JPH04274B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides, for example, when a large truck or the like makes a left turn.
The present invention relates to a double-tone generating device that can be used in left-turn alarms and the like that emit a warning sound when turning left in order to prevent accidents involving pedestrians and motorcycles.

It is well known that a left turn warning sound is generated in conjunction with the activation of a flasher when turning left, but the warning sound is required to be easily distinguishable from other warnings such as a horn or a backbuzzer.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a simple-structured and inexpensive double-tone generating device that can produce a double-tone tone.

An example will be described below.

In FIG. 1, 40 is a battery, and 41 is a well-known flasher relay. When the turn signal switch 25 is turned on to either the left or right side, the internal relay contact turns ON and OFF, and the left and right turn signal lamps (flash lamps) 28, 30 are turned on. It is now flashing. Reference numerals 26 and 27 are hazard switches, and when these switches are turned on at the same time, the left and right blinker lamps 28 and 30 flash at the same time.

24 is a lighting switch that is turned on at night, and 29 is a tail lamp, for example. 10
0 is a double tone generation circuit, which generates a double tone when the positive voltage of the battery 40 is applied to the terminal L of the power supply terminals L and R, and generates a double tone when a positive voltage is applied to the terminal R side. It's starting to not come out.

That is, when the turn signal switch 25 is turned to the left and the turn signal lamp 28 is turned on, a double beep is emitted, when the turn signal lamp 28 is turned off, no sound is emitted, and when the turn signal lamp 28 is turned on again, a double beep is emitted repeatedly. 25 is a turn signal switch, 251 is a movable contact, 252, 25
3 are fixed contacts on the left-turn and right-turn sides, respectively. 26, 27
is a hazard switch, and 24 is a lighting switch.

First, during the daytime (when the lighting switch is OFF), when the left turn switch is turned on (251 and 252 are short-circuited), current flows through the path of capacitor 1 → resistor 2 → transistor 3, turning transistor 3 on, and therefore transistor 6 turns off. At this time, a charging current flows through the capacitor 10 through the path of transistor 13→16→resistance 12→capacitor 10 (until charging is completed), and the buzzer composed of piezoelectric element 20 and transistor 13 emits a first reverberant sound.

Eventually, when capacitor 1 finishes charging, transistor 3 turns off, and transistor 6 turns on. As a result, a charging current flows through the capacitor 8 through the path of transistor 13→16→resistance 12→capacitor 8→transistor 6 (until charging is completed), during which time a second reverberation sound is generated.

At night, the lighting switch 24 is turned on, so no current flows through the diode 22, and the current flowing through the coil 17 is restricted by the resistor 19, resulting in lower sound pressure than during the day.

Also, in the event of a hazard, switches 26 and 27 are turned on at the same time, so terminals L and R of the left turn warning circuit 100
It does not work because there is no voltage difference between them.

In this embodiment, since the interval between two successive notes is determined by the capacitor 1, it has the advantage of being less susceptible to variations in the number of interruptions in flatness.

In this way, by combining with the existing flash relay, the double tones are repeated at a predetermined interval, so it is possible to easily generate a unique sound with a very high acoustic effect (for example, ping ping... ping ping... ping ping).

Also, in the drawings, 14, 15, 7, 9, 5,
4 is a resistor, and 21, 11, and 42 are diodes. Further, 17 is a boosting reactor, and the piezoelectric element 2 is
This is a known device that has the effect of increasing the zero amplitude and increasing the sound pressure.

Further, the resistor 18 is a resistor for temperature compensation of the transistor 16, and is also called a base leak resistor. To explain this effect, when the temperature of the transistor 16 increases, the temperature of the transistor 16 increases.
The leakage current flowing from the emitter of transistor 6 to the base increases, which causes transistor 16 to erroneously
Turning on may occur.

