| 摘要 |
PURPOSE:To provide the prominent ventilating fan, inexpensive and capable of opening a shutter quickly, by a method wherein the shutter is opened by a shutter operating member consisting of a shape memory alloy and large electric current is made to flow in a conducting circuit when the shutter is opened while the conducting circuit is switched to pass small electric current when the opened condition of the shutter is to be maintained. CONSTITUTION:A motor 2 is conducted to start the rotation of vanes 4. A secondary voltage, induced in the secondary coil 17b of a transformer 17, is impressed on the shutter operating member 12 and the member 12 generates heat. When the temperature of the shape memory alloy has arrived at the temperature of transformation by the heat generated, shrinkage transformation is generated and a connecting rod 6 is pulled down through a pull rod 11 and a connecting ring 13 to open the shutter 5. A microswitch 10 is pushed by descent of the pull rod 11 through the operating recess 14 of the switch, and a resistor 18 is conducted, causing a voltage decrease; then, a small electric power necessary for maintaining the opened condition of the shutter 5 is consumed. Accordingly, a big power is not necessitated for the opening operation of the shutter and whereby the shutter may be opened quickly and the ventilating fan may be used economically.
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