Special cargo is everyday business for Dutch company Van Grinsven Crane Hire and Transport B.V. Among the different types of special cargo that van Grinsven hauls, under contract, are temporary accommodation units for construction sites and over-length construction materials, for example, steel, concrete and PVC beams and pipes.
The 3 m tall units require a 1.15 m high flat bed trailer, based on a long term over height permit allowing 4.15 m overall height on Dutch roads. The length of the construction materials runs up to 22 m.
So far none of these are unusual requests for Broshuis. An additional request, however, from Marco van Grinsven, to add a 50 tonne-metre Kennis rolling crane, presented a real challenge for the Broshuis engineering team.
To comply with the requirements, the trailer had to be of a new design to meet the different stresses on the main central beam and its cross members imposed by the roll loader crane. The new design resulted in using high tensile steel to manufacture a slim central main beam and the complex low cross members. In this way the rigidity of the trailer remained uncompromised.
The new three-axle, 1.15 m tall and 2.42 m wide trailer runs on small 235/75 R17.5 tyres. Axle spacing measures 1.85 m, while axles one to three steer to a maximum angle of 20, 30 and 45 degrees, respectively. Independent steering is provided for manoeuvring the trailer. The air ride axles allow the first axle to be lifted if required.
As standard the flat bed trailer is 13.5 m long, but it can be extended in steps by a maximum of 7.5 m up to 21 m overall trailer length.
After delivery of the trailer, the 50 tonne-metre Kennis rolling knuckle boom crane was installed and tested to 125% overload by Kluitmans in Haren, a Kennis dealer. The fully rotating R50-0/169-6 crane weighs 8,820 kg and offers a capacity of 10,590 kg at 4.6 m minimum reach and 2,380 kg at 16.9 m maximum reach.
It looks like the new design fills a market niche as Broshuis has already reported a number of follow up orders.