OPERATION 800D
2-10
Published 5-27-2018 Control # 039-06
It is best to select a location on the site such that most of the
lifting can be done over the outrigger support or rear of the
truck.
BEFORE LEAVING THE CAB
1. Position the truck so that the outriggers can be extended
without encountering obstructions. Set the truck park
brake securely and turn front wheels into the curb.
Wheel chocks may be required under certain conditions.
2. With the gear shift in neutral, depress clutch (if equipped
with a manual transmission), and engage the power
takeoff by pulling out the shifting knob.
3. Bring the hydraulic system up to operating temperature
(oil reservoir warm to the touch) by allowing the system
to operate by actuating the outrigger retract switch with
all outriggers fully retracted.
Proper Leveling of the Crane
ASME B30.5 specifies that if a crane is not level within 1% of
grade, the allowable capacities must be reduced. Therefore,
it is essential that the crane is level to within 1% of grade.
The bubble level that is provided on the crane is calibrated to
be accurate within 1% of grade.
To properly level the crane, the boom must be positioned
over the front of the crane, fully lowered to horizontal and
fully retracted (for cranes fitted with a boom rest, the boom
shall be stowed onto the rest). Raise and level the crane
using the outriggers.
A working crane may settle during lifting operations.
Frequently check the crane for level. When rechecking the
crane for level, the boom must be positioned over the front of
the crane, fully lowered to horizontal and fully retracted (for
cranes fitted with a boom rest, the boom shall be stowed
onto the rest). If necessary, relevel the crane.
Bubble Level Adjustment
The bubble level adjustment should be checked periodically.
If it is suspected that the bubble level indicator is out of
adjustment, verify and adjust the bubble level as follows:
1. Position the crane on a firm, level surface.
2. Extend and set the outriggers. Level the crane, as
indicated by the bubble level indicator, using the
outriggers.
3. Place a miracle pointer level, carpenter level, or similar
type device on a machined surface such as the turntable
bearing or bearing mounting surfaces.
4. Using the outriggers, level the crane as indicated on the
leveling device used in step 3.
5. Using the bubble level indicator mounting screws, adjust
the bubble level indicator to show level.
CRANE SET UP
Do not operate the boom until all outriggers are
extended and set providing firm support.
If operating on sloping ground provide blocks. When lifting is
to be done on soft terrain or hot asphalt, support the
outrigger and stabilizer pads with bearing pads. Some
concrete and asphalt surfaces are relatively thin and cannot
support outrigger or stabilizer loading. Concrete can break
through and cause instability.
Variation in chassis, outrigger and mounting configurations
will cause outrigger foot loading to differ on each crane,
however, outrigger foot loads can be as high as 50,000 lb
(22 697 kg) when outriggers are at full span [154 psi (1.06
MPa) on standard outrigger pads]. Support surface bearing
capacities vary by a large amount—from 833 psi (5.7 MPa)
on bed rock down to 14 psi (0.1 MPa) on soft clay. Loose
sand or soft asphalt will support even less load. It is
imperative that the operator take proper precautions to
insure the outrigger foot has adequate cribbing for existing
soil conditions.
If specific outrigger foot loading is required for an individual
crane, contact National Crane with actual chassis weights
and crane details.
1. When Lifting Over the Rear of the Truck
Before conducting any boom operations, extend both
outriggers until the chassis weight is removed from the
wheels. Level the crane from side-to-side. A level
indicator is provided at either control station. Then
extend and lower the stabilizers to level the crane front-
to-back. Again refer to the level indicator to ensure that
the crane is properly leveled. Always keep the load as
close to the ground as possible.
Fo
r
Reference
Only
To Next Page
Loading...
