Auto injector with cartridge locking system

An auto injector for administering injection of a medicament from a cartridge containing the medicament, the auto injector comprising:

• a housing;
• a cartridge receiver with a cartridge receiver compartment configured to receive a cartridge assembly comprising at least one cartridge retention member when the cartridge assembly is inserted through a cartridge receiver opening along a longitudinal axis in a receiving direction;
• wherein the cartridge receiver has a passage configured to receive the at least one cartridge retention member when the cartridge retention member is inserted through the cartridge receiver at least in the receiving direction, and a member preventing movement beyond a retention position in a direction opposite of the receiving direction;
• an elongated ejector comprising an ejector support face for supporting the cartridge or the cartridge assembly, and a longitudinal ejector slot extending towards the ejector support face from an ejector rest portion;
• wherein the elongated ejector is suspended to move along the longitudinal direction and is spring-loaded in the direction opposite of the receiving direction;
• and
• an ejector lock supported for turning at least a fraction of a revolution and maintained in a longitudinal position relative to the housing;
• wherein the ejector lock has an ejector lock support portion that is configured to align with and slide along the longitudinal ejector slot at a first angle and to be brought to align with the ejector rest portion at a second angle.