Mechanical transmission device between a drive shaft and two driven shafts

Device configured to transmit a torque from a drive shaft (4) to two driven shafts (6, 6′), wherein the drive shaft (4) is mechanically connected to a wheel (8), and first engagement rotors (12, 12′) are coaxially arranged beside the wheel (8) so that the wheel (8) is located between the first engagement rotors (12, 12′) and can rotate together with them, wherein the first engagement rotors (12, 12′) are provided with an axial hole in which a driven shaft (6, 6′) is rotatably arranged, wherein the first engagement rotors (12, 12′) can be mechanically coupled or uncoupled with second engagement rotors (13, 13′) coaxially arranged beside the first engagement rotors (12, 12′), by extracting or retracting, respectively, at least one mobile tooth (14) which can rotate in a seat made in the first engagement rotors (12, 12′), each driven shaft (6, 6′) being keyed to a second engagement rotor (13, 13′), wherein driving rotors (18, 18′) are coaxially and rotatably arranged around the driven shafts (6, 6′) between the wheel (8) and the first engagement rotors (12, 12′) and are provided with a braking mechanism (19, 19′), so that the relative rotation of the driving rotors (18, 18′) with respect to the first engagement rotors (12, 12′) causes the extension or the retraction of the at least one mobile tooth (14) of the first engagement rotors (12, 12′) according to the direction of the relative rotation, wherein the wheel (8) is provided with a plurality of longitudinal holes in which longitudinal pins (11) are inserted so that one or both ends of the longitudinal pins (11) protrude from both sides of the wheel (8), the longitudinal pins (11) being inserted in longitudinal holes made in the first engagement rotors (12, 12′) and the driving rotors (18, 18′) being provided with longitudinal openings (21) crossed by the longitudinal pins (11), so as to allow a limited relative rotation between the wheel (8) and the driving rotors (18, 18′).