| 摘要 |
<p>The present invention provides a method and apparatus for forming an outwardly extending tubular portion (14, 16) in a side wall of a workpiece, such as a rocker arm (10). The method includes the following steps: (a) positioning the workpiece in a punch press (18, 20) having a central shaft (30) with a movable punch (64) mounted in an aperture (65) formed in the central shaft for lateral sliding movement with respect to the shaft; (b) extending the central shaft (30) into the interior cavity of the workpiece; and (c) actuating lateral sliding movement of the movable punch against the side wall of the workpiece to cold form the outwardly extending tubular portion (14, 16) in the side wall.</p> |
