A multi-cylinder assembly includes a cylinder assembly defining a bore and a piston-rod assembly slidably disposed in the bore of the cylinder assembly. The piston-rod assembly includes a piston rod, a piston-rod sleeve and a retainer. The piston rod includes a piston head, a first rod extending outwardly from the piston head and a rod extension extending outwardly from the first rod. The piston-rod sleeve is disposed about the rod extension of the piston rod. The piston-rod sleeve includes a head portion and a rod portion. The retainer is engaged to the rod extension. The retainer prohibits axial movement of the piston-rod sleeve.

An actuator device includes two drive units for an actuator output element. The first drive unit has a first piston chamber and a first piston displaceable therein and also first hydraulic means for displacing the piston. The second drive unit has a second piston chamber and a second piston displaceable therein and also second hydraulic or pneumatic means for displacing the piston. The second piston is joined to the actuator output element for conjoint movement therewith and can be coupled to the first piston for thrust, so that the second piston is displaceable in an outward direction by the first piston. The first drive unit is configured for a larger thrust force than the second drive unit, while the second drive unit is designed for a greater stroke speed than the first drive unit.

Provided is a hydraulic pressure control device and a braking system, which are capable of increasing a degree of freedom in layout of oil passages inside a housing. The hydraulic pressure control device includes a normally-closed type electromagnetic valve and a normally-open type electromagnetic valve. The normally-closed type electromagnetic valve includes a first valve part arranged so as to extend from a surface of the housing to an inside of the housing, and is configured to close an oil passage when a current is not supplied. The normally-open electromagnetic valve includes a second valve part being arranged so as to extend from the surface of the housing to the inside of the housing and having an axial length set to be equal to an axial length of the first valve part, and is configured to open the oil passage when a current is not supplied.

An apparatus for actuating a valve includes a first actuator having a first actuator housing and second actuator with a second actuator housing. A first plate is positioned within the first actuator housing and a second plate is positioned within the second actuator housing. An intermediate stem extends from a first pressure chamber of the first actuator housing to the second plate. A pressure media path extends through the intermediate stem and a second seal nut that extends into the second plate, the pressure media path providing fluid communication between the first pressure chamber, and a second pressure chamber of the second actuator housing. An injection port is open into one of the first pressure chamber and the second pressure chamber. The first plate and the second plate are movable in response to pressure media injected into the injection port, for actuating the valve.

Relates to a cylinder unit includes a rod and a housing, wherein the rod is guided on the housing so as to be displaceable along an adjustment axis, wherein a piston is fixed to the rod, which piston divides the interior space of the housing into a first chamber and a second chamber, wherein the housing has a safety outlet, and wherein the safety outlet is arranged such that the piston closes off the safety outlet in fluid-tight fashion when the rod is in a zero position.

A system for determining the operability of a valve in active service which provides a user with real time information pertaining to the Safety Margin, the valve torque or thrust, and the percentage of valve MAST that is required for operation. The system employs a combination of an actuator package comprised of a primary actuator, a tandem force module, and a controller operatively connected to the output shaft of the primary actuator, the controller including a processor for calculating the above-described values and providing an output which can be visually, audibly, or electronically observed.

A hydraulic actuator system includes a hydraulic actuator having a housing with a piston having a piston shaft arranged within the housing. The housing is formed to have first, second and third regions, wherein the first region is between the second and third regions and has a larger major dimension than the second and third regions. The system also includes first, second, and third piston heads connected to the piston shaft with the first piston head being tween the second and third piston, wherein the first position head is within the first region and divides the first region into two volumes, the second piston head is in the second region and defines a first volume and the third piston head is in the third region and defines a fourth volume. The system also includes a mode selection device operably connected to the first, second, third and fourth volume.

Provided is a cylinder connection assembly comprising a ventilation connection sleeve sleeved on a piston shaft of the cylinder, the ventilation connection sleeve fixedly provided in a cylinder barrel of the cylinder and separates an inner cavity of the cylinder barrel to form front and rear air chambers, a first ventilation hole communicating with the front air chamber and a second ventilation hole communicating with the rear air chamber are provided on the ventilation connection sleeve, so that when the compressed gas is filled into the front air chamber through the first ventilation hole, or the compressed gas is filled into the rear air chamber through the second ventilation hole, the piston assembly in the cylinder barrel can move axially. Through the ventilation connection sleeve provided in the cylinder barrel, the compressed gas can directly enter the front air chamber or the rear air chamber through the ventilation hole thereon.

A communication path that communicates with a first main pressure chamber is provided in a main piston and a piston rod. A check valve, which opens by being pressed by a booster piston and allows the communication path to communicate with a first sub-pressure chamber when the piston rod reaches a booster start position before a forward stroke end, is disposed in an end portion of the communication path. A plurality of steel balls are disposed in a coupling-member containing chamber formed in the booster piston. An engagement surface and an engagement groove, which engage with the steel balls when the booster piston moves forward due to an action of a pressure fluid supplied to the first sub-pressure chamber 11a through the communication path, are formed in the coupling-member containing chamber and an outer peripheral surface of the piston rod.

A triple piston fluid pressure cylinder is disclosed with a parallel arrangement of the pistons that allows a combination of the first two stages of the cylinder into one stage so that the first two stages of the cylinder are working into the same common space. As the result of that arrangement the overall length of the triple pistons cylinder is reduced by a significant amount. The saved length may be used to increase the stroke of the cylinder. The piston body assembly is built around the piston arrangement, and is composed of a cylinder tube with one head end cover and one rod end cover and one middle fixed pistons. The middle fixed piston is extended through an extension tube to an extension fixed piston.