| abstract |
The invention relates to an auto-injector for administering a dose of a liquid medicament, comprising:n an elongate housing arranged to contain a syringe with a hollow needle and a stopper for sealing the syringe and displacing the medicament, the housing having a distal end and a proximal end with an orifice intended to be applied against an injection site, wherein the syringe is slidably arranged with respect to the housing, spring 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, operating the syringe to supply the dose of medicament, and retracting the syringe with the needle into the covered position after delivering the medicament, activating means arranged to lock the spring means in a pressurized state prior to manual operation and capable of, upon manual operation, releasing the spring means for injection. The spring means is a single drive spring arranged to be grounded at a distal end in the housing for advancing the needle and for injecting the dose of medicament via a plunger and wherein the drive spring is arranged to have its ground in the housing switched to its proximal end for retracting the syringe. An interlock sleeve is telescoped in the proximal end of the housing, the interlock sleeve translatable in longitudinal direction between a proximal position and a distal position, wherein in its proximal position the interlock sleeve is arranged to be coupled to the syringe in the syringe's retracted position and wherein the interlock sleeve in its distal position is arranged to allow decoupling of the syringe. |