

The received energy present in tuned circuit 16 is fed to the control grid of a conventional pentode amplifier 17. After-amplification in amplifier 17, the signal is4 coupie'd by means of another tuned circuit 19 to a second pentode amplifier 18. Amplifiers 17 and 1S receive sup-` bias for amplifiers 17 and 18 and therefore determines the operating pointof the tubes.

The output circuit of amplier 1S comprises Va tuned resonant circuit 23 which is also tuned to the frequency of the signal transmitted from transmitter 6. This am. pl-ilied signal voltage. is supplied to the anode of 'a rectifier 25.v The rectifier 25 may be of any suitable, conventional type such as a silicon or germanium diode, or a standard vacuum tube diode. The cathode. of rectifier 25 is connected to a rcsistanceazapacitance iilter network comprising capacitors 26 and 27 and resistor 28. The output of the tilter network is a D.C. voltage for an ap plied A.C. signal from `tuned circuit-23.

The D.C. ,voltage output of the filter network is used to energize the coil 30 of a relay 31. The relay 31 has by the closing of switch contacts 33a, 33h, which con tacts, for example, can be used as the fon-ott switch for the alarm power supply (not shown). Any suitable type of alarm may be used, such a a bell, buzzer, gong or else connections may also be made to the centra police burglar alarm system.

By utilizing this holding type of relay, only a momentary signal from the transmitter 6 is necessary to energize relay 31 and io` keep the contact switches 33 and 34 in a closed position. In this manner,l even if the thief discovers the presence of transmitter 6 Vinside the safe and disables it, it will be impossible for him to turn off the alarm system unless he discovers receiver 14 which contains relay 31, and then disables the relay.

FIG. 2 shows one formo the actuating device 12 which j is utilizable with the transmitter 6. The actuating device. 12, as previously explained, is designed to be placed in the circuit of the transmitter 6, at the points indicated by the crossmarks 13. contact fingers 37, 37 are fastened by suitable means to an insulated housing 33. Another contact member 39 having two protruding contact arms l40---40' is secured ment insulating member 41 rests upon a-spring 42 and so long as spring 42 is depressed,v Contact arms l0-10'v v will not engage contact fingers 37-37'.

The spring 42 is depressed b r @lacing a suitable weight. such as that shown by sphericaiiy shaped object 43, upon a holder 4S.

'l'heholder 45 has a slightly concave upper surface 46 with a radius 'of curvature greater than that ot the object 43. 'ln another embodiment of the actuating device 12,

' shown in FIGURE 3, the upper surface ,47 of the holder actuating device 12 and disconnects the transmitter 6 In this embodiment, two metal y ,4S isralsoslightly concave. In 'this embodiment, how- Y y' V`cjver .uie holderjr issimilar toa golf tee, thevupper -stt'rl face -57 haviu a radius of curvature less than the' radius.

ofcurvature of the object 43. The object 43 maybe f any suitable weight such as golf ball, marble, ctc.

expandv and contact will be made between the contact S members 37-:37' and iO-40', thereby completing the i circuit from the power supply source 11 to the plate of oscillator tube 7. Once the object 43- has been knocked off its holder 45 the switch 12 cannot bedisabled, without first opening the safe 1 and restoring the object 43 to its original position. .The choice of the spring 52 and weight-43 will determinetfne amount of vibration necessary toactuate the switch y12.

FIGURE 2 shows only one form of switch which the actuating device 12 can assume.

Other suitable forms of vibration sensitive switches, for example, raz-ercuryl switches, inertia type switches, springloaded contact` switches, and othertypes of switches which are designed Yto be actuated upon mechanical shockercitaticn, can

also be utilized.

The operation of the. device shown` in FIGURE 1 is as follows. `The transmitter 6 is'setin an alert condition by an authorized person when he opens the sae 1 and places a suitable object 43 upon holder 45. This disables f' from the power supply 11. It' should be noted that transmitter 6 is inoperative except for the period when actuat= ing device 12 is enabled. This prevents any excess current drain on the power supply 11. 4The 'safe 1 is then closed by the authorized person and the alarm system l remains in an alert" condition until the transmitter 6 is energized. When a bouncing, bumping, meting or jarringofthe safe 1 occurs, the object 43 falls from its v holder 45 and thereby enables actuating device 12 which connects the plate of triode 7 to the power supplyv 11.

