| 摘要 |
A hypodermic safety syringe, according to the present invention, includes a barrel having an open end, a cone shaped end and an interior surface. A hollow needle and carriage assembly is temporarily attached and is restrained by four catches extending from the interior tapered surface. A plunger assembly is reciprocally received into the barrel and is in air-tight engagement with the interior surface of the barrel. Thus, an interior chamber is formed in the barrel whereby liquids are retrieved and emitted through the hollow needle. A cavity within the plunger contains a spring and retraction guide assembly with a mating member corresponding to mating members extending from the needle carriage. As the mating members contact and become captured the needle and carriage assembly is released by the approaching plunger assembly as the catches are deflected outward by the angled surface of the plunger. At the end of the injection stroke small spherical bearings, in locking contact with the retraction guide, are caused to move outward and into a radially concave interior surface releasing the retraction guide, captured needle and carriage assembly thereby retracted into the cavity within the plunger structure. Thus rendering the syringe safe for handling and transport to disposal. |
