Safety syringe for injecting liquid drugs, has needle assembly turned and drawn in cylinder by friction force between plunger and tapered hub, where assembly is mounted in retractable manner in open front end of cylinder

摘要

The syringe has a cylinder (10) with an open front end, an inner surface end and an inner threading (12) formed on the inner surface at the front end. A needle assembly (20) is mounted in a retractable manner in the front end, where the assembly has a tapered hub (22) and a needle (21) that is mounted on the hub. The hub has a front, an open back, an axial cavity and a longitudinal groove (224). A plunger (30) is slidingly mounted through an open rear end of the cylinder. The assembly is turned and drawn in the cylinder by friction force between the plunger and the hub.