| 摘要 |
<p>A hub (1) through which the axis of the motor runs has a circular cog-wheel (2), provided with two stubs (11), which fits into a hollowed disc (3) also provided with stubs. Between these pieces fits a shaped piece of rubber (12). The feet of the three propeller blades (6) are held in the hub by two brass pieces (8) are provided with a conical cog-wheel (7) which acts with the circular cog-wheel. Under normal conditions the baldes are at maximum pitch but under pressure the cog-wheels allow the blades to rotate and reduce th epitch by compression of the rubber piece between the stubs of the circular cog-wheel and the disc, returning to maximum pitch as the pressure is reduced.</p> |
