A pressure medium cylinder (1) for moving a toothed bar (3), comprising a toothed bar (3) on at least one side of which is formed a toothing (4). Inside the toothed bar (3), a cavity (6, 6a, 6b) is formed, extending to at least one end (7a, 7b) of the toothed bar. The pressure medium cylinder (1) further comprises a longitudinal structure (8, 8a, 8b), the longitudinal structure (8, 8a, 8b) and the toothed bar (3) being adapted movably in relation to each other, and the longitudinal structure (8, 8a, 8b) is adapted at least partly inside said cavity (6, 6a, 6b). The toothed bar (3) and longitudinal structure (8, 8a, 8b) are adapted in a sealed manner in relation to each other so that the toothed bar and the longitudinal structure are movable in relation to each other by the effect of a pressure medium.

A control valve is provided for construction equipment having a holding valve which prevents the natural lowering of an operation apparatus due to the dead weight of the operation apparatus when an actuator is in a neutral position. A control valve for construction equipment according to the present invention includes: a valve body in which a supply path in communication with a pump path, through which a hydraulic fluid is supplied from a hydraulic pump, and actuator ports connected to an actuator are formed; a spool which is embedded in the valve body so as to be switchable; a holding valve having a holding poppet which is formed at the actuator port of any one of the actuator ports, and an auxiliary spool which is connected to a back pressure chamber of the holding poppet and releases the held load of the actuator at the time of switching; a control valve provided in the valve body; a pilot pressure control valve, embedded in the holding valve so as to be switchable, which applies or blocks a pilot pressure applied to switch the auxiliary spool on or off through a path when the pilot pressure control valve is switched on or off by means of the pressure of the hydraulic fluid which is drained from the back pressure chamber of the holding poppet at the time of switching the auxiliary spool on or off.

A construction machine control system includes: a target construction ground shape generation unit which generates a target construction ground shape indicating a target shape of an excavation target; a working device control instruction determination unit which outputs an instruction for driving the working device in a working device operation plane orthogonal to at least one of a boom axis, an arm axis, and a bucket axis based on an operation state of at least one of an arm and a bucket and a distance between the bucket and the target construction ground shape; and a tilting control instruction determination unit which outputs an instruction for performing a tilting control of the bucket about a tilting axis based on a tilting state of the bucket and the distance between the bucket and the target construction ground shape.

A work machine control system that controls a work machine including a working device having a working tool that rotates about a shaft line includes: a target construction shape generation unit that generates a target construction shape indicating a target shape of a construction target of the work machine; a target shape calculation unit that calculates a control target shape which is a target shape when controlling rotation of the working tool from the target construction shape and calculates an extended target shape obtained by extending the control target shape; and a working device control unit that controls the rotation of the working tool about the shaft line based on a distance between the working tool and the control target shape and the extended target shape.

A ripper device for a work vehicle includes a first cylinder, a shank, and a second cylinder. The shank is actuated by the first cylinder and is aligned with the first cylinder in plan view. The second cylinder includes a proximal end attached to the work vehicle and a distal end on the opposite side from the proximal end. The second cylinder actuates the shank. The proximal end and the distal end of the second cylinder are located higher than the first cylinder in side view. The diameter of the first cylinder is larger than the diameter of the second cylinder.

A hydraulic excavator (1) provided with a controller (40) having a machine control section (43) that executes machine control for moving a work implement (1A) following a predetermined condition at the time of operation of operation devices (45a, 45b, and 46c) includes a level-of-intervention input device (96) that is operated by an operator. The controller includes a correction amount calculating section (43m) that calculates a correction amount of a level of intervention indicating a degree of intervention by the machine control in an operation of the work implement instructed through operation of the operation devices, based on an operation amount of the level-of-intervention input device. The machine control section executes the machine control to intervene in the operation of the work implement instructed through the operation of the operation devices at a level of intervention corrected based on the correction amount calculated at the correction amount calculating section.

A control system of a hybrid construction machine includes fluid pressure pumps, a regeneration motor, a rotating electric motor coupled to the regeneration motor, a storage battery configured to store electric power generated by the rotating electric motor, an assist pump provided coaxially to the regeneration motor to be driven by the rotating electric motor, the assist pump being configured to supply a working fluid to a fluid pressure actuator, and load adjusting units configured to change a load of the assist pump in accordance with a state of the storage battery.

An attachment monitoring system according to an embodiment includes a working machine, attachments, a measurement unit, a terminal device, and a server device. The working machine includes a working arm. Each of the attachments is attached to a leading end part of the working arm so as to be driven by a fluid pressure. The measurement unit is provided to measure at least one of a vibration and the fluid pressure when each of the attachments identified on the basis of individual identifying information is driven. The terminal device is provided in the working machine to acquire measured results of the measurement unit. The server device collects the measured results of the respective attachments from the terminal device, and analyzes operation states of the respective attachments on the basis of the collected measured results.

Soil compactor including a compaction drum rotatably supported by a compaction roller frame, wherein the compaction drum frame comprises two longitudinal members arranged in a direction longitudinal to the compactor on both sides of the compaction roller and supporting said compaction roller, and, connecting the two longitudinal members together, two cross members arranged in a direction perpendicular to the compactor and along both sides of the compaction roller, wherein the compaction roller frame is connected to a compactor main frame via one of the two cross members, and wherein at least one sight opening is provided within the other of the two cross members.

When hydraulic fluid discharged from a hydraulic actuator is to be recovered for driving a different hydraulic actuator, the recovery frequency is increased to achieve further energy saving. To this end, a pressure increasing circuit 36 is provided in which a communication pressure increasing valve 12 is disposed in a communication passage 26 that connects a bottom side line 23 of and a rod side line 24 a boom cylinder 4. A recovery control valve 11 is controlled such that, when a first operation unit 5 is operated in a boom lowering direction (own weight falling direction of the boom) and a second operation unit 6 is operated simultaneously, only if the pressure at the bottom side of the boom cylinder 4 is higher than the pressure at the arm cylinder side that is a recovery destination of hydraulic fluid, the recovery control valve 11 is opened to recover the flow rate discharged from the bottom side of the boom cylinder 4 to the arm cylinder side.