JPH06139467A - Theft preventing device - Google Patents

Abstract

PURPOSE:To provide the theft preventing device which can prevent a malfunction caused by a deviation of a tuning frequency of a receiving circuit, with regard to the theft preventing device which is attached to an exhibit in a store and protect a commodity from a shoplifting act. CONSTITUTION:The device is constituted of a theft preventing device main body 4 which contains an alarm means, and a receiving circuit for receiving a signal from the outside and operating the alarm means, and a transmitter 8 for radiating a signal to a specific area, and a frequency of an electromagetic wave radiated by the transmitter 8, and a tuning frequency of the receiving circuit are set to <=30KHz corresponding to a voice area. Also, since the tuning frequency of the receiving circuit is a frequency being remarkably lower than that in a conventional VHF area or UHF area, a degree of allowance to a deviation of the tuning frequency is large, and the device is operated stably.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-theft device for protecting an article from shoplifting by attaching an anti-theft device body to an in-store exhibit.

[0002]

2. Description of the Related Art In a record shop, an anti-theft device body shown in FIG. 5 is used to protect a CD record of a product from shoplifting.

This is a burglarproof device main body 4 [hereinafter, referred to as a main body] having a battery 1, a buzzer 2 driven by the battery 1, and a receiving circuit 3 built-in, and a back plate 5 and a U-shape. The transparent acrylic plate 6 is attached by a double-sided adhesive tape or the like, and a CD record 7 with a case is inserted into a storage part formed by the main body 4, the back plate 5 and the acrylic plate 6. .

In this state, the CD record is displayed in the store, and the customer who wants to purchase the product takes it to the cash register with the main body 4 still attached, and the clerk uses the jig to give an alarm. It is used in the form of sale in which the CD record 7 stored in the storage section is taken out and handed to the customer after being set in the non-use state.

When the CD record 7 is taken out without using a jig, the main body 4 is activated and an alarm is generated. In addition, without removing the CD record 7 from the storage unit, the main body 4
If the CD record is to be taken out of the store with the mark attached, the receiving circuit 3 detects the signal radiated from the transmitter only near the entrance of the store and an alarm is generated.

The signal frequency radiated from the transmitter is V
Electromagnetic waves in the HF range or the UHF range are used, and the tuning frequency of the receiving circuit 3 corresponds to the signal frequency radiated from the transmitter in the VHF range or the UHF range.
It is set to a single frequency in the area.

[0007]

When the receiving circuit 3 is manufactured, it is necessary to make an adjustment so that the tuning frequency of the receiving circuit 3 is accurately tuned to the oscillation frequency of the transmitter.

However, even if the tuning frequency of the receiving circuit 3 is accurately adjusted to the transmitting frequency of the transmitter before shipment, the V of the receiving circuit 3 is affected by the temperature of the operating environment or an external shock.
The tuning frequency set in the HF range or UHF range may shift greatly, and the CD remains attached to the main unit 4.
There are malfunctions such that no alarm is issued even if the record is taken out of the store, or a false alarm is likely to occur due to external radio waves.

Further, there is a problem that the electromagnetic waves in the VHF range or the UHF range radiated from the transmitter are likely to cause other devices to malfunction. It is an object of the present invention to provide an anti-theft device that has a larger margin of variation in the tuning frequency of the receiving circuit than the conventional one, and that the electromagnetic waves radiated from the transmitter are less likely to affect other devices.

[0010]

An anti-theft device according to claim 1, wherein the anti-theft device main body has a built-in alarm means for issuing an alarm and a receiving circuit for operating the alarm means by receiving a signal from the outside. A sweep means for sweeping a frequency band including the tuning frequency of the receiving circuit and changing the transmission frequency of the transmitter with time, the transmitter including a transmitter radiating a signal to a specific area. It is characterized by being provided.

According to another aspect of the present invention, there is provided an anti-theft device which has an alarm means for issuing an alarm and a receiving circuit for receiving an external signal to operate the alarm means, and a signal for a specific area. Consists of a radiating transmitter,
The frequency of the electromagnetic wave radiated by the transmitter and the tuning frequency of the receiving circuit are set to 30 KHz or less, which corresponds to a voice region.

According to another aspect of the present invention, there is provided an anti-theft device, which includes an alarm means for issuing an alarm and a receiving circuit for receiving an external signal to activate the alarm means, and a signal for a specific area. Consists of a radiating transmitter,
The frequency of the electromagnetic wave radiated by the transmitter and the tuning frequency of the receiving circuit are set to 30 KHz or less, which corresponds to the voice region, and the transmitter sweeps a frequency band including the tuning frequency of the receiving circuit to set the time. Accordingly, a sweep means for changing the transmission frequency of the transmitter is provided.

