NEY ONY YAATEA
`US005552773A
`5,552,773
`[11] Patent Number:
`United States Patent 1
`
`Kiihnert
`[45] Date of Patent:
`Sep. 3, 1996
`
`[54] METHOD AND APPARATUS FOR THE
`PROTECTION OF PEOPLE OR OBJECTS
`
`(76]
`
`Inventor: Eduard Kiihnert, Sauerbreystrasse 44,
`42697 Solingen, Germany
`
`0378301
`3119112
`3618416
`3733808
`2248331
`Wo092/02911
`
`.
`
`7/1990 Enropean Pat. Off.
`5/1981 Germany .
`5/1986 Germany .
`10/1987 Germany.
`4/1992 United Kingdom .
`2/1992 WIPO.
`
`[21] Appl. No.: 347,139
`.
`Filed:
`
`(22]
`
`Nov. 23, 1994
`
`Tint. C1o vccesssesssssssesssersee GO8B 13/22; GO8B 21/00
`{SVP
`[52] U.S. Che cess
`340/573; 340/539; 340/568
`
`[58] Field of Searehy o......ccsssssssssssecsssessansnnssse 340/539, 573,
`340/568
`
`[56]
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`6/1987 Narcisse ssssesssssssmsnsenseen 340/539
`4,675,656
`10/1989 Adriaenssens
`.. 340/539
`4,871,997
`
`10/1991 Dix, Jn ou...
`we 340/539
`5,053,768
`6/1992 De Sorbo 0...eceeceeseestseees 340/571
`5,126,719
`FOREIGN PATENT DOCUMENTS
`
`Primary Examiner—Glen Swann
`Attorney, Agent, or Firm—Diller, Ramik & Wight
`
`[57]
`
`ABSTRACT
`
`An alarm signal is triggered in the event of a prohibited
`approach or removal of people or objects which affords
`reliable and unobtrusive protection of such people or objects
`while retaining unhindered mobility. A signal is transmitted
`by a transmitter 14 which causes the blockage of an alarm
`signal until the distance between the transmitter 14 and the
`receiver 2 is greater or smaller than a predetermined value
`OF the transmission between the transmitter 14 and the
`receiver 2 is interrupted. It
`is also possible to gain a
`representative distance signal corresponding to the distance
`between the two security clements which causes a corre-
`sponding change of pitch or volumeof the alarm signal.
`
`
`
`0073681
`
`3/1983 European Pat, Off. .
`
`10 Claims, 3 Drawing Sheets
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`Sheet 1 of 3
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`5,552,773
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`Sep. 3, 1996
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`U.S. Patent
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`US. Patent
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`Sep. 3, 1996
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`Sheet 2 of 3
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`5,552,773
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`U.S. Patent
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`Sheet 3 of 3
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`Sep. 3, 1996
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`1
`METHOD AND APPARATUS FOR THE
`PROTECTION OF PEOPLE OR OBJECTS
`
`BACKGROUNDOF THE INVENTION
`
`The invention relates to a method ofand apparatus for the
`protection of people or objects whereby an alarm signal is
`actuated in case of a prohibited approach or removal of
`people or objects, whereby a signal
`is transmitted by a
`transmitter, causing a blockage of the release of the alarm
`signal until the distance between the transmitter and the
`receiver falls below or exceeds a predetermined valueor in
`case of an interruption of the transmission between the
`transmitter and the receiver by means of which a represen-
`tative distance signal is determined from a reception signal
`received by a receiver which corresponds to the distance
`between the transmitter and the receiver and which is
`compared to a preadjustable reference value, causing the
`triggering of the alarm signal
`in case of a positive or
`negative deviation from said reference value.
`Furthermore,the invention relates to an apparatus for the
`protection of people or objects comprising a first security
`element which is attachable to the protected object and a
`second, portable or arbitrarily attachable second security
`element, where a wireless connection or a wire connection
`betweenthe first and the second security elementexists, and
`a device for giving the alarm that is located in or close to one
`of the security elements which is triggered by a change of
`the distance between the two security elements or by an
`interruption of the connection.
