Patent ID: 7013768

Claim:
An Apparatus for friction stir riveting of fusible workpieces together at a point of engagement, the apparatus comprising: a rivet having a body formed of a material with a substantially higher melting point than that of the fusible workpieces and including an elongated cylindrical section and upper and lower stops at opposite ends of the cylindrical section, the rivet being capable of locally forming a cavity of plasticized material of the workpieces upon rotation and forcing of the rivet cylindrical section into the workpieces; a cap having a central opening surrounding the cylindrical section, the cap being slideable on the cylindrical section between the stops and configured to substantially close an open end of the cavity to restrict the escape of plasticized material from the cavity and limit the entry of external oxygen into the cavity; and a driver drivalby engageing the body of the rivet during installation of the rivet; and a biasing device acting between the cap and the driver and, during rotation and forcing of the rivet, biasing the cap against the open end of the cavity.