Pistons for direct subcutaneous injection of fluids - without using a needle, with cocking systems for a spring loaded hydraulic ram

摘要

A tool for injection of a physiological fluid such as a medicant or anaesthetic comprises a pistol with a discharge chamber primed via a hollow radial spike and discharged by a spring loaded piston cocked by a suitable mechanical or electromechanical device and released by a manual trigger. For applying subcutaneous injections without using a needle, to avoid associated physical and psychological distrubance. Pref. the piston passes through annular elastic seals located immediately upstream and downstream from the point at which the fluid is introduced from e.q. a container impaled on the priming spike.