TM 5-3895-382-24
When the vibratory control switch is in the OFF position, the
high amplitude and low amplitude solenoid coils are not
energized. Charge oil is blocked by the valve spool inside the
valve body and both ends of the servo piston assembly are
vented to the hydraulic oil tank through the electrical
displacement control. Piston (2) is held in the centered
position by adjusting screw (3) and a spring inside the servo
piston. The vibratory pump swashplate will remain at zero
angle and there is no oil flow from the vibratory pump.
When the vibratory control switch is depressed to the ON
position and the vibratory selector switch is at the HIGH
amplitude position, the high amplitude solenoid coil is
energized. The valve spool inside the valve body moves
against the force of the centering spring and allows charge oil
pressure to flow to cavity (4) of the servo piston assembly.
Cavity (5) is connected to the hydraulic oil tank through the
vibratory amplitude valve. Piston (2) is moved opposite cavity
(4) against the servo piston internal stop. This will move the
swashplate to the maximum angle for HIGH amplitude.
When the vibratory control switch is depressed to the ON
position and the vibratory selector switch is at the LOW
amplitude position, the low amplitude solenoid coil is
energized. The valve spool inside the valve body moves
against the force of the centering spring in the opposite
direction and allows charge oil pressure to flow to cavity (5) of
the servo piston assembly. Cavity (4) is connected to the
hydraulic oil tank through the vibratory amplitude valve. Piston
(2) is moved opposite cavity (5) against the servo piston
internal stop. This will move the swashplate to the maximum
angle for LOW amplitude.
13-10
