SkyTrak 6036 Service Manual - Manual (Page 266)

Stabil-TRAK™ System and Boom Interlock System
10-38 6036, 6042, 8042, 10042, 10054
10.11.13 Hydraulic Circuit Operation -
LOCKED MODE, Frame Level Left
a. Conditions
• Boom angle is above 40°
• Park brake ON, or service brake ENGAGED, or
travel select lever in (N) NEUTRAL
b. Operation
When the joystick control is placed in the frame level mode,
cables activate the frame level valve in the main control
valve assembly. As the joystick is moved to the right, the
frame level spool valve is shifted, allowing oil to flow
through the valve, through the check valve (1) to the base
end of the frame level cylinder (2).
Some of this oil is diverted to the pilot line of the check
valve (3) on the return side of the frame level cylinder,
opening the valve.
Oil from rod end of the frame level cylinder flows through
the check valve (3) opened by incoming pilot pressure oil,
to the FTR port of the Stabil-TRAK™
manifold.
Oil entering at port FTR flows through solenoid valve 3 (4)
through check valve 2B (5), to the rod end of the Stabil-
TRAK™
cylinder (6). Some of this oil is diverted to the
pilot line of check valve 2A (7), opening the valve.
Oil from the base end of the Stabil-TRAK™ cylinder flows
through check valve 2A (7) and through a 0.030 inch orifice
(8). This orifice slows the movement of the frame level.
The oil then flows through solenoid-operated valve 3 (4),
through port V, to the frame level spool valve in the main
control valve. Oil flows through the valve, dumping the
returned oil to the reservoir.
Pressurized oil entering Stabil-TRAK™ manifold at port P
is stopped at the four closed solenoid-operated valves 4A
(9), 4B (10), 12A (11), and 12B (12). At this time pilot
pressure will cause the 100 psi relief valve (13) to change
position, allowing the excess oil to vent to the reservoir.