| 摘要 |
<p>A drain outlet (40) is formed on a housing (20) of a hole plug (10), and a shaft (44) of a flap valve (42) is pivotally supported in a rotatable manner by a bearing (47) in the housing (20). A coil spring (50) is disposed on the bearing (47) of the housing (20), and when the quantity of water inside the housing (20) increases, the flap valve (42) rotates against the biasing force of the coil spring due to water pressure, opening the drain outlet (40), thereby draining the water.</p> |
