In a steam valve driving apparatus according to an embodiment, a control valve permits or blocks a flow of hydraulic oil from a supply port to an opening direction piston chamber. A dump valve blocks or permits the flow of the hydraulic oil from the opening direction piston chamber to a discharge port. A blocking valve permits or blocks a flow of the hydraulic oil from an accumulator to a closing direction piston chamber. The control valve permits the flow of control oil from the closing direction piston chamber to the discharge port in a state where the flow of hydraulic oil from the supply port to the opening direction piston chamber is permitted.

A hydrodynamic compression tool comprises an electrical motor, which can be powered by a control circuit, a hydraulic pump which can be actuated by the motor so as to increase the pressure of a hydraulic liquid acting on an actuating piston, two jaws, which can be mutually moved by the actuating piston between an open position and a closed position for carrying out the compression or the cut, an actuating button, which acts on a switch of the control circuit to actuate the motor, a return device which returns the jaws to the open position by a return of the hydraulic fluid from the actuating piston towards the hydraulic pump through a return valve, and a mechanism for delaying the opening of the return valve via the return device, so as to allow verification of the position of the jaws before the return of the jaws to the open position.

In a control unit of an electromagnetic valve system, a safety circuit includes a first switch and a second switch for switching, by control from a control circuit supply and shutdown of power from a drive power supply to an electromagnetic valve drive circuit. A common line extends to a plurality of electromagnetic valve units and is connected to one end of a plurality of solenoids. A plurality of power lines are connected to the other end of each of the plurality of solenoids. The electromagnetic valve drive circuit includes a plurality of open/close switches for switching, by control from the control circuit, supply and shutdown of power to the plurality of solenoids.

Working equipment including a hydraulically movable arm arrangement for a crane, an electric motor, a hydraulic pump, and a pump controller. An equipment controller is arranged to determine a maximum flow limit from the pump in dependence of a comparison of a current limit received from a battery system and a current consumption monitored by the pump controller, and to compare the determined limit with required flow of hydraulic fluid from the pump needed to move the movable arm arrangement in accordance with operating signals, and if the result does not fulfil a rule of a set of fluid control rules, the controller adapts the operating signals to reduce flow of hydraulic fluid to at least one of a plurality of actuators according to a rule of a set of adaptation rules, such that at least one rule of the set of fluid control rules is fulfilled.

A hydraulic drive system raises and lowers an object by supplying and discharging operating oil to and from each of two ports of an actuator and includes a control device, first to third electromagnetic proportional control valves, a hydraulic pump, a control valve, and a lock valve. When a second pilot pressure is output, the control valve causes the operating oil to be discharged from a first port in order to lower the object. The lock valve is disposed so as to be able to prevent the operating oil from being discharged from the first port by closing a path between the first port and the control valve, and only when a third pilot pressure is output, allows the operating oil to be discharged from the first port by opening the path between the first port and the control valve.

An actuator control arrangement comprising: a hydraulic actuator having a housing and a piston rod axially moveable within the housing between a neutral position, a retracted position and an extended position with respect to the housing in response to application of pressure to the piston rod; the arrangement further comprising a check valve moveable between a first position providing a flow path between a pressure source and the actuator, and a second position in which the flow path is closed off; and characterised by a mechanical link between the piston rod and the check valve, actuated in response to the piston rod passing a predetermined retracted position in a negative stroke direction, to set the check valve to the first position.

A hydraulic drive system raises and lowers an object by supplying and discharging operating oil to and from two ports of an actuator and includes a control device, first to fifth electromagnetic proportional control valves, first and second hydraulic pumps, a first and second control valve, and a lock valve. When a fourth pilot pressure is output, the second control valve causes the operating oil to be discharged from a first port in order to lower the object. The lock valve prevents the operating oil from being discharged from the first port by closing a path between the first port and the second control valve, and when a fifth pilot pressure is output from the fifth electromagnetic proportional control valve per an operating device, discharges the operating oil from the first port by opening the path between the first port and the second control valve, to lower the object.

An electric-powered fail-safe actuator for use with a valve, where the actuator stores potential energy for conversion to kinetic energy to close or open the valve to the fail-safe position.

A solenoid driven actuator system includes a first solenoid having at least one pressure input and a pressure outlet downstream from the at least one pressure input. A second solenoid has at least one pressure input and a pressure outlet downstream from the at least one pressure input. A transfer solenoid operatively coupled to the first and second solenoids. An actuator valve operatively coupled to a pressure outlet of the transfer solenoid.

An electric-powered fail-safe actuator for use with a valve, where the actuator stores potential energy for conversion to kinetic energy to close or open the valve to the fail-safe position.