EP2606924A1 — Autoinjector having a retracting syringe carrier

USPTO Abstract

Described is an autoinjector (1) comprising a case (2), a chassis (8) slidably arranged in the case (2), a syringe carrier (4) operably coupled to the chassis (8), an outer plunger (7) selectively engaged to the chassis (8), an inner plunger (12) selectively engaged to the outer plunger (7), and a drive spring (6) applying a biasing force to the outer plunger (7). The biasing force is applied to the inner plunger (12) when the inner plunger (12) is engaged to the outer plunger (7). Rotation of the chassis (8) causes the inner plunger (12) to rotate relative to the outer plunger (7) and disengage the outer plunger (7) to remove the biasing force from the drive spring (6) on the inner plunger (12). When the inner plunger (12) disengages the outer plunger (7), the biasing force of the drive spring (6) pushes the chassis (8) to retract the syringe carrier (4) relative to the case (2).