The tool has a main controlling gate (5) controlling an actuator performing movements of a movable active unit (3) e.g. fixed counter blade. An auxillary or secondary gate (6) is connected to the main gate by an articulation (7), and is arranged to form an angle (alpha) with the main gate. The secondary gate is pivoted around the articulation to activate a controlling unit of an organized system for realizing an additional function of maintaining medium rotational speed of the tool, where the controlling unit is constituted by a hall effect sensor or magnetoresistive sensor (8).
