JPS6117514Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention is designed to wrap a warning cord around items to be guarded, such as products in stores, doors, windows, etc., and to issue an alarm based on the disconnection detection signal when the warning cord is cut. The purpose of this invention is to provide a device that is simple and operates reliably, and in particular has a simplified operation when the alert is released.

In order to achieve the above object, the present invention includes a closed circuit consisting of a warning cord, a high resistance, and a light emitting element connected in sequence to a DC power source, and detects disconnection of the warning cord in this closed circuit and outputs a detection signal. It consists of a disconnection detection section, an alarm generation section that emits an alarm sound based on the detection signal from the disconnection detection section, a push button switch, a charging/discharging circuit, and a shut-off trigger circuit. an alarm that sends a signal to generate a start sound, and sends an alarm release signal to the disconnection detection section for a time set in the charge/discharge circuit, and sends a lighting signal to the light emitting element of the closed circuit; A mechanical release signal generating section is provided.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

The drawing is an electrical circuit diagram with some logic shown.
In this figure, 1 is a terminal of a DC power supply 2. This power supply terminal 1 is connected to a connection terminal 3 to prevent the product from being stolen while being entwined with the handle of the product 4a, 4b, 4c as a guarded object, and a connection consisting of a pin and a jack for attaching and detaching the product. It is connected to the warning cord 6 via the fixture 5, and further includes a connecting terminal 7, a high resistance 8, a protective resistor 9 and a light emitting element.
The LEDs 10 are sequentially connected in series, and the cathodes of the LEDs 10 are grounded to form a closed circuit 11.

Reference numeral 12 denotes a disconnection detection section for detecting disconnection of the warning cord 6 of the closed circuit 11, and the disconnection detection section 12 is mainly composed of a NAND gate 13, a transistor 14, and a charging/discharging circuit 15. That is, the input side of the NAND gate 13 is connected to the connection terminals 3 and 7, and the output side is connected to the base of the switching transistor 14 via a capacitor 16 and is grounded via a resistor 17. . The collector of the transistor 14 is connected to the power supply terminal 1, and the emitter is grounded via a charge/discharge circuit 15 formed by connecting a capacitor 18 and a resistor 19 in parallel, and is connected to the anode of a diode 20. ing.

The cathode of the diode 20 of the disconnection detection section 12 is connected to an alarm generation section 21 that generates an alarm sound in response to a detection signal. This alarm generating section 21
is a first oscillation circuit 27 consisting of NAND gates 22 and 23, resistors 24 and 25, and a capacitor 26.
A second oscillation circuit 33 consisting of NAND gates 28, 29, resistors 30, 31 and a capacitor 32 is connected in two stages, and a vibrating body 34 consisting of a piezoelectric element for generating an alarm sound is connected to the output side of the second oscillation circuit 33. It consists of

Reference numeral 35 denotes an alarm release signal generation section, and this alarm release signal generation section 35 includes resistors 36 and 3 connected in series.
7 and a capacitor 38 connected in parallel, a push button switch 40 inserted between this charging/discharging circuit 39 and the power supply terminal 1, and a resistor 41 connected to the charging/discharging circuit 39. The trigger circuit 45 is composed of a Schmitt trigger circuit 45 consisting of Nand gates 42 and 43 and a resistor 44, which are connected together.

The high resistance 8 of the closed circuit 11 on the output side of the shutter trigger circuit 45 of the warning release signal generating section 35
It is connected to the connection point A of the protection resistor 9 and can send a signal for temporarily cutting off the detection signal to the disconnection detection section 12, as well as send a lighting signal to the LED 10.

Charging/discharging circuit 39 of the alert release signal generating section 35
The connection point B between the resistors 36 and 37 is the diode 46
It is connected to the input side of the alarm generating section 21 via the terminal, and is configured to be able to send out a signal for generating a start sound for canceling the alarm.

Next, the operation of the present invention will be explained.

First, we will explain the warning situation.

First, the security cord 5 with the connector 5 interposed therebetween is sequentially passed through the handles of the products 4a, 4b, and 4c, and both ends are connected to the connection terminals 3 and 7. Next, power terminal 1
A DC power supply 2 is connected to the circuit, and a DC voltage Vcc is applied to a closed circuit 11 consisting of a warning cord 6, a high resistance 8, a protection resistance 9, and an LED 10. This is alert mode. At this time, even if the DC voltage Vcc is small, the high resistance 8 has a high resistance value such as several MΩ, so the warning current is small (2 to 6 μA).
LED10 does not light up. In addition, in this warning mode, since the connection terminals 3 and 7 are both at the H level, the output side of the NAND gate 13 is at the L level, and the transistor 14 remains off.

Here, it is assumed that the security cord 6 is cut or the connector 5 is disconnected in an attempt to steal a product. Then, the warning current is cut off, one connection terminal 7 changes to L level, and the output side of Nandogade 13 becomes H level.
level and turns on the transistor 14. Then, the capacitor 18 of the charging/discharging circuit 15 is charged, and a voltage appears across the resistor 19. This voltage is input to the alarm generation unit 21 as an H level signal via the diode 20, so it drives the first and second oscillation circuits 27, 33, activates the piezoelectric vibrating body 34, and alerts the store staff etc. . At this time, even if the cut caution cord 6 or connector 5 is quickly reconnected, the capacitor 18 is already charged, and at least the time constant T determined by the capacitor 18 and the resistor 19 of the charging/discharging circuit 15 20 seconds), the H level signal is sent to the alarm generator 2.
1, the vibrating body 34 operates and continues the alarm.

