Patent ID: RE42463

Claim:
A needle-less hypodermic jet injection device comprising: a pre-filled drug injection cartridge including: a medication cylinder having an outlet orifice, an injection nozzle, a flow path communicating the outlet orifice to said injection nozzle, a drug-injection piston in a first position cooperating with said medication cylinder to define a variable-volume chamber of first selected size, a dose of substantially incompressible liquid medication substantially filling said variable-volume chamber at said first size with substantially no ullage volume, said drug-injection piston having a second position cooperating with said medication cylinder to define a variable-volume chamber of second selected size smaller than said first selected size; a hand piece assembly having a body holding said drug injection cartridge, said hand piece assembly including a source of pressurized gas, and means for selectively applying force from said pressurized gas to said drug injection piston to move said drug injection piston from said second position to a third position substantially ejecting said dose of liquid medication via said injection nozzle; said hand piece assembly including a first body portion holding said drug injection cartridge, and a second body portion manually movable relative to said first body portion, said second body portion including an abutment member selectively movable into engagement with said drug injection piston in response to manual relative movement of said first and second body portions to move said drug injection piston from said first position to said second position.