New ship crane control from Liebherr
By Euan Youdale11 July 2008
Liebherr has introduced a new control system for ship cranes which allows tandem lifts with an anti-collision option.
The Litronic control has been designed to meet the capabilities of ship cranes with up to 450 tonnes capacity. The first cranes to use the anti-collision and automated tandem system are Liebherr's CBB type electro-hydraulic heavy lift rope luffing models.
The tandem lift system can be used in three modes:
- Standard mode requires each of the two cranes to have its own driver, with each driver being informed of the main functions.
- In automatic parallel mode, one driver controls both cranes. The traverse remains parallel to the ship or to the starting position and an automatic control system calculates the movement of the boom head of both cranes.
- The automatic rotation mode allows the traverse to rotate. The crane driver only has to control the direction and rotation of the traverse while the control system automatically calculates the required movement of the boom heads of both cranes.
The Dynamic Anti-Collision System option is unique to the industry, said Liebherr. "The system automatically calculates actual position, speed and the acceleration of each crane, as well as the load moment limitation. This provides the crane driver with maximum flexibility, backed with full safety," said the company.
Conventional anti-collision systems define a virtual border in order to prevent the cranes from colliding. This, explained Liebherr, results in a restriction of the working radius of each crane.
Another feature is the optional Vertical Line Finder designed to avoid side pull of the load resulting from long distances between the operator and load or asymmetric gravity centre point.