Heavy Trailer Built in New Zealand
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CONSERVING some £15,000 which might otherwise have been spent abroad, Tapper Transport Engineering, [ltd., Fanshawe Street, Auckland, New Zealand, have built an 80-ton trailer which is both the largest to have been made in that country and the biggest in use.
The frame is made up of welded box sections which were formed of 12-in. by 1.7i.n. plates. A 100-ton hydraulic press was specially constructed for this purpose. The well is 25 ft. long and the trailer deck is 10 ft. 3.in. wide:
At the rear are six wheels with hydraulic suspension to provide a vertical movement of 1 ft. 6 in. The' legs are of 6-in, diameter and move inside cast-steel steering sleeves with 1 ft. 6 in. of multiple spline cut on heavy machinery at a naval dockyard.
The sleeves are coupled to a 9-in. hydraulic ram fed from a Telehoist pump powered by a Holman Petrol-driven compressor. Steering lock is 60', and the wheels can be turned, if necessary, when the outfit is stationary.
Two types of wheel attachment are fitted to the legs. One provides for a width over the tyres of 10 ft., hut as the trailer was required to carry a paper roller 15 ft. in diameter, provision was 'Made for the track to be increased by '2 ft. to allow greater stability for wide loads of this sort. The normal arrangement is compatible with the narrow roads found in some parts of New Zealand.
Between the trailer and the Leyland Hippo six-wheeled tractor is a sub-trailer. A Davies Magnet 40-ton turntable connects the trailer and sub-trailer, and there is a similar component between the sub-trailer and the tractor. Usc of the sub-trailer was made necessary by local regulations concerning axle weights, and the need to spread the load so as not to overburden certain bridges.
Gross weight of the outfit is 108 tons. Air-pressure braking is applied to all wheels.
Heavy loads have been carried along a number of difficult routes in North Island, including from Auckland to New Ply—mouth via Mount Messenger, returning by Wanganui across the desert road and through the Parapara Gorge.