Transition Section (Slew Tower)

On a flat-top crane the apex and the suspension pendants are gone, so the transition section takes over their job: it is the short lattice tower that rises from the slewing bearing and forms the common root of the jib and the counter-jib.

Construction

Welded lattice of square-tube chords with tubular bracing, matching the mast chord spacing so the two can be bolted directly. The upper face carries the jib and counter-jib connection pins; the lower face bolts to the slewing bearing flange.

Role on the machine

It collects the horizontal thrust and the bending moment coming from both arms and feeds them into the slewing bearing. Because there is no pendant tension to share the load, this section carries a larger moment than the equivalent part of a hammerhead crane, and its connection pins are the first thing to inspect after an overload.

Inspection and maintenance

• Check pin wear and the clearance of the jib / counter-jib root connections.
• Inspect chord and bracing welds for cracks after any impact event.
• Verify bolt torque on the slewing flange and touch up paint where the coating is broken.