Untitled record

1541 BV

Giovanni Br & vi, 6112 large rooms

Signaling device for an alarm system

The invention relates to a signaling device according to the preamble of the main claim.

In alarm systems, which are used in particular for the monitoring of buildings, an alarm is usually reported by an acoustic and by an optical signal. The signaling device is mounted in a slotted housing at a suitable location of the building to be protected. In most cases, the acoustic signaling device is directly connected to a flashing light. For the choice of the place of cultivation of such combined signal devices, on the one hand, it is decisive that the generated A.1 tone can be heard aloud and the flashing light can be seen from a distance. On the other hand, the place of cultivation should prevent possible manipulation of the signaling device, so for example be sufficiently high. The latter exits, for example, in low-rise buildings or possibly also due to lack of approval of the building owner. It is therefore common for signaling devices to be removed from alarm systems before an alarm signal could be emitted as a result of a subsequent intrusion.

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In other known alarm systems therefore two or more signaling devices are already provided. However, an alarm can be prevented even in these alarm systems in that the signal devices are removed simultaneously.

Object of the present invention is to provide a signaling device in which an unauthorized removal or destruction is largely difficult.

The signaling device with the characterizing features of the main claim has the advantage that the electro-acoustic transducer is so small that it can easily be hidden over K -. \ Uvorsports, billboards or other objects attached to the building.

The measures listed in the dependent claims advantageous refinements and improvements of the main claim invention are possible.

Embodiments of the invention are illustrated in the drawing with reference to several figures and explained in more detail in the following description. It shows:

1 an embodiment,

2 shows a circuit arrangement for the embodiment,

Fig. 3 shows an example of the assembly of a signaling device according to the invention and

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Fig. 4 shows a further embodiment of a signaling device.

Identical parts are provided in the figures with the same reference numerals.

In the signal device according to Fig. 1, a known electro-acoustic transducer is arranged in a cavity of a housing which is provided with a sound outlet opening 2 and forms together with the housing one. Sounder 1. In a practically implemented signaling device according to the invention, the sounder has a diameter of 40 mm and is about 12 mm high. He can thus unobtrusively attached to buildings, for example, above shop windows obscured by awnings, billboards and similar objects. Via a cable 3, the electro-acoustic 'andler is connected to an AC voltage generator, which is housed in a separate housing 4. The AC voltage generator receives in a conventional manner operating voltage from an alarm, not shown.

In the circuit arrangement according to FIG. 2, a piezoelectric transducer 6 is provided as the transducer, to which the alternating voltage is supplied via a transformer 7 and the line. As a final stage, a transistor 8, which is connected upstream of a further transistor 9 with two resistors 10, 11 as a driver. Inverting amplifiers 12, 13, 14, 15 are formed, for the sake of simplicity, of NAND gates of a conventional integrated circuit including four such gates. The amplifiers 12 and 13, together with the capacitors 16, 17 an oscillator, which is supplied via resistors 18, 19 and a tunable resistor 20 is a S expensive voltage. Depending on the level of this control voltage, the oscillator oscillates at one of two frequencies. The output voltage of the

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Oscillator is supplied via a coupling condensing 21 to the driver transistor 9.

To generate a siren-like tone, the control voltage is switched with gradual transitions between two values. The purpose of a bistable multivibrator, which is formed from the two amplifiers 14, 15, the capacitors 22, 23 and the resistors 24, 25. About a low pass, consisting of the resistors 26, 27 and

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bistable multivibrators supplied as a control voltage to the oscillator.

The capacitance values ​​of the capacitors 22, 23 determine the frequency and duty cycle of the control voltage. It has now been found that the use of several adjacent Signaleinrichx.ungen a particularly conspicuous, audible sound is formed when the signal devices work with different sound lengths. This can be achieved in a simple manner by different choice of the capacitance values ​​of the capacitors 22, 23.

Fig. 3 shows a section through a portion of a wall 31, wherein on the outside 32 of the wall a sounder 1 is provided. The line 3 is passed through the wall, while the AC voltage generator is mounted in a housing 4 on the inside 33 of the wall.

Signalers with different tone lengths, which are each assigned to an alarm system, can be mounted in the manner explained with reference to Figures 1 and 3 at suitable locations of a building. However, it is also possible to accommodate several sounders in a compact housing, as shown in Fig. 4. The sound generator of Fig. 4 consists of two together

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connected cylindrical housings 34, 35, at the ends of each a ScbsLlau? ' -i.ttsöffnung is provided, of which in Fig, 4 only two 36, 37 are visible. Behind the sound outlet openings each an electro-acoustic transducer is arranged. In the central areas of the housings 34, 35 there is room for alternating voltage generators, which supply the transformers with voltage. Via a cable 38, the sound generator shown in FIG. 4 can be connected to an alarm system.