| For the flagship of the air |
Airbus A380 fuselage sections handled by Demag cranes
Airbus Deutschland GmbH manufactures fuselage sections for the new A380 wide body aircraft in Nordenham. These parts of the future "flagship of the air" demand gentle handling sequences, particularly when they are turned. Therefore, the solution selected for handling the fuselage sections consists of double-girder overhead travelling cranes supplied by Demag Cranes & Components, which are capable of co-ordinating the five load motion directions simultaneously.
The fuselage sections are used for the wide body aircraft which is scheduled to make its maiden flight in 2005. The first question to be answered was how to safely turn the sections from a vertical to a horizontal position and back again, and how they could be deposited and picked up again. Since the fuselage sections are up to 10.8 meters long, 6.7 meters wide and 2.3 meters high and weigh a maximum of 1.6 tonnes, they have to be suspended from four points when being handled. Airbus finally developed a solution together with Demag consisting of double-girder overhead travelling cranes, utilising experience gained at the Airbus plant in Hamburg.
To enable the cranes to co-ordinate five directions of load movement in parallel, Demag fitted them with rotating crabs. Two traversing crabs travel on the rotating H frame, which spans a width of seven meters. Two travelling hoists, which support the load at four points, operate beneath each of the load beams, which measure a good eleven metres in length. The other motion directions are provided by the crane and the lifting and lowering motions.
Two of the double-girder overhead travelling cranes transport sections of fuselage skin to a joining station, pivot them out of their vertical position into the horizontal and transfer them to the station. Here, Airbus joins three to five sections of skin to create a fuselage section, which is followed by the riveting process. The third double-girder overhead travelling crane removes the complete section from the joining station, returns it to the vertical and places it on an automatic guided vehicle, which is indexed to convey it to receive preservative at a surfacing facility. Following this, the crane transfers the component from the guided vehicle to the transport frame of a special sea container in which the parts are shipped for assembly into larger sections at the Hamburg factory.
By using frequency inverters, which facilitate high positioning accuracy as well as infinitely variable long and cross travel speeds, Demag prevents both excessive load sway and vibrations that could quickly damage the fuselage sections. In addition, safety functions are incorporated into the control system, such as synchronised operation, for example. This is automatically activated as soon as all four ropes have been tensioned with a low force of only 35 kilograms. Otherwise, the load would not be lifted in a uniform way. This would cause twisting and corresponding damage. An additional safety system, which works with photocells, prevents collisions between the fuselage sections and the rotating crab. Demag also integrated a safety brake into the rope hoists that would securely hold the valuable load in the event of a gearbox failure.
In total, Airbus operates three of the double-girder overhead travelling cranes customised by Demag, which each have a load capacity of four times 2.5 tonnes; two are used in the large section assembly area and have spans of some 37 and 39 metres, and one with a span of approx. 32 metres operates in the fuselage section shipping area. Thanks to the design of the cranes, which have their motion axes arranged beneath the main girders, optimum utilisation of the building space is achieved. The cranes travel at speeds of up to 40 metres per minute, the crabs at up to 30 metres per minute. The lifting motions are performed at up to eight and 16 metres per minute with and without loads, respectively. The traversing and travelling hoist speeds are limited to five metres per minute. Components can be positioned with millimetre accuracy thanks to the infinitely variable rotation motion of up to 0.8 of a revolution per minute.
In addition to the double-girder overhead travelling cranes, Airbus also operates four double-girder suspension cranes from Demag. The aircraft manufacturer needs this type of crane to achieve particularly close approach dimensions at the edges of the working bays to serve the adjacent high-bay warehouse.
The crane installations for this project entered service between the spring of 2002 and the end of the first quarter of 2003. The criteria which were decisive for the award of the contract to Demag Cranes & Components included the close proximity to the manufacturer and the associated guarantee of a short response time if operation of the cranes should ever be interrupted. This was backed up by the positive experience gained in the co-operative partnership during the previous 15 years. The most important factor, however, was Demag's promise to meet the required very short delivery deadline.
