Lull 1044C-54 Series II Service Manual - Manual (Page 301)

Frame Tilt and Oscillation
31200079 7-19
Boom Positioned Above 40°
Fig. 7-12: Circuit Operation Above 40°
(Ref. Fig. 7-12) The following describes the rear axle stabilizer circuit logic
when the boom is positioned above 40° elevation.
1. When the boom is above 40°, the proximity switch (S2) is not sensing
the boom. Therefore, the proximity switch (S1) opens and is also not
sensing the boom.
2. When the proximity switch (S2) is open, the Boom Over 40° relay is not
energized and power is directed to the coil of Relay K11 of the
transmission logic (see Transmission Section 8). When K11 is
energized, power is removed from all of the transmission solenoids,
which puts the transmission into Neutral and illuminates the
Transmission Disconnect Lamp in the instrument cluster.
3. Additionally, when the Boom Over 40° relay is not energized, Solenoid
Valves SV2 and SV3 are energized, which locks the rear stabilizer
cylinder. This prevents the frame from rotating on the rear axle and
illuminates the Rear Oscillation Lock lamp in the instrument cluster.
4. An additional effect of the Boom Over 40° relay not being energized is
theTransmission Disconnect Override Footswitch is enabled. Pressing
the Transmission Disconnect Override Footswitch, when the boom is
over 40°, reengages the transmission (first gear only) and allows very
slow, restricted oscillation of the frame on the rear axle. This allows
the machine to be moved. This is an extremely dangerous operation –
see the Operator's Manual.
5. The frame tilt is also restricted when the boom is over 40° because
Solenoid Valve (SV1) is energized.
ON REAR STABILIZER CYLINDER
REAR AXLE STABILIZER VALVE
2-WAY SOLENOID VALVE ON
(NOT ENERGIZED)
VALVE ON VALVE PLATE
REAR AXLE STABILIZER CONTROL
3-WAY SOLENOID VALVE ON
(NOT ENERGIZED)
SOLENOID VALVE ON
REAR AXLE STABILIZER
CONTROL VALVE
(NOT ENERGIZED)
MV0550
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
NOT ENERGIZED
NOT ENERGIZED
TO RESTRICT
TRANSMISSION
TO 1ST & 2ND
GEARS
TO ENABLE FOOT
SWITCH AND TO
DISABLE
TRANSMISSION