A double take from Sennebogen

You might think that you have seen the Sennebogen 673 R before. You would be correct – but only in name. Alex Dahm went to see the new crane at the factory in Germany prior to its launch at the 2013 Bauma exhibition in Munich...

At a first glance this Sennebogen 673 R telescopic boom crawler crane may look like the one shown at the last Bauma exhibition in Munich, Germany in 2010. It carries the same name but that is pretty much where the similarity ends, according to manufacturer Sennebogen. For various reasons that prototype shown in 2010 was not developed into a production model.

Erich Sennebogen explains, “In 2010 we presented a 673 telescopic crawler crane at the Bauma. After the show and, as a result of the discussions with our customers, we took the decision not to proceed with the roll-out. We wanted to deliver the best product to our partners, who want to use this product, sometimes for 20 or 30 years. Thus we had to modify some major components and, eventually, it turned into a completely new design and engineering project, with a totally new undercarriage, a telescopic boom system with much better flexibility, a completely new control system, a more compact dimension and easier in transport, plus compliance with Tier IIIB regulations.

“It was a difficult decision back then in 2010 but, today, we are glad that we took this path because today’s result is a totally new telescopic crawler crane with an excellent performance and, maybe most important, the best match in regards of our company philosophy: Keep it safe and simple,” Sennebogen continues.

The 673 R
At the time of IC’s visit in mid-February, the third unit of the 673 R was nearing completion at the factory in Straubing, about an hour from Munich. At 70 tonnes, capacity-wise, the new 673 R fits in the model range in between the existing 40 and 80 tonne models.

It is close to the 80 tonne 683 but is a different animal, Sennebogen says. In addition to having a longer boom, it is available with a wheeled undercarriage, which the 673 does not have. In addition, the larger model has a Star-Lifter undercarriage, which allows the crawler frames to be removed from the main bridge for transport reasons.

The 673 R has an hydraulic full power boom, designed for this application and not adapted from an existing one, for example, that was originally designed for an all terrain crane. Its 36 m can be further extended to 51 m with a 15 m fly extension. The heavy duty four section design with multiple hydraulic cylinders means that the boom extension and retraction system is different, Sennebogen says. It is always connected hydraulically and can be telescoped under load.

Travel is possible with up to 90% of the permitted load, the manufacturer says. In addition out of level working, with up to 4 degrees of sideways inclination, is also permitted. Capacity at 10 m radius with 17.4 tonnes of counterweight and the boom extended to 30.3 m, is shown in the preliminary chart as 13 tonnes. At 20 m radius capacity is given as 5.7 tonnes.

Power is from a 160 kW Deutz TCD 6.1 L6 diesel to Tier IIIb emissions standard. Also listed is a 148 kW Tier IIIa Deutz engine option. Drive is via planetary gearboxes to the 700 mm wide triple bar track shoes on the telescopic hydraulically adjustable width undercarriage.

Operating weight, with 8 m jib, 35 tonne hook block, two winches, 17.4 tonnes of rear counter weight and 8 tonnes of carbody counter weight, is just over 69 tonnes, Sennebogen says.

The operator is accommodated in the new Max Cab, which can be tilted up to 20 degrees for a better view of the load. An elevating system to lift the cab by up to 2.7 m is optional. Inside is the new Sencon control system. It is designed to be a simple and easy to use single point of reference for as many functions as possible while remaining clear and legible.

For maintenance, as standard there is a central lubrication point for the slewing ring, boom pivot and boom hoist cylinder pivot point. An automated system with interval timer is optional.

An additional option on the 673 R is to fit a basket to for aerial access applications. It is usual for this to be a light duty basket but this one is heavy duty, with 1,000 kg capacity and 360 degree rotation. Working height is 34 m and it has control from the basket and full certification. “We see good potential for this in, for example, maintenance, prefabricated assembly, facility management and so on,” Sennebogen says.

In the beginning
Sennebogen is a 100% family owned business that was started, making agricultural machinery, 60 years ago by Erich Sennebogen, father of current CEO Erich Sennebogen. Axles, gearboxes, winches, slew gears and other components were all built in-house. Mechanical rope operated cranes became the basis of the business, Sennebogen explains. “Then, in 1969, my father developed the first hydraulic crawler crane.” It was in the 20 to 25 tonne class.

Telescopic crawler cranes were introduced by the company in the 1990s, first with the 16 tonne capacity 613, on crawler tracks or wheels, a model that replaced the lattice boom 612. The range was developed with the addition of 40 and 80 tonne models, now the 643 and 683, respectively. There is also an 8 tonne model the 608, available with tracked or wheeled undercarriage.

“Now, with 20 years of experience in telescopic boom crawler cranes, we are one of the leading manufacturers in this market,” Sennebogen says. It remains a niche market but the concept is now more and more accepted. Rental companies are buying them and contractors are beginning to see their value, Sennebogen says. Easy transport and rigging are key benefits of the telescopic boom crane over lattice types.