EP2489385A1 — Auto-injector

USPTO Abstract

The invention refers to an auto-injector (1) for administering a dose of a liquid medicament (M), comprising: - a tubular chassis (2) telescopable in a tubular case (12), - a carrier subassembly comprising a tubular carrier (7) slidably arranged relative to the chassis (2) inside the case (12), the carrier (7) adapted to contain a syringe (3) with a hollow injection needle (4), a drive spring (8) and a plunger (9) for forwarding load of the drive spring (8) to a stopper (6) of the syringe (3), wherein the syringe (3) is lockable for joint axial translation with the carrier (7), - a control spring (19) arranged around the carrier (7) for translating the carrier (7) in a proximal direction (P) for insertion of the needle (4) through the chassis (2) into an injection site, wherein the control spring (19) is arranged to bias the case (12) against the chassis (2) in a distal direction (D) so as to extend the chassis (2) out of a proximal end (P) of the case (12), wherein an insertion depth of the needle (4) is defined by the carrier (7) abutting the chassis (2) in a predefined position, wherein the case (12) is arranged to release or allow release of the control spring (19) for needle insertion on translation of the case (12) in the proximal direction (P) relative to the chassis (2) against the bias into an advanced position.