4.5 OPERATION
Port p means “pump port”,and is connected to the pump,while port C means “Cylinder port”, and is
connected to the cylinder.Drain ports T1 to T4 are connected to the tank.
1) Neutral position
In the NEUTRAL position,Spring chamber of unloading valve connected to
TANK(T2),Therefore the force imposed upon the right hand side of the unloading valve, then
the fluid from the pump flows into TANK(T1).
The pressure in chamber becomes equal to the tank pressure.Consequently the fluid in the C
port becomes high,then the check valve and main check valve completely closes the cylinder
circuit enough to hold the piston steady.