The invention refers to an interlock mechanism for restricting a rotational movement of a rotatable component (1) of a drug delivery device(10) and to a method for controlling the rotational movement of the rotatable component (1). The method comprises the steps of: -translatively moving a trigger arm (6) engaged with a protrusion (7) of a latch arm (5) from an initial position for pivoting the latch arm (5) out of one of at least one catches (3) provided in a cam profile of the rotatable component (1) thus allowing the rotatable component (1), biased by an energy source, to rotate -pivoting the trigger arm (5) by one of at least one cams (4) provided in the cam profile during the rotation (R) of the rotatable component (1) whereby the trigger arm (6) is disengaged from the protrusion (7) thus allowing the latch arm (5) to re-engage with one of the catches (3) to stop the rotational movement (R) and whereby an interlock means (8) catches and holds the trigger arm (6) in its translatively moved and pivoted position until the interlock means (8) is released by a reset means -translatively moving the trigger arm (6) back into the initial position once the interlock means (8) is released thereby allowing it to pivot back and re-engage with the protrusion (7).Linvention concerne un mécanisme à enclenchement destiné à entraver un mouvement de rotation dun composant rotatif (1) dun dispositif (10) de distribution de médicament, ainsi quun procédé de commande du mouvement de rotation du composant rotatif (1). Le procédé comporte les étapes consistant à : - écarter par translation un bras (6) de gâchette coopérant avec une protubérance (7) dun bras (5) de loquet dune position initiale afin de faire pivoter le bras (5) de loquet de façon à lextraire dune encoche parmi au moins une encoche (3) pratiquées dans un profil de came du composant rotatif (1), permettant ainsi au composant rotatif (1), sollicité par une source dénergie, de tourner - faire pivoter le bras (6) de gâche
