Metal tube coupling arrangement and method of manufacture

A tube coupling arrangement that comprises a cylindrical metal tube coupled to a metal fitting,

• an end of said tube being flared to form a conical end configuration,
• said conical end configuration being inserted into the fitting to abut a shoulder within the fitting, and wherein said fitting is secured to the tube by being plastically shrink-deformed in the entire material of the fitting around the tube end at least in an area of the fitting generally radially aligned with the tube end such that the flared tube end and an external surface of a cylindrical portion of the tube adjacent the flared end are fluid sealingly engaged by such shrink-deformed material of the fitting.

A fluid-tight tube coupling arrangement that comprises:

• a fluid-conducting metal fitting and a fluid-conducting metal tube, said fitting having a tube-receiving end, an internal fluid-conducting through-passage having a tube-receiving passage portion opening at said end and extending axially inwardly of said fitting to a junction with a smaller diameter passage portion, and a circumferentially continuous conical shoulder extending radially and axially outwardly from the junction of said passage portions and away from said end,
• one open end of said fluid-conducting cylindrical metal tube being inserted in said tube-receiving passage portion of said fitting tube-receiving end to abut an outwardly flared, conical end of said tube against said fitting shoulder, said fitting and tube being coupled by externally applying shrink force on said tube-receiving end of said fitting so as to plastically deform said fitting end and thereby ensmall said tube-receiving passage portion around said tube in fluid sealing engagement with the flared end of the tube and a portion of the cylindrical external surface of said tube adjacent the flared tube end and to thereby firmly hold said flared tube end in fluid sealing engagement in a groove formed adjacent said shoulder during and by such plastic deformation.

A coupling comprising a fluid-conducting cylindrical metal tube sealably secured to a fluid-conducting metal fitting and wherein an end of the tube is flared to form a conical end configuration,

• said conical end configuration is inserted into said fitting to abut a shoulder within the fitting, and
• the fitting is secured to the tube end by plastically deforming the fitting to thereby shrink-engage fitting material in fluid sealing relation around the tube end by radially inwardly directed shrink forces applied to the exterior of the fitting in an area generally radially aligned with the flared end of the tube.