The invention relates to a linear drive device having a housing element in which at least one drivable actuating element is arranged, a guide unit which is coupled to the actuation element and moves relative to the housing element between two stroke end positions in linear direction, a stroke limiting device, by means of which a first stroke end position and a second stroke end position of the guide unit are adjustable, wherein the stroke limiting device has a first stop and a first counterstop for setting a limit of the first stroke end position and a second stop and a second counterstop for setting a first limit of the second stroke end position, wherein the stroke limiting device has a third stop which is adapted to set a second limit of the second stroke end position adjusted with the first counterstop.

A system for securing a valve actuator to body of a valve assembly includes an actuator housing having housing lugs protruding radially to define a plurality of housing slots therebetween. A bonnet has bonnet lugs protruding radially to define a plurality of bonnet slots therebetween. Each of the housing lugs are sized to pass axially through a respective one of the bonnet slots when the actuator housing is in a released position and, after passing through the bonnet slots, the actuator housing is rotatable to a locked position where at least a portion of one or more of the housing lugs is axially aligned with a portion of a respective bonnet lug to prevent axial movement of the actuator housing, the actuator housing rotating less than one full revolution between the released and locked positions. A securing mechanism prevents relative rotation between the actuator housing and the bonnet.

An actuator capable of preventing the inside of a cylinder from being scratched is provided. A two-way piston includes a cylinder having an opening, a piston, and a stroke sensor that detects a position of the piston. The stroke sensor includes a stay that extends from a portion exposed from the opening of the piston to the outside of the cylinder, a member to be detected that is attached to the stay, and a sensor that detects a position of the member to be detected. The piston including a fixing hole having a depth smaller than a diameter of the piston in the portion exposed from the opening. The stay is fixed by a bolt that is inserted into the fixing hole.

A piston body (11) of an advancing-retracting first piston (10) and a force-multiplying second piston (15) are arranged in series in a vertical direction in a housing (1). Force acting on the second piston (15) due to pressurized oil in a lock chamber (16) is multiplied and converted into multiplied upward force via engaging balls (32) of a force multiplier (30). Then, the multiplied upward force is transmitted to an output rod (12) of the first piston (10). At an intermediate part of a first air detection passage (38) for use in detection formed in the housing (1), a first detection valve (40) is provided. When the engaging balls (32) move inward in a radial direction, the first detection valve (40) is closed.

A plurality of detection valves (12 and 13) are provided to a housing (1), and at least one air passage (14 and 15), which communicatively connects the detection valves (12 and 13) to each other in series, are provided to the housing (1). One or some of the detection valves (12 and 13) are each configured as a throttle detection valve (13) including a throttle passage (56a).

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.

An electrohydraulic actuator includes a reservoir tank having a bladder that separates hydraulic fluid from any air in the reservoir tank and includes a sensor system that detects when the hydraulic fluid is depleted from the reservoir tank.

In a cylinder body of a fluid pressure cylinder, pistons are movably accommodated in respective cylinder holes, which are formed in a pair of main body portions. Further, a rod on which a magnet is installed is disposed movably in the axial direction in a connecting section that interconnects one of the main body portions and another of the main body portions. The rod and piston rods are connected to an end plate, whereby the rod is moved integrally with the end plate when the pistons are moved under the supply of a pressure fluid. Additionally, magnetism from the magnet is detected by a detection sensor mounted in the cylinder body, whereby the position of the pistons in the axial direction is detected.

A hydraulic cylinder includes a rod insertion hole formed in a piston member, an auxiliary rod provided to a head side end wall member and capable of being inserted into the rod insertion hole, a rod fitting hole formed to pass through the head side end wall member and the auxiliary rod, a movable rod installed in the rod fitting hole and whose end portion toward a head side end wall projects to the exterior, a movement restriction mechanism that prohibits shifting of the movable rod in an unclamping state and permits shifting of the movable rod in a clamping state.

A hydraulic fluid cylinder is equipped with a cylinder tube, a piston unit, and a piston rod. The piston unit has a piston body provided with a gasket-mounting groove. A gasket member is mounted in the gasket mounting groove. The gasket member has a gasket body provided with a magnet-mounting groove exhibiting groove depth in the axial direction of the piston unit, and also has a magnet mounted in the magnet-mounting groove.