Nozzle hydraulic actuator ring with cooling flow

A hydraulic actuator system in which the servo fluid supply to the system is used to provide for the operation and cooling of the system, comprises:

• a hydraulically operated piston arrangement including a plurality of hydraulically operated piston devices including at least one piston movable within one of said hydraulically operated piston devices which provides a master/controlling hydraulically operated piston means;
• a servo fluid input to the system, which is connected in a ring main to a first side of the hydraulically operated piston means;
• a servo fluid output from the system, which is connected in a ring main to a second side of the hydraulically operated piston means;
• a variable restrictor arrangement which provides an interface between the servo fluid input ring main and the servo fluid output ring main;
• a restrictor arrangement positioned in the servo fluid output side of the system;
• and
• means to vary the fluid output flow rate from the actuator system which comprises a dual line output arrangement, each of which lines include a fixed restrictor, and one of which lines is closed off when the actuator system is fully extended;
• wherein the position of the piston of the hydraulic piston means therein, and the adjustment thereof, are controlled by the restriction applied on the system by the variable restrictor arrangement.