Patent ID: 7235063

Claim:
An ampule for use with a hypodermic jet injector, said ampule comprising: a body portion with a proximal end, a distal end and a longitudinal axis extending between said proximal end and said distal end, said body portion having a chamber having a relatively large opening in said proximal end and terminating before said distal end, and further having a relatively small orifice extending between the termination of said chamber and said distal end; and a slidable spool located in said chamber between said piston and said proximal end, and a spring device associated with said spool locking said spool in said chamber against movement towards said proximal end; said piston being slidable in said chamber from a position adjacent said orifice to said spool in response to the flow of injectate under pressure through said orifice; and said spool forcing said piston towards said orifice by the high-speed impact of a plunger against said spool to force injectate through said orifice to effect an injection.