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Feature 4
The automated tandem lift
Liebherr’s innovative control system for shipboard cranes features new
anti-collision technology.
W
ith demand for heavy load
vessels continuously in the
ascendant, Liebherr has adapted
its existing range of equipment to meet
requirements, with ship cranes now offered
providing lifting capacity of up to 450tonnes.
In parallel, it has been developing its Litronic
control system for higher efficiency. This
sophisticated technology is designed to allow
automatic tandem operation, and includes
other optional features, such as anti-collision
and remote control of cranes for improved
safety.
The company’s dynamic anti-collision
system controls the simultaneous operation
of crane motions, ensuring best possible
performance and protection for the crane,
according to the supplier.
The basic idea behind the anti-collision
system is the prevention of collision between
cranes and/or obstacles. When a number
of cranes are operating simultaneously, the
action of each one can be controlled based on
information regarding the current position of
neighbouring units. According to Liebherr,
the unique feature of its system is that it
automatically calculates actual positions
and speeds, as well as the acceleration of
each crane and the load moment limitation.
This provides crane drivers with maximum
flexibility, backed by full safety.
Conventional anti-collision systems define
a virtual border, in order to prevent collisions.
This amounts to a restriction of the working
radius of each crane. With the dynamic
anti-collision solution, working radii are not
restricted, as the system calculates the actual
and anticipated crane movements.
Automated tandem lifts are another Automated tandem lifting – a new innovation from Liebherr designed to accommodate
important feature of the Liebherr control ever rising load weights.
system. Two cranes can be operated by one
crane driver to lift one heavy load, possibly
attached to the traverse. Tandem lifts can be to control simultaneous speeds of the boom head of both cranes. Speeds
carried out in three different modes: • A more efficient alternative is the automatic are derived from the calculated boom head
• Standard mode tandem lifts, requiring parallel mode, with only one crane driver speed. The traverse remains horizontal. As
each of the two cranes to have its own controlling both cranes. In this mode the the length and hook height difference is
driver and each driver to be informed of traverse remains parallel to the ship or to kept constant during motion, there will be
the main functions (speeds, etc) of both the starting position and an automatic no diagonal line pull in the cables. Another
cranes on their respective screens, in order control system calculates the movement big advantage here is that communication
The Naval Architect February 2008 97
NA Feb 08 - p97+99.indd 97 05/02/2008 09:55:31
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