A valve operating device includes a mounting for attachment to a vehicle and an elongate arm, the free end of which is only moveable across the underlying ground. The joints of the arm pivot around vertical axes and the arm is locked into a desired orientation by a brake at each joint. A valve turning machine is at the free end of the arm. The brakes are engaged and released by a control on the valve turning machine.

A crane, in particular a mobile crane, having a closed hydraulic circuit in which a hydraulic pump is hydraulically connected to at least one hydraulic motor via a feed and a discharge, and in which the feed is hydraulically connected to the discharge via at least one bypass which bypasses the at least one hydraulic motor, wherein the at least one bypass includes a continuously adjustable valve for variably controlling the fluid flow bypassing the at least one hydraulic motor. In addition, a corresponding control device and a corresponding crane control program for actuating a closed hydraulic circuit of a crane are provided.

A fluid pressure control device includes a switching valve, a main pilot passage and a sub pilot passage, the switching valve is configured to be switched to the communication position when the working fluid is supplied to the pilot chamber, and to be switched to the shut-off position with opening on the downstream side of the switching valve in the neutral passage, and the switching valve has a throttle portion configured to throttle the flow of the working fluid in the neutral passage at the communication position.

A valve body of a speed controller includes a main body that extends along a first axis and a mounting portion that projects from a side of the main body along a second axis that intersects the first axis orthogonally. A first port, a needle valve, and a check valve are disposed in the main body. The mounting portion, which is a portion to be mounted on a cylinder portion, includes a second port formed therein. A position at which the mounting portion is disposed on the side of the main body is away from the first axis in a direction of a third axis that orthogonally intersects the first axis and the second axis.

A fluid pump for a linear actuator causes a rod in the actuator to extend or retract by controlling fluid flow to and from portions of a fluid chamber on either side of a piston disposed within the fluid chamber and supporting the rod. The pump includes check valves that control fluid flow between a driven pump element and each portion of the fluid chamber and a shuttle movable in response to fluid pressure along a shuttle axis extending through the valves. At least one valve includes a valve member movable between a closed position and an open position defining a fluid flow path between the driven pump element and fluid chamber and means for limiting movement of the shuttle towards the valve such that the shuttle may, depending on the position of the limiting means, move the valve member to an intermediate position between the closed and open positions.

Provided is a construction machine capable of detecting a stuck-open state of a surplus flow control valve in real time during operation without involving a reduction in the operational speed. The construction machine is equipped with: a surplus flow control valve control section configured to output a closing command to a first surplus flow control valve at the operation start when an operation amount signal of an operation lever device is detected; a pump delivery control section configured to output a delivery flow rate command to an adjustment section of an open circuit pump; an assist valve control section configured to continue to output a closing command from before to an assist valve; a sticking detection determination section configured to compare a pressure signal with a previously set threshold value and determining that the surplus flow control valve is in a stuck-open state when the pressure signal is less than the threshold value and determining that the surplus flow control valve is normal when the pressure signal exceeds the threshold value; and a stop signal generating section configured to input therein a sticking determination signal, output in the case of a stuck-open state a control signal maintaining a closed state of the assist valve to the assist valve control section, and output in the case of a normal state a control signal causing the assist valve to perform an opening operation to the assist valve control section.

A vehicle hydraulic system includes: (a) a hydraulic pump device to be driven by a vehicle drive source to eject a working fluid through first and second outlet ports; (b) a first line passage that guides the working fluid ejected through the first outlet port, with a hydraulic pressure being regulated to a relatively high value; (c) a downstream-side passage in which the hydraulic pressure is regulated to a relatively low value; (d) a path-switching valve device configured to allow the working fluid ejected through the second outlet port, to flow into the first line passage, when the hydraulic pressure is lower than a predetermined value, and configured to allow the working fluid ejected through the second outlet port, to flow into the downstream-side passage, when the hydraulic pressure is higher than the predetermined value; and (e) a bypass passage provided between the second outlet port and the downstream-side passage.

A hydraulic system in of a work machine includes a hydraulic pump to supply pilot hydraulic oil in a hydraulic oil reservoir. A travel pump is to drive a travel motor according to a pilot pressure of the pilot hydraulic oil. A target pilot pressure of the pilot hydraulic oil is input through a travel operation device to control, according to the target pilot pressure, the pilot pressure supplied from the hydraulic pump to the travel pump. A pilot oil path connects the travel operation device and the travel pump to supply the pilot pressure to the travel pump. A drain oil path is divided from the pilot oil path. A pressure adjustment valve is provided in the drain oil path to adjust the pilot pressure to be less than the target pilot pressure when a condition is satisfied.

Modular directional valve with two or more crossing elements (E1 . . . En) able, acting only on the entry side, to manage a variable displacement pump (PA) of the load sensing type. In particular, this management allows in a single drive, unlike the conventional crossing distributors, to make the flow rate to the utility independent of the load and allows setting a maximum flow rate at the end of the stroke; in multiple drives, it ensures that the sum of the required flow rates is independent of the loads. A compensated flow rate regulator is placed in the entry side so as to act only on the bypass line LC upstream of the first element (E1 . . . En) while a proportional choke is placed on the load line consisting of a 2-way 2-position tray.

A valve block arrangement configured as a closed center system includes at least one main spool for controlling a hydraulic consumer. The main spool is configured to open and close at least one pressure medium connection between a hydraulic pump and the consumer in controlled, continuous fashion and, in at least one embodiment, is electrically activated. A bypass flow path with a cut valve branches off between the adjustable, hydraulic pump and the main spool. The cut valve is configured to open and close a pressure medium connection between the hydraulic pump and a tank in controlled, continuous fashion. The cut valve is electrically activatable.