GB279470A - Improvements in and relating to flying machines, helicopters and the like - Google Patents

Abstract

279,470. Perrin, E. A. Oct. 22, 1926, [Convention date]. . Screw and like propellers.-A helicopter supported by a single screw is provided with means for cyclically varying the pitch of the screw blades and means for varying the pitch of the screw as a whole. The blades of the propeller are pivoted about a tubular cross-piece 81 on a tubular shaft 54 which is surrounded near its lower end by a sleeve 59 carrying pawls 56 engaging a ratchet on a casing integral with a gear wheel 53 in mesh with a gear wheel 52 on the engine shaft. The sleeve 59 has a ring 60 notches to receive the ends of two levers 66 pivoted about a belt 67 extending through the shaft 54 and the lower ends of the levers engage inclined slots 68 in a sleeve 69 which can slide without relative rotation upon the shaft 54. When. this sleeve 69 is moved by a hand-lever 72 the sleeve 59 is turned relatively to the shaft 54 and this motion is transmitted to a tubular shaft 74 by means of a bolt 73 extending through oval holes in the shaft 54. The upper end of the shaft 74 carries a bail having cranked portions entering a ring 76 which carries arm 77 connected by short links to the under surfaces of the screw blades, so that the rotary movement of the shaft 74 is transmitted to the ring 76 and the pitch of the blades is varied equally. A joystick M is connected bv a link 141 to arm ML on a cross shaft having a lever 119 which moves a rod MLV connected through levers 131, 132 and rod OT to mechanism for moving a, frame 145, Fig. 13. This frame carries rollers 144 bearing on the ring 76 whereby the ring is displaced to cause a cyclical and opposite variation of the pitch of the screw blades which is a maximum as the blades pass through the transverse plane of the machine. This frame is also displaced through a, conection to the upper end of' the lever 131 when the hand-wheel 109 is turned, but at the, same time the bell crank 115 moves the rod MLV nearer to or further from the pivot of the lever 119 so that at high speeds the rod MLV is not movable by the joy-stick M. Lateral movements of the joystick M are transmitted through a rod 140, arm MT, and rod OL to arms 148, Fig. 13, connected to a sleeve 149 through which rods on the frame 145 can slide when moved by the rod OT. Movement of the rod OL moves the frame in a direction at right angles to that caused by the rod OT.