Medical Injection Device Comprising a Secondary Safety Limiter

A medical injection device for setting and injecting set doses from a held drug cartridge, comprising:

• a housing defining proximal and distal ends,
• a dose setting arrangement including a dose setting device that is moved in a first direction away from a predetermined stop in accordance with the size of a set dose and that moves back to the predetermined stop during injection of the set dose, the predetermined stop being configured for being fixedly arranged relative to the housing,
• a piston rod adapted to translate relative to the housing in a distal direction in order to expel a set dose,
• a driver coupled to the piston rod, the driver being adapted to rotate during dose injection to cause the piston rod to translate relative to the housing, and
• a mechanism adapted for coupling rotational movement of the dose setting device with rotational movement of the driver such that the driver exclusively rotates when the dose setting device moves back towards the predetermined stop during injection of the set dose, wherein the injection device defines:
• a first component that rotates around a first axis as the driver rotates during injection but remains rotationally fixed relative to the housing during dose setting, the first component having a first track disposed thereon,
• a second component that is arranged coaxially with the first component for rotation around the first axis, wherein the second component rotates as the dose setting device rotates during dose setting and wherein the second component is rotatably fixed relative to the housing during dose injection, the second component having a second track disposed thereon, and
• a secondary stop track follower arranged between the first component and the second component, the secondary stop track follower being in engagement with the first track and in engagement with the second track, wherein the first track and the second track are configured to cause the secondary stop track follower to move along the first axis when the first component and the second component rotate relative to each other, and wherein, if the predetermined stop fails to stop the driver at the end of injection, the secondary stop track follower moves towards a safety stop to prevent the driver from rotating further.