Crane operation
11.5 Crane operation with main boom
Operating manual 3 302 736 en 11 - 73
GMK4090
xx.xx.xxxx
Deformation of
the main boom
due to direct
sunlight
One-sided direct sunshine can lead to a temperature difference between the
left and the right main boom side. This results in a different length exten-
sion. A lateral deformation of the main boom is the result. The degree of
deformation depends on the actual temperature difference and the current
main boom length.
Assuming a temperature difference of 30° (86 °F) and a system length of
60 m (196.85 ft), a deformation without load of up to 1 m can occur.
This would be a deformation of 1.7%.
Preventive measures
• If possible, turn the superstructure to a (park) position where both main
boom sides are heated evenly to prevent deformation.
Before any lift with deformed main boom
The main boom must be telescoped out to the length required for the lift.
The maximum permissible lateral deformation of the unloaded main boom
(with reeved hook block) is 1% of the main boom length.
• Check the deformation before the lift.
• Only lift the load if the current deformation is permissible.
For any lift with deformed main boom
The maximum permissible lateral deformation of the loaded main boom
is 3% of the current boom length.
• Check the deformation during the lift.
• Put the load down before the maximum permissible deformation is
exceeded.
• Reduce additional, dynamic influences by wind.
• Carry out crane movements with minimal speed.
G
Risk of accidents due to overload of the truck crane
An excessively deformed main boom can be overloaded or suffer from
invisible damage which can lead to overloading of the main boom on sub-
sequent lifts with permissible deformation or reduce the life span of the
main boom.
Make sure that the maximum permissible values for lateral deformation are
not exceeded.
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