Single use disposable syringe

Claim 1

A single use syringe comprising: an elongated hollow cylindrical barrel having an interior sidewall, a proximal end, a distal end, and a nozzle closing said distal end of said barrel; a plunger member within said barrel for axial movement therein for drawing fluid into and expelling fluid out of said barrel through said nozzle, said beyond said barrel at said proximal end and having a piston at the distal end; a control device placed at a predetermined position within the barrel between the plunger shaft and the interior wall, which position determines the volume of the syringe to be filled with medication, the control device being elongate and including a distal portion and proximal portion, the proximal portion of the control device having (a) a proximally oriented outwardly facing element of a material harder than the interior sidewall and contacting and angled against the interior sidewall so that the control device is free to move toward the distal end but proximal movement of the plunger shaft after the piston contacts the distal portion of the control device causes the outwardly facing element to embed into the interior sidewall preventing further proximal movement of the piston and said control device, and (b) a proximally oriented inwardly facing element contacting and biased against the plunger shaft so that the plunger shaft is free to move first time toward the proximal end but distal movement of the plunger shaft causes the inwardly facing element to engage the plunger shaft so that the control device moves with the plunger shaft toward the distal end, whereby the control device permits the syringe to be loaded with medication in the volume defined by the predetermined position of the control device by proximal movement of the piston as far as the distal end of the control device; and after suppression of the plunger shaft to expel the medication, any second proximal movement of the plunger shaft is prevented by the outwardly facing element embedding into the interior sidewall.

Claim 12

A device for use in conjunction with a plastic syringe having an elongated hollow cylindrical barrel with an interior sidewall, a proximal end, a distal end, and a nozzle closing said distal end of said barrel; a piston within said barrel and a plunger shaft connected to said piston extending beyond said barrel at the proximal end, to allow selective adjustment of the volume, comprising: an elongate flute placed within the barrel between the plunger shaft and the sidewall of the plastic syringe, for preventing retraction of the piston beyond the flute whereby appropriate placement of the flute determines the volume of the syringe, said flute fabricated of a material harder than the material of the syringe.

Claim 13

A device for use in conjunction with a plastic syringe having an elongated hollow cylindrical barrel with an interior sidewall, a proximal end, a distal end, and a nozzle closing said distal end of said barrel; a piston within said barrel and a plunger shaft connected to said piston extending beyond said barrel at the proximal end, to allow selective adjustment of the volume, comprising: an elongate flute placed within the barrel between the plunger shaft and the sidewall of the plastic syringe, for preventing retraction of the piston beyond the flute whereby appropriate placement of the flute determines the volume of the syringe, said flute fabricated of a material harder than the material of the syringe.

Claim 14

A device for use in conjunction with a plastic syringe having an elongated hollow cylindrical barrel with an interior sidewall, a proximal end, a distal end, and a nozzle closing said distal end of said barrel; a piston within said barrel and a plunger shaft connected to said piston extending beyond the said barrel at the proximal end, to allow selective adjustment of the volume, comprising: a bent wire placed within the barrel between the plunger shaft and the sidewall of the plastic syringe for preventing retraction of the plunger beyond the bent wire whereby appropriate placement of the bent wire determines the volume of the syringe, said bent wire being fabricated of a material harder than the material of the syringe.

Claim 15

A device for use in conjunction with a plastic syringe having an elongated hollow cylindrical barrel with an interior sidewall, a proximal end, a distal end, and a nozzle closing said distal end of said barrel; a piston within said barrel and a plunger shaft connected to said piston extending beyond the said barrel at the proximal end, to allow selective adjustment of the volume, comprising: a bent wire placed within the barrel between the plunger shaft and the sidewall of the plastic syringe for preventing retraction of the plunger beyond the bent wire whereby appropriate placement of the bent wire determines the volume of the syringe, said bent wire being fabricated of a material harder than the material of the syringe.