A hydraulic control system for use with a work machine. The work machine has a platform which supports an operator. When the operator is not on the platform, the platform moves into a first position, causing a signal generator to send a signal to a controller. The controller is configured to limit the hydraulic flow to the ground drive motor when the platform is in the first position. The controller may directly reduce operation of the engine, or may adjust a valve which diverts a portion of hydraulic flow. The limitation may be overridden when desired by the operator.

A work vehicle a computing system configured to receive first and second input associated with controlling the operation of the first and second hydraulic load, respectively. Furthermore, the computing system is configured to control the operation of a first or second flow control valve corresponding to the one of the first or second hydraulic loads associated with the greater hydraulic fluid pressure such that the corresponding adjustable orifice is at a maximum flow position. Additionally, the computing system is configured to determine the first and second pressures of the hydraulic fluid being supplied to the first or second hydraulic loads. Moreover, the computing system is configured to control the operation of the first or second flow control valve corresponding to another of the first or second hydraulic loads based on the corresponding received first or second input and the determined first and second pressures.

When a first control valve and a second control valve are in non-neutral positions, respectively, a fifth fluid passage and a second fluid passage are closed, thereby generating a first pressure within a fifth portion of the fifth fluid passage and a second pressure within a second portion of the second fluid passage, so that the first pressure is applied to a first valve through a fourth fluid passage to move the first valve to close the third fluid passage and a second pressure is applied to the confluence valve through a first fluid passage to move the confluence valve to a confluence position. When the confluence valve is in the confluence position, the confluence valve directs working fluid from a first working fluid supply to the second control valve.

A hydraulic system for operating a circle drive gear of a grading machine includes a pump configured to output pressurized fluid, a directional control valve fluidly coupled to the pump, a bidirectional hydraulic motor located downstream of the directional control valve and fluidly coupled to the directional control valve via hydraulic lines. The hydraulic motor has an output shaft that is configured to be rotationally driven by pressurized fluid output by the pump. Dual counterbalance valves may be disposed within the hydraulic circuit of the directional control valve and hydraulic motor such that any gearbox driven by the hydraulic motor is protected from external opposing forces. Accordingly, motion in the circle drive system is hydraulically locked at the beginning and release of a circle rotation command with the help of fluid pressure in the hydraulic lines.

The present disclosure relates to a valve assembly including a valve moveable between an open position where hydraulic fluid flow is permitted between first and second ports of the valve and a closed position where hydraulic fluid flow is blocked between the first and second ports. A characteristic vibration is generated by turbulent hydraulic fluid flow within the valve when hydraulic fluid flow is first initiated between the first and second ports as the valve moves from the closed position toward the open position. The valve assembly also includes a controller for providing electrical current to control movement of the valve via a solenoid. The controller includes an accelerometer for sensing the characteristic vibration. The controller identifies an electrical current value of the electrical current at a time when the characteristic vibration is detected.

A quick coupler circuit includes a cylinder to attach and/or detach an attachment to and/or from a construction machine by expansion and/or contraction, a flow pump to supply fluid to the cylinder, a valve through which fluid for operating the cylinder passes, a spool valve which includes a spool, to move along an axial direction, and to form a pressure at a node of the flow pump according to movement of the spool, an electronic proportional pressure reducing valve to control the spool valve, a switch to perform an ON/OFF operation, and a controller to output a control current to the electronic proportional pressure reducing valve in response to the operation of the switch. The controller is maintains control current which it outputs during the switch's ON operation for a predetermined period of time after the switch's OFF operation.

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.

A technique is directed to methods and systems of an implement lock-out on lever-controlled machines. A lock-out system can monitor the position of an implement and lock-out the implement control(s) when the implement is within a threshold distance to parts of the machine. The lock-out system can generate an implement lock-out to slow, stop, or reduce the force of a hydraulic valve(s) controlling the implement. The lock-out system can use inputs such as electronic fence blade position system data, articulation angles, wheel lean angles, steering angles, ripper positions, mode selection or similar data to determine to generate the implement lock-out. The lock-out system can generate the implement lock-out by a flow supply shutoff to the implement while maintaining pressure to the steering valve. The lock-out system can send visual or audible notifications to alert the operator of the implement's proximity to the machine or of an implement lock-out.

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.

A hydraulic system for an agricultural system includes a hydraulic circuit and a bi-directional filter disposed on a bi-directional fluid line of the hydraulic circuit. The bi-directional filter includes a check valve fluid line having a check valve configured to block a fluid from flowing through the check valve fluid line in a first direction and to enable the fluid to flow through the check valve fluid line in a second direction, opposite the first direction, and a filter fluid line having a filter configured to enable the fluid to flow through the filter fluid line in the first direction and the second direction. The filter is configured to block particles that are greater than a threshold size from passing through the filter fluid line, and the filter fluid line is in a parallel flow configuration with respect to the check valve fluid line.