Tube fitting

Claim 1

In a tube fitting having a body provided with a through bore, and a one-piece element defining a frangibly connected nut and sleeve, said element being provided with a through bore adapted to receive coaxially the end of a tube to be connected to the fitting with the distal end of the tube projecting from the sleeve, said body bore defining a right cylindrical inner recess adapted to receive coaxially the projecting distal end of the tube for supporting and centering the tube end during make-up of the fitting, said recess having an outer diameter preselected to be slightly larger than the outside diameter of said distal end of the tube for facilitated insertion of said distal end of the tube thereinto during said make-up of the fitting, and having an inner diameter substantially equal to the inner diameter of said distal end of the tube, the inner end of said recess being defined by a radial, planar surface defining means for effectively positively fixing said distal end of the tube against longitudinal inward movement from a preselected inserted position in the body bore, said sleeve having a longitudinally inner nose portion defined by a radial inner end surface and a frustoconical outwardly widening surface, said sleeve further having a longitudinally outer portion defined by a radial outer end surface, a frustoconical outwardly narrowing surface, and a radial, annular surface at the inner, wide end of said outwardly narrowing surface, said body bore further defining a camming portion outwardly of said inner recess and tapering into said recess for causing constrictive mounting of said element sleeve to the supported, centered, and longitudinally fixed tube end and separation of said element sleeve froM said element nut during said make-up of the fitting, said sleeve being frangibly connected to said nut at said outwardly narrowing surface, said nut having a longitudinally inner portion defining a longitudinally outer, outwardly narrowing frustoconical surface and a longitudinally inner radial stop surface, said radial annular surface of said sleeve abutting said radial stop surface of said nut in the made-up arrangement of the fitting to provide a preselected constriction of the longitudinally outer portion of the sleeve by engagement of said nut inner portion with said sleeve outer portion frustoconical surface, said sleeve inner end surface having an unconstricted outside diameter substantially larger than the diameter of said body bore recess.