SkyTrak 8042 Service Manual - Manual (Page 885)

Stabil-TRAK™ System and Boom Interlock System
10.44 Model 8042, 10042, 10054 Legacy Rev. 10/03
10.12.9 Hydraulic Circuit Operation - SLOW PIVOT Mode, Base Oil Out
Conditions:
• Boom angle is above 40°
• Park brake OFF
• Service brake DISENGAGED
• 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 Stabil-TRAK™
cylinder (1), through solenoid-operated valve 4A (2),
through a .060" orifice (3), through another .060" orifice (4),
then through solenoid-operated valve 4B (5), to the rod
end of the Stabil-TRAK™ cylinder.
The .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.
STABIL-TRAK
CYLINDER
TM
FTR
P
T
V
Pressure
Suction
Return
Load Sense
G3 G2
G1
4A 4B 12B
3
2B
2A
12A
FRAME
SWAY
CYLINDER
.060 DIA.
.030 DIA.
.060 DIA.
100 PSI
SOLENOID COIL
STATE
ENERGIZED
DE-ENERGIZED DE
E
DE
E E DE DE
P
T
C
PS PB
PLT
PSG
PBG
G
IN T
T
AT
TA
C
H
TIL
T
P
FRAME SWAY EXT/
RET
LFT/
LW
R
AU
X
STABIL-TRAK
MANIFOLD
TM
HYDRAULIC
OIL COOLER
BYPASS
CHECK
VALVE
BYPASS
CHECK
VALVE
HYDRAULIC
RESERVOIR
SECONDARY
FUNCTION
MANIFOLD
PUMP
MAIN CONTROL
VALVE
MH3081
1
2
3
4
5
6