| 摘要 |
Method and apparatus for forming a generally cylindrical point on a tube by first flattening the tube from at least three sides to a polygonal cross section while forming curved sections between the flat sides, and then progressively contracting the tube to bring the curved sections together while buckling the flat sides inwardly into loops that are flattened inside the point. At least three die shoes arranged around a die recess in alternately overlapping relation have flat inner faces with an elongated lip along one side for shaping the curved sections, and also have flat, inclined bevels for shaping the transition zone of the tube during pointing, each bevel having a part-conical lip on one side for the final shaping of the transition zone to a conical shape. One actuating arrangement utilizes a mutual camming action to move all die shoes simultaneously at the same rate to maintain the point on a preselected axis, while a simpler form displaces the axis during pointing.
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