Abstract: A medical injection device is provided which includes a shield system and a syringe. The shield system includes a housing, a shield telescopically received in the housing and slidably coupled to the housing and a driver that pushes the syringe stopper to cause drug injection. The driver is equipped with sensing elements that automatically detect empty syringe. A spring resiliently urges the shield from a retracted position to an extended position shielding the needle. The syringe is coupled to the housing. The shield is positioned externally to the syringe and the driver. The shield includes flexible latches to keep its position relative to the housing during storage and use. The axial movement of the driver in respect to the syringe causes an automatic release of the spring by sensors when the syringe is empty, allowing the spring to move and lock the shield in the extended position after use.

Abstract: An auto-injection syringe is provided that includes an injection assembly and a retraction assembly operatively securable to the injection assembly. The retraction assembly includes a hypodermic needle having a needle hub, an end cap having a lower seal through which a portion of the hypodermic needle can pass, a retraction spring disposed between the needle hub and the end cap and maintained in a partially compressed condition therebetween, an upper seal urged against a facially sealing surface of the retraction assembly by the force of the retraction spring on the needle hub so that a sealed area is defined between the upper and lower seals, and a vent device in fluid communication with the sealed area for pressure equalization between the sealed area and an exterior of the retraction assembly.

Abstract: An automatic injection and retraction device having a longitudinal axis is provided that includes an injection assembly, a retraction assembly, and a pre-filled syringe cartridge. The injection assembly has an activation-prevention feature moveable between an on position and an off position. The retraction assembly has a needle guard that is removable in a direction along the longitudinal axis upon application of a removal force. The pre-filled syringe cartridge has a hypodermic needle with a needle sheath thereon. The retraction and injection assemblies are secured to one another so that the pre-filled syringe cartridge is in the retraction assembly with the needle sheath secured to the needle guard. The retraction and injection assemblies are configured so that, upon application of a twisting torque to the injection and retraction assemblies, the activation-prevention feature moves from the on position to the off position simultaneous with applying the removal force to the needle guard.

Abstract: A coupling for selectively securing a spring to a plunger is provided. The coupling has a first end defining a spring rest for receiving the spring and a second end defining a shoulder. The shoulder is moveable to a first position into contact with the plunger and to a second position out of contact with the plunger. The shoulder is normally in the second position and is resiliently moveable to the first position.

Abstract: An automatic mixing and injecting apparatus comprises a syringe assembly (400) within a housing (100). The syringe assembly (400) has a chamber (425) for holding a liquid, which can be a liquid medicine or a solvent. A second chamber (460) may hold a dry medicine. The second chamber (460) is releasably sealed with respect to the first chamber (425). A spring-operated plunger (300) forces liquid from the first chamber (425) and causes the releasable seal (430) to disengage when the needle (540) has entered the recipient. At this time, the liquid flows through the second chamber (460) and dissolves any dry medicine in that chamber (460). A releasable coupling (340) disengages the plunger (300) from the driver spring (500) and allows the plunger (300), syringe assembly (400), and needle (540) to retract under the urging of a return spring (505).

Abstract: An automatic injection and retraction syringe having a medicine cartridge, an injection assembly, and a retraction assembly is provided. The retraction assembly is selectively securable to the injection assembly to house the medicine cartridge. The retraction assembly includes an end cap, a hypodermic needle, a retraction spring, and an upper seal. The retraction spring is maintained in a partially compressed condition between the needle hub and the end cap. The upper seal is urged against a sealing surface by the retraction spring in the partially compressed condition to form a hermetic seal. In some embodiments, the injection assembly includes an injection spring, a plunger engaged to the injection spring, and a safety element to prevent the plunger from escaping the injection assembly if the injection spring is released from the normally stressed condition before the assemblies are secured to one another.