Disclosed is a hydraulic system for performing land preparation works by means of a simultaneous boom-up and arm-in operation. The hydraulic system according to the present invention includes: an arm cylinder and a boom cylinder that are connected to first and second hydraulic pumps, respectively; a first boom control valve that is disposed in the discharge flow path of the second hydraulic pump; a second boom control valve that is disposed in the discharge flow path of the first hydraulic pump and causes the working fluid of the first hydraulic pump to converge with the working fluid which is supplied from the second hydraulic pump to the boom cylinder; a first arm control valve that is disposed in the discharge flow path of the first hydraulic pump; a second arm control valve that is disposed in the discharge flow path of the second hydraulic pump and causes the working fluid of the second hydraulic pump to converge with the working fluid which is supplied from the first hydraulic pump to the arm cylinder; a recycle valve that is disposed in the flow path between the working fluid inlet port of the first arm control valve and a hydraulic tank; and a second boom control valve spool having a parallel pressure section in which the boom-up pilot pressure does not increase with respect to the boom-up strokes during the simultaneous boom-up and arm-in operation.

A cargo vehicle includes a hydraulic pump driven by an engine, a cargo handling apparatus operated by hydraulic oil from the hydraulic pump, a cargo operating unit for performing an instruction operation to operate the cargo handling apparatus, an electromagnetic proportional control valve disposed between the hydraulic pump and the cargo handling apparatus, a valve controller that controls the electromagnetic proportional control valve depending on an operation state of the cargo operating unit, and a revolution detector that detects a revolution of the engine, wherein the valve controller controls the electromagnetic proportional control valve such that an opening degree of the electromagnetic proportional control valve is limited for a certain time when the revolution of the engine detected by the revolution detector is lower than a predetermined value.

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.

A door breaching device comprising: a longitudinal chassis having a first and a second extremity; a piston assembly located at said first extremity of the chassis, said piston assembly comprising a piston rod, said piston rod having, at a first end, a head and a second end located inside a piston chamber, said piston chamber having two opposite ends, a first end having an opening adapted for the movement of the piston rod therethrough and a second end located opposite said first end; wherein said piston rod is adapted for linear displacement between a first position where the second end of the piston rod is positioned at the second end of the piston chamber and a second position where the second end of the piston rod is at the first end of the piston chamber; a motor operatively connected to a hydraulic pump which is operatively connected to the piston chamber; a control unit for user input, said control unit being operatively connected to the motor; a two-part head assembly comprising: a fixed jaw, attached to the first extremity of the chassis; and a movable jaw, operatively connected to the piston rod of the piston assembly; wherein, in the rest position, the piston rod is in a retracted position to allow the fixed jaw and the movable jaw form a L-shaped extension from the chassis, and upon actuation, the piston rod moves outwardly from the retracted position, the fixed jaw braces the device against an element of a door and frame assembly, while the movable jaw applies a linear force to an opposite element of the door and frame assembly thereby having the movable jaw and fixed jaw form a F-shaped extension from the chassis.

A control system and method for controlling the positioning of an adjustable deflector plate employed in a harvesting combine to adjust a side-to-side flow of crop residue to spreaders associated with the combine and the distribution thereby. The deflector plate is operably extendable into the flow of crop residue to redirect crop residue impinging the deflector plate. The deflector plate is adjusted based upon a comparison between the open/closed states of valves associated with the control system.

To provide a construction machine that can highly precisely control branch flows from a hydraulic pump to a plurality of hydraulic actuators without being affected by load conditions. A controller (100) has a meter-out valve control section (140) configured to calculate a target opening area of a second meter-out valve (65a) (65b) according to a pressure difference between a supply pressure and a second meter-in pressure, or calculate a target opening area of a first meter-out valve (55a) (55b) according to a pressure difference between the supply pressure and the first meter-in pressure.

A door breaching device includes a longitudinal chassis having a first extremity, a piston assembly with a piston rod adapted for linear displacement within a piston chamber, a hydraulic pump operatively connected to the piston assembly, and a two-part head assembly with a fixed jaw attached to the first extremity of the longitudinal chassis and a moveable jaw operatively connected to an end of the piston rod proximate to the first extremity. When the device is in a rest position, the piston rod is in a retracted position within the piston chamber to allow portions of the fixed jaw and the moveable jaw to fit between a first surface and a second surface. Upon actuation of the door breaching device, the piston rod is linearly displaced from the retracted position and the movable jaw applies a force to increase a distance between the first surface and the second surface.

An actuation pressure to actuate one or more hydraulic actuators may be determined based on a load on the one or more hydraulic actuators of a robotic device. Based on the determined actuation pressure, a pressure rail from among a set of pressure rails at respective pressures may be selected. One or more valves may connect the selected pressure rail to a metering valve. The hydraulic drive system may operate in a discrete mode in which the metering valve opens such that hydraulic fluid flows from the selected pressure rail through the metering valve to the one or more hydraulic actuators at approximately the supply pressure. Responsive to a control state of the robotic device, the hydraulic drive system may operate in a continuous mode in which the metering valve throttles the hydraulic fluid such that the supply pressure is reduced to the determined actuation pressure.

A door breaching device includes a longitudinal chassis having a first extremity, a piston assembly with a piston rod adapted for linear displacement within a piston chamber, a hydraulic pump operatively connected to the piston assembly, and a two-part head assembly with a fixed jaw attached to the first extremity of the longitudinal chassis and a moveable jaw operatively connected to an end of the piston rod proximate to the first extremity. When the device is in a rest position, the piston rod is in a retracted position within the piston chamber to allow portions of the fixed jaw and the moveable jaw to fit between a first surface and a second surface. Upon actuation of the door breaching device, the piston rod is linearly displaced from the retracted position and the movable jaw applies a force to increase a distance between the first surface and the second surface.

One object is to calculate the position of a rod of a linear actuator with a high precision. The linear actuator includes a rod capable of moving in an axial direction relative to a housing. The rod is moved by rotation of an output shaft of a motor. A position sensor for sensing the relative position of the rod relative to a preset reference position is provided in the housing. A rotation sensor for sensing the rotation angle of the output shaft of the motor is provided in the vicinity of the motor. The linear actuator includes a position calculating unit for calculating the position of the rod based on a position sensing value of the position sensor and a rotation angle sensing value of the rotation sensor.