| 摘要 |
PURPOSE:To obtain a buzzer having no sound-pressure variation caused by change of environment, by constituting a resonance device by a buzzer frame wherein a sound release plate and a sound release hole are provided in a buzzer of an electronic alarm clock. CONSTITUTION:A vibrating plate 17 is placed on a supporting frame 16 for an exciter 15 and is coupled to a buzzer frame 18 to which the edge of a sound release plate 19 is welded. The vibrating plate 17 and sound-release plate 19 are connected by an air spring. The buzzer frame 18 constitutes a Helmholtz's resonator with accoustic capacity of an air chamber 25 and inertance of the sound release hole 22, thereby the sound pressure of the buzzer is increased and the bandwidth is expanded. The buzzer is fixed to a case 26 by a packing 23 which is placed around a protruded portion 21 of the buzzer frame 18, a middle frame 34, and a packing 36, and electrical connections are made by lead plates 29 and 30 and a back cover 33. |
