Self-attaching fastener and panel assembly, method of installation and die member
A self-attaching fastener and panel assembly wherein the free open end of the tubular barrel portion is coined, collapsed axially, flattened and deformed radially inwardly and outwardly and axially against a panel surrounding the panel opening. The method of installation includes driving the free end of the tubular barrel portion against a substantially planar die surface, deforming an end portion radially, then collapsing an intermediate portion over the radially deformed end portion, flattening the end portion, substantially thickening the tubular barrel portion and forming an annular surface engaging and supporting the panel surrounding the opening. The die member includes an annular moat surrounding a central die post and a planar die surface extending generally perpendicular to the axis of the die button.
1. A method of attaching a self-attaching fastener to a panel, comprising the following steps:
forming a self-attaching fastener including a central fastener portion and an integral tubular barrel portion having a free open end;
receiving the free open end of said tubular barrel portion through an opening in a panel; and
driving said free open end of said tubular barrel portion against a substantially planar die face, deforming an end portion radially inwardly and buckling said tubular barrel portion, thereby forming an inwardly opening annular channel, then collapsing an intermediate portion over said radially deformed end portion, forming a crease by collapsing said annular channel, flattening said end portion, substantially thickening said tubular barrel portion and forming an annular surface engaging and supporting said panel surrounding said opening.
2. The method as defined in claim 1 , wherein said method includes deforming said end portion of said tubular barrel portion inwardly against a central die post of the die, and wherein said inwardly opening annular channel is U-shaped.
3. The method as defined in claim 1 , wherein said method includes forming the self-attaching fastener including a radial flange portion integral with and adjacent to the tubular barrel portion and the tubular barrel portion including a polygonal outer surface spaced from the radial flange portion, driving the polygonal outer surface of the tubular barrel portion into the panel opening preventing rotation of the self-attaching fastener relative to the panel.
4. The method as defined in claim 3 , wherein the method further includes driving the radial flange portion against the panel.
5. The method as defined in claim 1 , wherein the method further includes entrapping the panel between a radial flange portion of the self-attaching fastener and the deformed tubular barrel portion.