A drug delivery device for delivering a medicament, wherein the device comprises an insertion controlled needle cannula,
- wherein the drug delivery device comprises:
- an axially extending housing comprising a proximal end and a distal end,
- a drive mechanism for expelling an amount of medicament,
- a compression spring,
- a reservoir containing the medicament,
- an axially movable shield,
- a rotatable needle drum, wherein a needle assembly is axially movably arranged in the drum, wherein the needle assembly comprises a needle hub with a needle cannula comprising a distal end and a proximal end,
- wherein the needle drum is adapted to be axially locked to a distal end of the shield such that the drum can move axially together with the shield, the needle drum is further rotatably arranged relative to the housing to change position of the needle assembly,
- wherein the needle assembly can be arranged in an active position in axial alignment with the reservoir by rotation of the needle drum, wherein the needle assembly in the active position can be arranged in a proximal position relative to the housing, whereby a proximal needle portion of the needle cannula can be connected with the reservoir to establish fluid communication, and a distal position relative to the housing, whereby the proximal needle portion can be disconnected from the reservoir, and whereby there is no fluid communication,
- an activation mechanism for activating the drive mechanism comprising a shield biased in the distal direction by the compression spring, and wherein the shield can be arranged in a distal position, whereby the shield covers the distal end of the needle, and a proximal position, whereby the distal end of the cannula of the needle in the active position extends from the shield, and wherein moving the shield to the proximal position activates or can activate the drive mechanism,
- wherein the drug delivery device further comprises:
- a retaining structure axially locked to the housing and adapted for retaining the hub in the proximal position,
- a pulling structure axially locked to the shield and adapted for being disengaged from the hub, in a decoupled state, whereby the pulling structure is movable relative to the hub, and wherein the pulling structure is further adapted for engaging the hub, in a coupled state, whereby the pulling structure is movable together with the hub,
- wherein the retaining structure and the pulling structure are operatively connected to the shield and the needle assembly in the active position,
- wherein the drug delivery device is adapted to be arranged in:
- a proximal pulling state:
- (i) wherein the shield is in the proximal position, wherein the needle assembly is in the proximal position, (ii) wherein the retaining structure axially retains the hub in the proximal position, and the pulling structure is in the decoupled state and arranged for engaging the hub of the needle assembly, when the pulling structure is moved in the distal direction;
- an intermediate pulling state:
- (i) wherein the shield is in an intermediate axial position between the proximal and the distal position, wherein the needle assembly is in the proximal position, wherein the distal end of the needle cannula of the needle assembly is covered by the shield, (ii) wherein the retaining structure axially retains the hub, wherein the pulling structure is in the coupled state, and wherein the retaining structure and the hub are adapted to disengage from each other, when the hub is moved in the distal direction;
- and
- a distal pulling state, (i) wherein the shield is positioned in the distal position, and wherein the needle assembly is in the distal position, and (ii) wherein the retaining structure has disengaged from the hub of the needle assembly, and wherein the pulling structure is in the coupled state and engages the hub of the needle assembly;
- wherein the drug delivery device is changed from the proximal pulling state to the intermediate pulling state, in response to moving the shield to the intermediate axial position;
- and from the intermediate pulling state to the distal pulling state, in response to moving the shield from the intermediate position to the distal position,
- whereby the drug delivery device provides a needle insertion sequence control mechanism ensuring that the distal end of the cannula is covered before the proximal end of the cannula is pulled out from the reservoir.