| 摘要 |
PURPOSE:To automatically mass-produce uniform and satisfactory elbows with a simple mechanism by inserting a blank pipe which is scored at a prescribed interval into a mandrel, expanding the pipe under heating in the curving part of the mandrel, and pressing the pipe between segmental forming dies. CONSTITUTION:A long-sized blank pipe P is scored (d) to form the 1st pipe, 2nd pipes, P1, P2... and is inserted into the guide part 1b of a mandrel 1. The pipe P is pressed and while it is externally heated by a high frequency heater 6, the pipe is forced into a curing part 1a, where the pipe is expanded and plastically deformed to a bent pipe having a prescribed section. The bent pipe is passed through segmental forming dies 2 and when a detector S1 at the front end of the dies 2 detects the 2nd pipe P2 and the score (d) upon arriving of the top end of an intermediate product P1' at said detector, the dies 2 are operated. The dies 2 press relatively the product P1' to set and work the product to a round shape by means of setting and working grooves 3. At the same instant, the connecting wall part formed of the score (d) with the 2nd pipe P2 is torn and separated and therefore a product elbow is easily taken out by opening the dies 2. |
