An epicyclic gear train for a servomotor system includes a case, and, positioned in the case, a planet carrier carrying planet gears, a ring gear, and a sun gear. The epicyclic gear train includes a control for changing input and output speed ratio in response to an input applied from outside the case.

A telescopic hydraulic cylinder is disclosed which has automatic air bleeding and fluid flushing features. A method of removing air from a hydraulic cylinder is also disclosed. A hydraulic circuit with for removing air from a hydraulic cylinder is further disclosed.

An example robot includes a hydraulic actuator cylinder controlling motion of a member of the robot. The hydraulic actuator cylinder comprises a piston, a first chamber, and a second chamber. A valve system controls hydraulic fluid flow between a hydraulic supply line of pressurized hydraulic fluid, the first and second chambers, and a return line. A controller may provide a first signal to the valve system so as to begin moving the piston based on a trajectory comprising moving in a forward direction, stopping, and moving in a reverse direction. The controller may provide a second signal to the valve system so as to cause the piston to override the trajectory as it moves in the forward direction and stop at a given position, and then provide a third signal to the valve system so as to resume moving the piston in the reverse direction based on the trajectory.

An actuator control arrangement is provided comprising a pair of rotary control valves used in combination to control the operation of an actuator. The rotary control valves are driven synchronously through a hydraulic or mechanical coupling. Each rotary control valve has a by-pass mode which activates in the event of a jam. In addition each rotary control valve has a mechanism for activating the by-pass mode absent any jam. The actuator control arrangement further comprises a circuit coupling a pilot control and/or a flight control computer (FCC) to one or both of the mechanisms for remotely switching the rotary control valve(s) from an active mode to a by-pass mode under control of a pilot or FCC.

Embodiments of the invention provide a high-reliability, cost-effective electro-hydraulic servo-valve assembly that is not susceptible to failure caused by contaminated fluid. In particular embodiments, the electro-hydraulic servo-valve assembly includes a rotary valve that may be actuated by either a direct-coupled Limited Angle Torque (LAT) motor, a geared, brushless DC motor, or some other rotary electric actuating element with an integrated driver circuit. In particular embodiments, the rotary valve element made up of an outer sleeve element and an inner spool element, with matching ports and slots, respectively.

A directional control and servo valve is provided. The valve includes a valve housing and a valving element. The valve housing includes a space, and a plurality of first cavities. The valving element includes two sides thereof. Each side includes a plurality of second cavities that corresponds the plurality of first cavities. The valving element includes plurality of webs formed in the plurality of second cavities. Each web separates the plurality of second cavities on each side from each other. The plurality of webs includes a plurality of holes adapted to connect the plurality of second cavities of both sides. The valving element is disposed in the space of the valve housing such that a plurality of control edges is configured that separates at least one first cavity with respective at least one second cavity to form control orifices that are symmetrical along both sides of the valving element.

A hydraulic power tool includes a housing defining a cylinder, a piston at least partially positioned within the cylinder and movable between a retracted position and an extended position, a clevis supporting a head of the power tool, a nut coupled to an outer peripheral surface of the clevis, and a collar coupled to the housing and surrounding the nut to axially constrain the nut between the collar and the housing while permitting relative rotation between the collar and the nut.

Disclosed is a valve device, comprising at least one valve piston arranged in a valve housing in a longitudinally displaceable manner, which valve piston is moved by means of a drive in conjunction with the assigned drive train and interconnects individual fluid ports present in the valve housing in a fluid-conveying manner or separates them from one another. A sensor device monitors the respective positions of the drive train and thus the respective positions of the valve piston in the valve housing.

A servo actuator (1) comprises an actuator housing (4); an actuator member (2) located within the actuator housing (4) and at least one spool (8) located in a cavity (6) formed within the actuator housing (4). The housing (4) also comprises a first set of internal ports including an inlet port (P), an outlet port (T) and a pair of control ports (SI, S2), the inlet port (P) being arranged for connection to a first pressurised supply and a second set of internal ports comprising an inlet port (P), an outlet port (T) and a pair of control ports (SI, S2), the inlet port (P) being arranged for connection to a second pressurised supply. In use, movement of the spool (8) alters the flow path of fluid through the first and second set of internal ports to control the movement of the actuator member (2).

An automatically actuated shunt valve system opens and closes a passage between two chambers of a powered element operated by a power source. The shunt valve system includes a coupler connecting the powered element with the power source through two mating coupling elements. One of the coupling elements includes a valve contact and the other includes a shunt valve assembly. The shunt valve assembly includes a valve chamber connected with both chambers of the powered element, a valve element opening or closing a flow path between the conduits, and a shaft for moving the valve element. The shaft engages the valve contact to move the valve element to close the flow path when the coupling elements are mated together, and moves the valve element to open the flow path when the shaft disengages from the valve contact as the coupling elements are disconnected from one another.