Manitowoc MLC650, Service Maintenance Manual

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Reference
Only
Manitowoc
Published 09-09-16, Control # 229-09
10-37
MLC650 SERVICE/MAINTENANCE MANUAL ACCESSORIES
10
10
CAB TILT
The cab tilt cylinders are controlled by the cab tilt switch on
the right side console in the operator cab.
See Figure 10-29 for the hydraulic schematic of the cab tilt
cylinder circuit.
See Figure 10-31 for the electrical schematic of the cab tilt
cylinder circuit.
Cab Tilt in Neutral
See Figure 10-29 for the following.
When the cab tilt switch is not sending a command, the cab
tilt valve spool (5), located in the accessory valve manifold
(1), is held in the neutral position by the return springs.
When in neutral, the counterbalance valve (4) provides a
cylinder hold function. The sequence valves within the
counterbalance valve are closed, stopping the flow to and
from the cylinder. The cab tilt cylinder is held in position by
trapped hydraulic fluid.
Cab Tilt Up Using the Cab Tilt Switch
See Figure 10-30 for the following.
When a tilt up command is initiated from the cab tilt switch,
the IOSA22 control module sends the tilt up command to the
CCM-10 control module, which then energizes the cab tilt up
solenoid (5). The valve spool moves to a position that allows
hydraulic fluid from the accessory pump to flow to the
counterbalance valve (4), via the flow control valves (3).
Within the counterbalance valves, flow and control is as
follows:
• The rod side counterbalance valve is piloted open by the
rod side pressure and the accessory pressure from the
valve spool on the extend side. Once open, the hydraulic
fluid on the rod side is allowed to exit the cylinder and
return to tank, via the bypass check valve on the flow
control valve.
• The piston side counterbalance valve has an integral
bypass check that allows the metered flow to the piston
side of the cylinder, extending the cylinder.
Cab Tilt Down Using the Cab Tilt Switch
See Figure 10-30 for the following.
When a tilt down command is initiated from the cab tilt
switch, the IOSA22 control module sends the tilt down
command to the CCM-10 control module, which then
energizes the cab tilt down solenoid (6). The valve spool
moves to a position that allows hydraulic fluid from the
accessory pump to flow to the counterbalance valve (4), via
the flow control valves (3).
Within the counterbalance valves, flow and control is as
follows:
• The piston side counterbalance valve is piloted open by
the piston side pressure and the accessory pressure
from the valve spool on the retract side. Once open, the
hydraulic fluid on the piston side is allowed to exit the
cylinder and return to tank, via the bypass check valve
on the flow control valve.
• The rod side counterbalance valve has an integral
bypass check that allows the metered flow to the rod
side of the cylinder, retracting the cylinder.