A system. The system includes a valve assembly. The valve assembly includes a first port, a second port fluidically couplable with the first port upon application of negative pressure at the first port, a third port fluidically couplable with the first port upon application of positive pressure at the first port, and a first check valve positioned between the first port and the second port. The system also includes a second check valve fluidically couplable with the third port upon the application of the positive pressure at the first port. The second check valve is positioned external to the valve assembly.

There are disclosed a method and a lifting mechanism for actively damping in mobile working machines vibrations which may occur as a result of raised attachments during travel. The method or the lifting mechanism has a prediction or a predictor for estimating the future vibration. The prediction is preferably carried out with a recursive least squares algorithm. The mobile working machine may, for example, be a tractor.

An adaptor is used to couple a prime mover to an actuator. The adaptor includes a first portion that attaches to the prime mover and a second portion that attaches to the actuator. The outer surface of the first portion is defined by at least one flat portion connected by at least one arcuate portion. The second portion has a bore configured to accept the first portion, with an inner surface shaped to complement the outer surface of the first portion. A bore through the first portion accepts a drive shaft of the prime mover therethrough where the drive shaft is configured to engage the actuator.

A hydraulic actuator sealing device includes an annular piston, an annular cancel plate, a return spring, and an annular piston spring seat. The annular piston includes an annular pressure receiving plate portion receiving a load of the return spring, an inner cylinder portion extending from an inner peripheral side of the annular pressure receiving plate portion toward the annular cancel plate, and a bent portion connecting the annular pressure receiving plate portion with the inner cylinder portion and expanding with respect to the annular pressure receiving plate portion in a direction away from the return spring in an axial direction.

A hydraulic actuator sealing device includes an annular piston, an annular cancel plate, a return spring, and an annular piston spring seat. The annular piston includes an annular pressure receiving plate portion receiving a load of the return spring, an inner cylinder portion extending from an inner peripheral side of the annular pressure receiving plate portion toward the annular cancel plate, and a bent portion connecting the annular pressure receiving plate portion with the inner cylinder portion and expanding with respect to the annular pressure receiving plate portion in a direction away from the return spring in an axial direction.

A hydraulic circuit includes a prime mover that is configured to generate an oscillating flow of hydraulic fluid, and an actuator that is driven by the prime mover and configured to provide oscillating motion and to be connected to a load in each direction of the motion. The hydraulic circuit also includes a reclamation device that is disposed in the hydraulic circuit between the prime mover and the actuator. The reclamation device captures and stores a portion of hydraulic fluid displaced from the actuator during a transition between opposed motions, where the portion of hydraulic fluid corresponds to an amount of hydraulic fluid equal to a volume of fluid required to compensate for compression of fluid within the hydraulic circuit due to system pressure and load pressure. The stored fluid is used by the circuit in a subsequent motion.

An HST circuit has a hydraulic pump that converts a drive force of an engine into energy of oil, and a hydraulic motor that converts the energy of the oil converted by the hydraulic pump into drive energy. Pressure sensors detect a pressure of the oil within the HST circuit. A variable charge pump replenishes the oil into the HST circuit. A controller controls a capacity of the variable charge pump based on the pressure of the oil within the HST circuit detected by the pressure sensors.

A hydraulic device 10 includes a hydraulic pump 20, a tool 70, an oil passage 30, 32, 50, 52 for sending the pressure oil generated by the hydraulic pump 20 to the tool 70 and returning return oil from the tool 70 to the hydraulic pump 20, a handle 90 configured to be held by one hand of a worker, a switching part 88 disposed at the oil passage 30, 32, 50, 52 and configured to switch a path for at least one of the pressure oil and the return oil, and an operation part 80 for operating the switching part 88. The operation part 80 is disposed at a position that allows the operation part 80 to be operated with the hand of the worker holding the handle 90, or with a finger of the hand holding the handle 90.

Aspects of the present disclosure relate to fail open or fail close actuator assemblies and related methods for valve systems. In one implementation, an actuator assembly for valves includes an outer housing that includes an inner surface at least partially defining an internal volume. The actuator assembly includes one or more first fluid openings formed in the outer housing, one or more second fluid openings formed in the outer housing, and one or more ambient openings formed in the outer housing. The actuator assembly includes a valve stem disposed at least partially in the internal volume, and a first piston disposed in the internal volume and coupled to the valve stem. The actuator assembly includes a second piston disposed in the internal volume and disposed about the valve stem.

A controller and related system and method for controlling a choke for choking fluid flow are configured to take into account non-linear behaviors of the choke, to allow more accurate and effective control of the choke. To obtain a desired pressure drop across a choke valve, the controller is configured to monitor the position of a choke actuator coupled to the choke valve and the pressure at the inlet of the choke valve. The controller calculates an adaptive proportional gain coefficient, and optionally adaptive integral and derivative coefficients, based on the choke actuator position, to help mitigate the effects of non-linear behaviors of the choke and, where necessary, based on the inlet pressure, the controller calculates an augmentation correction to address any instability in the choke. The controller then commands the choke actuator accordingly to adjust the flow area through the choke valve.