| 摘要 |
PURPOSE:To prevent spoilage of a switchboard due to dust and also to improve maintainability by opening and closing intake ports by transmitting a change in the shape of a shape memory alloy due to an internal temperature of the switchboard to a perforated plate by a link mechanism. CONSTITUTION:When an internal temperature of a switchboard rises to a prescribed value or above, a shape memory alloy 7 senses this temperature and changes in the shape, making a perforated plate 5 slide through a link mechanism constructed of a lever 8, a fulcrum 9 and a hook metal fitting 52. In this way, louver holes 32 are aligned with holes of a multihole plate 5 and thereby intake ports 3 are opened. When the internal temperature of the switchboard lowers below the prescribed temperature, the shape memory alloy 7 senses this temperature and returns to the original state again, while the perforated plate 5 returns also to the original state and closes the intake ports 3. Accordingly, the intake ports 3 are opened only when the internal temperature of the switchboard, and thereby ventilation and cooling are conducted. |
