Lull 1044C-54 Series II Service Manual - Manual (Page 304)

Frame Tilt and Oscillation
7-22 31200079
Boom Positioned Below 20° With the Service Brake Applied
Fig. 7-15: Circuit Operation Below 20° With the Service Brake Applied
(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.
MV0580
ON REAR STABILIZER CYLINDER
REAR AXLE STABILIZER VALVE
2-WAY SOLENOID VALVE ON
(ENERGIZED)
VALVE ON VALVE PLATE
REAR AXLE STABILIZER CONTROL
3-WAY SOLENOID VALVE ON
(ENERGIZED)
SOLENOID VALVE ON
REAR AXLE STABILIZER
CONTROL VALVE
(ENERGIZED)
S2
BOOM ANGLE GREATER THAN 40 - OPEN
BOOM ANGLE LESS THAN 40 - CLOSED
BOOM ANGLE LESS THAN 20 - CLOSED
BOOM ANGLE GREATER THAN 20 - OPEN
S1
OVER 40°
BOOM
86 30
87 87A 85
B
A
SV1
OVER 20°
BOOM
86 30
87 87A 85
RELAY
RELAY
FROM
FUSE PANEL
+12 VOLTS
B
A
SV3
B
A
SV2
ENERGIZED
ENERGIZED
TO RESTRICT
TRANSMISSION
TO 1ST & 2ND
GEARS
TO ENABLE
FOOT SWITCH
AND TO
DISABLE
TRANSMISSION