Patent ID: 7240929
Filing Date: 2007-07-10
Classification: F16L

Abstract:
1. A tube gripping ferrule for a metal tube fitting, the ferrule comprising: a generally cylindrical interior wall through the center of the ferrule so that said ferrule can be installed over a metal tube end; said ferrule being case hardened over substantially its entire surface; an outer wall that axially tapers with a radially increasing dimension from a front portion of the ferrule towards a back portion of the ferrule; said front portion of the ferrule indenting and biting into an outer surface of a metal tube end after the fitting is assembled and pulled-up; said interior wall comprising first and second cylindrical portions, said first cylindrical portion being axially adjacent a front edge of the ferrule and having the smallest interior wall diameter of the ferrule, said second cylindrical portion having a larger diameter than said first cylindrical portion, wherein the tube fitting is a two ferrule tube fitting and comprises first and second components that are joined together to install the tube fitting on a metal tube end and enclose two ferrules that are axially driven together when the tube fitting is pulled-up, wherein said ferrule having said first and second cylindrical portions is a back ferrule in said two ferrule tube fitting.