Single use self:blocking hypodermic syringe

摘要

Syringe comprises a cylindrical barrel with a needle mounting at one end and the other end open for a slidable plunger. An elastic means for blocking the intake stroke of the plunger is initially located in an inactive position and moves to an active position during the first intake and injection cycle. In the active position the means is secured to the barrel and interferes with the intake stroke. The means is pref. a split-ring which before use embraces the minor dia. region of a frustoconical part of the plunger rod which converges in the plunger movement direction.