A valve (V, V1, V2) includes a housing (VG) and a piston (VK) displaceably guided therein. A first end (VK1) of the piston (VK) can be acted upon by a force, with the aid of which the piston (VK) is displaceable against a spring (F) acting upon a second end (VK2) of the piston (VK). The valve (V, V1, V2) has four switching conditions, in which four ports (A, B, P, T) in the housing (VG) are selectively connectable to one another or blocked with respect to one another. In a first switching condition, none of the ports (A, B, P, T) are connected to one another. The spring (F) is configured in such that, in the absence of an application of force onto the first end (VK1), the piston (VK) is held in a position, which corresponds to the first switching condition of the valve (V, V1, V2).

A hydraulic system for a working machine, the hydraulic system includes: a hydraulic fluid reservoir; a boom actuator having an ascending chamber and a descending chamber; a first pump; a first directional control valve comprising a first ascending state configured for moving the boom in the ascending direction, a descending state configured for moving the boom actuator in the descending direction, and a first neutral state; a second pump; a second directional control valve comprising a second ascending state configured for moving the boom actuator in the ascending direction, and a second neutral state; wherein the second directional control valve further comprises a float state configured to connect at least one of the ascending and descending chambers to the hydraulic reservoir for permitting the boom to move freely in the descending and/or descending directions.

To perform a work with the same operability under a dead weight of a front work equipment in any of a float work and a normal work, when a bucket descends in the air, and after contacting the ground, to perform a work with the operability being maintained as it is when performing the float work, and to perform a work while pressurized hydraulic fluid is supplied from a hydraulic pump when performing the normal work. A lower-ing control during a float working mode is performed in a valve passage state in a first region at which the lowering control is performed under the dead weight of the from work equip-ment without being supplied with hydraulic fluid from the hydraulic pump, regardless of whether or not the bucket is in contact with the ground, and the lowering control during a normal working mode is performed in a valve passage state at the first region in a non-ground-contacting state and at a second region in which the hydraulic fluid can be supplied from the hydraulic pump n a ground-contacting state.

An example valve section includes: a valve body configured to be fluidly coupled to the source and the actuator; a spool movable in the valve body intermediate the source and the actuator; a pressure compensator valve disposed upstream from the spool and configured to regulate flow received from the source, where the valve body defines (i) a first passage disposed upstream from the spool and configured to fluidly couple the pressure compensator valve to the spool, and (ii) a second passage disposed downstream from the spool and configured to fluidly couple the spool to the actuator; and a counterbalance valve disposed in the second passage downstream from the spool, where the counterbalance valve is opened to permit flow therethrough from the actuator to the spool in response to a pilot pressure derived from the first passage when the spool is shifted from a neutral position.

An energy saving directional-control valves (2-position and 3-position) are configured with standard manual override functionality and with the same steady-state input-output behavior as each respective standard/non-energy saving directional-control valve. This allows a standard non-energy saving valve to be replaced with an energy saving valve without reconfiguring the external electrical and manual override command logic.

A hydraulic system is provided, the hydraulic system including a hydraulic load defining a first chamber and a second chamber. Additionally, the hydraulic system includes a pressure source, a fluid storage vessel, a load sense line, and a spool valve. The spool valve fluidly connects the fluid storage vessel to one of the first or second chambers and fluidly connects the pressure source to the other of the first or second chambers. A bypass line is also provided defining a flow path between the hydraulic load and the fluid storage vessel that bypasses the spool valve. Fluid flow may encounter less resistance through the bypass line, such that the hydraulic system may run more efficiently and with a reduced risk for cavitation in the hydraulic load.

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.

A valve assembly is disclosed. The valve assembly includes a valve housing defining a bore, a first valve, and a second valve. The first valve and the second valve are disposed within the bore and each of the first valve and the second valve include a first end and a second end. Further, the first end of the first valve and the first end of the second valve are configured to contact each other. The valve assembly further includes a pilot chamber defined within the bore. The pilot chamber is configured to receive a pilot fluid. Further, a pressure of the pilot fluid inside the pilot chamber is controlled to permit independent movement of the first valve and the second valve within the bore.

A control device, for a hydraulic consumer (22) and susceptible to vibrations, includes a valve (24) having a control spool (40) controllable by an actuating device (46). The valve (24) has a pressure supply port (P), to which a pressure compensator valve can be connected, which can be supplied with pressure fluid from a pressure supply device. The actuating device (46) has a motor (74). A load-pressure-dependent force on the control spool (40) can be generated by a control device (66). That force at the control spool (40) acts on an electronic motor controller (208) of the DC motor (74), which detects a change of the force and acts as a damping of the vibrations of the consumer (22) against this change of force.

A header assembly for an agricultural harvesting machine comprises a first frame assembly, a second frame assembly that supports a cutter, and is movable relative to the first frame assembly, a float cylinder coupled between the first frame assembly and the second frame assembly, an accumulator, a controllable reservoir, and fluidic circuitry. The fluidic circuitry comprises a first conduit forming a first fluid path that provides a flow of pressurized fluid under pressure to the float cylinder, so the float cylinder exerts a float force on the second frame assembly, a valve mechanism that is actuatable to inhibit fluid flow along the first fluid path between the accumulator and the float cylinder, a second conduit forming a second fluid path fluidically coupled to the controllable reservoir, the controllable reservoir being controllable to add fluid to the float cylinder.