AUTO INJECTOR WITH CARTRIDGE LOCKING SYSTEM

An auto injector (4) for administering injection of a medicament from a cartridge containing the medicament, the auto injector (4) comprising: a housing (6); a cartridge receiver (300) with a cartridge receiver compartment (302) configured to receive a cartridge assembly (600), with at least one cartridge retention member (808), when inserted through a cartridge receiver opening (301) along a longitudinal axis (L) in a receiving direction; wherein the cartridge receiver (300) has a passage (316) through which the at least one cartridge retention member (808) travels at least in the receiving direction, and a member (312) preventing movement beyond a retention position in a direction opposite of the receiving direction; an elongated ejector (200) that is configured with: an ejector support face (204) for supporting the cartridge or cartridge assembly (600), a longitudinal ejector slot (228) extending towards the ejector support face (204) from an ejector rest portion (206); wherein the elongated ejector (200) is suspended to move along the longitudinal direction and is spring-loaded in the direction opposite of the receiving direction; and an ejector lock (212) supported for turning at least a fraction of a revolution and maintained in a longitudinal position relative to the housing (6); wherein the ejector lock (212) has a ejector lock support portion (214) that is configured to align with and slide along the longitudinal ejector slot (228) at a first angle and to be brought to align with the ejector rest portion (206) at a second angle.