JPH0228559Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Industrial application field] This invention is a small product that produces a loud alarm sound, such as for reversing automobiles, fire outbreaks, marine accidents, lifting cranes of construction vehicles, and theft prevention. It is related to alarm devices that can be used for necessary purposes.

[Prior Art] It has been desired for this type of alarm device to effectively generate a loud volume compared to the size of the alarm device and the amount of electricity supplied to the alarm device.

[Problems to be Solved by the Invention] An object of the present invention is to provide an alarm device that can satisfy the above-mentioned demands.

[Means for Solving the Problems] The means of the present invention is to provide a ring part with a plurality of large holes in the center of the front plate of a case in which a diaphragm is fixed, and to attach a ring part to the front plate around the ring part. Small holes are interspersed with holes, and protrusions are provided on the entire inner circumference of the annular portion to concentrate the sound generated by the diaphragm and reflected on surfaces other than the large and small holes. That's true.

[Example] In the figure, 1 generally shows the alarm device of the present invention, 2 is a case body with a diaphragm fixed therein, and the diaphragm 3 is arranged parallel to the front plate of the case body 2 at a constant distance. Set up A piezoelectric element 4 is closely fixed to the center thereof. A ring part 10 is formed in the center of the front plate of the case body 2, large holes 5, 5 are provided in four places in the ring part 10, and small holes 5' are provided on the outer periphery of the ring part 10.
are drilled in some places. What is important in this invention is that the ratio of the total opening area of the large holes 5, 5 and the small holes 5', 5' to the total area of the front surface is relatively small, and that the openings are concentrated in the center. The purpose is to form a convex portion 6 projecting inward on an annular portion 10 having large holes 5, 5.

Reference numeral 7 denotes an amplifier, which is installed at the rear inside the case body 2, and whose output side is electrically connected to the diaphragm 3 through a conductor 8. Reference numeral 9 indicates a urethane coating, which is filled to fix and protect the components of the amplifier 7.

[Function] The pulses generated by the amplifier 7 are supplied to the diaphragm 3 via the conductor 8, and the diaphragm 3 vibrates at a constant frequency to generate sound. Since the surfaces other than the ′ and 5′ portions act as a sounding plate, the reflected sound and the sound emitted from the diaphragm 3 resonate and become loud. In addition, the protrusions 6 have the effect of concentrating the above-mentioned echoes and further increase the resonance effect.As shown in the graph of Figure 3, the experimental results show that the maximum frequency of the conventional product was 2300 Hz, while that of the present invention. is 2400Hz, which is 100Hz higher than that.

The measurement specifications are as follows.

Measurement item: Measurement of sound volume when using a resonator Resonator: 1 piece each Piezoelectric element: 1 piece As for the sound volume of a piezoelectric element, there are differences depending on the instruction method, so there are 2 types of resonators, 1 piece of a resonator suppressor, and a piezoelectric element. It is one piece. One piezoelectric element was supported under the same conditions.

Measuring distance 120cm 120cm above ground Measuring equipment Indicating sound level meter, frequency meter, millibar meter, oscillator, power amplifier [Effect] The front surface of the case body is relatively wider than the large and small holes as a reverberation board, and the above-mentioned front surface By forming inwardly protruding protrusions on the edges of the large holes concentrated in the center, the sound volume generated by the diaphragm is very effectively magnified and emitted to the outside. That is, if the hole itself for emitting sound to the outside is too large or too small, the required sound pressure cannot be obtained. Generally, the structure is such that the sound is emitted only from the center hole, but the alarm of the present invention utilizes the reverberation sound generated between the diaphragm 3 and the annular portion 10, so it has a large size. Since the area of the holes 5 is made smaller than the required area and the remaining area is compensated for by the small holes 5' on the outer periphery, a good balance can be achieved between drainage of rainwater and directivity of sound. In addition, the protrusion 6 on the inside of the annular portion 10 acts as a partition between the reverberant sound generated between the diaphragm and the annular portion, which comes out from the large hole in the center, and the sound that comes out from the small holes on the outer periphery. However, it is possible to prevent the effect of reducing sound pressure such as "chattering sound" due to duplication.

[Brief explanation of drawings]

The drawings show an embodiment of the alarm device according to the present invention, and FIG. 1 is a front view, and FIG. 2 is taken along A-A in FIG.
A cross-sectional view taken along the line, FIG. 3 is a graph comparing the sound volume between the alarm device of the present invention and a conventional product. 2...Case body, 3...Diaphragm, 5...Large hole, 5'...Small hole, 6...Protrusion.

Claims (1)

[Scope of utility model registration request] A ring part with multiple large holes is provided in the center of the front plate of the case with the diaphragm fixed inside, and small holes are dotted in the front plate around the ring part. An alarm having protrusions protruding around the entire circumference of the inner surface to concentrate the sound generated by the diaphragm and reflected on surfaces other than the large and small holes.