Movement Detector

Abstract

A motion detector for protecting items such as loaded trucks such as when parked in warehousing facilities which includes a transmitter affixed to the truck and which includes a tamperproof switch actuated by the truck frame or other portion such that if the truck is moved a given distance from its parked position or if the transmitter is removed from the truck an alarm will sound at a remote position which continuously monitors the output of the transmitter. The central monitoring position may simultaneously monitor a plurality of transmitters and may be interconnected with police or other remote monitoring authorities so as to assure continuous protection for the truck load.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates, in general, to monitoring devices and in particular to safety devices for monitoring loaded trucks or other devices.

2. Description of the Prior Art

It has been customary to utilize guards to protect loaded trucks parked in warehouse areas with the guards periodically checking the trucks and turning a time key on their rounds about the warehouse. However, the guards may be rendered ineffective by thieves or the trucks may be moved at times when the guard is not present and the theft would not be discovered until the guard makes his next round which might be a substantial amount of time after the truck has been stolen.

SUMMARY OF THE INVENTION

The present invention comprises a monitoring system which includes individual transmitters mounted on the trucks and adapted to produce a transmitted signal as long as they are in position on the trucks. A central monitoring station monitors a plurality of transmitters which are modulated by suitable means as, for example, different tones or different pulse sequences so as to identify a particular transmitter. The monitoring station immediately detects and produces an alarm if the transmitter is moved from the truck or if the truck is moved with the transmitter in place a distance out of range of the receiver. The monitoring station may be provided with tie-in to local police monitoring stations so that simultaneously with an alarm police are given notice so that they may investigate at the indicated station.

DETAILED DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the invention will be readily apparent from the following description of a preferred embodiment thereof taken in conjunction with the accompanying drawings, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure, and in which:

FIG. 1 is a block diagram of the monitoring system of this invention;

FIG. 2 is a block diagram of a transmitter of the invention;

FIG. 3 is an enlarged detailed view of the magnetic responsive means of the invention;

FIG. 4 is a schematic view of a transmitter of the invention;

FIG. 5 illustrates the monitoring console of the invention;

FIG. 6 is a block diagram of the receiver and alarm system; and

FIG. 7 is a schematic view of the receiver of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The motion detector of this invention is a device which was developed for the purpose of protecting truck loads of sensitive material while parked in warehouse facilities. Although the invention is described with respect to protecting truck loads, it is to be realized, of course, that any other apparatus to be monitored may be detected by the device.

The invention comprises a transmitter attached to each of the devices to be monitored as, for example, trucks that require protection. The transmitters relay a signal to a monitoring console and should the transmitter be tampered with in any manner or the truck be moved a given distance the signal transmitted by the transmitter will become weak enough such that an alarm will sound at the central monitoring console. The monitor station may also be tied in with a central guard station as, for example, a police station, to simultaneously indicate that an alarm has been received due to a transmitter or truck being tampered with or moved out of range. Such tie-in may be interconnected through the local telephone lines with local police departments and/or central watch area stations so that any alarm will be recognized by a remote monitor at these points. The central console may handle any number of transmitters but for a preferred embodiment six transmitters may be utilized. Each transmitter may be on a separate frequency or may be on the same frequency with different modulations on each transmitter so that a particular transmitter may be recognized. For example, each transmitter might be modulated by a different tone or alternatively each transmitter might be modulated by a coded tone combination which is recognizable as associated with a particular transmitter.

The central console may continuously monitor each of the transmitters or may be alternately switched to each transmitter to monitor it in sequence.

The transmitter may be battery-operated such as with a 12 -volt nickel-cadmium battery that may be recharged. Such batteries are capable of energizing a transmitter according to the present invention for a period of 5 or more days. The transmitter output power may be less than that necessary for an FCC license and might be, for example, in the 88 megahertz band. The transmitter may be mounted in a small box with a size of about 3.times. 4.times. 8 inches which is attached to the truck by the use of powerful magnets. Such magnets may be strong enough that the transmitter will not fall off the truck even if the truck is in motion. The magnets are associated with a device for sensing whether the transmitter is attached to the truck. The sensing device turns the transmitter on when the transmitter is attached to the truck and held by the magnet. A magnetic-sensitive reed switch may be associated with the magnets such that the transmitter is turned on when the transmitter is on the vehicle and the transmitter is turned off when the transmitter is removed from the vehicle.

