SCHAAF - NEWS May 2004

Worldwide biggest Drop Forge Press disassembled with SCHAAF Bolt Tensioning Device
As already reported at this point, the worldwide biggest single bolt tensioning device was built in a 6 weeks record time by SCHAAF. In April 2004 TRANSGERMA GmbH (Germany) placed the order with us to dismantle the tie-rod tensioning of the worldwide biggest drop forge press with this tensioning device.

First disassembly of this press type
The drop forge press is a 25 years old 12.000 t press, type Mueller-Weingarten PZS900, at ThyssenKrupp Gerlach in Danville / Illinois (USA). There is less then one dozen of this press type worldwide and up to now there was no one disassembled. For this reason and viewing the fact that the complete disassembly was carried out with involvement of the press manufacturer, the operation was instructed by 2 SCHAAF specialists on-site.
Once more took effect our several 10 years experience in the field of bolt tensioning technique and our manufacturing high flexibility, which our customers could always rely on.

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PZS900 in production
(truck - crankshaft forging)

Consequent efforts of high pressure technology offer substantial advantages
The dismantled 4 tie-rods are "screws" M760x12, approx. 12 m lengths (part weight 26 tons) with a maximum tensioning force of 66.000kN (~6.600 tons) per screw. Tensioning tools were one tension cylinder (outer diameter 1.800 mm, weight approx. 3,5 tons)and one immersion nut with M760x12 tensioning thread (outer diameter 1.500 mm, weight approx. 5,3 tons). For comparison: The original weight of the tools for this operation designed by the press manufacturer had a total weight of nearly 30 tons (!) and must be transportet in a separate sea container. Only consequent efforts of highest pressure technology could reduce the tool weight by approx. 70% (!).



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SCHAAF - bolt tensioning device on the press crown

Disassembly within less than 4 hours
As system supplier SCHAAF delivered not only the main tensioning tool but also auxilliary and lifting devices. The real dismantling operation was carried out by 4 workers (incl. crane operator) within less than 4 hours per screw.

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Set up of the tensioning cylinder with assembly centering mendrel


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Lifting, set up and screwing of the tension nut with SCHAAF - lifting device.
The tension nut can be screwed by hand in spite of their weight of 5,3 tons.



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Screwing off and lifting of the main nuts with SCHAAF -lifting device.
Assembly order announced
As a result of succesful and qualified on-site assistance by our specialized staff during the dismantling procedure we already rest assured by our customer that the re-assembling of the press in Great Britain will be worked out with SCHAAF assistant in any case.
Further report will following at this point.

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2 of the 4 disassembled nuts