This actuates transmitter 6 anda continuous radio-fre .I

quency signal is radiated from the walls of the safe 1.

-Tlte radiated signal is picked up by the antenna 1S of the receiver 14, amplified by vacuum tubes. 17 and 18, rectified and filteredto produce a D.C. voltage, which is then used to energize the coil 30 of relay 31. Energization of reiay coil 30 closes contcts 33a and 34a of the relay thereby setting alarm 35 into operation. Since relay 31 is of the holding" type, a signal of only momentary duration from the transmitter 6 sets the 3:5 into continuous operation. Such an arrangement makes it impossible for "11e thief to silence the alarm system.

VYv'hile4 the alarm as shown' utilizes vacuum tn'ces, the device is of such a nature that it readily lends itself 'to transistorization. Utilizing transistors, the whole system can be made much more compact than when vacuum 'tubes are used. Also, the ransmitter 6 and the receiver .4- may each be housed rn its own sub-chasis. The

transmitter 'unit 6 may be located at any suitabie point within thesafe i, and the receiver unit 14 may' be located at any other point within "the radius of transmission of description or accompanying drawings shall be interi preted in an illustrative and not a limiting sense.

What is claimed is:

l. A safel alarm system comprising, a safe havza elecl trically conducting metal walls, a radio transrnjLJ for producing aV radio frequency signal entirely housed within" said safe, an actuating device -to energize said traas'nitter when enabled, said actuating devicezenabled upf@ *the* occurrence of u vibration of the safe, an ou 'cuit, for said transmitter,V a coil inductively coul.' output circuit, fncans lconnecting theends ot' sa... coil to' y walls of the sa`;'e,ithe metal walls tltfsaicl safe s' v" g Y 'an antennaA fof therr'adio freque y :l to saidl ItA is intended f radio frequencysignal, said receiver also having a rel aualarm, means connecting said relay to said alarm to operate said alarm upon receipt ofa radio frequency signal from the transmitter.

` 6. A safe alarm system as described lin claimrS wherein the means for energizing the transmitter comprises an actuating device which is in the norrnrdiy disabled posi- 2. A safe alarm system as described in claim 1 wherein the relay is of the holding type.

3. An alarm system for a safe or other type of a protective container comprising an electrically conductive enclosure, an oscillator for generating radio frequency energy within said enclosure, meansl for' supplying the radio frequency energy generated by said oscillator to the enclosure, said enclosure thereby serving as an antenna for radiating the radio-frequency energy generated by the oscillator, an alarm, and means for operating said alarm in response tothe radiated radio frequency energy.

4.' An alarm system for a safe or other type of a protective container comprising an electrically'conductive enclosure, an'osciiiator for generating radio frequency energy within said enclosure, means ror supplying the radio frequency yenergy 'generated by said oscillator to the enclosure, said enclosure thereby serving as an antenna for radiating tne radio frequency energy generated by the oscillator, mea-ns for energizing said oscillator when said enclosure is vibrated, an alarm, and means, for operating said alarm in response to the radiated radio frequency energy. i

5. An alarm system for a safe or other type of. protective container comprising an enclosure which is completely` electrically conductive, a transmitter within said enclosure for producing radio frequency oscillations, said transmitter having an output circuit coupled to said enclosure whereby said lenclosure radiates-the oscillations produced by said transmitter, a receiver, and an alarm tion and is enabled upon the occurrence of a vibration .Y

of the enclosure. Y

7. An alarm-system for a'safeor other type.- of protective container comprising an enclosure which is cornpletely electrically conductive, a transmitter located withA in said enclosure for producing a radio frequency signal, an actuating device for energizing said transmitter when said device is enabled, said deviceoeng enabled upon vibration of said enclosure, an ouin-:t circuit for s aid transmitter, means connecting said output circuit to said 4electrically conductive enclosure, said enclosure serving as an antenna for radiatingA the'radio frequency signal produced by said transmitter, a receiver for receiving the radiated radio frequency signal, and an alarm device operated by said receiver in response to the radiated signal. v

8. A safe alarm system as set forth n claim 7 wherein said receiver has a relay which is energized and operates said alarm device in response to the radiated signal.

in the relay is ofthe holding type.

system operated by' said receiver Vin response to the 35 oscillations radiated by said enclosure.

References Cited in the file of this patent UNITED STATES PATENTS anche Feb. 27, 19.12 p

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