| 摘要 |
PROBLEM TO BE SOLVED: To provide an alarm using sound and vibration in common that vibrates as a rigid body at an easily sensible vibration frequency although the alarm has a small-sized configuration. SOLUTION: In the sound-vibration common use alarm where an electroacoustic element is placed on a plate spring covering the lower opening of a cylindrical case and the ringer diaphragm of the element is covering the upper opening of the case, the plate spring 30 is formed to be an annular strip 32 surrounding a center hole 31 and spiral plate separation holes 33, 34, 35 laid out like three comma-shapes are formed to the annular-like strip 32. The natural vibration frequency can be decreased to a lower vibration frequency by punched parts formed by the three plate separation holes 33, 34, 35. Since an inner circumferential plate 36 is connected to an outer circumferential plate 37 via a plurality of spiral middle plates 38, the electroacoustic elements are separately suspended and supported, thereby increasing the support strength.
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