| 摘要 |
PURPOSE:To provide the excellent ventilating fan, capable of effecting not only the opening of a shutter but also the closing of the same quickly, by a method wherein the shutter is opened by a shutter operating member consisting of a shape memory alloy and airflow, generated by the vane of a fan, is collided against the shutter operating member to continue the conduction of a motor during a period till the transformation of returning of the shutter operating member. CONSTITUTION:A secondary voltage is induced in the secondary coil 21b of a transformer 21 simultaneously with the starting of a motor 2 and the rotation of the vanes 4 of the fan while the shutter operating member 14 is conducted by the secondary voltage, the operating member 14 generates heat by an electric resistance possessed by the member 14, the shape memory alloy generates the transformation of shrinkage and a connecting rod 6 is pulled down to open the shutter 5. The conduction of the motor, which drives the vanes 4, is still continued after opening a conducting circuit operating the shutter operating member 14 until the transformation of returning of the shutter operating member 14 is generated, and the collision of the airflow against the shutter operating member 14 is continued; therefore, the shutter operating member 14 may be cooled quickly to promote the transformation of returning of the same, whereby the closing of the shutter 5 as well as the control of driving of the vanes 4 may be effected together quickly.
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