GB490572A - Improvements in or relating to automatic steering devices for vehicles, in particular aircraft - Google Patents

Abstract

490,572. Fluid-pressure servomotorcontrol systems. SIEMENS APPARATE UND MASCHINEN GES. Sept. 20, 1937, No. 25488. Convention date, Sept. 18, 1936. [Class 135] In automatic steering devices for vehicles, especially aircraft, in which the rudder or other steering member 20 is adjusted by a pneumatic or hydraulic servomotor 17 provided with return or follow - up mechanism 15, a pressure responsive member 22 which is subject to a pressure differential dependent upon the control force is interposed between the servomotor 17 and the mechanism 15. As shown, a floating lever 15 is linked to a control valve 16 and to a further floating lever 12 connected at one end to a gyroscopic turn indicator 2 and at the other end to a rotary magnet 10 connected to contacts 7, 8, 9 on a compass 1. The lever 15, instead of being directly connected to the piston-rod 19 so that the inclination of the rudder or the travel of the servomotor bears a linear relation to the steering impulse or the travel of the end of the lever 15, is connected to a piston 22 normally centralized by springs 23, 24 which may be inside or outside the cylinder 21. The deflection of the rudder is thereby increased so as to produce the necessary moment for righting the craft after the deviation which produced this rudder deflection. This is shown graphically in the Specification. The compass housing 6 is adjusted by a worm 5 on a shaft 4 which also operates an indicator 3. The piston and cylinder 22, 21 may be replaced by a bellows subject to the differential pressure on its opposite sides. An isodromic device consisting of a dashpot piston and cylinder may be interposed between the piston 22 and the lever 15. The resultant pressure acting on the piston 22 may alternatively be converted into an electrical valve for controlling the valve 16.