[0013]

According to the structure of the present invention, since the transmission frequency of the transmitter is not single but is changed by the action of the sweeping means, even if the tuning frequency of the receiving circuit of the anti-theft device main body is shifted, the reception The alarm means issues an alarm when the transmitter's oscillator frequency matches the circuit's tuning frequency.

According to the second aspect of the invention, since the transmission frequency of the transmitter and the tuning frequency of the receiving circuit of the anti-theft device body are set to 30 KHz or less corresponding to the voice region, the frequency is much lower than the conventional band. Therefore, there is a large margin for fluctuations in the tuning frequency of the receiving circuit, and stable operation can be expected. Moreover, it is difficult for other devices to malfunction.

According to the structure of claim 3, the transmission frequency of the transmitter and the tuning frequency of the reception circuit of the anti-theft device body are set to 30 KHz or less corresponding to the voice region, and the transmission frequency of the transmitter is not single. Since it is changed by the action of the sweeping means, the margin with respect to the fluctuation of the tuning frequency of the receiving circuit is further improved, and more stable operation can be expected.

[0016]

Embodiments of the present invention will be described below with reference to FIGS. It should be noted that components having the same functions as those of the conventional example shown in FIG.

The transmitter 8 of the antitheft device of the present invention is shown in FIG.
As shown in FIG. 4, the sweep oscillation circuit 9 is used as the sweep means in the signal source. As the output signal of the sweep oscillation circuit 9, as shown in FIG. 2, a triangular wave whose output voltage changes with the passage of time is repeatedly output. Figure 3
Shows a specific circuit diagram thereof, which is output via the buffer 10.

The output signal of the sweep oscillation circuit 9 is a voltage −
Frequency converter [Model number AD65 manufactured by Analog Devices, Inc.]
4] The signal is converted into a rectangular wave having a repeating period according to the input voltage by 11, and the JK flip-flop [digital IC
The signal whose frequency is swept according to the output signal of the sweep oscillation circuit 9 is input to the power amplification unit 13 via the output control unit 12 configured by the model number 4027] or the like and is output from the loop coil antenna 14 to the store. Radiation near the doorway.

An infrared pyroelectric sensor 16 is connected to the terminal 15 of the output control unit 12 to detect the approach of a person, and the monostable multivibrator is detected by detecting that a person approaches the entrance and exit of the store. [Digital IC Model No. 4536] 18 is activated, and the signal on the output side of the voltage-frequency converter 11 is supplied to the power amplification unit for a specified time after the sensor 16 detects the approach of a person.
You are typing in 13. When a signal is continuously radiated from the antenna 14 regardless of the approach of a person, the switch 17 is switched.

The tuning frequency of the receiving circuit 3 of the main body 4 is set near the center frequency of the swept output frequency of the transmitter 8. With this configuration, even if the tuning frequency of the receiving circuit 3 fluctuates during use, the output frequency of the transmitter 8 is swept.
It is possible to reliably detect the signal from and to sound the buzzer 2 as an alarm means.

When an electromagnetic wave in the VHF range or the UHF range is used as the electromagnetic wave radiated from the antenna 14 of the above embodiment, the tuning frequency of the receiving circuit 3 is also the antenna 14.
It is set to a single frequency in the VHF region or the UHF region corresponding to the signal frequency radiated from the. In this case, the tuning frequency of the receiving circuit 3 is likely to fluctuate due to disturbance, but since the output frequency of the transmitter 8 is swept as described above, the margin for the fluctuation of the receiving frequency of the receiving circuit 3 is improved and stable. It is possible to achieve the desired operation.

When an electromagnetic wave of 30 KHz or less corresponding to the voice region is used as the electromagnetic wave radiated from the antenna 14 and the output frequency of the transmitter 8 is swept, there is a margin for fluctuations in the tuning frequency of the receiving circuit. Can be further improved and more stable operation can be expected. In this case, the malfunction of the receiving circuit 3 due to external noise is extremely unlikely to occur, and the malfunction is not given to other devices. In addition, since there is no need for compensation means for preventing the occurrence of false alarms and malfunctions in other devices, there is an advantage that the antitheft device body 4 can be made compact.

In each of the above-mentioned embodiments, the transmission frequency is not a single value but is swept in any case where the frequency of the electromagnetic wave radiated from the antenna 14 is set to 30 KHz or less corresponding to the VHF region, the UHF region or the voice region. However,
When the antenna 14 is configured to radiate electromagnetic waves of 30 KHz or less, even if the transmission frequency is set to a single frequency without sweeping, the frequency is low, so that the margin for fluctuations in the reception frequency is VHF. Area or UHF
Compared with the conventional device that handles the signal in the area, it can be greatly improved and stable operation can be expected.

