System for adjusting the rotation speed of a cross-cutting saw of a tree handling machine, especially grapple harvester

An apparatus for adjusting feeding power of a cross-cutting saw having a saw blade and included in a mobile tree handling machine capable of moving in terrain, said apparatus comprising,

• an actuator connected to transmit power to said saw;
• a line connected between said actuator and a source of pressure medium for creating a pressure in said actuator and a feeding power of said saw from said actuator, said line comprising a means for adjusting the pressure in said actuator;
• a hydraulic motor rotating the cross-cutting saw at a rotational speed,
• a rotational speed sensor arranged to measure the rotational speed of said saw directly from saw blade;
• a computing means for comparing measured rotational speed of said saw with a pre-set value and for controlling said means for adjusting so that when said measured rotational speed exceeds said pre-set value said pressure in said actuator and said feeding power increases and when said measured rotational speed decreases below said pre-set value said pressure in said actuator and said feeding power decreases, whereby said rotational speed of said saw is maintained substantially constant;
• and
• a transmitting connection communication with said rotational speed sensor and said computing means.