Patent ID: 6905142

Claim:
A coupling comprising: a fitting having a barrel, an externally threaded first nipple, and a second nipple, the first nipple protruding away from the barrel in a first direction, the second nipple protruding away from the barrel in a second direction, the barrel having an external surface that is structured to be engaged by a tool, the barrel including an annular shelf disposed adjacent the external surface, the barrel having a groove formed therein adjacent the shelf, the groove having an engagement surface that is undercut below the shelf and that is of a first frusto-conic shape that faces generally radially inwardly; a nut including an internally threaded collar and a plurality of elongated fingers extending from the collar, the collar having an outer surface that is structured to be engaged by a tool, each finger including a deflectable bar and a projection, the projections each including a first surface and a second surface, the first surface extending generally radially outwardly from the bar and being oriented generally perpendicular to the longitudinal extent of the bar, the second surface being of a second frusto-conic shape and facing generally radially outwardly, the first and second surfaces meeting at an edge; the first nipple and the collar being structured to be threadably connected together; the engagement surface having a vertex spaced from the barrel in the first direction; the second surface having a vertex spaced from the barrel in the second direction; and the bars being structured to be elastically deflected inwardly from a free state and the edges being structured to be frictionally engaged with the engagement surface when the coupling is assembled.