A fluid actuator arrangement comprises a piston rod member, at least two cylinders each said cylinder having a piston body, and a clamping mechanism associated to each cylinder. Each clamping mechanism is arranged to engage and disengage the piston body of the cylinder to the piston rod member. The fluid actuator arrangement comprises further a control element arranged to control a back and forward movement of the respective piston body so that forward movement is slower than the backward movement and to control the movement of the respective piston bodies in relation to each other such that at least one piston body is always moving forward and such that an overlap exists wherein at least two of the piston bodies are moving forward simultaneously during a cycle.

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.

The invention provides an auto-lock hydraulic hoist cylinder device, comprising: a lock actuator, a lock transmission mechanism and a load-bearing mechanism, wherein the load-bearing mechanism includes load-bearing locking shaft, a load-bearing nut is provided on the load-bearing locking shaft, installed on the upper side of the upper end cover of the main hydraulic hoist, a number of protrusions is provided on the lower end of the load-bearing locking shaft, a locking cover is provided with a through hole for the load-bearing locking shaft to pass through, a groove for matching the protrusions is provided on the side wall of the through hole, a piston rod is fixed on the lower end of the locking cover, the lock actuator is provided on the upper end cover, the lock actuator drives the load-bearing locking shaft through the lock transmission mechanism.

The subject matter of this specification can be embodied in, among other things, a locking apparatus for a rotary actuator includes an outer housing comprising a cylindrical interior surface having a recess. A rotor is disposed within the outer housing. The rotor has an interior cavity and a port extending radially from the interior cavity to the cylindrical exterior surface. A piston is disposed for reciprocal movement within the interior cavity between a first position and a second position and includes a first portion having a first thickness, a second portion having a second thickness larger than the first thickness. A key is disposed for radially reciprocal movement within the port and includes a radially proximal end and a radially distal end. The radially proximal end contacts the first portion and the radially distal end does not extend into the recess when the piston is in the first position.

An illustrative embodiment of a safety block may include an actuator bracket pivotally engaged with a pivot arm. The actuator bracket may be configured to engage a master actuator having a first end moveable with respect to a second end. A secondary actuator may have a first end engaged with the actuator bracket and a second end engaged with the pivot arm such the secondary actuator may cause the pivot arm to move between a first position, in which first position the pivot arm prevents the master actuator from retracting, and a second position, in which second position the pivot arm allows the master actuator to retract.

A hydraulic lock for a thrust vector actuator includes a lock cylinder. The lock cylinder includes at least one slot and at least one bore. The slot is defined through a perimeter of the lock cylinder, and the bore is defined through a portion of the lock cylinder at a second end to extend towards a first end. The hydraulic lock includes at least one biasing member coupled to the bore. 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 the shaft of the thrust vector actuator. 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 inhibit movement of the shaft, and a second, unlocked position.

A folding wing tip system of an aircraft includes a latch pin actuator having a primary mechanical lock and a secondary hydraulic lock. The mechanical lock may include a lock cam movable between a lock position, in which the lock cam engages the latch pin, and an unlock position, in which the lock cam is disengaged from the latch pin, and a first lock actuator mechanically coupled to the lock cam and configured to provide a bias force pushing the lock cam toward the lock position. The hydraulic lock may be disposed in an unlatching hydraulic line and has an initial state, in which fluid flow through the unlatching hydraulic line is blocked thereby to hold the latch pin in the latched position, and an open state, in which fluid flow through the unlatching hydraulic line is permitted thereby to permit retraction of the latch pin to the unlatched position.

An illustrative embodiment of a safety block may include an actuator bracket pivotally engaged with a pivot arm. The actuator bracket may be configured to engage a master actuator having a first end moveable with respect to a second end. A secondary actuator may have a first end engaged with the actuator bracket and a second end engaged with the pivot arm such the secondary actuator may cause the pivot arm to move between a first position, in which first position the pivot arm prevents the master actuator from retracting, and a second position, in which second position the pivot arm allows the master actuator to retract.

A system, including a magnetorheological (MR) fluid locking system, including a housing, a piston disposed in the housing, wherein the piston is configured to move axially within the housing, an MR fluid disposed in the housing, an MR fluid pump fluidly coupled to the housing, wherein the MR fluid pump is configured to pump the MR fluid into the housing, and an electromagnet configured to magnetize the MR fluid to control axial movement of the piston.

A modular fluid actuator system is provided for generating a relative motion between a first fluid transfer chamber of a first module unit and a piston rod arrangement in an axial direction. The modular fluid actuator system comprises a fluid supply, a valve device coupled to the fluid supply and to the first fluid transfer chamber, a control unit coupled to the valve device for controlling the relative motion between the first fluid transfer chamber and the piston rod arrangement, the first fluid transfer chamber is coupled to a first sleeve portion exhibiting a first expandable hollow space arranged for fluid communication with the valve device via the first fluid transfer chamber.