Tube coupling mechanism

Claim 1

Apparatus for coupling a tube to a fitting including a nipple attached to said fitting having an axially aligned aPerture passing therethrough, the aperture further containing an enlarged bore adapted to receive said tube therein and a second enlarged counterbore adapted to receive a deformable gasket, said bore and counterbore extending inwardly from the end face of said nipple, said nipple further having an external thread formed thereon extending rearwardly from said end face and being terminated at a predetermined depth by a radially extending shoulder, a pressure deformable gasket positioned within said counterbore intermediate said tube and said nipple, a compressible sleeve passing over said tube and having a flange seatable against the end face of said nipple, said sleeve further including a hub extending axially from said flange a predetermined distance into said counterbore whereby the hub deforms the gasket into sealing contact between said tube and said nipple when the flange is seated against the end face of said nipple, and an elongated body section extending axially from said flange in a direction opposite to said hub, the body having a circumferentially extended tooth formed on the interior wall thereof, a compression nut threadable upon said nipple having first and second camming surfaces positioned thereon to compress the free end of the sleeve body and the circumferentially extended tooth into contact against the tube as the nut is threaded onto the nipple, and a control surface upon said nut positioned in relation to said camming surfaces such that the free end of the sleeve is compressed under a predetermined load into sealing contact against the tube by said first camming surface and the circumferential tooth is compressed under a predetermined load into holding contact against said tube by said second camming surface when the control surface is seated against the shoulder of said nipple.