Automatic levelling of a feller head

A method for lateral levelling of a timber working head at a forestry machine with a computer-controlled hydraulic system for driving and regulation of functions of the forestry machine, which forestry machine comprises a chassis with a driver's cabin and an arm to which the working head is fixed and in such a manner that allows rotation, the working head comprising levelling equipment and a regulator for control and regulation of a lateral angle of the working head relative to a vertical direction, the method comprising the following steps:

• a) that a lateral position in the vertical direction, and a zero position, of the working head are recorded;
• b) that the working head is brought out of its zero position;
• c) that the deviation of the working head from the zero position is recorded by the levelling equipment;
• d) that a deviation signal is generated by the levelling equipment;
• e) that the deviation signal is transmitted to and received by a signal processor;
• f) that the signal processor defines the deviation from the zero position;
• g) that the signal processor transmits a correction signal to the computer of the hydraulic system;
• and
• h) that the regulator manoeuvres the working head to the zero position.