The outrigger circuit consists of four extension
of frame to the rear of the swivel. The extension and
cylinders, four stabilizer cylinders, an integrated
stabilizer solenoid valves are bolted to the frame at
outrigger valve, extension and stabilizer solenoid
the outrigger beams.
valves, and (pilot operated) check valves. The front
two extension cylinders are mounted in the front
The OUTRIGGER SELECTOR controls are located
outrigger beams and the rear two extension cylinders
in the superstructure cab on the front console. Both
are mounted in the rear outrigger beams. The front
the selector valve and the solenoid valves are
and rear stabilizer cylinders are mounted on their
electrically actuated from the control panel. The
respective stabilizer boxes; in turn the stabilizer
solenoid switches must be held depressed to actuate
boxes are mounted on the end of each outrigger
the solenoid valve. The selector valve switch is
beam. Each stabilizer cylinder has a port block
spring loaded to the OFF position. The control panel
incorporated into the cylinder rod. A fifth check
is placarded with switch positions.
valve, mounted to the frame, is positioned inline
between the integrated outrigger valve and the
A sight bubble level is mounted on the front console
outrigger circuit to prevent reverse flow from the
in the superstructure cab. The sight bubble level
piston side of the outrigger cylinders. The integrated
provides the operator with a visual indication of
outrigger valve is located on the left side
crane level attitude.
THEORY OF OPERATION
The appropriate OUTRIGGER SELECTOR switch
valve is directed to the rod side of the cylinder. The
and OUTRIGGER EXTEND/RETRACT switch must
oil in the piston side flows through the open solenoid
both be held in position. Flow from the 16 gpm (60.5
back to the integrated outrigger valve. If a stabilizer
lpm) pump section supplies the outrigger circuit.
cylinder is to be retracted, then pilot pressure from
Depressing one of the OUTRIGGER SELECTOR
the pressurized retract line unseats the cylinder
switches causes that solenoid valve to open. As the
check valve allowing oil to flow from the piston side
EXTEND/RETRACT switch is moved, the integrated
through the open solenoid valve to the integrated
outrigger valve shifts allowing flow to either the
outrigger valve. The integrated outrigger valve
extend or retract line as applicable.
directs the flow to the reservoir.
EXTEND/RETRACT switch is in the EXTEND
position, the flow continues through the open
The integrated outrigger valve has two internal relief
solenoid valve to the piston side of the cylinder. If
valves. A 300 psi (2068.5 kPa) thermal relief is in
the stabilizer(s) is/are to be extended, the flow first
the retract circuit and a 2000 psi (13,790 kPa) relief
unseats the cylinder check valve then extends the
protects the extend circuit.
cylinder. The oil from the rod end flows through the
integrated outrigger valve, and then to the reservoir.
The frame mounted pilot operated check valve has a
thermal relief set to open at 4000 psi (27,580 kPa).
When the EXTEND/RETRACT switch is in the
RETRACT position, the flow through the selector