Injection device with dosing control means

A method of assembling an injection device, comprising:

• providing an injection device comprising a first casing part and a second casing part which can be coupled to the first casing part;
• providing a reservoir for receiving a liquid drug;
• inserting the reservoir into one of the first casing part and the second casing part;
• and
• after inserting the reservoir, coupling the first casing part and the second casing part to each other such that the first casing part and the second casing part cannot move relative to each other in an axial direction of the injection device and cannot rotate relative to each another such that the reservoir cannot move relative to the one of the first casing part and the second casing part into which the reservoir was inserted,
• wherein one of the first or the second casing part comprises:
• a needle shield which is movable in an axial direction relative to the casing parts such that the needle shield moves in a proximal direction from an initial state to an injection position, and in a distal direction from the injection position to a blocking position;
• a spiral spring configured to bias the needle shield in the distal direction;
• and
• a needle shield locking means configured to lock the needle shield such that the needle shield cannot move axially relative to the casing in the blocking position after the injection device performs an injection,
• wherein the needle shield locking means comprises a first axial locking member disposed axially along the needle shield and a second axial locking member disposed axially along the casing,
• wherein in the initial state of the needle shield, the first axial locking member is deflected axially away from a longitudinal axis of the device in a first direction by a first side of the second axial locking member,
• wherein upon movement of the needle shield to the injection position, the first axial locking member and the second axial locking member lie opposite each other in the axial direction such that the first axial locking member is no longer axially deflected by the second axial locking member and the first axial locking member is not engaged with the second axial locking member, and
• wherein during movement of the needle shield to the blocking position, the first axial locking member is deflected axially away from the longitudinal axis by a second side of the second axial locking member, and upon reaching the blocking position, the first axial locking member engages with the second axial locking member on the second side to thereby prevent the needle shield from moving axially.

An injection device, comprising:

• a casing which accommodates or forms a reservoir for a liquid drug;
• a plunger rod which can move relative to the casing in a distal direction to deliver the drug;
• a needle shield which is movable in an axial direction relative to the casing such that the needle shield moves in a proximal direction from an initial state to an injection position, and in the distal direction from the injection position to a blocking position;
• a spiral spring configured to bias the needle shield in the distal direction;
• and
• a needle shield locking means configured to lock the needle shield such that the needle shield cannot move axially relative to the casing in the blocking position after the injection device performs an injection,
• wherein the needle shield locking means comprises a first axial locking member disposed axially along the needle shield and a second axial locking member disposed axially along the casing,
• wherein in the initial state of the needle shield, the first axial locking member is deflected axially away from the longitudinal axis of the device in a first direction by a first side of the second axial locking member,
• wherein upon movement of the needle shield to the injection position, the first axial locking member and the second axial locking member lie opposite each other in the axial direction such that the first axial locking member is no longer axially deflected by the second axial locking member and the first axial locking member is not engaged with the second axial locking member, and
• wherein during movement of the needle shield to the blocking position, the first axial locking member moves along a surface of the second axial locking member and is deflected axially away from the longitudinal axis, and upon reaching the blocking position, the first axial locking member engages with a second side of the second axial locking member to thereby prevent the needle shield from moving axially.