Crane Components, Configurations & Terminology Flashcards

What does the term 'parts of line' describe on a crane?

Answer: The number of wire rope lines supporting the load block

Parts of line is the number of hoist rope lines reeved between the boom tip sheaves and the load block. More parts of line raise lifting capacity but slow line speed.

What is the main function of a crane's counterweight?

Answer: To offset the load moment and increase stability

The counterweight sits at the rear of the upperworks. It balances the overturning moment the load and boom create, which increases the crane's stability-based capacity.

What is the main structural difference between a lattice boom and a telescopic boom?

Answer: Lattice booms are built from pinned truss sections, while telescopic booms extend nested sections hydraulically

Lattice booms are assembled from open truss sections pinned together, so changing length means adding or removing sections. Telescopic booms have nested box sections that extend and retract with hydraulics.

What does 'luffing' mean in crane operations?

Answer: Raising or lowering the boom angle

Luffing is changing the boom or jib angle, which also changes the load radius. Swinging is rotating the upperworks.

What is an 'overhaul ball' (headache ball) used for?

Answer: To provide weight so a single-part line pays out freely without a load

An overhaul ball is a weighted hook on a single-part line. Its weight lets the line lower (overhaul) through the sheaves when there is no load on the hook.

On a mobile crane, what are the 'upperworks'?

Answer: The rotating superstructure, including the operator's cab, boom, hoists and counterweight

The upperworks (superstructure) are everything that rotates above the swing bearing: cab, boom, hoist drums, engine (on many models) and counterweight. The carrier or lower works stays fixed.