For this intervention, we replaced the main shaft and bushings of the trimlist of a Liebherr QC crane at the Port of Antwerp.
The trimlist ensures that the crane operator can accurately position the spreader in relation to the container during loading and unloading operations. Since the trim of a vessel continuously changes, this system plays an important role in the safe and stable operation of the crane.
During an inspection round, the client noticed that the main or hinge shaft of the trimlist was rotating together with the mechanism. Further inspection showed that an intervention was necessary to replace the shaft and bushings.
After securing the work zone and carrying out the necessary preparations, the works started with:
The removal of the shaft could then begin. Since the shaft could not be dismantled using hydraulic cylinders, despite a pulling force of 100 tonnes, it was decided to thermally lance the shaft.
After two shifts of thermal lancing, the shaft and console were finally removed.
Inspection of the shaft seats showed that they were no longer perfectly round. Therefore, a specialized team for mobile line boring works was called in to restore the seats correctly.
While the welding and boring works were being carried out, a second team handled the overhaul of the console. The console was transported to our workshop using our truck-mounted crane, where the remaining part of the shaft and the old bushings were removed using a hydraulic workshop press.
The new bushings were then shrink-fitted using liquid nitrogen at a temperature of -196°C, ensuring a correct and durable fit.
After completion of the overhaul works, all components were reassembled and adjusted. The crane was subsequently tested successfully and returned to operation under the supervision of the end client.
