A Korean phoenix

In the 1990s, BKT saddle jib flat top cranes were successfully marketed in Germany by sales organization Zeppelin. But the deal with Zeppelin ended in 1996, and the German tower crane recession was harsh on small crane manufacturing companies like BKT Maschinenbau GmbH. With the sudden collapse of the Asian market, BKT Maschinenbau GmbH went into receivership in 1998.

That year, Potain bought BKT's intellectual property and assets, moved production from Arneburg, Germany to the Potain plant in Moulins, France, and incorporated the designs into its cranes. Manitowoc Crane Group continues to manufacture a range of large luffing-jib tower cranes and flat-top tower cranes based on BKT designs, says Frans Vanwinkel, Manitowoc senior vice president for EMEA sales and marketing. The company continues to support BKT cranes.

That should be the end of the BKT brand. But in 2005 a few new cranes that resembled the old designs started to pop up in Korea. These cranes are made by BKT Engineering—completely independent of Manitowoc Crane Group—at a plant in Valluhn, Germany set up in 2003 by the former BKT's Korean dealer, CNC Korea Trading Co.

“We are here to get back to the glorious time of the former BKT by supplying internationally better quality machines with longer life time of tower cranes,” says Hee Bang, managing director of BKT Engineering.

Bang says he had a pivotal role developing BKT Maschinenbau's range of tower cranes above 300tm, including the BN205, BN405 and BN605, and the topless saddle-jib BK302, and the conventional saddle jib crane BK560, up to the 1997 Asian economic crisis. A few years later, these models have become popular in the US market under Potain.

At first, Bang says he built the factory to make cranes exclusively for the South Korean market. With the recovered Asian economy, demand for tower cranes is rising again. The BKT name still has a good reputation in Korea, he says, and Korean customers are prepared to pay an extra amount for a crane made in Germany, because of the country's reputation for sophisticated engineering, fabrication quality and manufacturing standards.

BKT Engineering compensates for Germany's high wages, and shipping the cranes half way around the world, by only producing cranes to order, and by taking advantage of German government grants for development in rural east Germany. The company's limited factory capacity and philosophy to design cranes according to the customer's needs enable it to find a healthy niche market alongside mass production, Bang says. While the head office of the BKT Engineering business is located in Hamburg, fabrication is carried out in Valluhn, on highway 24 connecting Hamburg with Berlin. At the moment steel fabrication is located in one hall. However construction of a new factory providing two assembly lines near the existing plant is due to start soon. The new plant's yearly output will be 46 cranes next year, although the company will need to double its staff to 36 people. It is also building a new test ground so that the cranes can be assembled before shipment.

The cranes are being designed by engineers who worked for Peiner before new owner Terex shut down German production.

Bang says he is improving BKT designs by building more rigid steel structures, providing higher single line capacity and facilitating rigging. “In comparison to the former BKT cranes we pay more attention to the rigidity of the steel structure by changing the diagonal frame work and using stronger corner posts, 18mm thick instead of 15mm, in order to raise crane life well into 25 years. While some of our competitors are reducing rigidity of their steel structure due to the pressure on fabrication costs we will even raise the rigidity into the level of the proven original Liebherr HC crane range,” Bang says. Mechanical components are provided by third parties, such as Lebus (winches), Rothe Erde (slew rings) and Flenders (slip-ring motors). Frequency inverter drives are not popular in Korea, Bang says, but can be fitted.

BKT Engineering's biggest seller, the BN 280-18 luffing-jib tower crane, has a high line pull for the high-rise construction market. It can lift loads up to 9t on two falls of wire rope, 13.5t on three falls, or 18t on four. The crane fits in between the old BKT BN205 and BN405. The company's next crane, the BN660, designed by independent engineer Uwe Streb, will again provide three operation modes, 1-fall operation up to 8.5t, two falls up to 17t and four falls up to 34t. The company has made 11 units of the BN280 since 2005, and two BN660s are under construction. The BN660 prototype is due to be assembled for testing this month. Designed, but not built, is the BN880-50, with maximum single-fall lifting capacity of 26.3t. There are also three top-slewing tower crane designs following old BKT designs. A BN 1200 tower crane under development would have a maximum load capacity of 90t.

The BN280 features better access to, and safer set-up of, counterweight ballast blocks. From the machinery platform, engineers reach the ballast through a gate, up a ladder, and along a platform. The concrete blocks have been redesigned so that their vertical centre of gravity lies beneath the mechanical link to the ballast lever. Therefore no shock absorbers are required for the BN 80.

At the moment two tower systems are manufactured, the TS19 1.9m x 1.9m square system for cranes up to the BN280, and the TS24 2.4m x 2.4m square sized tower system for cranes up to the BN660 luffing jib crane. To reduce transportation costs jib sections can be inserted into the tower cranes sections. In all cases, towers connect with high-tension bolts.

All of the cranes sold to date have gone to Korea. But the company recently signed a deal with distributor AaS-International AG to set up a dealer and manufacturing network in Ras al Khaimah, United Arab Emirates. AaS-International will import parts and components from BKT Engineering's factory, and assemble the towers in the UAE (Cranes Today May 2007, p7).

BKT Engineering BN280-18 at the Courthouse Complex in Seoul BKT Engineering BN280-18 at the Courthouse Complex in Seoul Turntable with Flenders slewing drives of a BN280 under production. Turntable with Flenders slewing drives of a BN280 under production. a BN280-18 in three fall operation mode with a maximum of 13,5t capacity and a tip load of 4,3t at 50m radius. On the rear of the cabin platform a matching transformer copes with 10% variation of the feeding voltage of local electric power supply. BKT Engineering BN 280-18 Hee M. Bang, managing director of BKT Engineering GmbH (left) and Mr Aribert Just CEO of AaS-International AG (right) in front of the BKT manufacturing plant in Valluhn, Germany Bang and Just BKT Engineering tower crane cabins awaiting fitting to cranes under production BKT Engineering tower crane cabins awaiting fitting to cranes under production