crane operators test)
Side loading can occur when:
The crane is out of level, during rapid swing, dragging or pulling loads sideways,
improperly performed tilt-up operations, or high winds
Crane's leverage
Crane weight times the horizontal distance from the center of gravity to the tipping axis
Load's leverage
The horizontal distance from the center of gravity of the load to the tipping axis times
the load weight
Margin of stability for crawler mounted cranes
75%
Margin of stability for carrier mounted cranes
On outriggers extended 85%
On rubber or tires 75%
Margin of stability for commercial boom trucks
85%
Backward stability factors
Operating over the side, no load, shortest boom length maximum boom angle, and load
on wheels
Overloading the crane will cause:
Crane tipping or structural failure
Capacity charts are normally divided by:
Using a bold line, asterisks, or shaded area
Structural strength is found on the top or bottom of the capacity chart
Top
Stability is found on the top or bottom of the capacity chart
Bottom
What component can fail when operating in the structural area of the capacity
chart
Wire rope, boom, block, sheave, boom extension cylinder, boom lift cylinder, ring gear,
hydraulic hoses, outriggers, jib, jib pendants, jib mast, boom pendants,...
If boom length is between chart listings you should:
Always use lower capacity of the next longer or shorter boom length
Load radius is:
The horizontal distance from the center of rotation to the center line of the hook
If load radius is between chart listings you should:
Use the next longer radius
Boom angle is:
The angle between the center line of the base boom and the horizontal after the load is
lifted
Boom deflection will:
Decrease boom angle and increase load radius
Tire deflection will:
, Increase the load radius and decrease the boom angle
If boom angle is between chart listings you should:
Use the next lower boom angle
Gross capacities are:
The rated capacities listed in the capacity chart
What may need to be deducted
Wire rope, ball, jib, load block, rigging, net load, stowed jib, EXT., AUX. Boom head,...
When do you deduct weight of the crane's hoist rope
When the manufacturer specifies in the load chart, when the crane is reeved with more
then the minimum parts of line required, when the crane is reeved with hoist line not
being used to make the lift, or when there are parts of line below the ground
Net capacity is:
Gross capacity minus capacity deductions for load handling devices
Gross load is:
The net load plus the attachments, lifting devices, hook, blocks, balls, wire rope, and
Rigging
Net load is:
The actual weight of the item being lifted
Dynamic loading is:
The forces created by movement
Total load is:
The combined forces produced by the actual load weight, lifting attachments, and the
movement of the load and attachments
Capacity is limited by:
The lowest rated component
Parts of line is:
The number of hoist ropes directly supporting the lower load block
SWL means:
Safe working load
How do you find the minimum parts of line required
Add the weight of the hook block, the rigging, and the net load.
Divide the suspended weight by the safe working load of the hoist rope
The range diagram can be used to:
Derive the approximate distances when planning lifts and determining crane
configuration, ect.
Check the crane for:
Boom sway, droop, bulges, creases, waviness, worn wearpads, hydraulic leaks, and the
poor condition of the sheaves, pendants, end fittings, hoist ropes, outriggers, and frame.
All can lower capacity
Load chart capacities are generally based on the crane...
being level within 1% in all directions throughout the lift
In most cases crane operations should be stopped when...
the wind exceeds 30 mph.
High winds can...
cause the operating radius to increase or create a backward tipping condition.
The effect of the wind on the crane...