In a steam valve driving apparatus according to an embodiment, a control valve permits or blocks a flow of hydraulic oil from a supply port to an opening direction piston chamber. A dump valve blocks or permits the flow of the hydraulic oil from the opening direction piston chamber to a discharge port. A blocking valve permits or blocks a flow of the hydraulic oil from an accumulator to a closing direction piston chamber. The control valve permits the flow of control oil from the closing direction piston chamber to the discharge port in a state where the flow of hydraulic oil from the supply port to the opening direction piston chamber is permitted.

Particular embodiments of the inventive technology disclosed herein relate to the use of a dynamic valve to reduce motion caused by impulse force applied to a positioned component. Typically, the inventive technology finds application in an internally pressurized positioning system. At times, use of the inventive technology may lead to cost savings by, e.g., allowing for the use of smaller diameter positioner actuators and/or a reduced internal pressure.

A hydraulic cylinder enclosing a cavity, the cylinder containing a thru hole, an inner cylinder surface, and a longitudinal axis, and a piston within the cavity and movable relative to the cylinder in parallel to the longitudinal axis between a first and second positions. The piston includes a rod extending through the thru hole, the piston attached to the rod and in sealed engagement with the inner cylinder surface, and dividing the cavity into low and high pressure cavities, and each of the low and high pressure cavities containing a hydraulic fluid. The hydraulic cylinder further including a flexible bladder within the high pressure cavity containing a gas and preventing the gas from mixing with hydraulic fluid in the high pressure cavity. The flexible bladder is attached to an end of the cylinder, and is expandable within the high pressure cavity so that when the piston is in the first position, the flexible bladder and the gas are compressed, and as the piston moves toward the second position, the flexible bladder and the gas fill at least a portion of the high pressure cavity.

Aspects of embodiments of the invention relate to a spring-return actuator comprising a first piston movable between a first and a second position by pressurized fluid to move a load; a safety system comprising a second piston movable by the pressurized fluid to arm the safety system and which returns the first piston from the second position to the first position when de-energizing the 3/2 pilot valve or when the pressure of the pressurized fluid drops below a safety pressure threshold; and a differential fluid channel for providing the pressurized fluid and configured so that the first piston while working to move the load remains substantially disengaged from the safety system being armed.

An aircraft landing gear actuation system which uses two separate actuation forces to retract aircraft landing gear is disclosed. One of the actuation forces may be provided by an actuator, such as a hydraulic actuator. Another of these actuation forces may be provided by a pressurized fluid that is directed into the actuator through a conduit that extends into a hollow interior of an actuator rod of the actuator. The pressurized fluid may be provided from a pressurized fluid source that contains a fixed volume of pressurized fluid. This pressurized fluid may exert a force on an actuator piston of the actuator or the actuator rod. The pressurized fluid may also be used to dampen the deployment of the landing gear.

A linear actuator system includes a linear actuator including an outer body, an inner body disposed within the outer body, a fluid chamber at least partially extending between the inner body and the outer body, a piston chamber extending at least partially within the inner body, a valve configured to selectively fluidly couple the fluid chamber and the piston chamber to each other, a piston assembly including a piston, a variable volume within the piston chamber that extends between the piston and the valve, and a gas collector assembly including a fluid passageway. The piston assembly is disposed within the piston chamber, wherein a movement of the piston assembly causes a gas separated from a liquid within the variable volume to flow through the fluid passageway, through the valve, and into the fluid chamber.

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 control unit for pneumatic actuation of a cylinder, in particular an active creel of a textile-processing machine or a cabling machine, having a compressed air inlet for connecting a compressed air supply, a working air outlet for operating the cylinder, which acts at least on one side, a valve unit arranged between the compressed air inlet and the working air outlet, and an operating element for opening the valve unit to trigger a lifting movement of the cylinder. In order to provide a control unit for pneumatic actuation of an active creel, the actuation of the creel being particularly simple by the control unit, so that an operator can use the creel more easily, quickly and safely, and in addition the creel is protected from damage by incorrect operation, the control unit for achieving a self-retaining valve function, in which the lifting movement of the cylinder is fully executed with a single and/or brief actuation of the operating element, and for the control unit is connected to an end position sensor of the cylinder such that, when the end position sensor is activated, the valve unit is closed and/or the cylinder connected to the working air outlet is automatically depressurized when or after an end position is reached.

An automatic oil return structure is provided. The automatic oil return structure has an oil storage bag, a piston, and a main body assembly. The piston has an oil storage chamber. The main body assembly has a main channel, a piston oil channel, a pressure regulating channel, a control channel, an operation channel, a minor channel, and an oil return channel. When the pressure of the main channel achieves a limit pressure, the pressure pushes the control blocking assembly away such that the pressure regulating channel communicates with the communication channel, and the pressure also pushes the operating assembly away such that the minor channel communicates with the return channel. At the same time, the pressure of the oil storage chamber pushes the oil blocking assembly, so as to isolate the oil storage chamber from the main channel, and the oil storage chamber communicates with the oil return channel.

A compressed gas motor. The motor has a port and a hollow cylinder delimited by a wall with a ventilation opening, a rear closure, and a plunger axially movable in the cylinder. The plunger divides the cylinder into front and back chambers. The ventilation opening is periodically opened towards the back chamber during operation of the motor by movement of the plunger. A compression spring in the front chamber urges the plunger towards the rear closure and/or a tension spring in the back chamber draws the plunger towards the rear closure so that the back chamber is closed relative to the ventilation opening by the plunger and the back chamber is connected with the port when the same pressure prevails in the front and back chambers. The motor can be used in surgical drive systems, medical lavage systems and medical devices. Also disclosed is a method for operating the motor.