| 摘要 |
<p>A variable pitch propeller has blades (36), the position of which, at relatively low pitch angles is controlled by a beta valve through a lever (23) and a feedback collar (25), the position of the collar being controlled by a plurality of beta feedback rods (55). There is one rod (55) for each blade of the propeller, and the movement of the rods (55) is controlled by a blade yoke (50) which has arms (52) partially encircling the rods (55). A lost motion connection in the form of a sleeve (60) is carried on each of the rods (55) and is movable against a retraction spring (62) by the arms (52). A movable stop mechanism (75) engages the feedback rods (55) at a particular low blade angle position and temporarily interrupts the movement of the feedback rods (55) while the sleeves (60) move to a seated position against the retraction spring (62), and thereafter the movement of the rods (55) is again picked up, accompanied by movement of the stop mechanism (75) against a spring (80). The lost motion connection represented by the sleeve (60) permits movement of the blades under control of the beta feedback valve without accompanying movement of the feedback rod which causes a shifting of the blades to a still lower pitch position, thereafter followed by reclosing of the feedback valve with continued movement of the rods (55).</p> |