`Different processes and apparatuses concerning the pro-
`tection of people are known that give an automatically or
`manually triggered alarm signal.
`Such an apparatus in the form of a signaling device is
`knownthatis connected to the object to be secured by means
`of a flexible cord. This device can be activated by means of
`a personal code.In the activated status this apparatus sounds
`an alarm signal upon movementof the secured object and
`therefore of the device takes place.
`It is of a disadvantage that every time when the objectis
`to be secured the activation hasto be carried out. Next to the
`fact that this is rather time consuming andthat a deactivation
`hasto be carried out, since otherwise unpleasentfalse alarms
`are actuated, one often refrains from an activation, so that a
`protection is not given. For example, in case of a short term
`set down of luggage at a check-in counter or a railway
`station, where dangerof theft is rather high, the protection
`is often not carried out for the sake of convenience.
`Furthermore, an apparatus is knownconsisting of a main
`device and peripheral devices for sinaling. The main device
`is provided with a power supply and is connected to the
`peripheral devices for signaling in such a manner that an
`alarm signal on the main device is triggered if one of the
`peripheral devices sends a signal to the main device, which
`is the case, in case of a movement in the environment of
`detection of the signaling device.
`With this apparatus, depending on the field of use, a
`protection of objects or people can be carried out, but the use
`is alwaysrestricted to a stationary use and only gives signal
`in case of a movement in the environment of detection. A
`marking, for example for locating a stolen object, cannot be
`carried out.
`
`Further alarm devices are known which are preferably
`used for the protection of doors. To achieve this,
`two
`protection elements are used that are fastend to the door or
`the door frame and connected to one another by meansof,
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`for example, a magnetic coupler. If this connection is broken
`which is the case when the door is opened, an alarm signal
`is triggered. An activation/deactivation of the alarm appa-
`ratus and the turning off of the alarm signal is achieved by
`meansof a personal code. Thetriggering of the alarm signal
`can be adjusted with the time lag.
`Such an apparatusis usually restricted to a stationary use
`and usually used for objects that are very near to one another
`since only this enables the connection of the two security
`elements.
`
`From the DE-OS 36 18 416 a further apparatus for the
`surveillance of luggageor the like is known which consists
`of a first security element, constructed assatellite devices,
`and a second security element in form of a central unit. The
`first protection element and the second protection element
`are in wireless communication.
`
`Therewith, the central unit transmits signals to the satel-
`lite devices which cause returningsignals to be emitted from
`the satellite devices which comprise a code correspondingto
`the satellite device.
`
`This apparatus has the disadvantage that next to a con-
`tinuous transmission from the satellite devices, which has
`the disadvantage of a high energy consumption,the central
`unit can only evaluate if an object is within the area of
`surveillance or not. If they are outside of the area of
`surveillanceorif the transmission is interrupted, a search for
`the lost objects is no longer possible.
`The known apparatuses generally comprise two security
`elements which are in wireless communication with one
`another. Therewith, one security element
`is arbitrarily
`attachable to the protected object or to the person that is to
`be protected and the other protection elementis situated in
`a room that represents the area of surveillence or is carried
`by a person once to secure the object.
`In EP-A-0 073 681 a solution is described with a trans-
`mitter,
`located in a security element, which transmits a
`pulsing ultrasonic signal to a receiver in a second security
`element. The apparatus in the second security element
`functionsas a so called transmitter, with which the received
`signal
`is amplified and transmitted to the first security
`element via a transmitter. There, a receiver is present that
`passes the received impulse signals to an evaluation circuit.
`There, the received signal is evaluated in such a mannerthat
`an integration of the reception impulses takes place which
`render a preadjusted value within a predetermined time span.
`This is normally the case when the distance betweentile two
`security elements is too large or the connection is inter-
`tupted.
