Patent ID: 9636467
Date: 2017-05-02
CPC Classifications: A61M

Claim:
1. An 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 bung for sealing the syringe and displacing the medicament (M), the elongate 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, a spring mechanism 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) as well as operating the syringe to supply the dose of medicament (M), an activating mechanism arranged to lock the spring mechanism in a pressurized state prior to manual operation and capable of, upon manual operation, releasing the spring mechanism for injection, wherein the spring mechanism is a torsion spring grounded at one end in the housing and at the other end in a first gear member rotatable about a longitudinal axis but axially fixed, wherein the first gear member, upon rotation, is arranged for translatively moving a second gear member, the second gear member being prevented from rotating relative to the housing and coupled to the bung in order to push it towards the proximal end (P), wherein the first gear member is engaged with the activating mechanism prior to manual operation in a manner to prevent rotation and disengaged from the activating mechanism upon manual operation, wherein an essentially tube-shaped needle shroud is arranged around the syringe in the housing, the needle shroud slidable between at least a retracted position with the needle shroud almost hidden inside the housing and an advanced position with the needle shroud protruding from the proximal end (P) and covering the hollow needle in an advanced position of the hollow needle, wherein the needle shroud is biased by a second spring mechanism towards the advanced position, wherein the needle shroud is locked in the retracted position by a locking mechanism which is releasable by rotary movement transmitted from the first gear member through a clutch mechanism which is engaged by the second gear member shortly before the second gear member is fully advanced during an injection stroke.