Syringe/plunger coupling

Abstract

A medical fluid injector, replaceable syringe, and coupling mechanism to engage the syringe plunger to the plunger drive ram of the injector are provided wherein coupling involves a cam cleat-like mechanism, thereby allowing for cooperative movement between the plunger drive ram and syringe plunger. The coupling mechanism of the plunger drive ram is provided with first and second movable members, each having toothed, arcuate surfaces, while the coupling mechanism of the syringe plunger is provided with a knurled cavity. Disengagement of the coupling mechanism is facilitated by translational movement of a face plate located on the forward end of the injector housing.

What is claimed is: 
     
         1 . A syringe for mounting to an injector for injecting fluids into an animal subject, said syringe comprising:
 a cylindrical barrel;   a plunger snugly slidable in said cylindrical barrel, said plunger having a rearwardly facing drive ram engaging coupling element thereon in the shape of a rearwardly facing extension, wherein said rearwardly facing extension includes a knurled interior cavity and said rearwardly facing extension does not extend outside of said cylindrical barrel in at least one position of said plunger; and   a discharge tip in fluid communication with a forward end of said cylindrical barrel.