`The surveillance-alarm system according to GB-A-2 248
`331 functions in a similar manner. Hereby, a request signal
`from the base unit is sent to a portable transmission unit.
`This transmits a signal to the receiver in the base unit that
`evaluates a distance signal from the reception signal, which
`correspondsto the distance between the base station and the
`transmission unit. After comparison with the preadjusted
`value an alarm is actuated if a distance is evaluated thatis
`greater than the preadjusted value.
`The U.S. Pat. No. 4,871,997 describes an approach-
`sensor-apparatus. Hereby, it is possible to miniaturize the
`security elements, at least one security element, down to a
`size of a credit card. This apparatus also consists of two
`parts. One part is carried in a brief case, a wallet or another
`object that is to be secured. The other part is, for example,
`attachedto a belt, so that alarm is triggered if the brief case
`or wallet is out of reach.
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`A transmission device is provided in the first security
`element which includes an oscillatory circuit for the emis-
`sion of the timely defined pulsed electromagnetic signal. A
`reception device is provided in a second security element
`which includes means for the evaluation of the timely
`defined pulsed electromagnetic signal. Furthermore, logical
`elements are provided therein, with which the pulse signal is
`handled. Finally, the second security element includes an
`alarm circuit that is triggered by the logic elements if the
`reception device is taken out of reach of the transmission
`device and if the said evaluation device no longer receives
`a pulse signal.
`With such an apparatus it is possible to avoid the trans-
`mission of a feedback signal. Since the transmission of a
`signal is usually a rather energy consuming process, this
`apparatus avoids space consuming energy sources in the
`reception device. Therefore, a miniaturization down to the
`size of a credit card can be achieved.
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`4
`The changeofthe signal due to the change of distance then
`causes a corresponding changeof the pitch or volumeofthe
`alarm signal according to its value.
`In a very advantageous embodiment of the invented
`method an additional transmission signal is sent from an
`additional transmitter, located close to the receiver, to an
`additional receiver,
`located close to the transmitter. An
`additional distance signal corresponding to the distance
`between the transmitter and the receiver is evaluated by
`meansof this additional transmission signal, which causes a
`corresponding changeof pitch or volumeofthe alarm signal
`triggered by the additional transmission signal.
`Normally,
`the first security element is fastened to the
`protected object or to a person that is to be secured and the
`second security element is either stationary or is carried by
`a guarding person. Therewith,it is of interest to design the
`first security element as unobtrusively as possible, avoiding
`a high energy consumption that would make space consum-
`ing batteries necessary. Since, on the other hand, the alarm
`signal should also be audible on the second security element,
`A disadvantage of all known solutions is that the alarm
`which is for example carried by a guard, the additional
`signal is immediately triggered in its full extent in case the
`transmitter, which is preferably located in the first security
`security distance is exceeded. Should this alarm signal be
`element, can give an additional alarm signal by meansof a
`frequently triggered by minortransgressions, this will cause
`second security element, preferably located in the additional
`the alarm signal to be quickly ignored. Then thealarm signal
`receiver. According to the invention this is only the case if
`will also be ignored if an actual alarm status is at hand.
`the first security element is actuated to give an alarm signal,
`In addition, the known solutions do not give the possi-
`whichwill be the caseif the transmission is interrupted or by
`billity to determine wherethestolen or lost objectis situated.
`exceeding the preadjusted distance. Thefirst security ele-
`In this mannerit is, for example, possible that the stolen or
`ment will only, and only then, be induced to perform the
`lost object beeing searched for and a localisation is not
`energy consuming transmission if the signaling of the alarm
`possible withoutdifficulty.
`signal is necessary. Therefore, the first security elementis
`to make the
`It is therefore the task of the invention,
`normally switchedto its reception mode, which causeslittle
`urgency apparentbyatriggering of the alarm andto simplify
`energy consumption.
`the finding of a lost or stolen object.
`Furthermore, a version of the invented method provides
`According to the inventionthis task is solved by a method
`for a coded control signal that is switchably interconnected
`of which the distance signal causes a corresponding change
`with the transmission signal, causing the additional trans-
`in pitch or volumeof the alarm signal.
