GB829776A - Improvements in servo-controls - Google Patents

Abstract

829,776. Fluid-pressure servomotor-control systems. SOC. D'APPLICATIONS DES MACHINES MOTRICES. March 19, 1956 [March 22, 1955], No. 8445/56. Class 135. In an hydraulic servo-system for aircraft control surfaces the pilot's control column is connected by a link 4, Fig. 1, and floating lever 5 to a piston 2 which moves in a cylinder 1 and is connected by a link 3 to the controlled surface. The piston 2 is controlled by a rotating regulating valve 6 actuated by a crank 7 connected by link 8 and floating lever 10 to the floating lever 5. The lever 10 is also connected at one end 13 by a link 14 to an auxiliary compensating mechanism which moves the link 14 in accordance with, e.g..the yawing speed of the aircraft. In a modification, Fig. 3 (not shown), the lever 5 is replaced by a triangular-shaped lever. In another example, Fig. 5, in which the aircraft has automatic pilot control as well as a manual control, the control column is connected via the levers 8, 51, 54, 65 and floating lever 10 to the actuating crank 7 of the regulating valve 6. The automatic pilot input enters at the link 64 which is connected via levers 59, 56 to the lever 54 in the above chain to the regulating valve 6. The compensating input enters via the link 14 which is connected to the floating lever 10. The compensating mechanism may be of the type shown in Fig. 4 comprising a motor 44 the angular movement of which is transmitted via the reduction gear train 45 and the epicyclic gear 46 to the crank 39 connected by linkage to the actuating crank of the valve regulator. The crank 39 moves against the force of a spring 47 to an extent limited by stops 48, 49 and may be locked in a neutral position by an electromagnetically-controlled plunger 50. Normally the cage of the epicyclic gear 46 is locked by a plunger 57 but when the crank 39 is locked the cage is freed for idle rotation.