Adaptation of a 4WD tractor for wood extraction in steep terrain

In North-eastern Italian Alps wood extraction in steep terrain (up to 25-30%) is generally performed by means of 4WD agricultural tractors equipped with winches. One problem associated with the use of agricultural tractor in forestry, especially in off-road moving in steep terrain, is the stability and hence operator’s safety. In order to overcome such a problem an adaptation of a 4WD agricultural tractor for wood extraction in steep terrain has been developed. It considers different features especially designed to be installed on an agricultural tractor. The first feature consists in a self-levelling device, made by two arms, articulated on the tractor’s final drive box and moved by two hydraulic rams. On the end of each arm a free-turning bogie is mounted. Another feature is the elongation of the fork in which the front axle is articulated, in order to increase its tilting angle. Two side plates, bolted on the rear body of the tractor, represent the last feature. The plates allow moving the p.t.o. shaft and the three-point linkage to the back permitting the use of the mounted winch. The control of the levelling device is both automatic and manual. When manually operated the levelling device is controlled by means of a single lever on the right side arm of the operator’s seat. The adapted tractor has demonstrated to operate in efficient and safe way on sloping and rough terrain.