The maritime inspiration is that the machine’s centre of gravity can be altered. Not with ballast tanks like a boat, but with a variable track width on the front wheels and by being able to manoeuvre the bogie of the double rear wheels so that the machine supports itself on either the front or rear sets of wheels.
“Being able to vary the centre of gravity improves accessibility, and the ground bearing capacity is better when the front and back wheels go in different tracks,” Torbjörn explains.
The T-Bear has scarcely a single component that is familiar from other forest machines. Many of its components have been adapted from the processing industry and the machine is made mostly from aluminium to reduce weight. Various structural design solutions ensure that the machine remains stable.
But what most surprised the crowd of onlookers is that Torbjörn has developed his own control system. It is based on a digital bus like those used in automobiles. The bus has reduced the number of parts in the electrical system by seventy percent, resulting in a machine that is more reliable to operate and easier to repair.
The most spectacular feature, though, is the voice-operated boom and a computer system that speaks.
“If the computer is quiet I know everything’s working right,” Torbjörn says, looking down at his thumbs.
Why his thumbs? He is a forest contractor and the many years he spent pressing buttons as a machine operator damaged his thumbs. Nowadays he guides the harvester head into place with a joystick and then says “cut”.
“Many people develop thumb problems over time – this way they can avoid that,” he says.
The T-Bear’s entire design has been based on the concept of avoiding hassle and problems. The number of nuts has been minimised: most components are bolted fast onto a stable frame. As far as possible, the same dimensions are used in as many places as possible, and sensitive functions have built-in redundancy.
“I don’t want to sit on my sofa waiting for parts for days, I want to fix the problem right away and keep on working,” says Torbjörn Eriksson of Green Wood Logistics AB in Dalsland, Sweden.