In order to prevent this, a bypass current is passed through the base leak resistor 18 from the resistor 18 to the resistor 12 to the capacitor 10 to prevent malfunctions due to the leak current. Therefore, the resistance value of the resistor 18 must be set low, but if it is set too low, the capacitor 1
0 is charged, the rise of the base current of the transistor 16, that is, the charging current of the capacitor 10, immediately after the power supply voltage is applied is reduced, and the sound pressure generated from the piezoelectric element 20 of the sound generating device is reduced, resulting in less timbre and crispness. The problem is that it becomes bad. Therefore, the resistance value of the base leak resistor 18 must be appropriately selected.

Next, a second embodiment of the device of the present invention will be described. As shown in FIG. 2, this second embodiment is simply the addition of a diode 18a to the circuit of FIG. 1.

Diode 18a is resistor 12 → transistor 1
Base of 6 → Emitsuta → Reactor 1 of the sounding device
This prevents the reverse current flowing through the path No. 7, thereby preventing the breakdown current between the base and emitter of the transistor 16, thereby prolonging the life of the transistor 16. This will be explained in detail below.

Since the sound generating device has a reactor 17,
When the transistor 16 is switched from ON to OFF, the reactor 17 generates a back electromotive force. The direction of this back electromotive force is from the transistor 13 to the transistor 16.

It has been found that as a reaction to this back electromotive force, a current momentarily flows from the resistor 12 to the base emitter of the transistor 16 to the reactor 17. This current also flows through the resistor 18, but there is a limit to how low the resistance value of the resistor 18 can be made as described above. Therefore, a breakdown current flows from the base of the transistor 16 to the emitter,
To shorten the life of the transistor 16.

For this purpose, a diode 18a is provided to block the breakdown current. It goes without saying that this diode 18 can also be provided on the base side of the transistor 16 or between the transistor 13 and the reactor 17.

As described above, in the second embodiment shown in FIG. 2, in a circuit that uses a PNP transistor 16 to drive a sounding device (including a normal electromagnetic buzzer) having a reactor portion having an inductance, there is a circuit from the base of the transistor 16 to the emitter. Since the diode 18a is provided to block the onward breakdown current, the life of the transistor can be extended.

It should be noted that the present invention can be used not only as the above-mentioned flasher-linked left-turn sounder, but also as an alarm for the occurrence of an abnormality in a vehicle, for example.

Furthermore, in each of the above embodiments, the self-oscillation piezoelectric sounding device composed of the transistor 13, piezoelectric element 20, boosting reactor 17, etc. is well known, and its operation will be omitted. Moreover, a normal electromagnetic buzzer or the like can be used as the sounding device.

As described above, in the present invention, it is possible to generate two consecutive tones, that is, double tones, with a simple circuit configuration, and therefore it is possible to easily generate a resonant sound different from continuous tones. This has the effect of making it possible to construct a unique acoustic means for arousing attention at low cost.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram showing one embodiment of the apparatus of the present invention, and FIG. 2 is a partial electric circuit diagram showing the second embodiment. 16...Transistor, 10...First capacitor, 8...Second capacitor, 6T...Delay switch circuit, L...Power supply voltage application terminal.

Claims (1)

[Scope of Claims] 1. The first capacitor 10 and the second capacitor 8 connected to the base of the alarm circuit driving transistor 16, and the second capacitor 8 connected to the base of the transistor 16 for driving the alarm circuit, are turned on.
A delay switch circuit 6T is provided to flow the charging current of the second capacitor 8 through the capacitor 8 and the base of the transistor 16, and when the power supply voltage is applied, the transistor 16 is turned on by the charging current of the first capacitor 10. and the transistor 1
6 turns off, the delay switch circuit 6T
In order to charge the second capacitor 8 and turn on the transistor 16 again, the first capacitor 10 is turned on after the power supply voltage is applied.
A double tone generating device characterized in that a delay time from application of the power supply voltage until the delay switch circuit 6T is turned on is longer than the ON time of the transistor 16 due to charging. 2. The double tone generating device according to claim 1, wherein an intermittent voltage is applied to the power supply voltage application terminal L to which the power supply voltage is applied via a flasher relay 41.