US Patent 9931471 Auto-injector

Auto-injector for administering a dose of a liquid medicament includes a housing to contain a syringe with a hollow needle and a stopper for sealing the syringe and displacing the medicament (M), the housing having a distal end (D) and a proximal end (P) with an orifice to apply against an injection site. A spring means, upon activation, can push the needle from inside the housing through the orifice and past the proximal end (P), operate the syringe to supply the dose of medicament (M), and retract the syringe with the needle after delivering the medicament (M). An activating means can lock the spring means in a pressurized state prior to manual operation and capable of, upon manual operation, releasing the spring means for injection.