| 摘要 |
A method and apparatus for forming shouldered tubular rivets is disclosed in which three forming operations are provided, two of which are performed in a single die station. In the first operation, the head end of the blank is squared and the inner end is trapped extruded. In the second operation, both the shoulder and the inner end of the blank are squared. During such second operation, the volume required to form the entire shank is confined within the die and the projecting portion of the blank is headed so that variations in blank volume appear as variations in the head. In the last or third operation, the tubular section is extruded on the inner end of the blank. An apparatus for performing the method is disclosed which permits the accurate positioning of a sleeve and an extrusion pin with respect to the die during the second operation to insure proper squaring of the inner end of the blank and the confinement of the exact volume of material required to form the entire shank of the rivet.
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