Abstract: A system (10) of parallel hydraulic actuators (15) and (20) includes a pair of laterally spaced, longitudinally extending, discrete feedback levers (180) and (185) which independently provide feedback signals to a pair of actuator control valves (50) and (55) with enhanced accuracy and minimal lateral loading of the system.

Abstract: An actuator system for controlling the position of an aerodynamic control surface of an aircraft, such as an aileron, is disclosed. An actuator (12) having an output shaft (14) is mounted to a frame attached to the aircraft structure. A hydraulic coupling (32) is mounted on one side to the output shaft (14) of the actuator (12) and the other side to the control surface (50) and comprises a hydraulic cylinder (34) having a sealing member (36) movably mounted therein dividing the cylinder (34) into two portions (38, 40). The output shaft (14) of the actuator (12) is coupled to the cylinder (34) and an output shaft is attached to the sealing member (36) at one end and at its opposite end to the control surface or vice versa. A connecting tube (54) is provided coupling the two portions of the hydraulic cylinder together. The tube incorporates a valve (58) having a first position sealing off the two portions from each other and a second position providing a passageway therebetween.

Abstract: A device for reciprocating motion of a rotating drilling body of a drilling machine in the longitudinal direction of a hole drilled in rock or ground includes two cylinder-piston devices which via chains are connected to a carriage carrying the drilling body and which comprise parallel piston rods, the ends of which are supported by a frame on the machine, and cylinders movable along the piston rods and connected to each other and via the chains also to the carriage. To increase the feeding velocity of the carriage or to increase the force of the carriage one of the cylinders or both cylinders, respectively, are selectively fluid pressurized.

Abstract: A sluing mechanism driven by one or more electric or hydraulic motors, for excavating or bulk handling machines comprises a pivotable discharger boom mounted on a rotary support or turntable, and a coaxially pivotable superstructure carrying further equipment. The sluing drives of the two coaxially pivotable parts of the machine are connected to each other in such a way that upon pivoting the superstructure, the discharger boom does not follow this pivotal motion. The sluing drive of the discharge boom is designed as a superposed gear and connected to a drive motor for separately sluing the discharger boom. The turntable is provided with a second discharger sluing gear which is driven by a motor having a weaker characteristic than the drive motor or motors for sluing the superstructure. The characteristic of the motor driving the second discharger sluing gear may be adjustable.

Abstract: A redundant, dual-fail/operate fly-by-wire control system actuates a redundant tandem piston actuator (10) to provide a single composite output evidenced by movement of a piston rod (12). The basic fault-tolerate actuation system consists of dual hydraulic primary actuators, quadruplex electrical control loops (14-17), and control servo valves (22-25). A failure management system connects to the actuation system by means of lines (18-21) to control the servo valves (22-25). The four control loops (14-17) connect to a pilot controller that provides pilot individual input signals to amplifiers (26-29) for each of the control loops.

Abstract: A fluid flow controller comprises a casing and includes a valve that is actuatable by either a diaphragm or a piston. Diaphragm actuation is provided by a diaphragm held by a retainer, the retainer being axially moveable within the casing in response to fluid pressure on the diaphragm. Piston actuation is provided by (i) the retainer and (ii) sealing means at the periphery of the retainer for providing fluid tight engagement between the casing and the retainer. With either diaphragm or piston actuation, even if the diaphragm ruptures, substantially no fluid can bypass the retainer, and the flow controller continues to function. A relief valve prevents rupture of the diaphragm if the fluid pressure exceeds a predetermined valve.

Abstract: In a pressurized-fluid operated steering gear system for a ship of the kind in which a plurality of actuators (piston-and-cylinder or rotary vane) are disposed in opposed pairs to turn the tiller arm when a diametrically opposed pair is pressurized and the other diametrically opposed pair is relieved of pressure the improvement that there is located in the cylinder, or arcuate chamber, of each actuator a free moving member which separates two distinct pressurized fluid inlets of said cylinder or chamber. If there is no pressure delivery from one inlet the member moves to one end of the cylinder or chamber so that the actuator is worked by pressure solely from the other inlet.

Abstract: A control system for a hydraulic actuator comprising a first pump with large displacement capacity, a second pump with small displacement capacity, a pilot pump, a first pilot operated spring centered control valve connected at the input side thereof to the first pump, the output side of which is selectively connected to the hydraulic actuator and drain, a second pilot operated spring centered control valve connected at the input side thereof to the second pump, the output side of which is selectively connected to the hydraulic actuator and drain, and a third control valve for pilot pressure connected at the input side thereof to the pilot pump, the output side of which is connected to the first and second control valves wherein the second control valve is adapted to be actuated by a pilot pressure lower than a pilot pressure which actuates the first control valve.

