Fluid at constant pressure is delivered along pipeline a to valve spool 4. In the left-hand position of spool 4, fluid is discharged to the tank, and in the right-hand position, along pipeline b to valve spool 3. If valve spool 3 is in its left-hand position, fluid is delivered along pipeline d to the right end of cylinder 6, and piston 1, together with machine tool table 2, moves to the left. Fluid from the left (exhaust) end of cylinder 6 is discharged through pipelines c, g and e to valve spool 5. If valve spool 3 is in its right-hand position, piston 1 and table 2 move to the right and fluid from the right end of the cylinder is discharged along pipelines d and e to valve spool 5. If spool 3 is in its central position, the table stops. In the right-hand position of valve spool 5, the exhaust fluid is discharged a long pipeline f directly to the tank and the table travels at maximum speed. In the left- hand position of spool 5, the fluid is discharged along pipeline f to pressure reducing valve 7 and flow-control valve 8. This regulates the pressure in cylinder 6 so that piston 1 and table 2 travel at the required speed. Pressure reducing valve 7 provides for a constant pressure of the fluid before flow-control valve 8. As valve 8 is gradually closed, the pressure is increased and table 2 travels at lower speed. In this case, a part of the fluid delivered by pump 10 is discharged by relief valve 9 back to the tank through pipeline m. Fluid is delivered to valve 9 through pipeline k.
$4160$CHP,Dr$