Abstract: Exemplary embodiments provide automatic injection devices in which a shroud is automatically deployed to protectively sheath a needle after an injection is performed. Exemplary embodiments also provide shroud deployment assemblies including a shroud and a syringe carrier that, when cooperatively configured in an automatic injection device, ensure that the shroud is automatically and completely deployed after an injection is performed using the automatic injection device. Exemplary embodiments are also configured to ensure that, once the shroud is deployed to an extended position to sheath the needle, accidental forces applied to the shroud do not succeed in subsequently retracting the shroud to a retracted position in which the needle would become exposed.

Abstract: Exemplary embodiments provide a syringe plunger formed of a polymeric material. The syringe plunger includes a pressurizer disposed at a proximal end, and a distal end bifurcated into a first plunger arm having a first conical surface and a second conical surface, and a second plunger arm having a first conical surface and a second conical surface. The distal end includes a first contact surface defined by the first conical surface of the first plunger arm and the first conical surface of the second plunger arm, the first contact surface configured to initially contact a firing engagement mechanism, the first contact surface disposed at a first angle of between about 40° and about 80° relative to a longitudinal axis of the syringe plunger.

Abstract: Exemplary embodiments provide firing mechanism assemblies that minimize or eliminate a misfire of an automatic injection device that causes a delay in the delivery of an injection. Exemplary embodiments provide automatic injection devices including firing mechanism assemblies that minimize or eliminate a misfire that causes a delay in the delivery of an injection. Exemplary embodiments provide methods for minimizing or eliminating misfire that causes a delay in delivery of an injection in automatic injection devices. Exemplary embodiments provide methods for using automatic injection devices that are free of a misfire that causes delay in delivery of a therapeutic substance into a patient's body.

Abstract: Exemplary embodiments provide a syringe plunger formed of a polymeric material. The syringe plunger includes a pressurizer disposed at a proximal end, and a distal end bifurcated into a first plunger arm having a first conical surface and a second conical surface, and a second plunger arm having a first conical surface and a second conical surface. The distal end includes a first contact surface defined by the first conical surface of the first plunger arm and the first conical surface of the second plunger arm, the first contact surface configured to initially contact a firing engagement mechanism, the first contact surface disposed at a first angle of between about 40° and about 80° relative to a longitudinal axis of the syringe plunger.