Tube coupling

Claim 1

A tube coupling assembly including a coupling body means having a stepped bore therein defining at least a first wall, a seal ring receiving wall and a tube receiving wall defining a fluid passage, each of said walls being of progressively reduced internal diameter in the order named, said first wall and said seal receiving wall being interconnected by a flat shoulder and said seal receiving wall and said tube receiving wall being interconnected by an annular frusto conical shoulder, a tube of uniform external diameter and thickness has a free end thereof slidably received in said tube receiving wall, a ferrule is sealingly fixed to and encircles said tube adjacent to said free end, said ferrule including an annular radial outward extending flange of an external diameter so as to be loosely received in said first wall of said body means and defining opposed first and second radial walls and having a tubular stem extending from said second radial wall a predetermined axial extent, said first radial wall being located axially a predetermined distance from said free end of said tube for abutment against said flat shoulder, a seal ring encircling said free end of said tube in abutment against said first radial wall and sealingly engaging said frusto conical shoulder; and, a tubular nut, with a bore therethrough of an axial extent corresponding substantially to the axial extent of said tubular stem so as to slidably encircle said tubular stem of said ferrule and so as to be threadingly engaged with said coupling body means for abutment against said second radial wall whereby to force said first radial wall of said ferrule into sealing engagement against said flat shoulder.