JPS6319912Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a fire detector for home use that includes a battery power source, a fire detection circuit, and an alarm such as a buzzer.

Traditionally, this type of household fire detector, known as a single station, is powered by a built-in battery to monitor fires, and it typically operates for a period of approximately one year without having to replace the battery. Fire detection operation can be performed. In addition, when the battery voltage drops below a specified voltage, a so-called low battery alarm, which can be distinguished from a fire alarm, is issued to prompt the battery to be replaced, in order to minimize malfunctions caused by insufficient power supply voltage. ing.

By the way, the low battery alarm that is issued when a drop in battery voltage is detected is a one-off buzzer that sounds, for example, at regular intervals, and continues for about a week until the battery is completely exhausted. It will be held on.

Therefore, even if the battery voltage drops, the low battery alarm will not stop unless the battery is replaced.
Since the sound is emitted day and night, it can be too noisy for the user, and there is a problem that the user has no choice but to remove the battery if the sound suddenly starts, especially in the middle of the night. .

To solve this problem, for example, it is possible to install a light sensor in the detector so that the low battery alarm is issued only during the day, and the alarm is issued only when light is detected, but the brightness of the ceiling surface in each home There are various types of warnings, and it is difficult to ensure that the warning is issued only during the daytime.

The present invention was developed by focusing on these conventional problems, and solves the above problems by making it possible to issue a low battery warning only during a predetermined time period using a time setting circuit. The purpose is to

Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 is a block diagram of a fire detector according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing in detail a specific example of the time generating circuit of FIG. 1. First, the configuration will be explained. In Fig. 1, 2 is a time setting switch that sets the start time of the time period in which the low battery alarm is issued; 4 is a time signal that is output to output A, and output B is inverted only during the time period set by time setting switch 2; For example, in this embodiment, a time generating circuit 6 outputs a gate signal (which remains at a high level for only one hour from the set time), which detects when the voltage of the battery power supply drops below a certain level, and detects it at regular intervals. 8 is a fire detection circuit that detects the occurrence of a fire and generates an alarm signal, 10 is an AND gate, 12 is an OR gate, and 14 is a time signal buzzer.
BZ ₂ , 16 is a buzzer for fire/low battery BZ ₁
It is. In FIG. 2, 20 is a time setting circuit that converts the time signal inputted through the contacts selected according to the time set by the time setting switch 2 into digital data and outputs it, and 22 is a time signal signal similar to an ordinary watch. For example, it generates an output signal such as ringing a buzzer once at 1 o'clock and twice at 2 o'clock, and also outputs a time advance pulse at regular intervals (in this example, every hour at the same time as the time signal). A clock circuit 24 generates digital time data, one input of which is connected to the digit line 2.
1 to the output of the time setting circuit 20,
The other input is connected to the output of the clock circuit 22 via the time data line 23, and digital data (time setting data) is input as a reference value from the time setting circuit 20, and time data is input from the clock circuit 22. A comparator 26 which compares both signals and outputs a time setting pulse when they match, has a set input S connected to the output of the comparator 24 to input the time setting pulse, and a reset input R connected to one side of the time circuit 22. This is an RS flip-flop (RS/FF) connected to the output of the RS flip-flop (RS/FF) to input a time-feeding pulse, and configured so that when pulses are applied to the set input S and reset input R at the same time, the set input S takes priority. Circuit 2 excluding time setting switch 2 shown in Figure 2 above
0, 22, 24, 26 are time generating circuits 4 in FIG.
Configure. Incidentally, the buzzers BZ ₁ and BZ ₂ in FIG. 1 may be a bell or other time signal or alarm device.

