Autoinjector for Automatic Injection of a Product Into an Injection Site

Abstract

This autoinjector includes a housing extending along longitudinal axis A and configured to receive a medical container having a barrel defining a reservoir for containing a medical product, said barrel having a distal end provided with an injection needle and an opened proximal end configured to receive a plunger rod for pushing a stopper arranged inside the barrel. A needle cover is coupled to and axially movable with respect to said housing between a first extended position, a retracted position and a second extended position. A plunger rod is axially movable inside the housing between an initial position and an injection end position, the plunger rod being configured to push the stopper in order to expel the medical product when moving from the initial position to the injection end position. The autoinjector further includes biasing member for biasing the plunger rod in a distal direction towards the injection end position, and a retainer for maintaining the plunger rod in the initial position against the action of the biasing member, the retainer including a resilient blocking member radially deformable between a blocking position for blocking the plunger rod in the initial position, and a release position allowing for movement of the plunger rod in the distal direction. A lock ring is coupled to and axially movable with respect to the resilient blocking member, between a locking position for maintaining the resilient blocking member in the blocking position, and an unlocking position, axial movement of the lock ring from the locking to the unlocking position being caused by the needle cover moving from the first extended position to the retracted position.

CPC Classifications