Auto injector with bi-stable clutch plate

An auto injector (100) for delivery of a medicament to a patient, the auto injector (100) extending from a proximal end (102) to a distal end (104), wherein the auto injector (100) is adapted for receiving a cartridge assembly (200) supporting a syringe (300) comprising:

• a syringe compartment (302) containing the medicament;
• a hollow needle (304) through which the medicament can be delivered to a patient;
• a stopper (306) proximally movable inside the syringe compartment (302) for evacuating the medicament in the syringe compartment (302);
• a syringe cap (308) adapted for protecting the needle (304);
• wherein the auto injector (100) comprises:
• a housing (110);
• a plunger (120) movably positioned inside the housing (110), the plunger (120) being adapted for moving the stopper (306) inside the syringe compartment (302) proximally for delivery of the medicament;
• a plunger spring (140) adapted for moving the plunger (120) proximally for delivery of the medicament;
• a clutch assembly (150) position inside the housing (110), the clutch assembly (150) comprising a bi-stable clutch plate (170) comprising a flexible ring part (172) from where one or more retention arms (174) extend, the flexible ring part (172) being movable between:
• a first stable position where the one or more retention arms (174) protrudes outwardly and engages with an inside surface (116) of the housing (110), wherein the flexible ring part (172) is in the first stable position during delivery of medicament, and
• a second stable position where the one or more retention arms (174) protrudes inwardly and are disengaged from the inside surface (116) of the housing (110),
• wherein upon translation of the cartridge assembly (200) into the auto injector (100) after delivery of the medicament, the clutch plate retention arms (174) are brought into contact with release ribs (119) inside the housing (100) whereby the flexible ring part (172) on the clutch plate (170) is moved from the first stable position to the second stable position allowing the cartridge assembly (200) to be removed and the auto injector to be reset.