Abstract: A transmission, comprising a rotary shaft (14) for coupling with a first drive element, provided with a wheel (24) supported eccentrically and freely rotatably on the shaft for coupling with a second drive element, further comprising a ring arranged concentrically and rotatably with respect to the rotary shaft. The ring (8) is provided with a first tread (9) cooperating with the tread (10) of the wheel and a second tread (11) cooperating with the tread of an auxiliary drive element, such that rotation of the rotary shaft results in a corresponding circular revolving movement of the wheel about the centerline of the rotary shaft, while rotation of the wheel about its own axis depends on the rotation of the rotary shaft and on the rotation of the ring about the centerline of the rotary shaft. The wheel further cooperates with a tread of an auxiliary ring (26) arranged concentrically with the rotary shaft in a different transmission ratio as with the ring.