Non-return rotation transmission device

A non-return device for transmitting a rotational movement, comprising coaxial input and output shafts, a frame for guiding the rotation of the shafts, a locking element configured to move in radial translation through a channel of the output shaft between a locking position, in which said locking element projects out of said channel so as to prevent a rotation of the output shaft, and a radial unlocking position, in which the locking element is retracted so as to allow axial rotation of the output shaft, the input shaft including means for switching the locking element between its locking and unlocking positions, the switching means of the locking element including a cam having a profile adapted to move the locking element radially during a rotation of the input shaft, wherein the input shaft comprises a shoulder abutting against a flat portion of the output shaft in order to rotate the output shaft, the reaching of the abutment by the shoulder during a rotation of the input shaft coinciding angularly with the placing of the locking element in the unlocked position by the cam.