Abstract: An improved device for transmitting motion between the rotor of a synchronous permanent magnet motor and a working part. The device includes a first coupling, provided with a driving element, which is eccentric with respect to the rotation axis of the rotor, at a rotor shaft end. A second coupling cooperates in a kinematic series with the first coupling and is provided with a driven element, that is eccentric with respect to the rotation axis of the rotor and rigidly formed with said working part. The driving and driven elements lie in distinct and non-interfering axial positions. The device further includes two elastic elements, which are set angularly after each other, one of them interfering with the driving element of the first coupling and the other one interfering with the driven element of the second coupling.