Fluid control system having float control

A fluid circuit adapted for use in a fluid control system having a source of pressurized fluid connected to a reservoir, a source of pressurized pilot fluid, and a fluid actuator having first and second fluid actuating chambers, the fluid circuit comprising:

• a pilot operated directional control valve having pressure chambers at opposed ends, a first outlet port connected to the first fluid actuating chamber of the fluid actuator, a second outlet port connected to the second fluid actuating chamber of the fluid actuator, a pressure inlet passage, and an exhaust port, the directional control valve being movable from a centered, neutral position towards first and second operative positions and a float position, at the neutral position, each of the first and second outlet ports, the pressure inlet passage and the exhaust port is blocked from one another, at the first operative position, the first outlet port is in communication with the pressure inlet passage and the second outlet port is in communication with the exhaust port, at the second operative position, the second outlet port is in communication with the pressure inlet passage and the first outlet port is in communication with the exhaust port, and at the float position, the first and second outlet ports are in open communication with the exhaust port and the pressure inlet passage is blocked therefrom;
• a pilot control arrangement having an input control arrangement and first and second pilot control valves connected to the source of pressurized pilot fluid and being movable from a flow blocking position towards a flow passing position in response to movement of the input control arrangement, each of the first and second pilot control valves has an inlet port connected to the source of pressurized pilot fluid, an outlet port and an exhaust port, the outlet port of the first pilot control valve is connected to one of the opposed ends of the directional control valve and the outlet port of the second pilot control valve is connected to the other of the opposed ends;
• a first pilot controlled load check valve is disposed between the first outlet port of the directional control valve and the first fluid actuating chamber of the fluid actuator and a second pilot controlled load check valve is disposed between the second outlet port and the second fluid actuating chamber of the fluid actuator, each of the first and second pilot controlled load check valves having a valving element and a pressure chamber defined therein and being urged closed in response to pressurized fluid in the pressure chamber and opened in response to venting of the pressurized fluid from the pressure chamber;
• a first vent valve being disposed between the pressure chamber of the first pilot controlled load check valve and the reservoir and a second vent valve being disposed between the pressure chamber of the second pilot controlled load check valve and the reservoir, the first vent valve being spring biased to a closed position and movable to an open position in response to receipt of a signal from the second pilot control valve and the second vent valve being spring biased closed and movable to an open position in response to receipt of a signal from the first pilot control valve;
• and
• a sequence valve disposed between the second pilot control valve and the second vent valve, the sequence valve has an inlet port connected to the second pilot valve, an outlet port connected to the second vent valve and an exhaust port and movable between a first, spring biased position at which the inlet port is blocked and the outlet port is in communication with the exhaust port and a second position at which the exhaust port is blocked and the inlet port is in communication with the outlet port, the sequence valve is movable to its second position in response to a predetermined level of pressurized fluid being directed to the inlet port thereof from the second pilot valve.