To provide a free wheel coupling capable of automatic and really mechanical connection and disconnection of an auxiliary driving device in both rotational directions.

A fastening element 28 is connected to a boss 16 in the stop position. The fastening element 28 is provided with a contact surface which cooperates with an immovable element 18. The fastening element 28 reaches the first locking position or the second locking position in the rotational direction by the rotation of the boss 16 in relation to the immovable element 18. In these locking positions, the fastening element 28 is frictionally connected between the shaft 12 and the boss 16.