When valve spool 1 is shifted to the left, a part of the fluid delivered by pump 2 at constant pressure passes through pipelines a and shifts pilot-operated valve spools 3 to the right. At this, the rest of the fluid passes through flow-control valves 4 and 5, valve 6, flow-control valves 7 and 8, and valve 9, to the left ends of cylinders 10, 11 and 12. Pistons 13, 14 and 15 move to the right. Fluid from the right ends of the cylinders is discharged along pipelines c to the tank. In the right-hand position of valve spool 1, a part of the fluid is delivered at constant pressure through pipelines b and shifts valve spools 3 to the left, and the part of the fluid passing through the flow-control valves is delivered to the right ends of cylinders 10, 11 and 12. Pistons 13, 14 and 15 move to the left and the fluid from the left ends of the cylinders is discharged through pipelines c to the tank. In the central position of spool 1, no fluid is delivered through pipelines a or b, and pistons 13, 14 and 15 are stationary. In this case, fluid delivered by the pump is by-passed through relief valve 16 to the tank.
$4176$CHP,Dr$