Abstract: A blocking mechanism including a transmission casing and a movable pawl having a locking finger. The movable pawl is pivotably mounted in a plane about a pivot axis on the transmission casing between a locking position in which the locking finger is engaged in the locking recess and a release position in which the locking finger is disengaged from the locking recess. The movable pawl includes a cam surface. A linear actuator moves a movable carriage guided by a guide rail, in which the movable carriage includes a cam follower capable of moving on the cam surface, and a housing formed in the transmission casing, in which the guide rail is fitted in the housing.