Abstract: A marine steering gear equipped with an emergency steering means which comprises an emergency directional control valve capable of replenishing hydraulic fluid or oil to a plurality of pressure chambers of an actuator for a hydraulic steering engine through check valves and stop valves, and a relief valve designed to set a desired charge pressure and installed in lines of oil to be supplied through the directional control valve, check valves, and stop valves so as to forcibly reduce the air volumes in the pressure chambers and thereby hold the rudder blade substantially in a hydraulically locked state.

Abstract: An annular element which is stationary under normal operating conditions is interposed between a stationary sleeve and a central rotary plug. The annular element is provided with peripheral passages and radial openings, said radial openings being located in the line of extension of bores formed in the stationary sleeve. In the event of accidental seizure of the rotary plug, the annular element is automatically released and driven in rotation, thus permitting progressive transfer of the hydraulic fluid from one bore of the stationary sleeve to the adjacent bore via the peripheral passages.

Abstract: A two-circuit vacuum brake booster in which two pressure chambers are disposed in tandem with respect to each other, are atmospherically separated from each other and are controlled by its own valve arrangement. The two valve arrangements are arranged in a single control hub one behind the other and are simultantously controlled since their pistons are mechanically rigidly connected with one another.

Abstract: Hydraulic control.The unit is characterized in that it is provided, between an inlet well and an outlet well for pressurized fluid, with an obturator urged in the closed position by a resilient member arranged to act against the pressurized fluid in the inlet well in a chamber communicating with a conduit issued from the outlet well and separated from a return conduit by a relief valve which is urged in the closed position by a spring and by the fluid pressure prevailing in the inlet well.Application to transfer-machines with one single hydraulic station.

Abstract: Auxiliary control of fluid actuated steering apparatus for ships, boats and the like (hereinafter, "water vessels") includes isolating the existing steering control system from the steering apparatus and providing flow-communication between fluid under pressure and the steering apparatus through an auxiliary directional control sub-system enabling control of the steering apparatus independently of the main steering control system. According to a preferred embodiment, the source of the fluid includes a quantity of fluid stored under pressure and another quantity of fluid adapted to be provided under pressure. Isolation of the existing steering control system is carried out by coupling the source of fluid to a by-pass control sub-system preferably adapted both to isolate the main steering control system and to couple the auxiliary directional control sub-system to the steering apparatus.

Abstract: A fluid control unit comprising a drive piston having first and second faces and a drive rod. The drive piston has first and second fluid responsive faces exposable to fluid under pressure. The fluid under pressure acting on the first face urges the drive piston in a first direction and the fluid under pressure acting on the second face urges the drive piston in a second direction. First and second overridable detents drivingly couple the drive piston and the drive rod for movement in first and second directions, respectively. The coupling force provided by the first detent varies with the pressure of the fluid to which the first face of the drive piston is exposed, and the coupling force provided by the second detent varies with the pressure of the fluid to which the second face of the drive piston is exposed.

Abstract: A multiple servo system including two or more servo mechanisms, each having a pressure feed back including two pistons exposed in respective chambers interconnected by a low-pass hydraulic filter, in which the area of the two feedback piston faces differ by up to 25%. This reduces the tendency of the respective actuators to act in opposition and thus increases the service life of the system.

Abstract: Plural servo actuators are coupled to provide a redundant system for operating a common output device. Each servo actuator has plural servo valves each having one active output that causes controlled opposite operation of the output device and one passive output. A fault detector coupled to each servo actuator compares the sum of the passive output pressures with the pressures of two other fluid signals, in one case the supply and return fluid signals and in another case the two active output signals of the servo valves, to detect the condition thereof. A convenient checkout system and a fluid by-pass mechanism also are provided in the fault detector.

Abstract: A steering system .Iadd.40 .Iaddend.for an articulated vehicle .Iadd.10 .Iaddend.having a pair of double acting steering cylinders .Iadd.24, 26 .Iaddend.and power steering means .Iadd.44 .Iaddend.consisting of a pump .Iadd.48 .Iaddend.and a hydrostatic steering unit .Iadd.50 .Iaddend.to which the steering wheel .Iadd.42 .Iaddend.of the vehicle is interconnected. Control means .Iadd.46 .Iaddend.are disposed between the power steering means .Iadd.44 .Iaddend.and the double acting cylinders .Iadd.24, 26 .Iaddend.for causing fluid to be directed from the power steering means .Iadd.44 .Iaddend.to both of the first and second cylinders .Iadd.24, 26 .Iaddend.during rotation of the steering wheel .Iadd.42 .Iaddend.at a first steering ratio when the pump .Iadd.48 .Iaddend.is in operation, and at a second higher steering ratio when the pump .Iadd.48 .Iaddend.is not in operation to permit manual steering of the vehicle .Iadd.10.