| 摘要 |
High volume, belt-driven ventilation fans in which the bladed propeller assembly and the drive motor are operationally mounted upon a unitary structure. In one form of the invention a box-fan comprises a generally cubicle, or parallelepiped housing. In an alternative barrel fan the tubular housing is cylindrical. Both fans comprise a pair of rigid, vertically upright, parallel rails within their interior. A rigid, X-profiled mounting unit is fastened between the rails to mount both the propeller and the motor. The unitary mount comprises a rigid, central mandrel that coaxially receives the propeller assembly axle. Pairs of diverging arms extending away from each side of the mandrel are fastened to the rails within the fan interior. One of the arms pivotally supports a deflectable wing upon which the motor is mounted. The propeller assembly comprises a pulley-driven blade centered within the housing and an axle captivated within the mandrel. The motor drives a pulley mechanically coupled to the fan pulley with a V-belt. The axis of the wing's hinge, the axis of motor rotation, and the axis of rotation of the fan propeller are all parallel. A coiled spring biases the wing away from the mandrel, automatically tightening the belt as the motor borne by the wing is varied in position relative to the propeller axle in response to dynamic variables like start-up tension, load changes, aging, wear, and normal operational drive fluctuations. At all times proper drive belt tension is maintained.
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