Fig. 7-14: Circuit Operation Above 20° Below 40° With Service Brake Applied - JLG Lull 1044C-54 II Series Service Manual

Boom Positioned Above 20° Below 40° With the Service Brake Applied
31200079
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. 7-14: Circuit Operation Above 20° Below 40° with Service Brake Applied
(Ref. Fig. 7-14) The following describes the rear axle stabilizer circuit logic
when the boom is positioned above 20° below 40° elevation with the
service brake applied.
1. When the boom is above 20° and below 40°, the proximity switch (S2)
is sensing the boom, so the (S2) proximity switch closes. Proximity
switch (S1) is not sensing the boom, so it opens when boom is above
20°.
2. When the proximity switch (S1) is open, the Boom Over 20° relay is not
energized and Solenoid Valve (SV1) is not energized, which restricts
the frame tilt.
3. Applying the service brake locks the rear stabilizer cylinder
hydraulically, which prevents the frame from rotating 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°
NOT ENERGIZED
RELAY
85
87A 87
TO RESTRICT
TRANSMISSION
TO 1ST & 2ND
GEARS
Frame Tilt and Oscillation
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
(NOT ENERGIZED)
A
SV1
B
MV0570
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