BACKED-UP ELECTROHYDRAULIC ACTUATOR Russian patent published in 1995 - IPC

FIELD: aircraft facilities; backed- up power actuators for electric remote control systems of aircraft. SUBSTANCE: backed-up electrohydraulic actuator has hydraulic cylinder 1 with feedback pickups 2, distributor with twin power spool 3, multichannel servo unit with multichamber slave mechanism 4 and feedback pickups 5, locking mechanism 6 and differential bell-crank 7. Locking mechanism 6 has two two-step plungers 17 and 18 arranged in line in housing 16 and furnished with stops 19 and 20. Under the action of control signal electrohydraulic power amplifiers 10 and 11 distribute synchronously the flow of working fluid through cut-in operating valves 8 and 9 and hydraulic lines 12, 13, 14, 15 delivering the fluid into working spaces of slave mechanism 4 and providing displacement of slave mechanism rod and power spool 3 through value corresponding to control signal. EFFECT: enhanced reliability owing to provision of middle position of power rod in case of failure of electrohydraulic control channels. 3 cl, 1 dwg