A lifting area diagram is included as part of the load chart
to describe over-the-side, over-the-rear, and over-the-
front lifting areas. The lifting area diagram shows that the
locations of the outrigger stabilizer cylinders in the fully
extended position are used to mark the boundaries of the
The last major portion of the load chart is the section
concerning notes on lifting capacities. Be sure to read all
notes carefully so you understand what each one means.
The weights of any load handling devices must be added
to the weight of the load.
The following is a typical example of a
lifting problem and how to compute a lift.
However, numbers used in the example
may not coincide with the loadchart in
the crane cab.
The problem is to lift a container weighing 22.4 tons to a
height of 46 feet at a radius of 27 feet. Determine
whether or not the lift can be made safely. The range
diagram shows the lift can be made using a boom length
of 60 feet. A check of the on outrigger-360 degrees load
chart at a 27 foot radius with a 60 foot boom length
shows the crane has a lifting capacity of 48,000 pounds.
It appears from the listed capacity that 22.4 tons (44,800
pounds) can be lifted. But wait! The listed weight of all
load handling devices such as slings, chains, spreader
bars, or other rigging must be added to the load weight in
order to obtain the actual weight of the load being lifted.
For the purpose of this example we will assume that
these load handling devices weigh 1500 pounds and
must be added to the load weight (i.e., 44,800 + 1,500 =
46,300 pounds). Therefore, the total load weight of
46,300 pounds can be lifted since the total weight of
the load is less than the (48,000 pounds) maximum
crane capacity in this configuration. Following the initial
calculation, the load chart should be rechecked to assure
that the crane is capable of making the lift. Also note the
laden boom angle (found in parentheses under the
weight capacity of the load chart) will be approximately
MAXIMUM ALLOWABLE LOADS, WHICH ARE BASED
ON EITHER TIPPING OR STRUCTURAL LIMITATIONS
UNDER SPECIFIC CONDITIONS. KNOWING THE
EXACT RADIUS OF OPERATION, BOOM LENGTH
AND BOOM ANGLE SHOULD BE A PART OF YOUR
ROUTINE PLANNING AND OPERATION. ACTUAL
LOADS, INCLUDING NECESSARY ALLOWANCES,
SHOULD BE KEPT BELOW THESE CAPACITY
WORKING AREAS MUST BE ADHERED TO WHEN
DETERMINING ALLOWABLE LOAD FROM LOAD
IF THE CRANE IS NOT LEVEL, LOAD CAPACITIES
ARE REDUCED WHEN LIFTING ON THE LOW SIDE.
DONT BE MISLED BY OPTICAL ILLUSIONS. USE
YOUR BUBBLE LEVEL.
IF YOU FEEL THE CRANE IS BEGINNING TO TIP,
LOWER THE LOAD WITH THE HOIST LINE AND
RETRACT OR ELEVATE THE BOOM TO BRING THE
LOAD IN. NEVER LOWER OR EXTEND THE BOOM,
THIS WILL AGGRAVATE THE CONDITION.
WHEN USING THE HOIST AVOID SUDDEN STOPS.
INCREASED LOADING WILL RESULT AND COULD
CAUSE TIPPING OR A STRUCTURAL FAILURE.
EVEN IF A HYDRAULIC LINE BREAKS ON THE LIFT
OR TELESCOPE CYLINDER(S), THE CRANE WILL
STILL FUNCTION SUFFICIENTLY TO GET THE LOAD
MAXIMUM LIFTING CAPABILITY OCCURS AT THE
SHORTEST RADIUS, MINIMUM BOOM LENGTH AND
HIGHEST BOOM ANGLE.