When tie-rod 1, linked to the control lever, moves to the left, lever 2 turns about point O, shifting valve spool 3 to the right. At this, servomotor 4 is blocked off from the drain and is connected to the pressure main. The fluid moves piston 5 to the right. Lever 6, turning about fixed axis A, actuates the mechanism being controlled through tie-rod 7. If tie-rod 1 continues to move to the left, lever 2 turns about point D. If tie-rod 1 is stopped, lever 2 turns about point B, spool 3 is shifted to the left, disconnecting servomotor 4 from the pressure main and connecting it to the tank. When tie-rod 1 is returned to its initial position, valve spool 3 and servomotor 4 are also returned to the initial position.
$3950$LHP,Dr$