Hypodermic injection apparatus

In a pressure-operated hypodermic injection apparatus including a body and an actuator mounted on the body, a replaceable, medication-discharging ampule unit comprising:

• an elongate shell having inwardly facing wall means characterized by a substantially uniform cross-sectional configuration along a defined length portion of said shell, said shell further defining a discharge aperture adjacent a forward end thereof;
• a plunger slideably and sealingly disposed within said defined length portion in said shell, displaceable between a rearward, ready position, spaced one distance from said aperture, and a forward, spent position closer to said aperture than said ready position;
• said shell and plunger, with the latter in said ready position, defining an ampule chamber capable of containing dischargeable medication;
• and
• a compressed-gas containing cartridge including means for releasing its gas charge in a rearward direction upon actuation by the actuator to drive said plunger from said ready position toward said spent position.

A pressure-operated hypodermic injection apparatus comprising:

• an elongate shell having inwardly facing wall means characterized by a substantially uniform cross-sectional configuration along a defined length portion of said shell, said shell further defining a discharge aperture adjacent one end thereof;
• a plunger slideably and sealingly disposed within said defined length portion in said shell, shiftable from a ready position spaced one distance from said aperture toward a spent position closer to said aperture than said ready position;
• said shell and plunger, with the latter in said ready position, defining an ampule chamber capable of containing dischargeable medication;
• a pressurized-gas cartridge mounted to said plunger to shift therewith and having gas-releasing means facing away from said discharge aperture;
• a body sealingly and releasably joined to another end of said shell;
• and
• an actuator mounted on said body and manually operable for selectively operating said gas-releasing means to drive said plunger from said ready position toward said spent position.

A pressure-operated hypodermic injection apparatus comprising:

• an ampule unit having an elongate shell with wall means defining an internal chamber and a discharge aperture adjacent one end thereof, a plunger slideably and sealingly disposed within the chamber shiftable between a ready position spaced one distance from said aperture and a spent position closer to said aperture than the ready position, and a pressurize-gas cartridge slidingly disposed in said shell fixed to said plunger opposite from said aperture, said cartridge having a frangible seal on a side opposite from said aperture and accessible from the other end of said shell;
• an elongate body releasably fixedly and sealingly joinable at one end to the other end of said shell of said ampule unit, said body having a longitudinal passageway having an opening disposed adjacent said cartridge seal;
• a firing pin slidingly disposed in said passageway with a seal-fracturing end disposed adjacent said one opening of said passageway, said pin being shiftable from a cocked position remote from said seal to a fired position with said one end of said pin extending through said seal when said ampule unit is joined to said body with said plunger in said ready position;
• pin biasing means mounted in said body and joined to said pin for urging said pin from said cocked position toward said fired position;
• arming means for positioning said pin in said cocked position;
• and
• trigger means for retaining said pin in said cocked position and for selectively releasing said pin for traveling toward said fired position.

A pressure-operated hypodermic injection apparatus comprising:

• an elongate shell having inwardly facing wall means and defining a discharge aperture adjacent one ene thereof;
• a plunger slideably and sealingly disposed within said shell, shiftable from a ready position spaced one distance from said aperture toward a spent position closer to said aperture;
• said shell and plunger, with the latter in said ready position, defining an ampule chamber capable of containing dischargeable medication;
• and
• pressurized-gas means for driving said plunger and having gas-releasing means facing away from said discharge aperture.