GB412133A - Improvements in aeronautical metal propellers - Google Patents

Abstract

412,133. Air-screws. REED, S. A., 113, East 55th Street, New York, U.S.A. Jan. 11, 1934, No. 1138. [Class 114.] Variable pitch air-screws having separate forged metal blades with inner ends forked so that the branches are bent towards each other are adjustably mounted on the boss and connected to means under the pilot's control for adjusting the pitch. The propeller shaft carries a boss member 2 having pintles 17, 17<1> upon which the root member of the blade may be mounted. This comprises a block 19 with flanges 10 and restraining edges 21 about which the forked branches 15, 16 of the blade are disposed and to which they are secured by screws 23. The blade also has a bracket 24 having a hole 26 which also fits over the pintle 17 or 171. Further pins 29 on the main boss are adapted to carry levers 28, pinned at one end to part 25 of the bracket 24 and at the other to links 38, 37 which are carried by a ring 39. Movement of the ring longitudinally relative to the shaft results in an alteration in the pitch angle of the blades. This ring 39 is supported by U.shaped brackets 41 and 40 mounted in a pivoted forked lever 46. The lever 46 is connected with a chain 51 movable by the pilot through screw gearing and a handle 56. The lever 46 carries a plate 57 having holes 58 adapted to be engaged by a slidable rod 59 also under the control of the pilot through the medium of a cable 61. The pilot is thus able to lock the blades in any desired pitch position and has to release the lock before effecting a further pitch change.