A central receiving and monitoring station receives the signal transmitted by the plurality of transmitters and as long as the transmitters are within range, which indicates that the truck has not been moved a substantial distance from its assigned position, or as long as the transmitter is not removed from the truck frame which would cause the magnetic-responsive switch to turn off the transmitter, no alarm will be indicated at the central monitoring console. However, if the truck is moved or if the transmitter is removed from the truck, the signal received at the central receiving and monitoring station will either disappear or become so weak that an alarm will be given indicating which particular transmitter has been turned off or has a weak signal. The transmitters of this invention may be operated with a signal of 50 microvolts per meter at 50 feet which is the maximum limitation that does not require FCC licenses. With such a transmitted signal strength, approximately 15 microvolts would exist at an antenna terminal and assuming a degradation of 12 db. per octave, voltage would degrade by one-fourth, such that at 100 feet the signal strength would be 4 microvolts. At 200 feet a signal strength of 1 microvolt would exist and at 400 feet one-half microvolt would exist.

The central monitoring console might be 24.times. 8.times. 12 inches and might be provided with openings for charging the batteries in the six transmitters simultaneously. The monitoring console may have a master front panel upon which is arranged means for giving output information on each of the six transmitters. Each of the positions might include a galvonometer meter movement and the meter may have three ranges which are identified by color or other suitable means. An actuating switch at each position is provided such that when the actuating switch is on and the transmitter being monitored is on and producing a signal the meter will read in the green. If the transmitter is tampered with as by moving it from the truck so that it goes off, the meter will automatically switch to red and an audible alarm in the console will be energized. Since the monitoring console may monitor the transmitters on a time sequential basis, a small monitoring light may be installed above each of the meters for each station and be turned on to indicate when a particular transmitter is being monitored. Thus, the lights would continuously flash, changing from one position to the next, as the console selectively monitors each transmitter. If the actuate switch for a particular position is not on the receiver will not monitor that particular position.

To initially enable the safety device of the invention, a guard would be dispatched to place a transmitter on a vehicle to be monitored. The actuating switch for that particular transmitter would be in the off position and the meter associated with the transmitter would be yellow indicating that the switch has been deactivated and that no transmitter is on the air.

The instant that the transmitter comes on the air due to the fact that the guard has placed it on the truck and the magnetic switch has been energized, the meter will move into the green indicating that the monitoring station is receiving a signal for that particular transmitter. When the meter moves into the green indicating that a transmitter is on the air, the actuate switch may be moved to the on position without causing an alarm. Once the actuate switch has been turned on any change will automatically cause an alarm. Should either the transmitter go off the air, which would cause an alarm, or the actuate switch be switched to the off position, the console will alarm. The provision that the console alarms when the actuate switch moves to the off position is a protective measure to insure that potential hijackers will not be able to invade the guard's office and force him at gunpoint to deactivate the system. In the event he does deactivate the system an alarm will be sounded at a remote monitoring station as, for example, at a central police station.

FIG. 1 is a block view illustrating a plurality of transmitters 10 through 15 which may each be mounted on different trucks to protect them and which radiate a signal. A central receiving and monitoring station 16 receives emission from the transmitters 10 through 15 and produces an alarm if any of the transmitters are turned off or move out of the range of the receiving station. A cable 17 which might comprise telephone lines or other suitable electrical connections ties in the central receiving and monitoring station with the remote monitoring station 18 which might be mounted at a central guard office or at a police station to allow duplicate protection such that if the central receiving and monitoring station is taken over by hijackers the remote monitoring station will provide a warning to the police at a remote location.

FIG. 2 is a block diagram of transmitters such as transmitters 10 through 15. The transmitter is mounted in a suitable case 21 which includes a battery 22 that may be a nickel-cadmium battery which is rechargeable and which has charging terminals 23 and 24 that extend from the case. An oscillator 26 oscillates at a radio frequency and supplies an output to a modulator 27 which modulates a tone of a particular frequency on the output of the oscillator. The tone which is modulated on the oscillator signal is obtained from a tone oscillator 28 which supplies an input to the modulator 27. The output of the modulator is supplied to a power amplifier 29 which supplies an output to an antenna 31. It is to be realized, of course, that the antenna 31 may be an internal antenna mounted in the case 21 of the transmitter 10. A magnetic-responsive switch and holding device 32 is mounted within the case 21 and turns the transmitter on and holds it to a truck when placed against magnetic material of a truck.

The magnetic switch and holding device is shown in greater detail in FIG. 3. The case 21 may be made of a suitable nonmagnetic material as, for example, aluminum, and a pair of magnets 34 and 36 are mounted adjacent a reed switch 37 which has contacts 38 and 39. The envelope of glass or other suitable material 41 may enclose the contacts 38 and 39. Contacts 38 and 39 are connected to the input of one of the transistors in oscillator 26 to short it out when the switch 37 is closed. When a magnetic member 46 of a truck comes close to case 21, switch contacts 38 and 39 open and the input to the transistor in oscillator 26 is ungrounded and the oscillator starts to oscillate and the transmitter 10 radiates. The magnets 34 and 36 hold the transmitter 10 to the plate 46. The leakage field between magnets 34 and 36 holds the contacts 38 and 39 closed when metal 46 is not close. When metal 46 is attached, the magnetic lines of force take the path of least resistance which is through the metal 46 rather than through the air.