[0024]

According to the first aspect of the invention, the transmitter that radiates a signal to a specific area sweeps a frequency band including the reception frequency of the reception circuit of the antitheft device body attached to the product to be protected. Therefore, since the sweep means for changing the transmission frequency with time is provided, even if the tuning frequency of the receiving circuit fluctuates during use, the receiving circuit reliably detects the signal from the transmitter and activates the alarm means. Therefore, stable operation can be expected over a long period of time.

According to the second aspect of the invention, since the transmission frequency of the transmitter and the tuning frequency of the reception circuit of the anti-theft device body are set to 30 KHz or less, which corresponds to the voice region, the frequency is much lower than in the conventional band. Because of this, there is a large margin for fluctuations in the tuning frequency of the receiving circuit, and stable operation can be expected. Moreover, it is difficult for other devices to malfunction.

According to the third aspect of the present invention, the transmission frequency of the transmitter and the tuning frequency of the reception circuit of the anti-theft device body are set to 30 KHz or less corresponding to the voice region, and the transmission frequency of the transmitter is not uniform. Instead, since it is changed by the action of the sweeping means, the margin for fluctuations in the tuning frequency of the receiving circuit is further improved, and more stable operation can be expected.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an anti-theft device body and a transmitter that constitute an anti-theft device of the present invention.

FIG. 2 is an output waveform diagram of a sweep oscillation circuit of the same device.

FIG. 3 is a circuit configuration diagram of a sweep oscillation circuit of the device.

FIG. 4 is a circuit configuration diagram of the transmitter.

FIG. 5 is an external perspective view of the anti-theft device body.

[Explanation of symbols]

 2 Buzzer [alarm means] 3 Receiver circuit 4 Anti-theft device body 8 Transmitter 9 Sweep oscillation circuit [sweep means] 11 Voltage-frequency converter 13 Power amplifier 14 Antenna

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[Procedure amendment]

[Submission date] March 25, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Delete ───────────────────────────────────────────── ────────

[Procedure amendment]

[Submission date] November 4, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Added

[Correction content]

[Brief description of drawings]

FIG. 1 is a configuration diagram of an anti-theft device body and a transmitter that constitute an anti-theft device of the present invention.

FIG. 2 is an output waveform diagram of a sweep oscillation circuit of the same device.

FIG. 3 is a circuit configuration diagram of a sweep oscillation circuit of the device.

FIG. 4 is a circuit configuration diagram of the transmitter.

FIG. 5 is an external perspective view of the anti-theft device body.

[Explanation of Codes] 2 Buzzer [alarm means] 3 Reception circuit 4 Anti-theft device body 8 Transmitter 9 Sweep oscillation circuit [sweep means] 11 Voltage-frequency converter 13 Power amplification part 14 Antenna

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Added

[Correction content]

[Fig. 2]

[Figure 1]

[Figure 3]

[Figure 4]

[Figure 5]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junji Higaki 2-35, Jimmucho, Yao City, Osaka Prefecture Kubota Kyuhoji Factory Co., Ltd. (72) Kohei Miyata 2-35, Jimmucho, Yao City, Osaka Prefecture Kubota Kyuhoji Factory (72) Inventor Hiroshi Matsushima 3-29 Hachiman-dori, Chuo-ku, Kobe, Hyogo Prefecture Shinwa Industry Co., Ltd.

Claims (3)

[Claims] 1. An anti-theft device main body comprising an alarm means for issuing an alarm and a receiving circuit for operating the alarm means by receiving a signal from the outside, and a transmitter for radiating a signal to a specific area. An anti-theft device, wherein the transmitter is provided with sweep means for sweeping a frequency band including the tuning frequency of the receiving circuit to change the transmission frequency of the transmitter with time. 2. An anti-theft device main body having a built-in alarm means for issuing an alarm and a receiving circuit for operating the alarm means by receiving a signal from the outside, and a transmitter for radiating the signal to a specific area. An anti-theft device in which the frequency of electromagnetic waves radiated by the transmitter and the tuning frequency of the receiving circuit are set to 30 KHz or less, which corresponds to a voice region. 3. An anti-theft device main body having an alarm means for issuing an alarm and a receiving circuit for operating the alarm means upon receiving a signal from the outside, and a transmitter for radiating the signal to a specific area. The frequency of the electromagnetic wave radiated by the transmitter and the tuning frequency of the receiving circuit are set to 30 KHz or less, which corresponds to the voice region, and the transmitter sweeps a frequency band including the tuning frequency of the receiving circuit to set the time. Anti-theft device provided with sweeping means for changing the transmission frequency of the transmitter according to.