| 摘要 |
The water-proof horn has an open/close unit to be closed in usual time and to be opened when emitting alarm sound by use of a switch so that it may prevent water or abnormal substances from entering. It comprises a solenoid(11) assembled with a back-and-forth action rod(9) supported by a coil spring; a packing wheel(13) installed on end of the back-and-forth action rod(9) with separable water proof packing ring(6).
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