ONE type of bottom slewing (self-erecting) crane that should be considered for use in Australia for small to medium level construction is the new three model Liebherr TT range of telescopic self-erecting tower crane, which is a new step forward into the future.
This new crane series from Morrow Equipment Company is fast to erect or dismantle on site, versatile, cost effective, adaptable and a compact transportable unit to move.
It has an innovative telescoping jib that can be stowed (retracted) in the event of high winds, or while working the jib telescopes in or out where there are obstructions to prevent it slewing at full radius. The telescopic jib eliminates the problem of encroaching on neighbouring air space, which is more common on CBD sites. The jib can be raised to a 20-degree angle from the horizontal operation position for increased lifting height.
It has an automatic device for changing from 2 to 4 falls of line depending on whether the requirement is for speed or capacity. The telescoping tower grows with the crane and construction height using an automatic locking system
This crane series is so easy to erect (or dismantle) using a radio remote control system that the crane is ready for operation (complete with ballast) less than half an hour after arriving on site. Swing-out outrigger arms with adjustable outrigger support stands provide a cruciform base for complete crane stability on site.
Economical top performance is provided through the mechanical/electrical drive system using a frequency converter for variable speed operation.