Spring-actuated needleless injector

A needleless injector for use with a vial which holds a volume of liquid medication to inject the volume of medication through skin, the needleless injector comprising:

• a vial piston which moves to force said liquid medication out of said vial;
• and
• a power mechanism which applies force to said vial piston, said power mechanism comprising:
• a power piston having a length and opposite sides, said power piston having ratchets formed on said opposite sides at equal locations along the power piston;
• a spring having a first end and a second end, said first end of said spring positioned to apply force to said power piston;
• a pair of independent pivoting triggers on opposite sides of said vial piston, each of the triggers independently engaging said ratchets on said power piston to hold said power piston in place against a force applied by said spring and which selectively release said power piston in response to the concurrent oppression of said triggers, the power piston being released to move in response to said force applied by said spring, said power piston applying said force to said vial to enable the vial piston to force the liquid medication out of the vial piston;
• a cocking mechanism, said cocking mechanism applying force to said power piston to move said power piston against the force of said spring to engage said ratchets, wherein the inadvertent release of said power piston is avoided by requiring the concurrent oppression of the opposing triggers before the volume of medication is ejected from the vial, and so that the release of the power piston is accomplished by the concurrent squeezing of the triggers.

A needleless injector adapted for use with a vial which holds a volume of liquid medication to inject the volume of medication from the vial through skin, the needleless injector comprising:

• a vial piston which moves to force said liquid medication out of said vial;
• and
• a power mechanism which applies force to said vial piston, said power mechanism comprising:
• a power piston adapted for cooperating with said vial piston, the power piston having a length and opposite sides along the length, said power piston having ratchets formed in a symmetrical arrangement along said opposite sides;
• a spring having a first end and a second end, said first end of said spring positioned to apply force to said power piston;
• a pair of independent triggers on opposite sides of said vail piston, each of the triggers being independently biased against said ratchets to allow independent engagement of said ratchets on said power piston to hold said power piston in place against a force applied by said spring and which selectively release said power piston in response to the concurrent oppression of said triggers, the power piston being released to move in response to said force applied by said spring, said power piston applying said force to said vial piston to enable the vial piston to force the liquid medication out of the vial;
• a cocking mechanism, said cocking mechanism applying force to said power piston to move said power piston against the force of said spring to engage said ratchets, wherein the inadvertent release of said power piston is avoided by requiring the concurrent oppression of the opposing triggers before the volume of medication is ejected from said vial.