GB352260A - Automatic pitch adjusting device for variable pitch screw propellers and rotating wings - Google Patents

Abstract

352,260. Screw propellers. SOC. ANON. DES ATELIERS D'AVIATION L. BREGUET and BREGUET, L., 115, Rue de la Pompe, Paris. July 12, 1930, No. 21184. [Class 114.] In automatically variable pitch screw propellers, the boss is displaceable axially on and rotatable through a small angle around the propeller shaft and the blade is connected with a projection on the shaft so that its pitch is varied automatically as the boss moves in relation to the shaft and in accordance with the ratio of the tractive effort to the driving couple of the propeller. In one form the boss 2 has a projection 13 carrying a roller 12 which is in contact with a cam face 11 on a fixed sleeve on the propeller shaft 1. The roller 11 thus communicates the drive from the shaft to the roller whilst allowing the boss the two degrees of freedom. A propeller blade 3 pivotally mounted in a socket on the boss has an arm 7 engaging at 8 with a projection 9 from the shaft whereby its pitch angle is varied as the propeller boss 2 takes up new positions. In another form the driving shaft 30 is keyed to a cylindrical member 31 upon which the boss is freely mounted. Keyed to this member are cross members 34, 35 which are coupled by rods 36, the member 34 having pins 52 which project into curved slots 51 in the pitch-adjusting arms 50 pinned to a projection on each blade root. The coupling rods 36 have pins 56 with self-adjusting ball races for driving rods 53 which at their other ends are similarly connected to pins 57 on sockets 42 carrying the blades.