Variable-displacement pump 1 delivers fluid to the left end of power cylinder 2. From the right end of the cylinder, fluid is discharged to the tank. The delivery line of pump 1 is connected to valve spool 3, which is subject to the action of spring 4. Upon a change in pressure in the system, spool 3 is shifted, actuating the mechanism for changing the output of pump 1. The required pressure in the system is set up by usinig screw 5 to regulate the force exerted by spring 4.
$4179$CHP,Dr$