JPS6339821Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a sound stop circuit for a fire alarm bell, etc.

Each floor of the building is equipped with a bell that rings all at once in the event of a fire, and these bells are connected to a fire receiver so that they ring in conjunction with the operation of the fire detector. This fire receiver is generally equipped with a bell stop switch that can stop the ringing of the bell after receiving a fire signal from a fire detector in a certain area and ringing the bell.

However, recently, people often forget to operate this bell stop switch, or in hotels, etc., they are afraid of confusion due to false alarms from fire detectors.
Because the sound stop switch was operated in advance, detection of an actual fire was delayed, leading to a major disaster.

This invention is characterized in that, in the sound stop circuit of such a fire alarm, the sound cannot be stopped artificially unless the sound stop switch is forgotten to be reset and a predetermined condition is not met.

The present invention will be explained below with reference to the embodiment shown in the drawings.

FIG. 1 shows a conventional bell ringing stop circuit. In the drawing, a fire detector De installed in each fire warning area is connected between the power terminals via a recovery switch SW ₁ via a district relay L. Furthermore, a fire alarm bell B is connected via a normally open contact _l1 of a district relay L and a normally closed contact of a bell stop switch _SW1 . Each district relay L is provided with a self-holding contact _l2 , and a switch caution light Lp is connected between the power supply terminals via the normally open contact of the bell stop switch _SW2 . In such a conventional circuit, when the fire detector De is operated, the district relay L is operated, and the self-holding contact _l1 holds the relay L1, and the bell B rings when the contact _l1 is closed.

After confirming that there is a fire, operate the bell stop switch SW ₂ to open the bell circuit and stop the ringing of the bell. Therefore, this bell stop switch SW ₂ is of a lock type, and even if the recovery switch SW ₁ is operated after the fire has been extinguished, the bell stop state _remains maintained. There was a drawback that the fire alarm bell B would not ring if the fire alarm bell B was not rung due to forgetting to restore it or intentionally stopping the bell.

FIG. 2 is a diagram showing an embodiment of this invention that solves the above-mentioned drawbacks, and shows the connection between the series connection point A of the series circuit between the normally open contact _l1 of the district relay L and the bell B, and the negative terminal of the power supply. Non-locking bell stop switch in between
A series circuit between SW ₃ and a bell stop relay R is connected, and when the bell stops ringing, a bell stop warning light Lp is turned on by switching contact r ₂ of the bell stop relay R.

In addition, the bell stop relay R has a self-holding contact r ₁
is provided.

In such a configuration, when the fire detector De operates, the district relay L operates, and the bell B rings when its contact _l1 is closed. Therefore, when the non-locking type bell stop switch _SW3 is closed, the bell stop relay R is activated and self-holds, and the ringing of the bell B is stopped by its switching contact _r2 , and the switch caution light Lp is turned on.

After that, after confirming that the fire is extinguished, the recovery switch is turned on.
When SW ₁ is operated, both the district relay L and the bell stop relay R are restored, and everything is restored to its normal state.

Bell stop switch under normal fire watch conditions
When SW ₃ is operated, contact l ₁ of district relay L is open, so bell stop relay R does not operate, and as a result, the bell does not stop.

Note that these circuits can be replaced with semiconductor circuits, and the present invention is not limited to this embodiment.

As described above, the sound stop circuit of the fire alarm of this invention has a simple circuit added to the conventional one, so that it can prevent the sound from being stopped due to forgetting to restore the sound stop switch to the normal position or due to human operation. This has the effect that the sound device does not stop ringing due to operation.

[Brief explanation of the drawing]

FIG. 1 is a conventional sound stop circuit for a fire alarm, and FIG. 2 is a circuit diagram showing an embodiment of the present invention. L ₁ ~ _{L o} ...District relay, De...Fire detector,
B...Sound device, R...Sound stop relay, SW ₁
...Recovery switch, SW ₂ , SW ₃ ...Sound stop switch.

Claims (1)

[Scope of utility model registration request] In the acoustic circuit of a fire alarm in which a normally open switch that is closed based on the operating signal of a fire receiver and an acoustic device are connected in series between the power terminals, an acoustic stop switch and an acoustic stop relay with a self-holding function are used. 1. A sound stop circuit for a fire alarm, characterized in that a series circuit consisting of the following is connected in parallel to the above-mentioned sound device, and is configured to stop sound only when a fire receiver is activated.