Improvements in control mechanism

摘要

1,083,156. Releasable fastenings. GENERAL ELECTRIC CO. May 17, 1965, No. 20692/65. Heading E2A. [Also in Divisions F1 and F2] To prevent loads on a member 36, movable between two extreme positions by a doubleacting linear actuator 51, from being fed back to the actuator, the linkage connecting the actuator to the member 36 comprises a rightangle bell-crank 58 pivoted at 62 to the member 36 and having one arm 60 pivoted to a rod 54 of the actuator while the other, longer arm 61, which is substantially parallel to the rod 54 and to the direction of movement of the member 36, carries at its end a pin 64 engaging in a Z-shaped fixed cam slot 72. With the member 36 in either extreme position, the pin 64 rests in a respective one of the ends 74, 75 of the slot 72 so that a load on the member 36 causes a purely axial load in the arm 61, and is reacted by the slot 72. A force applied by the actuator on the bell-crank 58 first rotates the latter to move the pin 64 into a main portion 73 of the slot 72, the member 36 then being free to move until the pin 64 reaches the other end of the slot 72 and is brought into the other locking position by rotation of the bell-crank. The cam slot 72 is formed in parallel plates 77, 78 one on either side of the arm 61, and spring clips 80 may be provided at the ends of the slot to locate the pin 64 in its locking positions. The invention is applied to the control linkage of movable final stage stator blades in the compressor of a jet engine, (see Division F1), the member 36 forming a ring about the engine casing.