Abstract: The device permits locking of a control knob which can rotate around a cylindrical support and includes a lateral face with at least one first locking boss and a lateral face of a ring which has at least one second locking boss. The ring is movable in translation according to the axis between a locked position of the knob, in which the ring is prevented from rotating around the axis when the first and second bosses are engaged, and between a released position in which the first and second bosses are decoupled.