Patent attributes
A tube coupling comprising a coupling body having a throughway open at one end to receive an end portion of the tube and having an internal cam surface tapering towards the open end in which a collet is located for locking the tube in the coupling body by engagement with the tapered cam surface. The coupling body has a main body portion the throughway of which receives the end of the tube and a stop to limit the insertion of the collet and an end cap in screw threaded engagement with the main body having an open end into the throughway and the tapered cam surface. The cap is retained on the main body by an annular diaphragm encircling the body which engages in a wide slot formed in the inner periphery of the cap. The diaphragm snaps into the slot when the cap is screwed onto the main body portion to a first position in which a tube can be inserted through the collet into the coupling body and released. The diaphragm allows the cap to be screwed further onto the coupling body to a position in which the collet is locked to the tube to prevent release of the tube.