| 摘要 |
PURPOSE:To mass-produce a rivet having a prescribed eccentric quantity, by forming a cut base material to an eccentric blank by a drawing die having an expanded hole part and a small hole part, and thereafter, executing preliminary forming and finish forming by a forming die. CONSTITUTION:A wire rod 13 is inserted into a cutting die 9 of a cutting mechanism 8, is cut to prescribed size by a cutter 11 and is transferred to the following stage. Subsequently, a cut base material 14 is inserted into a forming device 15 by a drawing pin 17 and an eccentric blank 19 is formed. In this case, a die hole 21 of a drawing die 4 is constituted of an expanded hole part and a small hole part, and also the expanded hole part and the small hole part are connected by a curved face. Accordingly, the cut base material 14 is inserted easily, also compressive force applied to the drawing die 4 is softened by the curved face, and the eccentric blank 19 can be formed. Thereafter, the eccentric blank 19 is transferred to a forming device 26, and is formed to an eccentric rivet 1 having a desired shape, by a preliminary forming punch and a finish punch 29. |