`mission signal to be transmitted continuously or intermit-
`By changing the pitch or the volume ofthe alarm signal
`tently.
`according to the magnitude of the distance signal a greater
`Due to this advantageous embodiment,it is possible to,
`accuracy in the perception of the alarm signal or in the
`for example, switch to search mode in the second security
`realization of the urgency of the alarm signal is achieved. In
`element in which a necessary means modulate the coded
`this manner, for example, the volumeincreasesif the object
`contro] signal upon the.
`transmission signal which, for
`is taken from the predetermined range or if a person to
`example, cause a continuousor intermittent transmission of
`whom thefirst security element is attached comesclose to a
`the additional transmission signal by the first security ele-
`predetermined distance area, e.g. a safety zone.
`ment when the actuation of the additional
`transmission
`In a advantageous embodiment of the invented method
`signal is necessary.
`the distancesignal is obtained by a measurementofthe level
`If the search mode is not desired the modulation of the
`of the reception signal and by caiculating the difference with
`coded transmission signal is not performed andit is further-
`the value of a known transmission signal.
`moresufficient that the additional transmissionsignal is only
`This version requireslittle effort for the evaluation of the
`for a short time sent to an additional receiver located, for
`signal representing the distance, since mostly easily detect-
`example, in the second security element where this short
`able signal changes, e.g. changes of amplitude, caused by a
`occurence of the additional transmission signal is sufficient
`distance increase or decrease,are utilized.
`to actuate the alarm signal.
`A further possibillity for acquiring a distance signal is by
`The task is furthermore solved by an apparatus for the
`measuring the time difference between the point of trans-
`protection of people or objects comprising a second trans-
`mission and the point of reception. In doing so, the trans-
`mitter located in the first security element and a correspond-
`mitter and the receiver are pulsed synchronously. Therewith,
`Ing second receiver located in the second security element,
`the time difference between the occurrence of a reception
`which is connected to the second device to give alarm.
`signal and the time of transmission, which is also known to
`Between the second receiver and the second device to give
`the receiver due to the synchronized pulse generation, can be
`alarm there are means to produce an additional distance
`measured.
`signal and a modulations circuit, connected therewith, for
`the modulation of the second device to give alarm.
`A preferred embodiment of the invented apparatus com-
`prises a codification circuit with an outwardly located switch
`whichis, by meansofthe transmission signal, in connection
`with an activation circuit in the first security element to
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`SUMMARYOF THE INVENTION
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`5,552,773
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`If the signal is sent intermittently it is possible to always
`have the same time interval between two transmissions. The
`generation of the signal corresponding to the change of
`distance is achieved by measuring the interval of the recep-
`tion signal and comparing it with the preceeding interval.
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`5
`activate the continuous transmission of the additional trans-
`mitter.
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`BRIEF DESCRIPTION OF THE DRAWINGS
`
`In the following, the invention shall be illustrated more
`closely by means of an example. The accompanying draw-
`ings show
`FIG.1 is a schematic depiction of the assembled invented
`apparatus;
`FIG. 2 is a view of the invented apparatus with said first
`and said second security elements which are shownin front
`and side view;
`FIG. 3 is a schematic depiction of the assembled invented
`apparatus, and illustrates change-overcircuitry for effecting
`“surveillance” and “search” modes of operation of the
`secondary security element.
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENTS
`
`The first security element is provided with an ultrasonic
`sensor 2 that is connected to a decoder 4 by means of an
`amplifier 3. The output of the decoder 4 is connected to the
`reset input of the counter 5. This counter 5 is connected to
`a synchronouspulse generator6 on its counter input. By this
`the impulse generated by the synchronous pulse generator 6
`is counted until the decoder 4 gives an impulse to reset the
`counter 5. This causes the counter 5 to restarts counting from
`the beginning.
