Sod harvesters can have hydraulic systems that are configured to actuate components with precise timing. The hydraulic system of a sod harvester can be configured to maintain the temperature of hydraulic fluid both during harvesting and while harvesting is paused to thereby eliminate or minimize the occurrence of periods of variation in the timing of actuation of the components that the hydraulic fluid drives. As a result, these components can be consistently actuated with precise timing even after harvesting has been paused. Additionally, such configurations can minimize the amount of time required to warm the hydraulic fluid to a steady operational temperature.

Power machines and control systems used thereon include a lift cylinder, a tilt cylinder, and a slave cylinder mechanically connected to assist the lift cylinder with raising a boom. With a lift control valve controlled to cause extension of the lift cylinder to raise the boom, pressure from a hydraulic source is provided to the slave cylinder to aid in raising the boom. Resulting increased pressure on a side of the slave cylinder opens load holding valves, allowing hydraulic pressure from the tilt cylinder to be communicated to the slave cylinder such that tilt cylinder pressure due to a heavy load on an implement aids in raising the boom.

A landing gear lifting/lowering EHA system includes: a hydraulic actuator configured to lift and lower the leg of an aircraft; at least one electrically operated hydraulic pump; a hydraulic path; a pressure sensor attached to the hydraulic actuator or the hydraulic path and configured to output a measurement signal corresponding to hydraulic pressure; and a controller configured to output a control signal to the electrically operated hydraulic pump, wherein, when a state in which the hydraulic pressure exceeds a set pressure continues for a set time, the control unit stops the electrically operated hydraulic pump in operation and resumes the operation of the electrically operated hydraulic pump after the hydraulic pressure drops to or below a second set pressure after the electrically operated hydraulic pump is stopped.

A gangway comprises a fixed platform and a support structure connected to the fixed platform in a manner that allows the support structure to rotate with respect to the fixed platform between a raised stowed position and a lowered deployed position. A self-raising assembly is operative to rotate the support structure from the deployed position to the stowed position. The self-raising assembly includes at least one fluid actuated cylinder connected between the fixed platform and a distal end of the support structure. A raising actuator is usable by an operator to cause operation of the cylinder in a manner that rotates the support structure toward the stowed position.

A hydraulic circuit includes a prime mover that is configured to generate an oscillating flow of hydraulic fluid, and an actuator that is driven by the prime mover and configured to provide oscillating motion and to be connected to a load in each direction of the motion. The hydraulic circuit also includes a reclamation device that is disposed in the hydraulic circuit between the prime mover and the actuator. The reclamation device captures and stores a portion of hydraulic fluid displaced from the actuator during a transition between opposed motions, where the portion of hydraulic fluid corresponds to an amount of hydraulic fluid equal to a volume of fluid required to compensate for compression of fluid within the hydraulic circuit due to system pressure and load pressure. The stored fluid is used by the circuit in a subsequent motion.

Provided is a work machine which can achieve both of excellent operability when an operator manually operates a machine body or a work device and an accuracy of control of the machine body or the work device when a controller performs automatic control. The controller is configured to, in a case where the automatic control function selector switch gives an instruction to disable the automatic control function, adjust an opening amount of a bleed-off valve to a maximum opening amount or an opening amount corresponding to input amounts of control levers, and in a case where the automatic control function selector switch gives the instruction to enable the automatic control function, adjust the opening amount of the bleed-off valve, in at least part of an operation region of the control levers, so as to be smaller than the opening amount with the instruction to disable the automatic control function being given.

A hydraulic control circuit operable to selectively hydraulically link first and second hydraulic actuators and to bypass that hydraulic link.

An agricultural machine includes a float cylinder interconnecting a header linkage system and a frame. A rod side accumulator is in fluid communication with a rod side fluid port of the float cylinder. A float control valve is selectively controllable between an open position allowing fluid communication between a pressure source and the rod side accumulator, and a closed position blocking fluid communication between the pressure source and the rod side accumulator. A downforce accumulator is in fluid communication with a piston side fluid port of the float cylinder. A downforce control valve controls fluid communication between the pressure source and the downforce accumulator. A downforce return valve controls fluid communication between the downforce accumulator and the tank.

An agricultural machine includes a float cylinder interconnecting a header linkage system and a frame of the machine. A first rod side accumulator and a second rod side accumulator are both in fluid communication with a rod side fluid port of the float cylinder. A first accumulator control valve is positioned to control the first rod side accumulator, and is selectively controllable between an open position allowing fluid communication between the first rod side accumulator and the rod side fluid port of the float cylinder, and closed position blocking fluid communication between the first rod side accumulator and the rod side fluid port of the float cylinder. The system provides a slower first float response with the first accumulator control valve open, and a faster second float response with the first accumulator control valve closed.

A balancing valve includes four ports. While the pressures at a pair of balancing ports of a hydraulic balancing valve are equal, the valve maintains two other ports in a closed position. Upon a pressure differential between the balancing ports, fluid communication can occur between one of the balancing ports and either of the other ports based upon the direction of the pressure differential. A hydraulic ride control system utilizes the balancing valve together with other control valves to provide ride control functionality.