Fluid valve

Claim 1

In a stopcock valve including a plastic valve body with internal passages leading from external fittings to ports on an internal bore and including a plastic valve core received in said bore and having at least one radially-directed internal passage for connecting said ports, the improvement wherein said bore and a portion of said core are cylindrical, the external diameter of said core is larger than the internal diameter of said bore to achieve an interference fit, the cylindrical surfaces of said bore and core are sufficiently close to a perfect cylinder in shape to maintain an interference fit all around said cylindrical surfaces so as to prevent leakage from said ports, a plurality of fingers extend from said body, said fingers are angled radially inward toward the longitudinal axis of said bore and are capable of resilient radial motion with respect to said axis, said valve core includes a lip, said lip including a tapered surface for deflecting said plurality of fingers radially outward as said core in installed by translation in a first longitudinal direction and a retention surface substantially normal to said longitudinal axis for acting against the tips of said fingers to permanently lock said core into said body longitudinally once said fingers snap radially inward past said lip, said substantially normal inclination of said retention surface and said radially-inward angle of said fingers acting to prevent radial separation of said fingers under an axial force applied to said core in a second axial direction, opposite said first direction, thereby preventing said core from being removed from said body along said section direction.