| 摘要 |
PURPOSE: To form a bell part on a tube in a fin pack heat exchanger by making a frame and a jaw finger which forms and expands a bell part perform step motion in a transverse direction to a fin pack. CONSTITUTION: A finger 30 reaches the under part of a tube plate flange 20 and opens in a transverse direction. These bell part forming jaw fingers 30 are tightened by considerable strength to tighten a smooth tube. The male and female jointing surfaces of the fingers 30 are given with a contour surface along which the metal of a tube end 12 is expanded to form a bell part 22. The bell part forming jaw fingers 30 grasp the tube end 12 while a part forming tool 34 is being moved between the fingers to form the bell part 22, A bell part forming tool is of two-stage device including a pinch bullet which is put in the tube end 12 to flare the tube end 12 outward and a flare part forming collar which is put in the tube end to form a bell flare part. After the bell part 22 is formed, the bell part forming tool 34 is pulled out and the fingers 30 are opened. |