FIG. 4 is a schematic view of a transmitter such as transmitter 10 and includes a crystal-type oscillator 26 including the transistor T.sub.1 which supplies an output to an RF driver T.sub.2 when the reed switch 37 is open to apply power to the oscillator. A signal from a modulator comprising transistors T.sub.3 and T.sub.4 is coupled to the RF driver T.sub.2 through the transformer L.sub.4 . The tone oscillator 28 supplies a signal to audio amplifier T.sub.6 which is coupled to audio driver T.sub.5 which in turn drives the modulator transistors T.sub.3 and T.sub.4 which supplies a modulating signal to the RF driver T.sub.2. The RF power amplifier includes a transistor T.sub.7 which is coupled to the antenna 49.

FIG. 5 illustrates the central receiving console of this invention which could be mounted, for example, in the central offices of a trucking concern so that it could be monitored during the day by employees in the office and at night by a guard at the central office. A case 61 has a front panel 62 formed with six compartments 63 through 68 into which the transmitters 10 through 15 may be placed for recharging their batteries. The charging prongs 23 and 24 of transmitter 10, for example, are receivable in mating charging receptacles 70 and 71 in compartment 63. A charger is mounted in the case 61 and connected to each of the charging contacts in the openings 63 through 68 for charging the batteries. The console includes a master switch 72 which may be moved to off or on. The console also includes a night-day switch 73 so that during the day a local alarm will be given at the trucking firm's office but at night when the switch 73 is moved to the night position, a remote alarm at a police station or other safety monitoring station will also be given at the same time that the local alarm is given. This feature protects a single guard who might be in the trucking office at night so that if he is overcome by robbers a remote alarm will be given also.

A reset switch 74 is mounted on the front panel 62 to allow reset of the system.

Six monitoring stations indicated 75 through 80 are mounted on the top portion of the panel 62 and each includes an indicator light designated 81 through 86, and on-off switches designated 87 through 92. Card holders indicated 93 through 98 are associated with each indicator station and cards for identifying the particular truck being monitored at that station may be placed into the slots 93 through 98. Meter indicators 100 through 105 are associated with each of the monitoring stations 75 through 80 and include indicator needles 106 through 111 which move on the indicators 100 through 105. Each of the indicators 100 through 105 have three areas designated A for alarm, OK which indicates that the truck being monitored is not being molested and a central off or inactive position.

FIG. 6 is a block diagram of the central console station. An antenna 115 is connected to a receiver 116 which receives signals from the transmitters 10 through 15. A motor 117 or other switching device controls switching circuits 118 and a brush 119 of a switch 121. The switching circuits 118 are connected to the receiver by lead 122 so as to tune the receiver to the output frequency of the transmitters 10 through 15 in sequence so the the output signal on brush 119 is in timed sequence with the outputs received from the transmitters 10 through 15. An alternative system for receiving the outputs of the transmitters 10 through 15 could comprise a plurality of receivers each tuned to one of the transmitters which would monitor the transmitters on a continuous basis rather than on a timed sequence basis as illustrated in FIG. 6. The brush 119 contacts in sequence contacts 123 through 128 to supply outputs to the indicators 100 through 105 and the associated alarm systems. For example, contact 123 is connected to a relay 130 which has its second side grounded. The contact 123 is also connected to the indicator 81 and the indicator 100 to drive the indicator needle 106. When the transmitter associated with indicator 100 is producing an output indicating that the truck is not being tampered with or is not being moved, an output will appear from the receiver 116 and will be supplied by brush 119 to the relay 130 and to the indicator 100. This output will be sufficient to hold the relay 130 energized continuously since the pulse received by the relay 130 as the brush 119 rotates will constitute sufficient energy to hold the relay energized. The relay 130 controls an alarm switch 131 which is connected to power lines 132 and 133 so that when the relay is energized the switch 131 is open. If the relay 130 is deenergized due to failure to receive a signal from the transmitter 10 associated with contact 123 the relay will drop out applying power from lines 132 and 133 to contacts 134 and 135 which will energize local alarm 136. Simultaneously, the indicator 100 will move into the alarm position to give a visual indication of the failure of the signal from transmitter 10. When the transmitter 10 is producing a signal indicating a safe condition, the light 81 will flash as the brush 119 contacts contact 123 and the indicators 81 through 86 will flash in sequence as the brush rotates. The night switch 73 connects the contacts 134 and 135 to contacts 137 and 138 when in the night position so as to supply through telephone or other suitable conductors 139 and 140 a signal at a remote position. The leads 139 and 140 might, for example, be connected to a relay 141 located at a police station which controls a switch 142 to energize a remote alarm 143 when the switch 131 applies power to contacts 134 and 135.