`Only when the counter 5 overflows it gives a signal to the
`counter output which is connected to the circuit for trigger-
`ing the alarm 7. In this manner, an acustic generator ofthe
`alarm signal 8 is acutated and the alarm signal in the first
`security element is sounded.
`A synchronouspulse generator 10, provided in the second
`security element 9, agitates an ultrasonic generator 11 in
`predetermined time spans. A coding device 12 performs the
`codification of the ultrasonic signal which is transmitted to
`an ultrasonic transducer 14 via an amplifier 13 of whichit is
`transmitted to the ultrasonic sensor 2 of the first security
`element 1 if the distance betweenthe first security element
`1 and the second security element 9 is only so big, as to
`insure a proper reception.
`The first security element has the shape of a credit card.
`It is therewith possible to putit in a bag, for example a brief
`case, that is to be secured. Dueto the slot 15 (FIG.2) the first
`security element can also be used as a luggagetag orthelike.
`Forthis purposeit is also provided with an addressfield 16,
`which reduces its conspicuousness.
`The generator for the alarm signal 8 is directed towards
`the outside of the device to make the alarm signal audible
`without difficulty.
`The circuit to trigger the alarm 7 is furthermore provided
`with a second ultrasonic generator that creates a coded
`ultrasonic signal which is directed to a second ultrasonic
`transducer 19 via an amplifier 18.
`This ultrasonic signal has a much larger amplitude than
`the ultrasonic signal of the ultrasonic transducer 14 dueto
`the amplifier greatly increasing its range. When an alarm
`signal is received by the first security element, that is if the
`ultrasonic sensor 2 no longer receives an ultrasonic signal,
`a second ultrasonic sensor 20 with a following amplifier 21
`and a decoder 22 can trigger a secondcircuit to trigger the
`alarm located in the second security element, which causes
`the second security element 9 to sound its alarm signal.
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`The second security element 9 is spaciously much larger
`since the energy consumption, supplyed by space consum-
`ing batteries, is muchlarger. The energy consumption ofthe
`first security element 1 is much smaller, since it only uses
`transmission power in case an alarm signal is sounded. This
`power can be provided by miniature battery cell.
`The second alarm signal generator 24 is also directed
`towards the outer side of the second security element 9. In
`addition it is comprises an on/off-switch 25 (FIG. 2) with
`which the secondsecurity element9 can be turnedoff. When
`utilizing the switch 25 it is advisable to send a coded
`switching signal to the first security element which blocks
`the circuit to trigger the alarm 7 up to the momentuntil a
`further activation inpulse, which is transmitted when acti-
`vating the switch 25, returnsit to the correct operationstatus.
`As not shown in the drawings, it is of course further
`possible to provide a second on/of-switch on the first secu-
`rity element which can also be realized by a coding switch.
`The second security element 9 is comprises means to
`signal its state of readyness in form ofa light emitting diode
`that is illuminated when the security elementis turned on or
`the power supplied by the battery falls below a minimum
`value. It
`is also possible to utilize a two colored light
`emitting diode (LED) that can fullfill both functions at the
`same time or to have a second light emitting diode.
`By meansof a potentiometer 27 (not shownin FIG. 1) the
`amplification of the amplifier 3 can be adjusted to regulate
`the strength of the sent ultrasonic signal making it possible
`to indirectly determine the distance at which the alarm signal
`is actuated.
`
`The second security element 9 can be attached with a clip
`28. The explainedrealization of the invention was especially
`described for the surveillance of luggage. Especially,if other
`means of transmission are utilized the spane of possible
`applications is muchlarger.
`Theutilization of the invention on a car key and a car, for
`example, can be used to warn the driver if he has forgotten
`to lock his car whenheis leaving his car or, in fact, to carry
`out the locking of the car automatically if the device to give
`the alarm signal is combined with an automatic locking
`system for the car.
`In a similar manner the utilization in housing, condo-
`miniun, and hotel doors is conceivable.
`Children and baby carrages can be secured.In addition, an
`application on living animals, for example with dogs, is
`possible.
