SELF-ATTACHING FASTENER AND METHOD OF INSTALLATION

摘要

A self-clinching nut fastener, which may be used as a pierce nut, having a central cylindrical pilot portion, an annular flange portion surrounding the pilot portion, having a generally flat annular panel-supporting end face and an annular groove defined in the flange end face surrounding the pilot. The bottom wall of the groove includes a projecting convex annular protuberance which extends circumferentially around the pilot and radially from the pilot to a midportion of the groove bottom wall spaced from the groove outer wall and the groove outer wall is inclined inwardly toward the pilot to define a restricted opening to the annular groove. The installation apparatus includes a die button having a projecting annular clinching lip configured to be received within the nut groove. The method of installation includes locating a panel on the die button lip with the die button lip coaxially aligned with the nut groove, then driving the nut against the panel to deform an annular portion of the panel into the nut groove and against the annular protuberance to deform the panel portion beneath the inclined outer groove wall and preferably radially inwardly against the pilot portion. In the most preferred embodiment, the protuberance comprises a plurality of semi-circular protuberances which are integral with the pilot portion and extend radially to beyond the radial center of the grooved bottom wall and the panel is deformed against the groove bottom wall into radial channels between the spaced protuberances preventing relative rotation of the nut on the panel.