Next, a description will be given of the time when the guard is released, such as when the connector 5 is pulled out in order to hand over the product to the customer. First, press the push button switch 40 lightly and immediately release it. Then, DC voltage Vcc is applied to the charging/discharging circuit 39 of the alarm release signal generating section 35, and the capacitor 38 is charged instantaneously. And this capacitor 38
When discharging, for a short time (t' = 2 to 3 seconds) when the divided voltage appearing across one of the series-connected discharging resistors 36 and 37 is at H level,
The alarm generator 21 is activated via the diode 46 to notify the start of release.

Furthermore, when the capacitor 38 is discharged,
The time t during which the voltage appearing across the discharge resistors 36 and 37 is at H level (for example, t = 4 to 10 seconds>
During t'), the output side of the Schmitt trigger circuit 45 is set to H level, so the LED 10 is lit to indicate that the alarm is released, and the output side of the Nandogade 13 of the disconnection detection section 12 is maintained at L level. ing. Therefore, during the time period t, the transistor 14 is off and the alarm generating section 21 is not activated, regardless of whether or not the warning cord 6 is disconnected.

Therefore, in this state, the connector 5 is pulled out, the products 4a... are removed, and the connector 5 is inserted again. Then, the above t
As time elapses, the output side of the Schmitt trigger circuit 45 changes from the H level to the L level, so that the normal alert state is automatically established. In this way, if the product 4a... is removed and the warning cord 6 is reconnected within the time t set by the capacitor 38 and the resistors 36 and 37 of the charging/discharging circuit 39, the vibrating body 34 will be activated. No, but alert code 6 for t time
If not connected, the vibrating body 34 is activated and an alarm sound is generated. At this time, even if the connector 5 is connected and the transistor 14 is turned off, the capacitor 18 and the resistor 1 of the charge/discharge circuit 15 of the disconnection detection section 12
The alarm continues for a time constant T (for example, about 20 seconds) determined by 9 and 9, and the alarm does not stop even if the push button switch 40 is pressed within this time T.

Since the present invention is configured as described above, the warning current flowing through the closed circuit during warning is as small as about 4 to 6 μA, and the power consumption is small even if the power switch is not turned on or off and is always in the warning state. It is safe and works reliably when the warning cord is cut. Furthermore, when canceling the alert, a sound is generated to start alert canceling, and an LED is lit, making it clear whether the alert is being activated or canceling, thereby preventing the user from performing the wrong operation. Furthermore, since the alarm release signal generation section is mainly composed of a push button switch, a charging/discharging circuit, and a shutter trigger circuit, the release state can be set by simply turning on the push button switch momentarily, making the release operation extremely easy. Become. Moreover, after a certain period of time (for example, 4 to 10 seconds) set by the charging/discharging circuit required for cancellation has elapsed from the start of cancellation, the state will automatically return to the alert state, so there is no need to forget to return to the alert state. . In addition, if the discharging resistor of the charging/discharging circuit is configured with two resistors connected in series, and the alarm generating section is activated by the voltage appearing across one of the resistors, the voltage division ratio may be changed. Accordingly, it is possible to appropriately change the start time that signals the start of alert release.

[Brief explanation of the drawing]

The drawing is an electrical circuit diagram with a portion of logic showing an embodiment of the warning device according to the present invention. 2...DC power supply, 3, 7...Connection terminal, 4a,
4b, 4c...product, 5...connection tool, 6...warning cord, 8...high resistance, 10...LED, 11...
... Closed circuit, 12 ... Disconnection detection section, 15 ... Charge/discharge circuit, 21 ... Alarm generation section, 27, 33 ... Oscillator, 34 ... Vibrating body, 35 ... Warning release signal generation section, 39 ... Charge/discharge circuit, 40...Push button switch, 45...Shmitt trigger circuit.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A closed circuit consisting of a warning cord, a height resistor, and a light emitting element connected in sequence to a DC power source, and a disconnection that detects disconnection of the warning cord in this closed circuit and outputs a detection signal. It consists of a detection section, an alarm generation section that emits an alarm sound in response to a detection signal from the disconnection detection section, a push button switch, a charge/discharge circuit, and a shut-off trigger circuit, and when the push button switch is pressed, the alarm generation section is configured to initiate disarming of the alarm. A warning device that sends out a signal to generate a sound, sends out a warning release signal to the disconnection detection unit for a time set in the charge/discharge circuit, and sends out a lighting signal to the light emitting element in the closed circuit. A warning device comprising a release signal generating section. (2) The charging/discharging circuit of the alarm release signal generator is composed of a capacitor and two resistors connected in series, which are connected in parallel, and the signal detected by one of these resistors activates the alarm generator. The warning device according to claim 1 of the utility model registration, which is activated. (3) The disconnection detection section is mainly composed of an AND gate, a transistor, and a charging/discharging circuit, and the scope of the utility model registration claim is such that when the warning cord is disconnected, an alarm sound is generated for a set time in the charging/discharging circuit. The warning device according to item 1 or 2.