JERINGA HIPODERMICA CON AGUJA SELECTIVAMENTE RETRACTIL.

摘要

A syringe (10) has a retractable needle (54) and a barrel (14) having an open proximal end (16) and an open distal end (18) defining a receiver (20) with an inward shoulder (22). The barrel (14) has a hollow bore (24), an elongate plunger (26) with a proximal end (28) and a distal open end (30) with a cavity (32) therewithin. A stopper (36) occludes the open end (30) of the cavity (32). The syringe (10) has an elongate hub (38) with a proximal flange (40). The hub (38) is within and sized for slidable movement within the receiver (20) at the distal end (18) of the barrel (14) with the flange (40) defining a distal end (42) of a chamber (34). There is a sleeve (46) sized to fit with a clearance about the hub (38) disposed between the shoulder (22) and the flange (40) when the hub (38) is in the receiver (20), the sleeve (46) having a sharpened proximal end (60) to function as a cutting surface (48) disposed against the flange(40). The needle (54) has a pointed distal end (58) and a proximal end connected to the passageway (44) of the hub with the pointed end of the needle extending outwardly. There is a spring (62) disposed about the hub (38) compressed to provide a bias between the receiver inward shoulder (22) and the flange (40) so that when a force greater than required to expel fluid from the chamber (34) is applied, the plunger (26) causes the cutting surface (48) to cut through the flange (40) and stopper (36) and expose the cavity (32) to allow the spring (62) to urge the hub (38) into the cavity (32) in the plunger (26) and retract the needle (54) to a position within the syringe (10).