Everyone knows that European loader crane manufacturers specialise in knuckle-boom cranes, but they also produce one or two types of stiff-boom crane. For example, a small market has long existed in Germany for simple truck-mounted telescopic cranes that lift roofing materials to the tops of buildings under construction. It is a market that both Palfinger and the German manufacturer MKG – both of whom are generally thought of as knuckle boom manufacturers – are seeking to exploit.
Both manufacturers exhibited these so-called assembly cranes at the Bauma fair in Munich earlier this year. Assembly cranes typically have two or three section main booms plus a permanently attached jib that extends hydraulically and folds back on the main boom for stowage during transport. Regular truck loader cranes are primarily designed as a transport tool – to load and unload goods onto the deck of a truck. Truck-mounted assembly cranes are a pure construction tool, and one that some people think open up new possibilities for the market. The design is, in effect, a regular truck-mounted crane – not vastly different from a US-style boom truck – but with a single knuckle in it, a long way along the boom.
Palfinger Europe product manager Michael Voelker says: ‘It could fill a gap that we feel there is between traditional knuckle boom crane and the mobile crane. It will not replace typical mobile crane applications. But with the huge advantage of this additional hydraulic knuckle boom which a mobile crane concept cannot offer there are new applications for it. There are similar advantages as you have with knuckle boom cranes with hydraulic fly jib. You can reach over roofs, you can work horizontally over the flat roof, where you have advantages in the geometry of the crane compared to a mobile crane.’
In Germany, mobile cranes are registered differently from goods vehicles, which adds ther the attractiveness of this hybrid machine, Voelker believes. ‘I think there is something in between [a mobile crane and a truck] that could offer advantages on the tax of the vehicle and also on the fuel tax,’ he says.
MKG sales manager Andreas Lueschen thinks the market could extend beyond German roofing contractors. ‘I think it would be possible to sell these cranes in other countries because they are much easier to handle as telescopic cranes than those of Liebherr or Demag. They are faster,’ he says.
Leuschen adds: ‘Compared to large loader cranes, the stability of these cranes is much greater. With loader cranes you have for example eight extensions in the main boom and then four extensions in the jib arm. These connecting points are weak. Our telescopic crane has only three extensions in the main boom and two extensions in the jib arm and they are much stronger.’
Voelker adds that the hydraulically-powered jib gives the cranes an edge over US boom trucks because they can extend their jibs while operating, unlike boom trucks which he says use manually-pinned jibs. Lueschen also argues that MKG’s models have more powerful hydraulic systems than US boom trucks.
Palfinger showed the prototype of its 84tm PK 800 TK at Bauma. It expects assembly of the prototype of its smaller sibling, the 60tm PK 600 TK to continue through next month. Neither prototype had sold as of last month, but the company plans to manufacture five units in total this year, in advance of serial assembly.
Palfinger’s two new models will be some of its first serial-production cranes sold factory-installed on a truck. (The company already sells its lines of aluminium-boom aerial work platforms with truck). This is because the outriggers are not attached to the crane but instead they mount on to a Palfinger-manufactured subframe. The PK 800 TK prototype is mounted on a four-axle MAN TGA 41.460 chassis, though according to Voelker customers will be able to choose their truck. The PK 600 TK will be supplied on a three-axle truck.
‘The idea is to have a complete concept that cost-wise could be very interesting for the customer,’ says Voelker. The PK 800 TK is expected to retail roughly at Euro 150,000 excluding truck, though an official price list had not, at time of writing, been released to dealers. (The PK 600 TK is estimated to cost about Euro 135,000).
Also at Bauma, MKG launched its 70tm T-type (for telecoping boom) and 55tm L-type (long boom) models with a new octagonal boom shape. MKG claims that this profile is stronger than its older hexagonal designs. Two of these, with lifting capacities of 95tm and 125tm, remain in its product range. Since Bauma MKG has sold eight of the T-type and seven of the L-type assembly cranes, since Bauma.
MKG’s T-type crane has a three-section telescoping main boom and at up to three sections of powered jib (it also has a further three manual extensions). Maximum powered hook height is 40m. The L-type has a longer single-section main boom and a jib with a maximum of four extensions. Maximum hook height is 25m.
Both Palfinger and MKG cranes use a counterweight rack mounted at the base of the crane that is pushed out hydraulically from a compact transport position. The crane cannot operate until the counterweight is pushed out. It is then retracted again for transportation.
Palfinger’s 84.1tm PK 800 TK has a four-stage main boom and four-stage hydraulically-operated jib. It can lift 1.2t to about 44m, or 250 kg to about 36m radius. Because the fly jib articulates, the crane can also lift a load of 1t to about 21m radius at a height of about 28m. When it is built, the 60.1tm PK 600 TK will be mounted on a three-axle truck. It has three main boom cylinders and four hydraulically extending fly jib stages. According to the design, it will lift 1.2t to about 38m, or with boom horizontal can reach 36m with 200kg. With fly jib horizontal, it can lift a load of .9t to a radius of about 20m at a height of about 23m. Minimum counterweight is 2t.
The market for assembly cranes remains a small niche. MKG sells between 50 and 80 units a year in Germany, accounting for no more than 10% of its total sales. However, outside of Germany Palfinger is studying market possibilities for this type of crane and MKG is ‘looking for new dealers everywhere,’ Lueschen says.