Subcutaneous injector

An automatic injector comprising:

• a body having a forward and rearward end;
• a charge of medicament disposed within said body;
• a needle having at least a portion thereof normally disposed in an air-space within said body, said needle having a longitudinal axis and being moveable along said axis to a fully projecting position in which a forward portion thereof projects from the forward end of said body, said needle being capable of dispensing said medicament when in said fully projecting position;
• a moveable plunger capable of forcing said medicament through said needle to enable said needle to dispense said medicament;
• and
• a releasable spring which, when released, operates to move said needle along said axis to said fully projecting position and to move said plunger so that said plunger forces said medicament through said needle when said needle is in said fully projecting position;
• said injector being provided with an air release path through which air can escape from said air-space during an injection operation in which said releasable spring is released so that said needle moves along said axis to said fully projecting position, said air release path extending in a direction transverse to said longitudinal axis.

An automatic injector comprising:

• a body having a forward and rearward end;
• forward and rearward pistons, said pistons being slidably moveable within said body;
• a charge of medicament disposed between said forward and rearward pistons;
• a needle having at least a portion thereof disposed in a sealed air-space within said body, said needle having a longitudinal axis and being moveable along said axis into a fully projecting position in which a forward portion of the needle projects from the forward end of said body, said needle having a rearward opening for receiving said medicament and a forward opening for dispensing said medicament;
• and
• a releasable drive means for (1) driving said forward piston, said rearward piston and said medicament contained therebetween toward the forward end of the body, and (2) moving the needle along said longitudinal axis to said fully projecting position, said needle reaching said fully projecting position before said medicament is permitted to be dispensed from said forward opening of said needle;
• said injector being provided with an air release path through which air contained within said air-space can be exhausted from said body as said needle is moved into said fully projecting position, said air release path extending in a transverse direction from said longitudinal axis of said needle.

An automatic injector comprising:

• a body;
• a barrel liner disposed within said body;
• a charge of medicament normally disposed within said barrel liner;
• a first plunger rearwardly confining said medicament within said barrel liner, said first plunger being movable within said barrel liner to dispense said medicament;
• a second plunger forwardly confining said medicament within said barrel liner;
• a seal disposed in normally sealing relation with said barrel liner at a forward portion thereof, said seal and said second plunger defining a normally sealed air space therebetween in said barrel liner;
• a needle normally disposed in said sealed air-space within said barrel liner generally between said seal and said second plunger, said needle being drivable from said sealed air-space through a predetermined portion of said seal into a projecting position from the forward end of said body;
• said seal being conditionable to permit at least a portion of the air normally sealed within said air space to escape therefrom at a position spaced from said predetermined portion of said seal through which said needle is driven;
• and
• a releasable spring being releasable to i) drive said second movable plunger forwardly within said liner and thereby compress air normally disposed within said air space ii) drive said needle from said normally sealed air-space through said predetermined portion of the seal into said projecting position from the forward end of the body, iii) condition said seal to permit at least a portion of the air compressed in said air space to escape therefrom, and iv) move said first plunger within said barrel liner to dispense said medicament through said needle.