Piezoelectric sounder

Abstract

A piezoelectric sounder quickly discharges water when such water enters and eliminates the influence of water or moisture thus intruded. A cylindrical case with a closed bottom is made of glass-fiber reinforced polyester resin, a metal vibrating plate with a piezoelectric ceramic disk mounted on it is fixed on a graded step formed inside the cylindrical case with a closed bottom using a silicon type adhesive, and a conductive layer and the disk-like metal vibrating plate are contacted with two connection terminals. On a circumference side of the case, at least one opening serves as a sound releasing hole and a water drain hole and silicon varnish is coated on at least the surface where the piezoelectric vibrator contacts the two terminals. This sounder has no sound hole at the bottom and even when water drops enter, water is discharged through the opening extended to the bottom of the case. Silicon varnish is coated on at least the surface of the piezoelectric vibrator with which the two connection terminals are in contact so water has no effect. The side of the metal vibrating plate where silicon varnish is coated may be water-tightly fixed on the graded step formed inside the cylindrical resin case using a silicon type adhesive, and the sound and water releasing hole opening on the circumference side of the case may extend from the graded step in the cylindrical resin case toward the bottom thereof.

Dependencies are inferred from the claim text.