JLG Lull 1044C-54 II Series Service Manual page 304

Frame Tilt and Oscillation
Boom Positioned Below 20° With the Service Brake Applied
7-22
BOOM ANGLE GREATER THAN 40 - OPEN
BOOM ANGLE LESS THAN 40 - CLOSED
S2
+12 VOLTS
FROM
FUSE PANEL
BOOM ANGLE GREATER THAN 20 - OPEN
BOOM ANGLE LESS THAN 20 - CLOSED
S1
Fig. 7-15: Circuit Operation Below
(Ref. Fig. 7-15) The following describes the rear axle stabilizer circuit logic
when the boom is positioned above 20° with the service brake applied.
1. When the boom is below 20°, the proximity switch (S1) is sensing the
boom, so the (S1) proximity switch closes.
2. When the proximity switch (S1) is closed, the Boom Over 20° relay is
energized and Solenoid Valve (SV1) is energized, which allows
unrestricted frame tilt.
3. Applying the service brake locks the rear stabilizer cylinder
hydraulically, which prevents the frame from rotating on the rear axle.
4. Releasing the service brake unlocks the rear stabilizer cylinder
hydraulically, which allows the frame to rotate freely on the rear axle.
86 30
BOOM
OVER 40°
ENERGIZED
RELAY
85 87A 87
TO ENABLE
FOOT SWITCH
AND TO
DISABLE
TRANSMISSION
86 30
BOOM
OVER 20°
ENERGIZED
RELAY
85 87A 87
TO RESTRICT
TRANSMISSION
TO 1ST & 2ND
GEARS
20° With the Service Brake Applied
3-WAY SOLENOID VALVE ON
REAR AXLE STABILIZER CONTROL
VALVE ON VALVE PLATE
(ENERGIZED)
A
SV2
B
2-WAY SOLENOID VALVE ON
REAR AXLE STABILIZER VALVE
ON REAR STABILIZER CYLINDER
(ENERGIZED)
A
SV3
B
SOLENOID VALVE ON
REAR AXLE STABILIZER
CONTROL VALVE
(ENERGIZED)
A
SV1
B
MV0580
31200079