Fig. 7-13: Circuit Operation Above 20° Below 40° - JLG Lull 1044C-54 II Series Service Manual

Frame Tilt and Oscillation
Boom Positioned Above 20° Below 40°
7-20
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. 7-13: Circuit Operation Above 20° Below 40°
(Ref. Fig. 7-13) The following describes the rear axle stabilizer circuit logic
when the boom is positioned above 20° below 40° elevation.
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 power is directed to the coil of relay K13 of the
transmission logic (see Transmission Section 8). When K13 is
energized, the transmission is restricted to first and second gears only,
regardless of the gear selected with the transmission shifter.
3. Additionally, when the Boom Over 20° relay is not energized, Solenoid
Valve (SV1) is not energized, which restricts movement of the rear
stabilizer cylinder so that the frame may oscillate on the rear axle only
in a slow or restricted mode. The Boom Over 20° relay also illuminates
the Rear Oscillation Lock lamp in the instrument cluster.
4. The frame tilt is also restricted when Solenoid Valve (SV1) is not
energized.
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
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
MV0560
31200079