Manitowoc MLC650 Service Maintenance Manual

Reference Only
UNDERCARRIAGE MLC650 SERVICE/MAINTENANCE MANUAL
8-12
Published 09-09-16, Control # 229-09
Extend Carbody Jacks Using Manual Control
See Figure 8-9 for the following.
NOTE: The following describes the operation to extend
one carbody jack cylinder. The operation is the
same for all carbody jack cylinders.
When the HPU is connected, the selector solenoid valve (1)
is de-energized, causing the valve to shift to the default
position. When in the default position, the selector valve
routes the flow to the carbody manual control manifold (5).
When a valve handle for a jack cylinder extend function is
pulled, hydraulic fluid is routed to the corresponding port on
the six-section lower accessory valve assembly (2). Inside
the valve assembly, fluid flows through a shuttle valve, then
to the corresponding valve spool. This causes the spool to
move to a position that allows hydraulic fluid from the
accessory pump to flow to the corresponding jack cylinder
counterbalance valve (4).
Within the counterbalance valves, flow and control is as
follows:
• At the rod side valve, the hydraulic fluid pressure from
the rod side of the cylinder and the accessory pump
pressure opens the counterbalance valve. As the
cylinder extends, the hydraulic fluid from the rod side of
the cylinder goes through the now open counterbalance
valve, then back to tank.
• At the piston side valve, the hydraulic fluid from the
accessory pump flows through the counterbalance
bypass check valve (3), then into the piston side of the
cylinder.
Retract Carbody Jacks Using Manual Control
See Figure 8-9 for the following.
NOTE: The following describes the operation to retract one
carbody jack cylinder. The operation is the same
for all carbody jack cylinders.
When the HPU is connected, the selector solenoid valve (1)
is de-energized, causing the valve to shift to the default
position. When in the default position, the selector valve
routes the flow to the carbody manual control manifold (5).
When a valve handle for a jack cylinder retract function is
pulled, hydraulic fluid is routed to the corresponding port on
the six-section lower accessory valve assembly (2). Inside
the valve assembly, hydraulic fluid flows through a shuttle
valve, then to the corresponding valve spool. This causes
the spool to move to a position that allows hydraulic fluid
from the accessory pump to flow to the corresponding jack
cylinder counterbalance valve (4), via the orifice with bypass
check valve (3).
NOTE: The orifice decreases the maximum flow during the
retract operation.
Within the counterbalance valves, flow and control is as
follows:
• At the piston side valve, the hydraulic fluid pressure from
the piston side of the cylinder and the accessory pump
pressure opens the counterbalance valve. As the
cylinder retracts, the hydraulic fluid from the piston side
of the cylinder goes through the now open
counterbalance valve, then back to tank.
• At the rod side valve, the hydraulic fluid from the
accessory pump flows through the counterbalance
bypass check valve (3), then into the rod side of the
cylinder.

Manitowoc MLC650 Specifications

General

Brand	Manitowoc
Model	MLC650
Category	Construction Equipment
Language	English