| 摘要 |
A hypodermic syringe (10) with a selectively retractable needle (12) includes an elongate barrel (14) having an open proximal end (16), an open distal end (18) and a hollow bore. The syringe (10) includes an elongate plunger (22) including a hollow outer housing (24) having an open proximal end (26) and an open distal end (28). The plunger (22) has a hollow inner sleeve (30) defining a cavity (34) therein. The plunger (22) has releasable engagement elements (29,78) preventing relative axial movement between the outer housing (24) and the inner sleeve (30), the elements allowing the relative axial movement when relesed and a distal stopper (46). There is an open cutter (50) mounted at a distal end (38) of the inner sleeve (30) to cut through the stopper (46) to expose the cavity (34) in the inner sleeve (30) when the engagement elements (29,78) are released and sufficient distal axial force is applied to the plunger (22). The syringe (10) has a hub housing (52) with an open proximal end having an inwardly projecting shoulder, a hub (60) with a proximal flange (62) and an axial stem (64), sized to fit within the hub housing (52). There is a spring (70) disposed about the stem (64) between the flange (62) and the shoulder. The syringe has a needle (12) with a sharp point extending outwardly. The needle retracts into the cavity (34) in the plunger (22) when sufficient distal force is applied to the plunger (22) to release the engagement elements (29,78). The release allows movement of the inner sleeve (30) with respect to the outer housing (24) so that the cutter (50) cuts through the stopper (46) and the flange (62) and the spring (70) urges movement of the needle (12) into the cavity (34). <IMAGE> |
