PREFILLABLE AUTO-RETRACTABLE SAFETY SYRINGE

摘要

A retractable safety syringe includes a retractable needle hub holding a needle and having a first guiding means; and a hollow barrel having a second guiding means set correspondingly to the first guiding means; and a collapsible plunger comprising of a first plunger element having a protrusion releasably coupled with a second plunger element having a longitudinal slot with a pinched zone to curb the movement of said protrusion; and a spring disposed between the needle hub and hollow barrel and acts between the needle hub and the hollow barrel. The uncoupling of the collapsible plunger triggers the retraction mechanism to enable the needle hub to retract into the barrel by the decompression force of a spring. The reliability of retraction is further improved by a longitudinal slot and a protrusion to facilitate the retreating of the collapsible plunger in an orderly way.

主权项

1. A retractable needle assembly of a retractable syringe, comprising:
a need hub having
a first end to receive and hold a needle extending distally,a nearby first guiding means on an side wall of the needle hub, and a second end being opposite to the first end; and a hollow barrel having
an internal surface defining a chamber allowing the needle hub releasably disposed in the chamber of the hollow barrel,a distal open end allowing the first end of the needle hub to protrude distally, and having a second guiding means nearby on a sidewall of the hollow barrel, anda proximal open end being opposite to the distal open end;wherein the second guiding means of the hollow barrel has a first portion and a second portion; and the first guiding means of the needle hub releasably engages with the first portion of the second guiding means, so that the first and the second guiding means are capable of releasably holding the needle hub until the first guiding means disengages from the first portion of the second guiding means and moves toward the second portion of the second guiding means.