Patent ID: 8556008

Claim:
A method in the power transmission of a forest machine ( 1 ), the forest machine comprising a front chassis ( 2 ) and a rear chassis ( 3 ) articulated to one another, a primary hydrostatic power source ( 5 ) arranged on the front chassis ( 2 ) for generating hydrostatic power required for moving and controlling the forest machine and an actuator ( 6 , 7 ) therein, the primary power source under control of control devices ( 23 ), said method comprising the steps of: converting at least part of the power generated by the primary power source ( 5 ) into electric energy by a generator arrangement ( 8 ); storing the electric energy generated by the generator arrangement ( 8 ) in an electricity storage means ( 9 ); leading at least part of the electric energy from the storage means ( 9 ) to a conversion means ( 14 ) located separated from the primary power source ( 5 ) on the rear chassis ( 3 ), the conversion means ( 14 ) being a pressure medium-transmitted power generating source separate from the primary power source ( 5 ), and, when an operating instruction obtained from a user of the forest machine is conveyed by the control devices ( 23 ) to the primary power source ( 5 ) includes an immediate increased power requirement of the forest machine which exceeds a power generation capacity of the primary power source, with the electric energy from the storage means ( 9 ) providing additional electric energy for use by the conversion means ( 14 ), simultaneously and parallel with the power source ( 5 ), generating additional pressure medium-transmitted power for implementing a pressure medium-transmitted function of one of i) the forest machine ( 1 ) and ii) the actuator ( 6 , 7 ) responsive to the immediate increased power requirement; and at least partly hydraulically controlling a hydraulic timber-processing device responsive to the immediate increased power requirement of the forest machine ( 1 ) using hydraulic power from the additional pressure medium-transmitted power generated in said conversion means ( 14 ).