Auto-injector

An auto-injector for administering a dose of a liquid medicament (M), comprising:

• an elongate case arranged to be held by a user,
• a tubular chassis telescopable in the case and biased against the case so as to protrude from the case,
• a syringe with a hollow injection needle, a drive spring and a plunger for forwarding load of the drive spring to a stopper of the syringe,
• a trigger button distally arranged in or on the case,
• wherein the trigger button is initially coupled to the case in a manner to protrude distally from the case and interlocked to the chassis in a manner preventing the trigger button from disengaging the case and thus preventing actuation of the trigger button in an initial position, wherein the case is arranged to translate in the proximal direction (P) against the bias relative to the chassis thereby also translating the trigger button releasing the interlock to the chassis so as to allow actuation of the trigger button, wherein the trigger button is arranged to lock in a more proximal position on actuation,
• wherein a carrier subassembly is arranged comprising a tubular carrier slidably arranged relative to the chassis inside the case, the carrier adapted to contain the syringe with the hollow injection needle, the drive spring and the plunger, wherein the syringe is lockable for joint axial translation with the carrier, wherein the trigger button exhibits at least one proximal beam arranged to be in a ramped engagement with the case in a manner to inwardly deflect the proximal beam and decouple it from the case when the trigger button is forced in the proximal direction (P) against the case, wherein in the initial position the proximal beam inwardly abuts the carrier so as to prevent inward deflection, wherein the carrier is initially coupled to the chassis for joint axial translation by a detent mechanism, wherein the detent mechanism is arranged to decouple the chassis from the carrier upon actuation of the trigger button thus allowing the carrier to move relative to the chassis, wherein a first window in the carrier is arranged so as to allow inward deflection of the proximal beam when the case is translated in the proximal direction (P) from the initial position.