`Next to the mentioned theft protection of merchandise,
`preferably in shopping centers, a surveillance of people in
`buildings is also possible to, for example, hindervisitors of
`a companyto enter in certain zones. They can carry a second
`security element 9, not recognized as such, which is at the
`same time an entrance ticket.
`
`As shownin FIG.3 thefirst security element 1 is provided
`with an ultrasonic sensor to that is connected to the decoder
`4 via an amplifier 3. The output of the decoder 4 is connected
`to the reset output of the counter 5. This counter 5 is
`connected to the synchronous pulse generator 6 on its
`counter input. By this the impulses created by the synchro-
`nous pulse generator 6 are counted until the decoder 4 gives
`an impulse to reset said counter 5. The counter 5 then begins
`to recount from the beginning.
`Only when the counter 5 overflows does the counter
`output, which is connected with the circuit for triggering the
`alarm signal 7, activate said circuit. Therewith, an acustic
`alarm signal generator 8 is switched on and an alarm signal
`sounds from the first security element 1.
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`A synchronous pulse generator 10 is provided in the
`second security element 9 that agitates the ultrasonic gen-
`erator 11 in certain time spans. A codification device trans-
`formsthe ultrasonic signal into a coded signal that is passed
`to the ultrasonic transducer 14 via an amplifier 13 which
`then emits it to the ultrasonic sensor 2 of the first security
`element1, if the distance between thefirst security element
`1 andthe second security element 9 is just so big as to insure
`reception. The circuit to trigger the alarm 7 is furthermore
`provided with a second ultrasonic generator 17 whichcre-
`ates a coded signal that is passedto an ultrasonic transducer
`19 via an amplifier 18.
`This ultrasonic signal has an much greater amplitude than
`the ultrasonic signal of the ultrasonic transducer 14 due to
`the higher amplification, giving it a much greater range.
`With the occurence of an alarm signal on the first security
`element 1,
`i.e., when the ultrasonic sensor 2 no longer
`receives an ultrasonic signal, an ultrasonic sensor 20 with a
`succeding amplifier 21 and a decoder 22 clear the device to
`trigger the alarm 23 that activates the second alarm signal
`generator 24, sounding an alarm signal in the second secu-
`rity element 9.
`In addition, the codifier 12 is connected to a control signal
`transmitter 29, This control signal transmitter 29 can be
`activaded via a switch 30 which causesa control signal to be
`modulated upon the transmission signal inside the codifier
`12 and to be passed to the ultrasonic transducer 14 via the
`amplifier 13.
`This control signal is received by the ultrasonic sensor 2
`in the first security elementand is passed to the decoder 4 via
`the amplifier 3, causing a direct control wire 31 to be
`activated and turning the second ultrasonic generator 17 on.
`Therewith, an additional ultrasonic signal is transmitted to
`the second ultrasonic sensor 20 in the second security
`element 9 via the amplifier 18 and the ultrasonic transducer
`19.
`A distance measurementcircuit 32 and a therewith swit-
`chably connected modulator 33 are provided in the second
`security element 9 in between the decoder 22 and the second
`alarm signal generator 24.
`In this connection a change over switch 34 which is
`coupled to the switch 30 gives the possibility to switch from
`the mode “surveillance” to the mode “search” by utilizing
`the switch 30 and therewith bringing the signal over switch
`34 in a different position than shown in the drawing in case
`of a purposely ment search of an object, to which thefirst
`security element is attached. The control signal transmitter
`therewith creates a control signal, causing the continuous or
`intermittent transmission of an additional transmission sig-
`nal whichis a evaluatedin a distance measurementcircuit 32
`and passed to the modulator 33 in form of a distance
`measurement signal that modulates the pitch or the ampli-
`tude in the second alarm signal generator according to the
`adjusted distance.
