Abstract: A releasable coupling for plastic or metal tubes wherein the means for retaining one end of a tube within the coupling body comprises a metal retainer ring having circumferentially spaced spring fingers thereon which incline radially and axially inwardly from the outer periphery of the ring. The inner ends of the fingers are adapted to frictionally engage and bite into the surface of a tube inserted therethrough to prevent its withdrawal. Axial movement of the ring within the coupling body is prevented in one direction by axially extending fingers on the ring engaging an inwardly projecting annular shoulder in the bore of the body. Axial movement of the ring in the opposite direction is prevented by retaining means located at least partially within the bore of the body positioned adjacent an annular seal engaging one face of the ring.

Abstract: A releasable tube coupling wherein the tube is retained in a coupling body by means of a resilient tube clamping sleeve which encircles the tube and has radially outwardly projecting detents thereon engaging radially outwardly extending apertures or recesses in the bore of the coupling body. The sleeve is circumferentially contractible to enable its insertion into the coupling body and for tightly clamping the tube. The sleeve is dimensioned to frictionally engage the outer surface of the tube and, when an axially outward force is applied to the tube, the detents are cammed inwardly to cause the sleeve to contract and tightly grip the tube.

Abstract: A releasable tube coupling wherein the tube is releasably retained in the coupling body by means of a coil spring which embraces the outer cylindrical surface of the tube. In the relaxed condition, the spring has an inner diameter less than and frictionally engages the outer diameter of the tube. When an axial outward force is applied to the tube the spring tends to contract as it elongates and more firmly grips the tube. The spring is axially compressible to insert the tube in the fitting body and to release it therefrom.

Abstract: A releasable tube coupling wherein the tube is releasably retained in the coupling body by means of a sleeve in said body surrounding said tube and held in clamping engagement therewith by means of a U-shaped clip. The clip extends transversely through the body and engages a pair of cams or ramps on the sleeve which retain the sleeve and are effective to more firmly clamp the tube when a force is exerted on the tube in the direction outwardly from the fitting.