GB145180A - Improvements in and relating to airscrews - Google Patents

Abstract

145,180. Ireland, A. J. T. April 4. 1919. Screw propellers.-In screw propellers with cylindrical or cored roots adjustably engaging sockets in the boss, a multiple-part collar and uninterrupted ring are used to encircle the portions of the blade root. The blades are formed from two metal sheets welded together, and to the flanges 8 are secured the metal roots which are in two pieces and have half-cylindrical extensicns 11 with flanges 12, 13, Figs. 1, 2. The blades are kept in the bosses 14 of the propeller hub by two half-rings 15 which are encircled by the ring 16, a flange 18 holding the coned portion of the pieces 15 up against a corresponding bevel on the hub. At the inner end, a plain ring 20 is provided. For adjusting the pitch, the cap 21 carried by a pin 24 mounted in a curved slot has a projection 22 adapted to engage a slot 23 in the blade root. For ready adjustment, the pin 21 is engaged by a right-angled lug on a ring, the ring having a second pin which passes through a slot in the front face of the propeller hub. For securing the second pin, the washer of the securing-nut and the face of the hub are serrated. In a modification, the ring has teeth which engage pinions on the first pins. Further, the pins may be fixed at right-angles to the blade roots and project through the blade bosses and engage a radial slot in a disk on the propeller shaft. When wooden blades are employed, the root is coned and surrounded by a three part sleeve upon which the internally coned two part collar seats itself. Specification 132,070 is referred to.