JPS6229840B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a detector configured to detect damage to metal lockers, safes, cash dispensers, vending machines, etc. and obtain an alarm output. The object of the present invention is to provide a detector that is stable without malfunctions and whose sensitivity can be easily adjusted.

Conventionally, detectors for detecting metal destruction have been of mechanical construction such as vibration switches, but when the sensitivity is increased, even the slightest vibration causes detection to occur, making malfunctions more likely.
If the sensitivity is lowered to eliminate this malfunction, the required detection will not be obtained, so it is difficult to set the sensitivity of the mechanical type.

The present invention was developed in view of the above, and includes a high level detection circuit and a low level detection circuit that process the detection signal of the vibration detection element, and the output of the high level detection circuit and the low level detection circuit are provided. This detector is characterized in that it is constructed such that an output obtained by connecting an integrating circuit to the circuit is taken out through an OR circuit to drive a switching circuit.

The detector of the present invention will be explained below with reference to the figures listed as examples. Reference numeral 1 denotes a vibration detection element made of a piezoelectric material such as ceramic. 2 is a high level detection circuit that detects a signal a from the vibration detection element 1 that is generated when a metal object to be detected is hit with a hard object such as a hammer.
is amplified and detected at a value above a certain level. 3 is a low level detection circuit, 4 is an integration circuit, and the series connection of the low level detection circuit 3 and the integration circuit 4 is connected in parallel with the high level detection circuit 2. Then, when the detected object is destroyed by a drill or a metal saw, a low level signal b
is amplified and detected, and an output is obtained when such a low-level signal continues to occur for a certain period of time.

5 is an OR circuit, and 6 is a switching circuit, which extracts the OR output from the outputs passed through the delay circuit 4 of the high level detection circuit 2 and low level detection circuit 3, drives the switching circuit 6, and drives the alarm. It is something that makes you FIG. 2 shows a state in which the vibration detection element 1 made of a piezoelectric material such as ceramic in the embodiment outputs different voltages by detecting different types of vibrations. A shows a high-level single wave caused by a strong blow when breaking with a hard object such as a hammer, b shows a drill,
This figure shows the case of relatively low-level continuous waves that require a long time to break with an object such as a metal saw.

The high level detection circuit 2 detects both the high level output such as that of a hammer and the low level output that continues for a certain period of time such as that of a drill or metal saw, and the high level detection power circuit 2 detects a signal that is above a certain level. In order to do this, it is possible to prevent malfunctions due to vibrations that do not lead to destruction, by lowering the signal from a simple clap of hands or kick with a foot to a level lower than the detection level.

When such a low level signal continues for a certain period or more, it is detected by the low level detection circuit 3 side. Furthermore, the low level detection circuit 3 can be stabilized without malfunction by not detecting the level due to vibrations of the floor. Note that the low level detection circuit 3 detects the level of a high level signal such as a hammer, but since the duration of this type of high level signal is short, it does not reach the set level of the integrating circuit 4 and is sent from the integrating circuit 4 to the next stage. No output is obtained, and the high level detection circuit 2 detects it.

In addition, vibrations that are single-shot and below the detection level of high level detection circuit 2 (vibrations not intended for destruction)
There is no output to the OR circuit 5, and no alarm is generated.

What requires the high level detection circuit 2 and the low level detection circuit 3 is the integration circuit 4 connected to the low level detection circuit 3.
is necessary to set the duration of vibration exceeding the detection level of the low level detection circuit 3, and it is impossible to allow the integration circuit 4 to also set the level of the high level to be detected. To be for the sake of others.

This is because the output of the low level detection circuit 3 to the next stage does not depend on the detection strength (voltage value) of the vibration detection element 1 and is configured to be a constant level output.

As described above, according to the detector of the present invention, the level of the detection signal of the vibration detection element 1 is detected using the OR output of the high level detection circuit 2 and the low level detection circuit 3 having the integrating circuit 4. In particular, a detector that does not malfunction except for short-term low-level vibrations and vibrations that do not affect destruction, such as floor vibrations, can be obtained, and the high-level detection circuit 2, low-level Since the detection circuit 3 can easily adjust the respective level values and the integration time of the delay circuit 4, the sensitivity can be easily adjusted and the detector can operate reliably without malfunction. Although metal destruction has been disclosed in the embodiments, the present invention can also be applied to destruction of structures made of concrete, wood, or resin.

[Brief explanation of the drawing]

The figures show an embodiment of the detector of the present invention, FIG. 1 is a block diagram of the circuit, and FIG. 2 is a diagram showing a detection signal from a vibration detection element. 1... Vibration detection element, 2... High level detection circuit, 3... Low level detection circuit, 4... Integrating circuit,
5...OR circuit, 6...Switching circuit.

Claims (1)

[Claims] 1. A high-level detection circuit and a low-level detection circuit are provided to process the detection signal of the vibration detection element, and the high-level detection circuit is designed to prevent the detection of non-destructive vibrations such as clapping hands or kicking with feet. It is set to detect vibrations that can lead to destruction, such as when struck with a hammer.
The low level detection circuit is set to detect a relatively low vibration level such as when cutting with a hacksaw, and an integrating circuit is connected to the output of the high level detection circuit and the output of the low level detection circuit. A destruction detector characterized in that it is configured such that the output is taken out through an OR circuit to drive a switching circuit.