INTRODUCTION 16000 SERVICE/MAINTENANCE MANUAL
1-42
Published 05-09-17, Control # 014-28
ACCESSORY SYSTEM COMPONENTS
Accessory Systems
Accessory system components includes rotating bed jacking
cylinders, mast raising cylinders (high pressure), and rigging
winch, rotating bed pins, boom hinge pins, cab tilt,
counterweight pins, crawler pin cylinders (low pressure), and
the engine cooling fan.
The accessory/MAX-ER pump is the hydraulic pressure
source to operate accessory system components. The
accessory system proportional relief valve is controlled by
Node-3 controller. The accessory system and the lower
accessory system is monitored by separate pressure
senders. During stand-by, the relief valve is set at
approximately 400 psi (28 bar). Excess supply flow from
accessory/MAX-ER pump is dumped through valve to tank.
When an accessory system component is enabled, an input
signal is sent to Node-1 controller. Node-3 controller sends a
variable 0 to 24 volt signal to accessory system proportional
relief solenoid HS-68 to increase the relief valve setting up to
3,000 psi (207 bar). The accessory systems pressure
increases to operate selected component.
Jacking Cylinders
See Figure 1-32, Figure 1-33, and Figure 1-35 for the
following procedure.
Telescopic type jacking cylinders are mounted on each
corner of rotating bed. Jacking cylinder operation is
controlled with switches on hand-held wireless remote and
programming. Operation of all four jacking cylinders is the
same. The following description of operation is for right front
jacking cylinder.
The rotating bed level sensor keeps rotating bed level when
the ALL switch is used. The sensor controls fluid to each
cylinder by opening/closing proportional control valves.
Each jacking cylinder has a counterbalance valve at the
cylinder ports. Counterbalance valves ensure smooth control
when raising or lowering the crane on jacks. Counterbalance
valves lock the jacking cylinders in place if there is a
hydraulic line breakage or accidental operation of control
valve when the crane's power is shut down. Also,
counterbalance valves provide relief protection for the
cylinders and shields them from mechanical overloading.
When a jacking cylinder proportional control valve is not
enabled, it shifts to neutral position where both valve section
cylinder ports are connected to tank. This prevents in-line
pressure from opening counterbalance valve, holding
rotating bed load in position by the counterbalance valve.
Rotating Bed Jacking - Raise
Move jacking switch to extend position and hold (front right
jack is shown in Figure 1-32
). An input voltage is sent to
Node-1 controller. Node-4 controller sends a 24 volt output to
enable selected jacking cylinder proportional control
solenoid HS-62 and shifts valve to the extend position.
Node-3 controller sends a variable zero to 24 volt output to
enable accessory system proportional relief solenoid HS-68.
Hydraulic fluid pressure at approximately 3,000 psi (207 bar)
flows to selected jacking cylinder(s) proportional control
valve. Hydraulic fluid exits valve and enters free-flow check
valve section of jacking cylinder counterbalance valve.
Hydraulic fluid then enters piston end of jacking cylinder,
extending cylinder to raise the rotating bed. Node-4
controller monitors accessory system pressure sender to
control jacking cylinder raising speed rate.
Hydraulic fluid returning to tank from rod end of the jacking
cylinder is blocked by the free-flow check valve section of
counterbalance valve and flows through flow restraining
section that has a relief setting of 2,500 psi (172 bar). The
counterbalance valve acts as a deceleration control and
functions with a 3:1 pilot ratio of the relief pressure. This
permits the valve to open when the pressure in rod end of the
cylinder is approximately 833 psi (57 bar). Restraining
section of counterbalance valve opens, controlling the fluid
out of the jacking cylinder. Hydraulic fluid then flows through
free-flow check valve section of flow control valve before
entering lower accessory valve. Hydraulic fluid leaving the
accessory valve is returned to tank.
When jacking switch is moved back to center position, an
input voltage is sent to Node-1 controller. Node-4 controller
sends a zero volt output to disable selected jacking cylinder
WARNING
Collapsing Hazard!
Keep rotating bed as level as possible while jacking.
Operating jacking cylinder with rotating bed more than
three degrees out of level can cause structural damage to
jacking cylinders and possible collapse of rotating bed.
FIGURE 1-32
HS-63
HS-61
Left
Front
Pressure
Sender
HS-60
Accessory
Pump
Crane Level
Sensor
Hand-Held
Wireless Remote
Right
Front
Left
Rear
Right
Rear
HS-64
HS-65
HS-66
HS-67
HS-68
HS-62
16-1024
500 to 3,000 psi
(35 to 204 bar)
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