Pedal 1 turns about fixed axis A and is connected by turning pair E to spring link 7. When pedal 1 is depressed, rocker arm 2, connected by turning pairs C and D to link 7 and to link 6, pushes piston 3 upward. This opens valve 4 and fluid from the pump is delivered to the brakes. When pedal 1 is released to release the brakes, piston 3 moves downward and opens valve 4'. At this, fluid from the brakes passes out of port 5 and drains to the tank.
$3957$LHP,Va$