A drive assembly for a drug delivery device (100) is provided. The drive assembly comprises a housing (10) having a proximal end (17) and a distal end (16) and a drive mechanism comprising a piston rod (30) and a drive member (40) to drive the piston rod (30) to dispense a dose of drug and a dose member (70) coupled to the drive member (40). The assembly further comprises a return mechanism comprising a spring member (130). The assembly further comprises a movable member (110) which is coupled to the spring member (130). In a setting mode of operation, the movable member (110) is coupled to the dose member (70) and, the movable member (110) is movable from an initial position to a dose set position, thereby biasing the spring member (130). In the dispensing mode of operation, the drive member (40) and the movable member (110) are decoupled such that the drive mechanism is operable by the user by application of a driving force to the drive mechanism, wherein the spring member (130) of the return mechanism drives the movable member (110) independently of the driving force towards its initial position.Linvention porte sur un ensemble dentraînement pour un dispositif dadministration de médicament (100). Lensemble dentraînement comprend un boîtier (10) ayant une extrémité proximale (17) et une extrémité distale (16) et un mécanisme dentraînement comprenant une tige de piston (30) et un élément dentraînement (40) chargé dentraîner la tige de piston (30) afin de délivrer une dose de médicament et un élément de dosage (70) couplé à lélément dentraînement (40). Lensemble comprend en outre un mécanisme de retour comprenant un élément à ressort (130), ainsi quun élément mobile (110) couplé à lélément à ressort (130). Dans un mode opératoire de réglage, lélément mobile (110) est couplé à lélément de dosage (70) et lélément mobile (110) peut être déplacé depuis une position initiale vers une position de réglage de la dose, mettant ainsi sous tension lélément à ressort (130). Dan
