The disclosed apparatus, systems and methods relate to devices, systems and methods for the selective application of down pressure or downforce to a row unit. Each row unit has a dual-action actuator which is in fluidic communication with the hydraulic system for independent control of the supplemental downforce. The pressure line can be directly routed to the lift chamber for a constant supply of up pressure, with down pressure selectively applied to the down chamber for accurate control of the supplemental downforce system.

A valve subassembly includes a pump connection location, a tank connection location, and two constantly adjustable direction control valves each with first and second operating connection locations and an input connection location. A first valve group includes one direction control valve whose input is connected in parallel to two separate pump lines such that pressurized fluid is directed exclusively from the two pump lines to the control connection location. The two pump lines include a maximum of a first pump line and each remaining pump line is a second pump line. The maximum one first pump line is directly connected to the pump connection location in fluid terms, and a separate constantly adjustable pump valve is associated with each second pump line. Pressurized fluid is directed from the pump connection location via the pump valve into the associated second pump line.

To keep operability of a hydraulic actuator excellent even in a state pressure has been sufficiently accumulated in a pressure accumulator. In a hydraulic driving device of a work machine including a hydraulic actuator, a tank, a flow control valve, and a pressure accumulator, there are further provided with a first pressure compensation valve that is for controlling difference between front and back pressures of the flow control valve constant and a second pressure compensation valve that is arranged between the pressure accumulator and the tank and is for controlling difference between front and back pressures of the flow control valve and the first pressure compensation valve constant.

In one aspect, a pressure sensor for detecting a pressure differential between first and second fluid sources may include sensor body defining a cavity and a seal plate slidably positioned within the cavity. The seal plate may define first and second chambers within the cavity, which may respectively be in fluid communication with the first and second fluid sources. The sensor may also include a sensing element configured to detect a position of the seal plate relative to the sensor body, which may be indicative of the pressure differential between the first and second fluid sources. The sensor may further include a first spring positioned within the first chamber and compressed between a first side of the seal plate and the sensing element. Additionally, the sensor may include a second spring positioned within the second chamber and compressed between a second side of the seal plate and the sensor body.

The present application relates to a crane hydraulic system and a controlling method of the system, wherein the crane hydraulic system includes a load sensing subsystem, and the subsystem includes a variable pump, a variable pump oil inlet line, a load feedback line, an oil return line and a pressure compensator; the pressure compensator is provided with an oil inlet, an oil outlet, a first control oil port, a second control oil port and a control spring; the oil inlet communicates with the variable pump oil inlet line, the oil outlet communicates with the oil return line, the first control oil port communicates with the load feedback line, and the second control oil port also communicates with the variable pump oil inlet line; and wherein the control spring and the first control oil port are located on the same end of the pressure compensator, and a set pressure of the control spring is greater than a pressure difference of the variable pump. According to the present application, since the load sensing subsystem is arranged, at the start and stop moments of a winch system, the pressure compensator can be opened, and the variable pump oil inlet line communicates with the oil return line to realize pressure relief, so as to reduce the pressure impact.

The present invention provides a liquid supplying device that can determine whether a CLC can be used appropriately. A liquid supplying device for supplying a liquid from a liquid source to a cleaning device is provided. The liquid supplying device includes a flow rate control device that measures a flow rate of a liquid from the liquid source and controls the flow rate based on the measured value, an IN-side pressure gauge provided between the liquid source and the flow rate control device and an OUT-side pressure gauge provided between the flow rate control device and the cleaning device.

A control system for hydraulic supply system (64) which includes electronic load sensing is configured to adjust the pump supply pressure PSP in dependence on a determined rate of increase of a load sensing pressure LSP. Below a threshold value T of the rate of increase of the load sensing pressure LSP, the pump supply pressure PSP is adjusted so that it is higher than the load sensing pressure LSP by a stand-by pressure differential ?P.sub.st. At or above the threshold value T, the pressure differential is increased to include a dynamic pressure differential ?P.sub.dyn in addition to the stand-by pressure differential ?P.sub.st. A method of controlling a hydraulic system is also disclosed.

An inlet section for use in a hydraulic distributor including a valve body and a slider with a first area and a second area. The inlet section further including said slider being longitudinally slidable within the valve body between a first position in which it prevents passage of fluid from a high pressure line to a low pressure line, and a second position in which it enables passage of fluid. The inlet section further including a main spring active on the second area of the slider in a direction consistent with action of the second pressure and a control device of the slider. The control device of the slider includes a mechanical actuator member selectively active on the slider in a direction consistent with the action of the first pressure on the first area of the slider so as to force the slider in the second position.

A working machine includes a machine body, a left traveling device located left on the machine body, a right traveling device located right on the machine body, and a controller configured or programmed to perform automatic deceleration to automatically reduce a first rotation speed of a left traveling motor and a second rotation speed of a right traveling motor by shifting a speed stage of each of the left and right traveling motors from a second speed stage to a first speed stage that is lower than the second speed stage. The controller is configured or programmed to: not perform the automatic deceleration when the first rotation speed or the second rotation speed is equal to or higher than a predetermined rotation speed; and perform the automatic deceleration when the first rotation speed and the second rotation speed are less than the predetermined rotation speed.

To keep operability of a hydraulic actuator excellent even in a state pressure has been sufficiently accumulated in a pressure accumulator. In a hydraulic driving device of a work machine including a hydraulic actuator, a tank, a flow control valve, and a pressure accumulator, there are further provided with a first pressure compensation valve that is for controlling difference between front and back pressures of the flow control valve constant and a second pressure compensation valve that is arranged between the pressure accumulator and the tank and is for controlling difference between front and back pressures of the flow control valve and the first pressure compensation valve constant.