MEGA Corp. MCC-OPS-1 - Manual (Page 15)

MCC35-CAT735-1
5 Aug 2010
SECTION 2
System Description
2-8
Twistlock Sensors
Each twistlock sensor is mounted inside the
tubular frame and attached to its respective
twistlock by a bellcrank and adjustable clevis.
The sensor provides individual twistlock
position information to the body assembly
ECM. It is the body assembly ECM that
commands the in-cab twistlock light indications
after processing all sensor information.
External Twistlock Status Beacon
The blue twistlock status beacon assembly is
mounted to the top of the chassis cab and is
controlled by the additional ECM. The blue
beacon will only flash when all twistlocks are
DISENGAGED, indicating to the crane operator
it is safe to remove the container from the bed
assembly.
THEORY OF OPERATION
The bed assembly, controls systems, indicators
and components operate as follows:
LOCKING THE CONTAINER TO THE
BODY ASSEMBLY
Once a container is lowered to the body
assembly the container must be secured to the
body for transportation and dumping. Initially
the external twistlock status beacon is ON and
in-cab twistlock status lights are OFF. The
operator then activates the in-cab twistlock
switch that in turn sends a lock signal to the
body assembly ECM. The ECM then
commands the twistlock solenoid to provide
hydraulic pilot pressure to all twistlock
actuators. Hydraulic pressure will begin to
rotate all twistlocks and twistlock sensors to a
position that will require the ECM to turn OFF
the twistlock external status light. Once all
twistlocks are in an ENGAGED position, the
ECM will illuminate the in-cab twistlock status
light. If the twistlock light does not illuminate
and a fault exists, the twistlock fault light will
illuminate.
RAISING THE BED ASSEMBLY FOR
DUMPING
The operator moves the hoist control lever from
FLOAT to RAISE. The chassis ECM will
command the hoist valve to route pressure to the
tailgate operation valve assembly. The solenoid
control valve will provide pressure to the
tailgate hydraulic cylinder and lower (OPEN)
the tailgate to unsecure the container doors.
Once the tailgate restraint (stinger) is fully
lowered, hydraulic pressure is routed to the lift
cylinders and the bed begins to RAISE. The in-
cab body position light will illuminate and the
chassis is restricted to 1
st
gear.
When the bed reaches a predetermined dump
angle, as sensed by the bed position sensor, the
body assembly ECM will command the hoist
valve to stop supplying pressure to the lift
Blue Twistlock
Status Beacon