Auto-injector

Auto-injector for administering a dose of a liquid medicament (M), comprising:

• an elongate housing arranged to contain a syringe with a hollow needle and a stopper for sealing the syringe and displacing the medicament (M), the housing having a distal end (D) and a proximal end (P) with an orifice intended to be applied against an injection site, wherein the syringe is slidably arranged with respect to the housing,
• driving means capable of, upon activation:
• pushing the needle from a covered position inside the housing into
• an advanced position through the orifice and past the proximal end (P) via
• a plunger,
• operating the syringe to supply the dose of medicament (M) via the
• plunger, and
• retracting the syringe with the needle into the covered position
• after delivering the medicament (M),
• a retraction sleeve, axially movably arranged in the housing,
• at least one latch for axially fixing the retraction sleeve in a maximum proximal position,
• a delay mechanism for slowing down motion of the retraction sleeve in distal direction, the delay mechanism comprising a circumferential outer wall with a back collar attached to the housing and a circumferential inner wall with a front collar attached to the retraction sleeve wherein a cavity is defined between the outer wall and inner wall, the cavity sealed by the back collar against the inner wall and by the front collar against the outer wall, the cavity filled with a viscous fluid, wherein at least one orifice is arranged in the delay mechanism for allowing the viscous fluid to be pushed out as the volume of the cavity decreases due to axial motion of the retraction sleeve with respect to the housing at least one aperture arranged in the retraction sleeve,
• wherein the latches are arranged to be disengaged by the decoupling member before the stopper has reached a maximum proximal position in the syringe when moved in proximal direction, wherein the apertures are arranged to meet the decoupling arms after the stopper has reached its maximum proximal position by means of the motion of the retraction sleeve, characterized in that a decoupling member is arranged to decouple the latch when being moved in proximal direction (P) nearly into a maximum proximal position, thus allowing the retraction sleeve to move in distal direction (D) and retract the needle, wherein the aperture is arranged to allow a respective decoupling arm of the decoupling member to be flexed outward, and wherein a gap is provided between a front face of the retraction sleeve and a syringe holder in their respective maximum proximal positions, wherein the syringe is arranged for joint axial movement with the syringe holder, wherein the gap is arranged to allow the retraction sleeve to travel a distance before retracting the syringe holder so the syringe holder is retracted after the decoupling arms met the apertures.