US Patent 9913942 Auto-injector

Described is an injection device for administering a dose of a medicament (M) comprising a carrier adapted to contain a syringe having a hollow injection needle and a stopper, a drive spring, a plunger adapted to forward load of the drive spring to the stopper, and a noise component adapted to generate an audible and/or tactile feedback by impacting a component of the injection device when the stopper is located at a proximal end of the syringe. In a first state, a resilient arm on the plunger is maintained in engagement with the noise component by the carrier. In a second state, the arm disengages the noise component and deflects at least partially into an aperture in the carrier.