| 摘要 |
<p>The fan hub (1) has a curved outer surface (4) on which are mounted radial or axial flow blades (6). Each blade has a vane shaft (7) which passes through the outer annulus (4) of the hub and an internal lug (5) of the hub within which it can pivot. The shaft carries an eccentric weight (8) and a cam (9) at its lower and and is also attached to one end of a spring (30) which pulls it to bring the blade into its feathered position. When the fan starts rotating the centrifugal force on the weight (8) has a tangential component which turns the blade against the spring force and brings it into its operating position. The feathered position is set by the cam (9) acting against an adjustable sleeve (23).</p> |
