MOTION-SENSITIVE ALARM WITH LINE-CORD-RESPONSIVE AUTOMATIC ARMING MEANS
United States Patent 3836901
A circuit and apparatus adapted to be mounted entirely or in part within the device to be protected includes an alarm circuit loop and a control loop, with the state of the control loop being determined by whether the line cord of the protected device is in or out of the wall socket. The control loop can thus disable or enable the alarm circuit, depending on the position of the power cord. However, actual operation of the alarm circuit requires both a change in the state of the control circuit due to the state of the line cord and a change in the alarm circuit due to movement of the protected device.
US Patent References:
Power line sensing appliance theft alarm
King - November 1966 - 3289194
THEFT-PREVENTING ALARM DEVICE
Tellerman et al. - January 1969 - 3425050
SENSING RESISTANCE DEVICE
Sliman - April 1969 - 3440636
/3559203.html
Hall et al. - January 1971 - 3559203
Power line sensing appliance theft alarm
King - November 1966 - 3289194
THEFT-PREVENTING ALARM DEVICE
Tellerman et al. - January 1969 - 3425050
SENSING RESISTANCE DEVICE
Sliman - April 1969 - 3440636
/3559203.html
Hall et al. - January 1971 - 3559203
Inventors:
Matto, Victor G. (Kinnelon, NJ)
Schubert, Howard C. (Leonia, NJ)
Schubert, Howard C. (Leonia, NJ)
Application Number:
05/420536
Publication Date:
09/17/1974
Filing Date:
11/30/1973
View Patent Images:
Export Citation:
Assignee:
Aerolite Electronics Corporation (Union City, NJ)
Primary Class:
Other Classes:
340/670, 340/571
International Classes:
G08B13/14; G08B13/14
Field of Search:
340/280,256,261,420
Primary Examiner:
Swann III, Glen R.
Parent Case Data:
CROSS-REFERENCES TO RELATED APPLICATIONS
This application is a division of application Ser. No. 119,115, filed May 15, 1972 as a continuation-in-part of Ser. No. 820,169, filed Apr. 29, 1969.
Claims:
What is claimed is
1. An alarm circuit for protecting an electrical device including
2. An alarm circuit for protecting an electrical device including
3. The circuit defined in claim 2 wherein said first switch means closes when said electrical device is physically moved, and
4. The circuit as defined in claim 2 wherein said electronic switch is a controlled rectifier having anode, cathode and control electrode, said anode and cathode being in said first current flow path.
5. The circuit defined in claim 1 and including an isolating power transformer connected between said second power source and said second switch, whereby said circuit is isolated from said second power source.
6. The apparatus defined in claim 1 wherein said motion-sensitive switch includes at least one curved, dish-shaped plate on which a conductive ball is seated.
7. The apparatus defined in claim 1 wherein said motion-sensitive switch includes upper and lower plates secured together but insulated from each other with one being concave and the other convex and with a conductive ball seated on the lower plate.
1. An alarm circuit for protecting an electrical device including
2. An alarm circuit for protecting an electrical device including
3. The circuit defined in claim 2 wherein said first switch means closes when said electrical device is physically moved, and
4. The circuit as defined in claim 2 wherein said electronic switch is a controlled rectifier having anode, cathode and control electrode, said anode and cathode being in said first current flow path.
5. The circuit defined in claim 1 and including an isolating power transformer connected between said second power source and said second switch, whereby said circuit is isolated from said second power source.
6. The apparatus defined in claim 1 wherein said motion-sensitive switch includes at least one curved, dish-shaped plate on which a conductive ball is seated.
7. The apparatus defined in claim 1 wherein said motion-sensitive switch includes upper and lower plates secured together but insulated from each other with one being concave and the other convex and with a conductive ball seated on the lower plate.
Description:
BACKGROUND OF THE INVENTION
Many circuits and apparatus are known for operating alarm circuits, and at least one type of circuit is known for protecting TV sets, radios and the like in hotel and motel rooms and subject to considerable thievery. Some known circuits operate directly on removal of the power line cord, and others operate on movement of the protected device; however, none of the prior art provides a combination of controls, depending on both the condition of the line cord and movement of the protected device in the manner taught by the present invention. Such a combination is foolproof but permits authorized movement of the line cord and the protected device separately without energizing the alarm.
DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic circuit embodying the principles of the invention; and
FIG. 2 is a sectional view of one type of motion-sensitive switch useful in the circuit of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The circuit of the invention 10 includes a self-contained power source 20 such as a battery having a positive terminal connected to a bus 30 and a negative terminal connected to a bus 40. Bus 30 is connected through a resistor 50 to one side of a motion-sensitive switch 60 which is of the type which closes when it is moved or tilted. The other side of switch 60 is connected to the gate of a three-electrode controlled rectifier 70, known as an SCR. The anode of the SCR 70 is connected through a resistor 80 to the bus 30. SCR 70 is a three-electrode semi-conductor switch; however, other devices of this type might also be used to perform the indicated function. An alarm bell 90 or other signalling device is connected across the resistor 80. The cathode of the SCR 70 is connected by lead 100 through a reed switch 110 mounted inside a coil 120. A bias resistor 130 is connected between the gate and cathode of the SCR.
Bus 40 is connected through a resistor 132, lead 134, and coil 120 to bus 30 to permit a trickle charge to flow if battery 20 is a rechargeable battery such as a nickel cadmium battery.
The circuit 10 also includes the power cord of the device to be protected represented by numeral 140 and connected from the usual commercial A.C. power supply 142 to a transformer 150, the secondary of which has one end 160 connected through a diode 170 to lead 134 and to coil 120 with a capacitor 180 connected from the diode 170 to the other end 190 of the secondary of transformer 150. The diode 170 and capacitor 180 provide a D.C. voltage from the A.C. applied to the transformer 150 to energize the coil 120 of the reed switch. The end 191 of the coil 120 is connected to bus 40 and to the end 190 of the transformer secondary.
A switch 200 operates by a key, so that authorized disabling of the alarm circuit can be effected, is provided in the alarm circuit, for example, in the bus 30, so that the battery 20 can be disconnected from the alarm portion of the circuit by authorized persons.
The alarm warning system 10 works in the following manner: If the line cord 140 is connected to the A.C. power line 142 and power is supplied to the primary of the transformer 150, the A.C. in the transformer secondary is rectified by the diode 170 and filtered by the capacitor 180 to produce a D.C. voltage which energizes the coil 120 of the reed switch 110. Energy generated in the coil opens the reed switch and thus opens the lead 40 which extends from the battery 20 through lead 100 to the cathode of the SCR 70 and disconnects the battery from the SCR and thus prevents the alarm 90 from being activated. In this condition, the alarm-protected appliance can be moved to the length of the line cord without setting off an alarm. The key switch 200 permits authorized personnel to remove the appliance when the line cord is disconnected by opening bus 30 and removes the battery power that operates the alarm.
If the line cord 140 is removed or disconnected from source 142, the primary power to the transformer is removed from the circuit and coil 120 is de-energized and reed switch 110 closes. This supplies battery power to the cathode of the SCR 70. Now any motion or vibration of the TV set causes the motion switch 60 to close, and the closing of this switch, no matter of what duration, supplies a positive voltage pulse to the gate of the SCR 70, and this causes the anode and cathode of the SCR to conduct. This conduction supplies a current flow over the anode resistor 80 from the battery, and the current across this anode resistor activates the alarm 90 which is connected in parallel with the resistor.
Those skilled in the art will appreciate that the utility of the circuit of the invention goes beyond that specifically disclosed. For example, it could be adapted to other types of uses than protecting a TV set or the like. By selecting a different alarm condition sensing member other than the motion-sensitive switch 60, other conditions could be detected such as the opening or closing of doors or windows or conditions such as fire or the like.
Considering the motion-sensitive switch 60, a particularly suitable structure is shown in FIG. 2 and includes a relatively shallow, slightly concave annular lower plate 220 and a generally cup-shaped annular upper plate 230 spaced apart and secured together by a suitable annular insulating member 240 which may be of rubber or the like. A ball-type contact member 250 which may be solid and of a suitable metal or which may be of mercury is seated in the lower plate, and it can be seen that, if the lower plate is sufficiently shallow, then the slightest tilting of the protected device which carries the switch 60 will cause the ball 250 to roll to a side, shown in dash lines, and make contact between the top and bottom plates which are the two electrodes of the switch. In the circuit 10, even the slightest contact of the ball to the two plates, represented by the dash line position of the ball, is sufficient to operate the alarm system. Other motion-sensitive switches, such as pendulum switches, may also be used. Of course, the alarm itself may be of any suitable type and number and may include an alarm on the protective device itself and/or remote alarm signal devices.
Many circuits and apparatus are known for operating alarm circuits, and at least one type of circuit is known for protecting TV sets, radios and the like in hotel and motel rooms and subject to considerable thievery. Some known circuits operate directly on removal of the power line cord, and others operate on movement of the protected device; however, none of the prior art provides a combination of controls, depending on both the condition of the line cord and movement of the protected device in the manner taught by the present invention. Such a combination is foolproof but permits authorized movement of the line cord and the protected device separately without energizing the alarm.
DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic circuit embodying the principles of the invention; and
FIG. 2 is a sectional view of one type of motion-sensitive switch useful in the circuit of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The circuit of the invention 10 includes a self-contained power source 20 such as a battery having a positive terminal connected to a bus 30 and a negative terminal connected to a bus 40. Bus 30 is connected through a resistor 50 to one side of a motion-sensitive switch 60 which is of the type which closes when it is moved or tilted. The other side of switch 60 is connected to the gate of a three-electrode controlled rectifier 70, known as an SCR. The anode of the SCR 70 is connected through a resistor 80 to the bus 30. SCR 70 is a three-electrode semi-conductor switch; however, other devices of this type might also be used to perform the indicated function. An alarm bell 90 or other signalling device is connected across the resistor 80. The cathode of the SCR 70 is connected by lead 100 through a reed switch 110 mounted inside a coil 120. A bias resistor 130 is connected between the gate and cathode of the SCR.
Bus 40 is connected through a resistor 132, lead 134, and coil 120 to bus 30 to permit a trickle charge to flow if battery 20 is a rechargeable battery such as a nickel cadmium battery.
The circuit 10 also includes the power cord of the device to be protected represented by numeral 140 and connected from the usual commercial A.C. power supply 142 to a transformer 150, the secondary of which has one end 160 connected through a diode 170 to lead 134 and to coil 120 with a capacitor 180 connected from the diode 170 to the other end 190 of the secondary of transformer 150. The diode 170 and capacitor 180 provide a D.C. voltage from the A.C. applied to the transformer 150 to energize the coil 120 of the reed switch. The end 191 of the coil 120 is connected to bus 40 and to the end 190 of the transformer secondary.
A switch 200 operates by a key, so that authorized disabling of the alarm circuit can be effected, is provided in the alarm circuit, for example, in the bus 30, so that the battery 20 can be disconnected from the alarm portion of the circuit by authorized persons.
The alarm warning system 10 works in the following manner: If the line cord 140 is connected to the A.C. power line 142 and power is supplied to the primary of the transformer 150, the A.C. in the transformer secondary is rectified by the diode 170 and filtered by the capacitor 180 to produce a D.C. voltage which energizes the coil 120 of the reed switch 110. Energy generated in the coil opens the reed switch and thus opens the lead 40 which extends from the battery 20 through lead 100 to the cathode of the SCR 70 and disconnects the battery from the SCR and thus prevents the alarm 90 from being activated. In this condition, the alarm-protected appliance can be moved to the length of the line cord without setting off an alarm. The key switch 200 permits authorized personnel to remove the appliance when the line cord is disconnected by opening bus 30 and removes the battery power that operates the alarm.
If the line cord 140 is removed or disconnected from source 142, the primary power to the transformer is removed from the circuit and coil 120 is de-energized and reed switch 110 closes. This supplies battery power to the cathode of the SCR 70. Now any motion or vibration of the TV set causes the motion switch 60 to close, and the closing of this switch, no matter of what duration, supplies a positive voltage pulse to the gate of the SCR 70, and this causes the anode and cathode of the SCR to conduct. This conduction supplies a current flow over the anode resistor 80 from the battery, and the current across this anode resistor activates the alarm 90 which is connected in parallel with the resistor.
Those skilled in the art will appreciate that the utility of the circuit of the invention goes beyond that specifically disclosed. For example, it could be adapted to other types of uses than protecting a TV set or the like. By selecting a different alarm condition sensing member other than the motion-sensitive switch 60, other conditions could be detected such as the opening or closing of doors or windows or conditions such as fire or the like.
Considering the motion-sensitive switch 60, a particularly suitable structure is shown in FIG. 2 and includes a relatively shallow, slightly concave annular lower plate 220 and a generally cup-shaped annular upper plate 230 spaced apart and secured together by a suitable annular insulating member 240 which may be of rubber or the like. A ball-type contact member 250 which may be solid and of a suitable metal or which may be of mercury is seated in the lower plate, and it can be seen that, if the lower plate is sufficiently shallow, then the slightest tilting of the protected device which carries the switch 60 will cause the ball 250 to roll to a side, shown in dash lines, and make contact between the top and bottom plates which are the two electrodes of the switch. In the circuit 10, even the slightest contact of the ball to the two plates, represented by the dash line position of the ball, is sufficient to operate the alarm system. Other motion-sensitive switches, such as pendulum switches, may also be used. Of course, the alarm itself may be of any suitable type and number and may include an alarm on the protective device itself and/or remote alarm signal devices.