Next, the operation of the circuits shown in FIGS. 1 and 2 will be explained with reference to the timing diagram shown in FIG. first,
Set the time setting switch 2 to a desired time, for example 8am. The time setting switch 2 used in this embodiment is a rotary switch having at least 24 contacts, and when set at 8 a.m., the contact at the corresponding position and common are connected, and the time setting circuit 20 in FIG. It is connected to the input corresponding to 8 o'clock and starts transmitting a signal. This set time is the start time of the low battery alarm, and essentially it can be set at any time the customer desires, but in this embodiment, in order to simplify the design, the clock circuit 22 In order to start the low battery alarm according to the time signal of 1.
It is possible to set only the hour to 24 hours (there is no setting for the minutes in between). Incidentally, the time may be set by a vendor at the factory or at the time of sale to a customer, or may be set by a wire connection or the like instead of a rotary switch. Next, the time setting circuit 20 which received the input at 8 a.m. inputs the 8 a.m. input to the digit line 21.
Outputs binary digit data “01000” as time setting data. On the other hand, the clock circuit 22 is a normal clock circuit, and outputs an ordinary time signal to the terminal A (same as the output terminal A of the time generating circuit 4 in FIG. 1), that is, as shown in FIG. At times, one pulse is generated, at two times, two pulses, etc. are generated, and one hour-feeding pulse is output to the output line 27, and a digital signal corresponding to each time is output to the comparator 24 via the digit line 23. Outputs time data. That is, at 8 a.m., eight time signal pulses are output to terminal A, one time advance pulse is output to reset input R of RS flip-flop 26 via output line 27, and digital data "" is output to comparator 24. Outputs 01000”8. Since the comparator 24 has already received the digital data "01000" 8 as a reference signal from the time setting circuit 20, when it receives the time data 8 from the clock circuit 22, it outputs the set input of the RS flip-flop 26 via the output line 25. A time setting pulse indicating a match is output to S. As described above, the flip-flop 26 is set on when pulses are simultaneously input to the set input S and the reset input R, so its Q output (also terminal B) is output at 8 a.m. as shown in FIG. reach a high level in time. The output terminals A and B in FIG. 2 are the same as the output terminals A and B of the time generation circuit 4 in FIG. activates the time signal buzzer BZ ₂ 14 to sound the time signal 8 times. On the other hand, the Q output (FIG. 3) of the RS/FF 26 output from the terminal B is connected to one gate of the AND gate 10 to open the AND gate 10. Since the output line 7 of the low battery detection circuit 6 is normally at a low level, the AND gate 10
normally does not work anymore. However, once the battery voltage drops below a certain level,
The low battery detection circuit 6 detects this and sends a low battery alarm signal, which is a continuous pulse at regular intervals, to the AND gate 10 as shown in FIG.
Output to. Therefore, from the output of the AND gate 10, only the low battery alarm signal after 8 a.m. is output, as shown in FIG. 3 and FIG. On the other hand, since the output line 9 from the fire detection circuit 8 is normally at a low level, it does not affect the OR gate 12.
Therefore, the OR gate 12 uses only the alarm signal from the AND gate 10 as a fire/low battery buzzer.
It outputs to BZ ₁ 16 and activates it, causing the buzzer to sound for the duration of the pulse width. The interval between pulses of the low battery alarm signal may be set in any manner, but it is sufficient to set the alarm to be issued once every 5 to 10 minutes. On the other hand, if a fire occurs, the fire detection circuit 8 detects it and outputs a high level to the OR gate 12 via the output line 9. The OR gate 12 outputs a fire detection signal to the buzzer 16 and causes it to sound regardless of the presence or absence of the low battery alarm signal. When one hour has passed and it reaches 9:00 a.m., the clock circuit 22 outputs time data of a time signal (9 pulses), a time advance pulse, and a digit pulse 9. At this time, the two inputs to comparator 24 are digits 8 and 9, respectively.
Therefore, they do not match, and the time setting pulse to the set input S of the RS/FF 26 is not output. Therefore, only the time feed pulse is the reset input R of RS/FF26.
is input to reset the RS/FF26.
The Q output (terminal B) of the RS/FF 26 falls to the low level again, as shown in FIG. 3, and the AND gate 10 is closed. Therefore, after that, the AND gate 10 does not output the low battery alarm signal as shown in FIG. The alarm buzzer will not sound.

In the embodiment described above, the time setting switch 2
Although it is possible to freely set the time period (start time) during which the low-battery alarm can be sounded, there are cases where there is a common time when it is allowed to sound, for example, if it is happening in every household and there is a large If it is clear that most people prefer the time between 8:00 a.m. and 9:00 a.m., the low battery alarm may be set in advance at the factory at 8:00 a.m. so that it sounds only during that time. In that case, the time setting switch 2, the time setting circuit 20, and the comparator 24 do not need to be used, but only the clock circuit 2
2, store 8:00 a.m., and connect the clock pulse to the set input S of flip-flop 26 at 8:00 a.m., and set the RS/
All you need to do is set the FF26 so that the low battery alarm sounds only between 8am and 9am.

As explained above, according to the present invention, it is possible to set the desired low battery alarm time by using the output of the clock circuit and adding a very simple circuit, and the low battery alarm is activated only within the set time. This prevents the low battery alarm from sounding during quiet times such as at night and causing trouble to the user and those in the vicinity. Furthermore, by listening to the time signal of the clock circuit used in the present invention, it is possible to recognize in ordinary life that the fire detector is operating normally.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a fire detector according to an embodiment of the present invention, FIG. 2 is a circuit diagram showing a detailed example of the time generating circuit of FIG. 1, and FIG. 3 is a timing diagram of the operation of the circuit of FIG. 3 and FIG. 2; 2... Time setting switch, 4... Time generation circuit, 6... Low battery detection circuit, 8... Fire detection circuit, 10... AND gate, 12... OR gate, 14... Buzzer (for time signal), 16... ...Buzzer (for fire/low battery), 20...Time setting circuit, 22...Clock circuit, 24...Comparator,
26...RS flip-flop.

Claims (1)

[Scope of utility model registration request] In a fire detector that has a battery power source and activates an alarm to issue a fire alarm when it detects a physical change associated with a fire, it detects and outputs when the voltage of the battery power source drops below a predetermined value. The present invention is characterized by comprising: a voltage drop detection circuit for detecting a voltage drop, a gate circuit for inputting the output of the voltage drop detection circuit to an alarm at a predetermined time period, and a time setting circuit for setting a permissible output time period for the gate circuit. fire detector.