| abstract |
A hypodermic injection device is provided comprising a cylindrical holder closed at one end and slidably carrying an ampoule with attached cannula facing the closed end of the holder, medicament is provided in the ampoule between the cannula and the piston in the ampoule, a gun spring assembly is associated with the holder and in operative association with the ampoule to force the ampoule and attached cannula forward thus driving the cannula out of the closed end of the holder and into the locus of injection, and a counterbalancing spring is positioned in the holder between the closed end thereof and the cannula end of the ampoule to counteract the gun spring force. |