The Nordic countries have a long and proud tradition of using the tractor to power the axles of trailers in a bid to increase traction, mainly for forestry and military purposes.

Now one Finnish company is looking to greatly expand the concept and bring it firmly into the agricultural sector as well.

Pietu Lehtikuusi, sales director of Black Bruin Oy, is clear about how he sees the future.

Major development

He explained: "We are seeing the same kind of development with trailers that we saw with tractors in the early 1980s, when manufacturers began to shift from rear-wheel to four-wheel-drive.”

The company has recently announced further developments to its B200 series of 'On-Demand Wheel Motors' which allow operators to control a motor's tractive effort.

The effect is to allow the tractor and trailer to travel "together" instead of the tractor simply pulling the trailer.

The axles are intended to be driven off the tractor's hydraulic circuits, although a PTO-powered pump may also be used.

Matching the trailer's speed to the tractor's ground speed may be controlled automatically by the 'On-Demand' system which can also independently vary the wheel speed to replicate the effect of a mechanical differential.

Black Bruin has been manufacturing hydraulic motors for nearly 60 years and claims that, besides providing extra traction, the system can save fuel by allowing heavier loads to be carried more easily.

It also suggests that trailers equipped with powered axles are less likely to get bogged down and cause soil damage in tillage fields.

When not in the field, there's a "unique mechanical free-wheeling system. which enables driving at road speeds without any power losses; the wheel motor operates like a traditional wheel hub when there is no hydraulic pressure".

The wheel hubs may be fitted with either disc or drum brakes and can carry loads of up to 15.4t.