Prefilled hypodermic syringe system

An injection device for use with a needle assembly comprising:

• a syringe body having a fluid chamber formed therein for retaining an injection fluid, said syringe body having an outlet for dispensing fluid from said fluid chamber, and
• a plunger assembly including a plunger slidably disposed in said fluid chamber for creating positive pressures to cause ejection of a fluid from said fluid chamber and an actuator releasably coupled to said plunger for movement of said actuator between a first position with said actuator released for movement of said actuator through said fluid chamber relative to said plunger and a second position with said actuator in cooperative engagement with said plunger for driving said plunger to create said positive pressures, said actuator including sealing means for sealing said outlet of said fluid chamber, said sealing means being movable away from said outlet for breaking said seal upon retraction of said actuator from said fluid chamber.

An injection device for use with a needle assembly comprising:

• a syringe body having a fluid chamber formed therein for retaining an injection fluid, said syringe body having an outlet for dispensing fluid from said fluid chamber and
• a plunger assembly including a plunger slidably disposed in said fluid chamber for creating positive pressures to cause ejection of a fluid from said fluid chamber and an actuator releasably coupled to said plunger for movement of said actuator between a first position with said actuator released for movement of said actuator through said fluid chamber relative to said plunger and a second position with said actuator in cooperative engagement with said plunger for driving said plunger to create said positive pressures, and
• supply means for filling said fluid chamber with said injection fluid.

An injection device for use with a needle assembly comprising:

• a syringe body having a fluid chamber formed therein for retaining an injection fluid, said syringe body having an outlet for dispensing fluid from said fluid chamber, and
• a plunger assembly including a plunger slidably disposed in said fluid chamber for creating positive pressures to cause ejection of a fluid from said fluid chamber and an actuator releasably coupled to said plunger for movement Of said actuator between a first position with said actuator released for movement Of said actuator through said fluid chamber relative to said plunger and a second position with said actuator in cooperative engagement with said plunger for driving said plunger to create said positive pressures,
• and further comprising a needle assembly coupled to said syringe body, said needle assembly including a protective sheath mountable to said syringe body and a needle carriage slidably positioned within said sheath, said needle carriage being movable between a forward position with said needle projecting from said front end of said sheath and a retracted position with said needle positioned inside of said sheath.