An assembly system for components of a pressurized fluid supply system for an agricultural vehicle includes a body having at least one fluid duct connectable at one end to a pressurized fluid supply and having a socket at the other end. A detachable component such as an accumulator or oil filter is connectable in releasable mechanical engagement with the body to receive pressurized fluid from the at least one fluid duct. The engagement results from insertion of at least a portion of the component into the socket and rotation of the component to a locked position. The body has at least one discharge duct extending therethrough. In a partially rotated position of the component portion within the socket, the component remains mechanically attached to the body and the fluid duct and discharge duct are in fluidic connection, discharging accumulated pressure in the fluid duct.

A hydraulic system controller is disclosed. The hydraulic system controller may determine a maximum active circuit pressure of a set of active hydraulic circuits of the hydraulic system, wherein the hydraulic system includes a hydraulic pump to cause fluid to flow throughout the set of active hydraulic circuits; determine a circuit pressure of a hydraulic circuit of the hydraulic system; determine, based on a hydraulic flow command for the hydraulic circuit and the circuit pressure, a desired circuit delta-pressure for the hydraulic circuit; determine, based on the desired circuit delta-pressure and a pressure difference between the maximum active circuit pressure and the circuit pressure, a circuit valve setting for a circuit valve of the hydraulic circuit; and cause a control device to set a position of the circuit valve according to the circuit valve setting.

An example valve includes: a first port, a second port, and a load-sense port; a valve piston configured to block fluid flow from the first port to the second port when the valve piston is in a neutral position; a reverse flow spring applying a first biasing force on the valve piston in a proximal direction; and a pressure compensation spring disposed in a spring chamber and applying a second biasing force on the valve piston in a distal direction, wherein when pressure level of fluid at the second port is higher than pressure level of fluid at the load-sense port, fluid flows from the second port to the spring chamber and the load-sense port, and wherein when pressure level of fluid at the load-sense port is higher than pressure level of fluid at the second port, fluid of the load-sense port is provided to the spring chamber.

To enable to arbitrarily change a hydraulic pump which supplies pressure oil to a hydraulic actuator at first in a hydraulic control system equipped with the hydraulic actuator using both first and second hydraulic pumps as a pressure oil source. An operation means is installed which can arbitrarily change working order of the first flow rate control valves for boom and stick for controlling the supply flow rate from first hydraulic pump to boom cylinder and stick cylinder and second flow rate control valves for boom and stick for controlling the supply flow rate from second hydraulic pump to boom cylinder and stick cylinder.

To enable to arbitrarily change a hydraulic pump which supplies pressure oil to a hydraulic actuator at first in a hydraulic control system equipped with the hydraulic actuator using both first and second hydraulic pumps as a pressure oil source. An operation means is installed which can arbitrarily change working order of the first flow rate control valves for boom and stick for controlling the supply flow rate from first hydraulic pump to boom cylinder and stick cylinder and second flow rate control valves for boom and stick for controlling the supply flow rate from second hydraulic pump to boom cylinder and stick cylinder.

A system and method for detecting the functional state of a piloted or direct-operated isolation valve in a hydraulic circuit is presented. In some examples the hydraulic circuit is a steering circuit and the isolation valve provides selective isolation between a hydraulic actuator and one or more metering valves. In some examples, the isolation valve assembly is movable between a first position, in which fluid flow between the metering valve and the actuator is enabled, and a second position, in which fluid flow between the metering valve and the actuator is blocked. When the isolation valve assembly is moved to one of the first and second positions, an inlet port and a pressure sensing port of the isolation valve assembly are placed in fluid communication with each other. When the isolation valve assembly is moved to the other of the first or second position, a second inlet port and the pressure sensing port are placed in fluid communication.

A system and method for detecting the functional state of a piloted or direct-operated isolation valve in a hydraulic circuit is presented. In some examples the hydraulic circuit is a steering circuit and the isolation valve provides selective isolation between a hydraulic actuator and one or more metering valves. In some examples, the isolation valve assembly is movable between a first position, in which fluid flow between the metering valve and the actuator is enabled, and a second position, in which fluid flow between the metering valve and the actuator is blocked. When the isolation valve assembly is moved to one of the first and second positions, an inlet port and a pressure sensing port of the isolation valve assembly are placed in fluid communication with each other. When the isolation valve assembly is moved to the other of the first or second position, a second inlet port and the pressure sensing port are placed in fluid communication.

A flow rate controller and a drive device are provided with a cylinder flow passage connected to an air cylinder; a main flow passage for supplying air to and discharging air from the air cylinder; an auxiliary flow passage that has a first throttle valve and through which exhaust air discharged from the air cylinder passes with a smaller flow rate than that of the main flow passage; a switch valve that switches between a first position in which the cylinder flow passage communicates with the main flow passage and a second position in which the cylinder flow passage communicates with the auxiliary flow passage; and a pilot air adjustment part that guides a portion of the exhaust air from the air cylinder as pilot air to the switch valve.

To make it possible to control supply, discharge, and recycled flow rates independently of each other for the stick cylinder in a construction machine comprising first and second stick spool valves respectively connected to first and second hydraulic pumps. [Solution] A poppet valve is provided at upstream side of the first stick spool valve for controlling a supply flow rate from first hydraulic pump, the first stick spool valve is configured to supply hydraulic flow from the poppet valve to the stick cylinder without restricting the flow, and when the stick cylinder is extended, the poppet valve is configured to control supply flow rate from the first hydraulic pump to head side oil chamber, the first stick spool valve is configured to control recycled flow rate from a rod side oil chamber to the head side oil chamber, and the second stick spool valve is configured to control the supply flow rate from second hydraulic pump to head side oil chamber and the discharge flow rate from the rod side oil chamber to an oil tank.

To make it possible to control supply, discharge, and recycled flow rates independently of each other for the stick cylinder in a construction machine comprising first and second stick spool valves respectively connected to first and second hydraulic pumps. [Solution] A poppet valve is provided at upstream side of the first stick spool valve for controlling a supply flow rate from first hydraulic pump, the first stick spool valve is configured to supply hydraulic flow from the poppet valve to the stick cylinder without restricting the flow, and when the stick cylinder is extended, the poppet valve is configured to control supply flow rate from the first hydraulic pump to head side oil chamber, the first stick spool valve is configured to control recycled flow rate from a rod side oil chamber to the head side oil chamber, and the second stick spool valve is configured to control the supply flow rate from second hydraulic pump to head side oil chamber and the discharge flow rate from the rod side oil chamber to an oil tank.