Single-use needle-less injection apparatus

A hypodermic injection device needleless jet comprising: an injection cartridge of the drug (414) comprising: a cylinder of medicine, an injection piston drug which cooperates with the cylinder medicament for defining a variable volume chamber, said chamber having a dose of substantially incompressible liquid medicine, and a hole injection thin dimension (418) in liquid flow communication with the variable volume chamber for receiving the liquid medicine and download this medically as a strong jet at high speed to hypodermic jet injection of medication after the forced movement of said piston in said cylinder; and assembling handpiece (112, 412) having a body (412a) that contains said cartridge drug injection (414), said assembly handpiece (112, 412) a hermetically sealed pressurized gas source (182, 482) having a portion penetrable wall and a penetrator to penetrate said portion penetrable wall of said pressurized gas source (182, 482) and release the pressurized gas to actuate said piston drug injection to move said drug injection piston to cause said piston to expel drug injection of liquid medicine that dose; characterized in that said injection device further comprising: a trigger assembly to start the forced movement of said piston, said trigger assembly a striker member (184, 484) to selectively pass through said source of pressurized gas in said portion penetrable wall on said penetrator, wherein said member striker (184, 484) includes a plurality of legs extending axial (220, 490) configured to resist movement of said member striker (184, 484) to said penetrator, and a sheath of trigger (122, 422) for moving said legs extending axially (220, 490) to allow the striker member to move said source of pressurized gas to said penetrator, further comprising said trigger assembly member stiffener ring type (222) or hollow pins (492), on which the end surfaces of said legs extending axial rest, said sleeve shutter (122, 422) surrounding said striker member (184, 484) and comprises a plurality of contact portions, each engaging one of the plurality of legs to move said legs out of engagement with said abutment ring type (222) or hollow pins (492) upon axial movement of said trigger sleeve member; and means (192, 494) to drive the striker member to move the source of pressurized gas to the penetrator.