An actuation unit includes an actuating arm pivotable between an open and closed position; a pneumatic cylinder comprising a stem movable linearly along a cylinder axis and configured to control pivoting of the actuating arm; and a closing device that includes a braking unit configured to brake movement of the actuating arm having a surface portion configured to come into contact with at least one braking assembly. The braking assembly is locked against rotation and axially movable between a non-braking and braking configuration. The surface portion is in a non-orthogonal arrangement with respect to the cylinder axis and the braking assembly includes a plurality of rollers retained in the braking assembly with clearance at least with respect to a radial movement thereof, the rollers being able to assume a first radial configuration not in contact with the surface portion and a second radial configuration in contact with the surface portion.

A fluid actuator arrangement comprises a first cylinder housing including a first head member and a second head member; a first piston body is slidable arranged in said first cylinder housing; the first piston body divides the first cylinder housing interior into a first cylinder chamber and a second cylinder chamber, at least the first cylinder chamber is coupled to a fluid supply. The first piston body exhibits a first through-bore and a second through-bore that extend through the first piston body in an axial direction; a first piston rod is arranged slidable in the first through-bore and a second piston rod is arranged slidable in the second through-bore; and the first through-bore comprises a first engagement and disengagement device and the second through-bore comprises a second engagement and disengagement device, which are arranged for providing individual engagement or disengagement to or from the respective first and second piston rod.

An apparatus and control system of a programmable air servo motor includes an air servo motor and an air servo motor driver, which are bi-directionally communicable with each other via communication units. The air servo motor includes an air motor, a sensor module, and a brake module that is normally locked and can be unlocked or locked by the air servo motor driver. The air servo motor driver includes a control module, an actuation module and a communication module. After actuating the air servo motor, the air servo motor driver receives torque, rotational speed and angle signals output by the sensor module. The actuation module drives the air servo motor to stop emergently, switch between forward and reverse rotation, increase or reduce rotational speed, operate at a specific angle, move by inching and operate at controlled torque similar to an electric servo motor without the need of an encoder.

An aircraft secondary control system comprises a rod arrangement of a driving actuator, configured for performing the motion. The rod arrangement is coupled to the aircraft secondary control member via a linkage arrangement. The driving actuator comprises a first engagement and disengagement device of a piston body and comprises a second engagement and disengagement device, each of which being configured for alternately and/or simultaneously engaging said rod arrangement. The piston body is arranged in a cylinder body and is configured to make a working stroke from a first position to a second position.

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 system for operating a circle drive gear of a machine includes a pump configured to output pressurized fluid, an implement control valve fluidly coupled to the pump, a bi-directional hydraulic motor located downstream of the implement control valve and fluidly coupled to the implement control valve via a first delivery line and a second delivery line. The hydraulic motor has an output shaft that is configured to be rotatively driven by pressurized fluid output by the pump. A brake is disposed on the output shaft of the hydraulic motor and engages with the output shaft with the help of a spring force for reducing a rotational speed of the output shaft in a brake engage state. The brake operatively disengages from the output shaft in a brake release state with the help of fluid pressure in at least one of the first delivery line and the second delivery line.

Embodiments of the present disclosure provides an anti-loosening device and a plunger pump. The anti-loosening device includes a first bracket, a second bracket and an elastic member. The first bracket includes a first clamping part defining a first accommodating space; a first connecting part extending in a first direction and fixedly connected to the first clamping part; and a limiting part fixedly connected to the first clamping part via the first connecting part, wherein the limiting part protrudes from the first connecting part in a second direction perpendicular to the first direction. The second bracket includes a second clamping part defining a second accommodation space, wherein the second clamping part is opposite to the first clamping part in the first direction; and a second connecting part extending in the first direction and fixedly connected to the second clamping part.

This disclosure describes techniques for a self-aligning system within a belt-driven linear actuator that enables a keyless or round profile piston to be sealed while maintaining an aligning and/or torque resisting ability. This enables the airspaces within the electromechanical actuator could be pressurized to perform a secondary load holding function that is redundant to the linear screw device.

An exemplary assembly includes a cylinder, a piston, and a lock. The lock is transitionable between an unlocked position that permits extension and retraction of the piston relative to the cylinder, and a locked position that limits retraction of the piston relative to the cylinder. The lock is blocked from transitioning from the locked to the unlocked position when a load supported by the piston exceeds a threshold load. An exemplary method includes transitioning a lock from an unlocked to a locked position. The lock in the unlocked position permits extension and retraction of a piston relative to a cylinder. The lock in the locked position limits retraction of the piston relative to the cylinder. The method further includes holding the lock in the locked position using a load supported by the piston that exceeds a threshold load.

An exemplary assembly includes a cylinder, a piston, and a lock. The lock is transitionable between an unlocked position that permits extension and retraction of the piston relative to the cylinder, and a locked position that limits retraction of the piston relative to the cylinder. The lock is blocked from transitioning from the locked to the unlocked position when a load supported by the piston exceeds a threshold load. An exemplary method includes transitioning a lock from an unlocked to a locked position. The lock in the unlocked position permits extension and retraction of a piston relative to a cylinder. The lock in the locked position limits retraction of the piston relative to the cylinder. The method further includes holding the lock in the locked position using a load supported by the piston that exceeds a threshold load.