| 摘要 |
An improved fan for moving air unto or out a building having a shutter operated by a novel centrifugal mechanism engineered for high precision and made up of a smaller number of parts and joints required to prevent looseness and vibrations even after long term use. The fan comprises a compact streamlined housing made of two identical parts connected together by means of a single member. The centrifugal mechanism is driven by the fan impeller and comprises an hermetic housing in which there are at least a pair of radial sliding masses pivotally connected to an axial sliding reciprocating actuator that, upon operation of the fan, can travel inwardly or outwardly said housing. When the fan starts to operate in either direction, the centrifugal forces of said masses pull said actuator toward said housing causing the opening of the shutter, when the fan stops the force of a spring pushes said actuator outwardly against the shutter causing its closing. |
