CA1178503A — Needleless hypodermic injector

USPTO Abstract

ABSTRACT OF THE DISCLOSURE A needleless hypodermic injector includes an elongated cylindrical casing defined by front and rear telescoping sections, with an injection orifice at the closed front end of the front section and a push button trigger at the rear end of the rear section. A piston slidably mounted in a cylinder in the front section of the casing moves rearwardly to define a medicine chamber for receiving medicine from a bottle directly or through a valve incorporated in the front end of the front casing section. The piston is moved rearwardly by an internally threaded collar on the externally threaded cylinder, the collar pressing against a bushing, which presses against disc springs in the rear section of the easing. A latch mechanism retains the bushing against the springs until the trigger is pressed, at which time the springs drive the piston forward to discharge the medicine from the chamber through the injection orifice.