| 摘要 |
PURPOSE:To inform a wearer of the soundproof ear cover of an alarm and sound pressure respectively exceeding regulated values while to prevent the use of the device in the state of not obtaining a desired soundproof effect by providing an electric circuit which triggers an alarm device in case of such excess at a proper point of the soundproof ear cover. CONSTITUTION:Soundproof material layers 2 consisting of synthetic resin sponge, etc., are internally mounted within cup-shaped sheaths 1 of the soundproof ear cover and cushion members 3 are mounted at the peripheral end edges of the cup-shaped sheaths 1. A microphone 4 which senses the sound pressure on the inner side of the soundproof ear cover is mounted to the inner side of the soundproof material layers 2. An alarm buzzer 5 and alarm lamp 6 as well as the electric circuit 7 and power source battery 8 both of which compare the electric signal from the microphone 4 with a reference value for comparison and trigger the alarm buzzer 5 and the alarm lamp 5 when the level thereof exceeds the reference value for comparison are disposed between the cup-shaped sheaths 1 and the soundproof material layer 2. |
