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• A sudden stop when lowering a load. This creates high forces of inertia on the crane structure with
relevant dangerous overload.
• Hitting the rope where the load is suspended, overload is generated.
• Side pull, dragging the load on the ground. All these operations originate strong overloading forces on
the crane.
• The outriggers are badly positioned or the ground is not firm: in both cases the truck tilts and could tip
over.
• Working with strong wind or wind gusts
• The manual boom sections are not correctly installed.
• The load is not correctly slinged. So the lifting accessory used (chain, rope, etc) breaks or flips out and
the load falls down to earth. The boom, suddenly unloaded, springs back and this could result in tipping
over.
• Trying to lift fixed load up(rooting of trees, raising of culverts, etc). Even if their load is smaller than the
capacity of the crane, the dynamic force created when it is suddenly stripped, may easily exceed the
capacity, and make the truck tip over.
• Swinging movements of the load. When acting on the slewing control too suddenly, the load starts
swinging. Danger of overload. And boom’s breaking.
7.8
STANDARD HAND SIGNALS
Pict. 19
