| 摘要 |
A method of permanently attaching a fastening element, such as a nut or bolt to panels having a range of panel thicknesses, such as the metal panels used by the automotive and appliance industries. The fastening element includes a tubular barrel portion and preferably an annular bearing face surrounding the barrel portion. The method includes punching a hole in the panel, then plasticly deforming and drawing the panel surrounding the hole into a dome or frusto-conically shaped portion. The panel hole is thus enlarged to receive the fastener element barrel portion from adjacent the apex of the frusto-conically shaped panel portion and the bearing face is then driven against the panel, deforming the panel to a generally planar shape. The panel surrounding the hole is thereby driven against the tubular barrel portion which, in the preferred embodiment, includes radially projecting ribs, providing securement against rotation even in very thin panels. Finally, the free end of the barrel portion is deformed radially outwardly and preferably squeezed to form a secure interlock between the fastening element and the panel.
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