Patent ID: 8449505
Filing Date: 2013-05-28
Classification: A61M

Abstract:
1. A medically safety injector, comprising: a needle hub having a first end and a second end with the first end being attached by a needle; a hollow barrel for engaging with the needle hub and guiding the needle hub to retract into the hollow barrel after the medically safety injector is used to perform an injection operation; and a collapsable plunger combination having a two-piece structure and settled in the hollow barrel, comprising a retractable plunger positioned near the second end of the needle hub rather than attached to the needle hub, and a hollow shank partially telescoped with the retractable plunger, wherein the retractable plunger and the hollow shank are separately molded through an injection molding process and then assembled together, at least one raised portion is formed on an outer wall of the retractable plunger at a telescoping portion, where the retractable plunger and the hollow shank are partially telescoped, for engaging at least one depression formed on an inner wall of the hollow shank, so that when the plunger combination continuously receives a pushing force after the medically safety injector is used to perform the injection operation, the raised portion detaches from the depression to force the retractable plunger to smoothly retract into the hollow shank so that space in the hollow barrel originally occupied by the retractable plunger is freed for accommodating the retracted needle hub, whereby the needle hub is retained in the hollow barrel rather than retracted into the collapsable plunger combination, after the completion of the injection operation.