| 摘要 |
The present invention relates to propeller blades which are mounted in a rotatable propeller hub and pivotable in the same by means of inner shafts with axes substantially radial to the axis of rotation of the hub and countersunk in said hub and located inside an outer peripheral edge of the same. The propeller hub is positioned in an shroud means, a tunnel or similar with a surrounding wall, which is substantially circular and concentric to the axis of rotation of the hub. The propeller blade has a blade vane with an outer edge with portions shaped as peripheral arcs concentric to the hub axis and having a play to the surrounding wall which is smaller than the necessary radial movement which is required for the lifting of said shaft over the peripheral edge of the hub when the propeller blade has to be demounted from the hub. According to the invention the peripheral arcs of the outer edge are limited to the front and rear portion of the edge while the centric portion extends inside the circle forming said arc shaped portions so that a play is formed between this centric portion and the wall of the shroud means when the blade is pivoted to a position in which the same is substantially parallel to the axis of the shroud. This play allows the blade to be moved in radial direction so that the shaft can pass said peripheral edge of the hub. With this arrangement a demounting and mounting of the propeller blade in axial direction is possible without removing the hub from the shroud means and without the negative influence on the propeller efficiency from an enlarged all over play between the outer edge of the blade and the wall of the shroud means. |
