Syringe retractable needle and method

摘要

A syringe carrying a needle with a barrel and hollow piston for dispersing an injectant through the end of the retractable needle. A resilient chuck seal is independently formed for positioning at the transition from the syringe barrel to the needle shank holding portion of the end of the barrel. The needle is propelled by the coaxial spring into the interior portion of the piston and totally retracted when the chuck seal is released. The method of the present invention relates to the use of a symmetrical chuck seal, annular in configuration, for not only gripping the head of the retractable needle, but simultaneously serving as the seal for the needle at the lower portion of the barrel so that the injectant escapes through the hollow syringe needle.