| 摘要 |
A friction welded fastening system comprises a thermoplastic fastener 40 having a primary fastening element 42, a base 44 carrying the fastening element 42, and having a surface 46 arranged to be fused to a workpiece by the heat of friction generated by the application of rotational and axial forces to the fastener when its base surface is in contact with the workpiece; and an application tool 10 for rotating and applying axial pressure to the fastener 40. Such a system includes means automatically to stop rotation of the fastener 40 when its base surface 46 has been heated to a predetermined degree to enable it to fuse to the workpiece. The means automatically to stop rotation of the fastener 40 comprises at least one heat-sensitive protrusion 50 adjacent the base surface 46, and at least one projection 19 on the tool 10. One of the protrusions 19 of the tool 10 engages the projection 50 on the fastener 40 to rotate the fastener 40 until the base surface 46 has been heated to a predetermined degree and then the protrusion 50 reaches a predetermined minimum strength at which point it yields under the applied load from the projection 19 of the tool 10 and the fastener 40 then stops rotating. |
