Retracting needle syringe

摘要

A retracting needle syringe is described which allows safe and easy disposal of a syringe and prevents re-use of the syringe by destroying the plunger rod and needle hub and retracting the needle into the plunger rod. Once the safety feature is activated, positive or negative pressure in the barrel to draw out medication is defeated. The retracting needle safety feature requires only an increase of force along the same line of action as the injection stroke. This allows for safe, one-handed injection, which is critical in some situations. The retracting needle syringe of the present invention also minimizes the amount of wasted medication because the plunger rod incorporates a plunger tip that occupies the entire volume inside the barrel. Because the retracting needle syringe uses standard luer-lok fittings, it can be used with a variety of standard needles that do not have retracting cannula. This gives the healthcare professional or patient the ability to use a large gauge needle to fill the syringe from a vial or other container before attaching the safety needle for injection. Lastly, the plunger can be completely encapsulated by the barrel upon activation of the retracting needle syringe safety feature which will prevent re-use of the syringe and allow for safe and easy disposal.