Nozzle assembly with lost motion connection for medical injector assembly

Nozzle assembly for a needleless injection device having an energy source for propelling medication through said nozzle assembly comprising:

• a generally hollow body defining a chamber having an end terminal wall with an orifice for passage of medication therethrough and an open end opposite said terminal wall, said body having means for removably connecting to an injection device;
• a plunger movably positioned within said chamber, said plunger having means for sealing said chamber from said open end, wherein said plunger is movable toward and away from said terminal wall to introduce and expel medication into and out of said chamber through said orifice;
• and
• a lost motion connecting means for removably connecting said plunger to an energy source, wherein said plunger is connected to an energy source by pushing said plunger toward an energy source and disconnected by pulling said plunger away from an energy source, wherein the force required to disconnect said plunger from an energy source is substantially greater than the force required to move said plunger away from said terminal wall during introduction of medication into said chamber, wherein said lost motion connecting means comprises a resilient snap fit member for association with an enlarged head of an energy source, said resilient snap fit member extending from said plunger in the direction opposite said terminal wall, wherein said snap fit member includes a plurality of prongs made of resilient material, which upon being attached to an enlarged head expand and return to their original configuration once said enlarged end is fully connected, with each prong extending from said plunger and, each of said prongs having a tab extending radially inwardly and confining an enlarged end connected to said plunger, wherein said entire prongs are confined within said ampule chamber, said prongs being dimensioned to slide inside said ampule chamber and an inner wall of said ampule chamber confining said prongs from moving laterally outwardly to maintain an enlarged end locked to said plunger during use.

A nozzle assembly for a needleless injection device having an energy source for propelling medication through said nozzle assembly comprising:

• a generally hollow body defining a chamber having an end terminal wall with an orifice for passage of medication therethrough and an open end opposite said terminal wall, said body having means for removably connecting to an injection device;
• a plunger movably positioned within said chamber, said plunger having means for sealing said chamber from said open end, wherein said plunger is movable toward and away from said terminal wall to introduce and expel medication into and out of said chamber through said orifice;
• and
• a lost motion connecting mechanism for removably connecting said plunger to an energy source and for providing a predetermined free travel distance between the plunger and an energy source, said lost motion connecting mechanism including a resilient snap fit member which extends from said plunger in a direction opposite said terminal wall,
• said snap fit member including a plurality of prongs, each prong extending from the plunger and having a tab extending radially inwardly, said prongs forming a connection between said plunger and an energy source, wherein said prongs are confined within said chamber and are dimensioned to slide inside said chamber with an inner wall of said chamber confining said prongs from moving laterally outwardly to maintain locking engagement between said plunger and an energy source during use.