The hydraulic apparatus is set so that the ratio of the pressure-receiving area of the respective bottom oil chambers of the boom cylinder, the arm cylinder and the bucket cylinder to the pressure-receiving area of the respective rod oil chambers matches the ratio of the extruded volume drawn into or discharged from the bottom oil chambers per single rotation by the respective extrusion members of the first hydraulic pump motor, the second hydraulic pump motor and the third hydraulic pump motor to the volume discharged from or drawn into the rod oil chambers.

The invention relates to a pressure-limiting device designed to be installed in a system comprising a first line (11) and a second line (12) that can comprise pressurised oil, as well as comprising a discharge and/or booster line (10). The device also comprises a pressure selector (130, 150) in the form of a cage defining two seats (132, 134) and two pressure relief valves (160, 180). The limiting device is characterised in that it further comprises at least one means (170, 172; 190, 192) for regulating a pressure relief valve, disposed on the outside of an axial end of the pressure selector (150), in the form of a cage that allows the loading of the associated pressure relief valve to be regulated.

A power transmission device may include a first power transmission unit configured to connect to an input portion and to receive a power from the input portion, a second power transmission unit configured to deliver the power to an output portion, and a connecting unit configured to connect the first power transmission unit and the second power transmission unit, and to deliver a pressure of a transfer fluid occurring due to the first power transmission unit to the second power transmission unit.

In a hydraulic control device, when the rotational speed of an electric motor is an appropriate rotational speed, a first spool is in a first position, in which communication between a sixth port and a second port is blocked. When the rotational speed of the electric motor exceeds the appropriate rotational speed, the first spool is in a second position, in which the sixth port and the second port are placed in communication.

A hydraulic drive system for an agricultural implement includes a high pressure supply line configured to provide hydraulic fluid under pressure. The hydraulic drive system also includes a low pressure return line configured to return the hydraulic fluid. The hydraulic drive system further includes a plurality of hydraulic motors and coupled to the high pressure supply line. The hydraulic drive system still further includes a plurality of cylinder systems isolated from the high pressure supply line to minimize a supply pressure of the hydraulic fluid provided from a pump coupled to the high pressure supply line and to minimize throttling losses in the hydraulic drive system during operation of the hydraulic drive system.

A hydraulic drive system for an agricultural implement includes a high pressure supply line configured to provide hydraulic fluid under pressure. The hydraulic drive system also includes a low pressure return line configured to return the hydraulic fluid. The hydraulic drive system further includes a plurality of hydraulic motors and coupled to the high pressure supply line. The hydraulic drive system still further includes a plurality of cylinder systems isolated from the high pressure supply line to minimize a supply pressure of the hydraulic fluid provided from a pump coupled to the high pressure supply line and to minimize throttling losses in the hydraulic drive system during operation of the hydraulic drive system.

Disclosed embodiments of power machines, implements and hydraulic systems utilize a hydraulic flow control circuit and method to implement multiple modes of operation while optimizing hydraulic fluid flow to either or both of primary and secondary function actuators. In a first mode the hydraulic flow control circuit is configured to receive pressurized hydraulic fluid flow from a first conduit and to provide the pressurized hydraulic fluid to the primary and secondary function actuators. In the first mode, the circuit is configured to direct return flow from the primary and secondary function actuators through the second conduit for return to the power machine. In a second mode, the circuit receives flow from the second conduit, provides the flow only to the secondary function actuator, and directs the return flow to the power machine through the first conduit.

A hydraulically powered implement is designed for use in connection with a tractor that has a hydraulic pump that supplies pressurized hydraulic fluid to the implement. The implement includes a variable displacement hydraulic motor, an operative element driven by the hydraulic motor, a speed sensor configured to measure the rotational speed of the operative element and output a speed signal representative of the measured speed, a shift module that adjusts the displacement of the hydraulic motor in response to a shift command signal, and a controller. The controller sends the shift command signal to the shift module in response to speed signal output by the speed sensor.

A stabilizing system includes a plurality of jacks, each operated by a corresponding hydraulic actuator. A hydraulic fluid transfer pump supplies hydraulic fluid to and receives hydraulic fluid from one or more pressure chambers of the actuator. A pilot-operated check or directional valve may be provided in fluid communication with one or more of the pressure chambers and configured to regulate the flow of hydraulic fluid to and from the pressure chamber. A directional control valve may connect the pump output with the jacks via respective pilot-operated directional valves. The directional control valve may include a plurality of switch positions respectively connecting the pump output with pairs of the jacks.

The present disclosure discloses a hydraulic machine including a support assembly and a main cylinder device connected with the support assembly. The main cylinder device includes at least two main cylinder assemblies and at least two piston rods respectively. The at least two piston rods are opposite to each other and move along opposite directions and on the same straight line. A support worktable device is disposed on the support assembly and spaced with the main cylinder device. At least two pressing mechanisms are formed between the support worktable device and the at least two main cylinder assemblies or between the support worktable device and the at least two piston rods. The at least two pressing mechanisms are configured for pressing work pieces simultaneously.