`Whatis claimed is:
`1. A methodofprotecting people or objects by which an
`alarm signal is triggered in case of a prohibited approach or
`removal of people or objects comprising the steps of trans-
`mitting a signal, by a transmitter-to a receiver determining
`therefrom a distance signal representative of the distance
`betweenthe transmitter and the receiver; blocking the actua-
`tion of an alarm signal until the distance signal is decreased
`to or exceeds a predetermined value, or the transmission
`between the transmitter and the receiveris interrupted; and
`the method being characterized in that the distance signal
`causes a corresponding variation in pitch or volumeof the
`actuated alarm signal.
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`2. The method of protecting people or objects according
`to claim 1, characterized in that
`the distance signal
`is
`evaluated by a measurement of the level of the received
`signal and a difference from the knownlevel of the trans-
`mitted signal is calculated.
`3. The method of protecting people or objects according
`to claim 1 characterized in that
`the distance signal
`is
`determinated from the time difference between transmission
`and reception of the signal.
`4. The method of protecting people or objects according
`to claim 3 characterized in that it comprises employing
`mutually synchronized pulse generation for transmission
`and reception of said signal, which determines the time of
`transmission and that the time difference between the occur-
`rence of the reception of said signal and the time of
`transmission (which is also knownto the receiver due to the
`mutually synchronized pulse generation) is measured.
`5. The method of protecting people or objects according
`to claim 1 characterized in that the signal is transmitted
`intermittently, and that the interval between two transmis-
`sions ofthe signal is always the same andthat the change of
`the signal due to the change of distance is obtained by
`measuring the time span between consecutive receptions of
`the signal and comparingit to the preceding time span, and
`that the change of the signal due to the change of distance
`causes a corresponding change of pitch or volumeof the
`alarm signal.
`6. The method ofprotecting people or objects according
`to claim 1 characterized in that an additional transmitter
`located close to the receiver transmits an additional signal to
`an additional receiver located close to the transmitter by
`which a representative distance signal corresponding to the
`distance between the transmitter and the receiver is deter-
`mined, which causes a corresponding change of pitch or
`volume of an alarm signal actuated by the additional trans-
`mission signal.
`7. The methodofprotecting people or objects according
`to claim 6 characterized in that a coded control signal is
`modulated upon the transmission signal,
`in response to
`which the additional transmission signal is transmitted con-
`tinuously or intermittently.
`8. An apparatus for the protection of people or objects
`with a first security element (1), which is attachable to an
`object or a person, and a portable and arbitrarily fastenable
`second security element (9) wherein a wireless connection
`between thefirst and second security elements exists, and a
`device to give an alarm actuated by a change of distance
`between the two security elements or by an interruption of
`the connection, characterized in that the first security ele-
`ment (1) comprises a transmitter (19), a corresponding
`receiver (20) located in the second security element (9)
`being connected to a second device to give an alarm (24), the
`second security element (9) further comprising means (32)
`for producing a distance signal corresponding to the distance
`between the receiver (20) and the transmitter (19) to give an
`alarm (24), and a modulation circuit (33) to modulate a
`second alarm signal with said distance signal.
`9. The apparatus for the protection of people or objects
`according to claim 8 characterized in that the second secu-
`rity (9) element comprises a codingcircuit (29) with a switch
`(30) which triggers an activation circuit (31) in the first
`security element (1) via a wireless signal to activate the
`continuous transmission of the transmitter (19).
`10. A methodofprotecting people or objects by which an
`alarm signal is triggered in case of a prohibited approach or
`removal of people or objects comprising the steps of trans-
`mitting a signal by a transmitter to a receiver; determining
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`9
`therefrom a distance signal representative of the distance
`between the transmitter and the receiver; blocking the actua-
`tion of an alarm signal until a distance signal corresponding
`to the distance between the transmitter and the receiver is
`determined and comparedto a preadjustable reference value
`and a positive or negative deviation from the reference value
`
`10
`causes the release of the alarm signal, and the method being
`characterized in that the distance signal causes a correspond-
`ing variation in pitch or volumeof the actuated alarm signal.
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