Each of the contacts 123 through 128 are associated with an indicator and alarm relay. The warning system connected to contact 128, for example, is illustrated and comprises the indicator 101, indicator 82 and an alarm relay 144 which is similar to relay 130 and controls a switch 148 which is connected to power lines 146 and 147. The relay 144, when energized, holds the switch 148 out of contact with contacts 149 and 150, but when deenergized due to a failure from the transmitter associated with contact 128 closes switch 148 so that power is applied to contacts 149 and 150 to energize the local alarm 136 and the remote alarm 143 if the night switch 73 is closed.

It is to be realized that similar circuits for energizing the local alarm 136 and/or the remote alarm 143 are associated with the contacts 124 through 127.

FIG. 7 illustrates a schematic view of a receiver that may be used in this invention. The antenna 115 is coupled to an RF stage including a transistor T.sub.8. The switching circuits 118 include a switch 160 which has a rotating brush 161 that selectively connects capacitors C.sub.1 through C.sub.6 into the RF stage so as to tune the receiver to the transmitters 10 through 15. An IF amplifier stage receives the output of the RF section and includes a transistor T.sub.9. A second detector includes a diode D.sub.1 which drives an audio driver transistor T.sub.10 which feeds into a power amplifier transistor T.sub.11. The power amplifier supplies an output through transformer L.sub.3 to rotating brush 119 of switch 121.

In operation, to actuate the monitoring system, a guard would be dispatched with a transmitter 10 through 15 to a vehicle to be monitored and the switches 87 through 92 associated with that particular transmitter would be placed in the off position which, for example, if the transmitter 10 associated with indicating station 75 was to be installed the switch 87 would be placed in the off position thus causing the needle 106 of indicator 100 to stay in the central off position. This indicates that the switch 87 has been turned off and that no transmitter is on the air. The instant that a transmitter is placed on the truck and goes on the air due to the switch contacts 39 and 38 opening the needle 106 will move into the OK area indicating that a signal is being received from transmitter 10. The meter will flicker into the OK area since it receives a signal for one-sixth of the time. The actuate switch 87 may then be closed without causing an alarm as the signal applied to contact 123 will be sufficient to energize relay 130, holding switch 131 out of engagement with contacts 134 and 135.

Once the actuate switch 87 has been engaged any change will automatically cause an alarm. For example, should the transmitter 10 go off the air an alarm will be caused or if the actuate switch 87 is moved to the off position the console alarm and remote alarm, if the night switch is closed, will be energized. This is to assure that hijackers do not invade the guard's office once the truck is being monitored and force him at gunpoint to deactivate the system.

During the day the system can be monitored by the employees of a manufacturing organization or warehousing company's own guards. At night, however, when the guards are there alone, the night switch 73 will be moved to connect the remote alarm system. The alarm system is automatically latching such that once activated for any reason it must be reset. This is the purpose of the reset switch 74. The unit will not automatically reset. In other words, in order to reset the unit, the switch must be on normal, with an alarm sound, then switched to reset and back to normal.

Although a motor and brush is used as an example for the system of FIG. 6, it should be realized that the switching may be accomplished with a digital logic circuit. Also the alarm system may be connected with standard burglar alarm systems which use plus twelve volts and minus twelve volts.

It is seen that this invention provides a warning and monitoring system for protecting a vehicle or other device and although it has been described with respect to preferred embodiments it should not be so limited as changes and modifications may be made which are within the full intended scope as defined by the appended claims.

Claims

We claim as our invention:

1. A monitoring system for protecting a plurality of movable objects comprising, a plurality of transmitters connected to said plurality of movable objects, each of said transmitters having means for turning it off when the transmitters move relative to its associated movable object, said means for turning each transmitter off comprising a magnetic responsive switch connected to the respective transmitter and which turns the transmitter on when the transmitter is placed near a magnetic material of said movable object but which turns it off when said transmitter is removed from said movable object, receiving means located at a position remove from said transmitters receiving a plurality of signals from said plurality of transmitters, distributing means including a sequential scanning means connected to the output of said receiving means, a plurality of alarms connected to said distributing means and adapted to indicate when one of said plurality of transmitters is turned off or when one of the transmitters is moved relative to the receiving means out of the range of a signal effective to prevent the alarm from being actuated, and a second alarm system connected in circuit with said plurality of alarms and located at a remote position from said receiving means to indicate at a remote position when one of the plurality of transmitters is turned off or moved, and further including means including a reset switch whereby when said second alarm is energized the system cannot be rendered inactive at the position of the receiving means.

2. A monitoring system according to claim 1 comprising a switch for disconnecting said second alarm system.

3. A monitoring system according to claim 1 comprising a plurality of indicators connected to said distributing means to indicate which of said transmitters is turned off or moved.