Movement transmission device for motor vehicle fans with coaxial operation of the coupling system

Device for transmitting the movement to a fan (1) for cooling the coolant in a motor vehicle, comprising:

• movement generating means (3,21) on which the fan (1) is mounted by means of an idle support (la);
• a first electromagnetic clutch (30), engagement of which causes rotation of the fan at a number of revolutions equal to that of the movement generating means;
• a second clutch (60;160;260;360), engagement/disengagement of which causes rotation of the fan at a number of revolutions lower than that of the movement generating means or at zero revolutions;
• characterized in that it comprises:
• means (50;150;250;350) for engaging/disengaging the second clutch comprising an actuating element (41) coaxially displaceable, in both directions, with respect to the movement generating means (3;21), but idle upon rotation of the latter;
• engaging/disengaging means (50;150;350) which are coaxially locked in rotation with the movement generating means (3;21) and connected to said displacement actuating element (41), said engaging means comprising coupling elements (47;147;347) suitable for engagement/disengagement with the rotor (61;161;261;361) of the said second clutch (60;160;260;360):