An agricultural system that includes a cylinder and a rod that moves axially in and out of the cylinder to raise and lower a header. A cylinder lock system controls movement of the rod. The cylinder lock system includes a cap-end fixture that couples to the cylinder and receives the rod. A rod-end fixture couples to an end of the rod. The system includes a lock piston. The lock piston includes a protrusion. The lock piston rotates about the rod and selectively couples the protrusion to the cap-end fixture to lock and unlock the rod-end fixture to the cap-end fixture.

A hydraulic actuator can be provided for actuating a functional part by a movement of a force transmission element, with a working piston which can be acted upon by a hydraulic pressure of a pressure supply and is movable thereover between a first extreme position and a second extreme position in a piston/cylinder unit, wherein two chambers separated from one another by the working piston are present and a first chamber is formed as a first working chamber with a pressure inlet and a hydraulic pressure applied to the first pressure inlet urges the working piston in the direction of the first extreme position in order to enlarge the first working chamber.

At least one retaining means is provided which is capable of automatically locking the working piston in one of the extreme positions when this extreme position is reached, even without any hydraulic pressure being applied.

The subject matter of this specification can be embodied in, among other things, a linear actuator lock apparatus, including a housing having an inner surface defining an axial cavity including a first housing portion where the axial cavity has a first lateral size, a second housing portion where the axial cavity has a second lateral size that is larger than the first lateral size, and a face from the first housing portion to the second housing portion, a piston configured for axial movement within the axial cavity, a lock finger affixed to and extending away from the piston, where a finger end is configured to contact the face when extended and fit within the first housing portion when retracted, and a sleeve configured to move between a position in which the lock finger is permitted to extend and a position configured to contact and retract the lock finger.

A locking mechanism includes a linkage assembly having a first link (6a) and a second link (6b) joined at a pivot point (110). The assembly also includes a linkage assembly spring to bias the linkage assembly into a first, locked, position and a rotational rod (1) having a cam (120) formed thereon with a cam surface in engagement with the linkage assembly in the region of the pivot point (110). The assembly also includes a solenoid assembly (3) arranged, in a first mode, to rotate the rotational rod (1) such that the cam acts as a stop against the linkage assembly at the pivot point in a locked position, and, in a second mode to rotate the rotational rod such that the cam surface presses against the linkage assembly sufficiently to overcome the linkage assembly spring and to force the linkage assembly into a second, unlocked position.

A telescopic actuator comprising a cylinder (2) in which a rod (3) is mounted to slide along a sliding axis (X), the actuator including a locking member comprising a locking finger (10) that is movable along a locking direction (Y) that is perpendicular to the sliding axis, between a locking position in which an end (9) of the locking finger (10) is engaged in a groove (8) of the rod in order to lock the rod in position, and a retracted position in which the end of the finger is disengaged from the groove in order to release the rod, a locking indicator (20) being secured to the locking finger to be movable between a position indicating locking when the locking finger is in the locking position, and a position indicating unlocking when the locking finger is in the retracted position, the actuator being characterized in that the locking indicator is secured to the locking finger by a connection (22, 23, 24) suitable for being interrupted in the event of the end of the finger being broken off while the rod is locked, a thrust spring (25) being arranged in the locking finger to push the locking indicator towards the position indicating unlocking when said connection is interrupted.

An actuator system comprising a rotatable lock mechanism defining a path for an actuator pin as the actuator is expanded and retracted, wherein the lock mechanism defines an entry passage through which the pin enters as the actuator extends, a guide surface along which the pin travels from the entry passage as the actuator retracts, a locking recess into which the pin is guided by the guide surface, and an exit passage into which the pin is guided as it is caused to leave the lock recess by extension of the actuator and subsequent retraction; whereby a detent surface is provided to prevent the pin returning back into the lock recess when the actuator is extended to cause the pin to leave the lock recess; and whereby the lock mechanism provides a sloping engagement surface for the pin, either side of the entry passage.

A hydraulic lock for an actuator having a movable shaft includes a lock cylinder having a first end and a second end. A slot is defined through a perimeter of the lock cylinder adjacent to the second end, and a bore is defined through a portion of the lock cylinder at the second end to extend towards the first end. The hydraulic lock includes at least one pawl having a first pawl end and a second pawl end. The first pawl end is releasably coupled to a groove defined in the shaft, and the second pawl end is coupled to the slot. The pawl is movable relative to the slot between a first, locked position in which the first pawl end is coupled to the groove to inhibit movement of the shaft, and a second, unlocked position in which the first pawl end is released from the groove.

A failsafe piston retention assembly, and related components, systems, and methods are disclosed. A failsafe piston retention assembly comprises a head comprising a head body having a first surface. The assembly also includes a piston having second surface, the piston slidably coupled with respect to the head. The piston has a retracted configuration and an unretracted configuration. In the retracted configuration, the second surface is fixed with respect to the first surface by a magnetic force. One advantage of this arrangement is that the piston is retained in its retracted configuration in the event of an operational failure of the piston mechanism. For example, for a hydraulically controlled piston, the magnetic force retains the piston in a retracted configuration even in the event of a loss of hydraulic pressure.

The invention relates to a telescopic actuator comprising a cylinder (1) having a closed end (2) and an open end (3) for passing a hollow rod (4) mounted to slide axially in the cylinder. The actuator includes a central support (10) that extends from the closed end of the cylinder inside the rod and that carries obstacles (15) that are movable radially between a setback position leaving the rod free to slide and a projecting position in which the obstacles are engaged in a groove (9) in the rod in order to lock the rod axially relative to the cylinder, the flanks of the obstacles and of the groove being shaped so as to prevent any setting back of the obstacles by movement of the rod, the obstacles being arranged at the ends of spring blades (14) extending longitudinally and arranged to urge the obstacles from the setback position towards the projecting position, the central support carrying controlled means (20) for flexing the blades in order to cause the obstacles to be set back towards the setback position.

A railroad switch device for moving railroad switch points is provided. The device includes a hydraulic unit comprising a hydraulic manifold, a hydraulic cylinder to provide constant forward movement and reverse movement, and a hydraulic circuit unit. The railroad switch device also includes a mechanical target to automatically indicate the position of a point rod, where the hydraulic unit is coupled to the point rod. Additionally, the railroad switch device includes a plurality of spring units to produce a continuous thrust force for holding the railroad switch points closed in forward position and reverse position, where the plurality of spring units control the target rotation to approximately 90 degrees. A plurality of proximity sensors detect the point rod position, and a power unit supplies hydraulic power to the hydraulic unit for moving the hydraulic cylinder.