When lever 1 turns clockwise, lever 2 and shaft A turn in the same direction, the end of lever 2 being withdrawn from piston 3. This piston is moved out of cylinder 4 by spring 5 and the cylinder is filled with fluid through opened check valve 6. When lever 1 turns in the opposite direction, lever 2 and shaft A turn with it. At this, the end of lever 2 pushes piston 3 to the right, compressing spring 5. Check valve 6 closes and the fluid can escape into the housing only through the passage provided by the flat on pin 8 without lifting valve 7. Only a small amount of fluid can flow out of cylinder 4, thereby decelerating the motion of the piston. Valve 7 opens only upon a drastic increase in the load transmitted to lever 1.
$3946$LHP,DC$