Lull 944E-42 Service Manual - Manual (Page 233)

10-21 944E-42
Stabil-TRAK™ System
10.5.10 Hydraulic Circuit Operation - Slow Pivot Mode, Base Oil Out
Conditions:
• Boom angle is above 40° OR
(On SN 0160003881 & Before Only) below 40°
• Park brake OFF
• Service brake DISENGAGED OR
(On SN 0160003881 & Before Only) with enough
pedal movement to produce required pressure in
brake system
• Travel select lever in (F) FORWARD or (R) REVERSE
position
Operation:
As the boom is raised above 40°, the boom proximity
switch is deactivated causing solenoids 12A and 12B to
de-energize and solenoids 4A and 4B to energize. This
allows oil to flow from the base end of the stabilizer
cylinder (1), through solenoid-operated valve 4A (2),
through a 0.060" orifice (3), through another 0.060" orifice
(4), then through solenoid-operated valve 4B (5), to the
rod end of the stabilizer cylinder.
The 0.060" orifices (3 and 4) in solenoid-operated valves
4A and 4B will slow the movement of the rear axle in
reaction to terrain changes. The frame sway will react
normally in this mode.
Because of the greater volume of oil in the base end,
extra oil is returned to the tank through the 100 psi (7 bar)
reducing cartridge (6) in the Stabil-TRAK™ manifold. The
restrictions produce the slow movement, or SLOW PIVOT
mode.
Suction
Return
Load Sense
Pressure
Pilot Pressure
HYDRAULIC
RESERVOIR
ACCUMULATOR
CHARGE/SECONDARY
FUNCTION VALVE
LS
DRAIN P1
LSG ACR
SW P
ACF EF CF PIL PB
PBG
PPG
SW
HYDRAULIC OIL
COOLER
FRAME SWAY
JOYSTICK
CHECK
VALVE
FITTING
CHECK
VALVE
FITTING
SOLENOID COIL
STATE
ENERGIZED
DE-ENERGIZED
E
DE
Ø .041
P
T
2 1
ATTACH
TILT
FRAME EXT/RET LFT/LWR
AU
X
TRANS
MAIN CONTROL
VALVE
INLET
OUTLET
PUMP
Ø .048
FRAME
SWAY
CYLINDER
FTR
FTB
STABILIZER
CYLINDER
.060 DIA.
FTR
P
T
V G3 G2
G1
4A 4B 12B
3
2B
2A
12A
.060 DIA.
.030 DIA.
100 PSI
STABIL-TRAK TM
MANIFOLD
DE
E DE E DE
200
PSI
MU4802
2
3
1
4
6
5