When hydraulic fluid is delivered into cylinder 1, designed integral with the cover, piston 2 moves downward, compressing springs 3 and 4. One end of the springs bears against the bottom of piston 2 an the other against plate 5, which rests on a boss of the housing. As the springs are compressed, energy is accumulated that can be utilized upon a drop in pressure in the system. If the pressure of the fluid increases above the permissible value, the fluid is discharged through radial holes in the cylinder (not shown) which are uncovered by the piston when it has travelled a certain distance downward.
$4128$EHP,FD$