An apparatus for directing fluid flow is disclosed, including a valve structure having a chamber, a main port, a first port, and a second port, each of the ports being connected to the chamber. A poppet structure in the chamber is moveable between a first position blocking the first port and a second position blocking the second port. A first compliant member connecting the poppet structure to an inner wall of the chamber, is configured to alternate application of forces to the poppet structure, in opposite directions, between the first and second positions.

A shuttle valve is disclosed. The shuttle valve comprises a valve body, a valve member, and a catch. The valve body comprises a first and a second fluid inlet, a central chamber, and a fluid outlet. The first and second fluid inlets and the fluid outlet open into the central chamber via a first and a second inlet mouth and an outlet mouth. The valve member is configured to move between a first and a second position, the valve member closes the first inlet mouth and allows fluid communication between the second inlet mouth and the outlet mouth when the valve member is in the first position, and the valve member closes the second inlet mouth and allows fluid communication between the first inlet mouth and the outlet mouth when the valve member is in the second position.

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.

An air cylinder in which a flow rate controller is built in, has a head cover and a rod cover. A pilot air adjustment unit guides exhaust air to a switch valve of the flow rate controller as pilot air, and the switch valve is switched by an increase in the pressure of the pilot air.

The present invention provides a switching valve comprising: a housing including a first port, a second port, and a third port; a valve element configured to be movable in the housing so as to selectively allow one of the first port and the second port to communicate with the third port in accordance with a pressure difference between the first port and the second port; and a pressing member configured to press the valve element toward a side of the first port.

An apparatus for directing fluid flow is disclosed, including a valve structure having a chamber, a main port, a first port, and a second port, each of the ports being connected to the chamber. A poppet structure in the chamber is moveable between a first position blocking the first port and a second position blocking the second port. A first compliant member connecting the poppet structure to an inner wall of the chamber, is configured to alternate application of forces to the poppet structure, in opposite directions, between the first and second positions.

Disclosed is a hydraulic control valve assembly of automatic steering system for agricultural machine including a proportional directional valve (3). A balancing valve (1) is arranged between the proportional directional valve (3) and the steering cylinder. A first shuttle valve (2) is arranged between the proportional directional valve (3) and the balancing valve (1). The first shuttle valve (2) is positioned on one side of the proportional directional valve (3). An overflow valve (4) is positioned on another side of the proportional directional valve (3). The overflow valve (4) is connected to a second shuttle valve (6) and a logic valve (5) respectively. The hydraulic control valve assembly has a large control power, a rapid response, and is more suitable for the autonomous navigation operation of agricultural machine. Moreover, the system saves more energy, such that the autonomous navigation operation of agricultural machine is more stable.

An example shuttle valve includes: (i) a valve body comprising a longitudinal cylindrical bore, a first inlet port, a second inlet port, an outlet port, and a key that protrudes radially inward within the longitudinal cylindrical bore; and (ii) a shuttle mounted in the longitudinal cylindrical bore and configured to move axially therein, wherein the shuttle comprises a plurality of radial protrusions that protrude radially outward from, and are circumferentially spaced apart about, a peripheral surface of the shuttle, and wherein the key of the valve body is interposed between two radial protrusions of the plurality of radial protrusions.

A hydraulic control assembly for a plurality of consumers includes, for each consumer, a supply metering orifice configured to control fluid flow. A flow-sensing fluid-flow-path extends over detection orifices positioned hydraulically in series, whereby a detection orifice is assigned to each supply metering orifice. The fluid-flow-path is connected to a hydraulic pump upstream of the detection orifices, and a control device of the hydraulic pump downstream of the detection orifices. Each detection orifice is configured to close the fluid-flow-path upon detecting a fluid supply deficiency for a corresponding consumer, whereby the control device is configured to interact with the fluid-flow-path such that fluid flow from the hydraulic pump is increased. When no customers have a supply deficiency, the fluid-flow-path over the detection orifices is fully opened, and the control device is configured to reduce fluid flow from the hydraulic pump.

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.