Patent ID: 8596575

Claim:
A hydraulically operated aircraft actuator for driving a control surface ( 100 ) of an aircraft, comprising: a plurality of tandem actuators ( 11 , 12 ) each including two pistons ( 21 a , 22 a and 21 b , 22 b ) and a piston rod ( 23 a , 23 b ) that is arranged such that the two pistons ( 21 a , 22 a and 21 b , 22 b ) are aligned in series, wherein the plurality of tandem actuators ( 11 , 12 ) are disposed in parallel, and wherein the plurality of tandem actuators ( 11 , 12 ) are hydraulically connected to each other via a plurality of hydraulic fluid communication passages (e.g., 31 a , 31 b ; 32 a , 32 b ; 42 a , 42 b ; 43 a , 43 b ), each of the plurality of tandem actuators ( 11 , 12 ) is provided with a case portion ( 24 a , 24 b ), inside of which two piston movement areas ( 25 a , 25 b and 26 a , 26 b ) are defined so as to be aligned in series along the piston rod, each of the piston movement areas ( 25 a , 26 a and 25 b , 26 b ) being provided as an area in which the piston is moved and that is divided by the piston into a first hydraulic chamber (e.g., 27 a , 27 b and 28 a , 28 b ) and a second hydraulic chamber (e.g., 29 a , 30 a , and 29 b , 30 b ), a rod end portion ( 13 ) is further provided that couples the respective piston rods ( 23 a , 23 b ) of the plurality of tandem actuators ( 11 , 12 ) on the outside of the case portions ( 24 a , 24 b ) and that can be rotatably linked to the control surface ( 100 ), and, for each of the plurality of tandem actuators ( 11 , 12 ), the first hydraulic chambers (e.g., 27 a , 27 b and 28 a , 28 b ) disposed in the piston movement areas ( 25 a , 25 b and 26 a , 26 b ), respectively, on the side opposite to the side on which the rod end portion ( 13 ) is provided are in communication with each other via a first hydraulic chamber communication path ( 35 a ), and the second hydraulic chambers (e.g., 29 a , 30 a , and 29 b , 30 b ) disposed in the piston movement areas ( 25 a , 25 b and 26 a , 26 b ), respectively, on the rod end portion ( 13 ) side are in communication with each other via a second hydraulic chamber communication path (e.g., 35 b ).