MANUFACTURE OF VERTICAL TROUGH INTEGRATING JOINT STRUCTURE AND WORKING DEVICE

摘要

PURPOSE: To obtain a vertical trough having easy mutual connection and good finishing of the construction. ;CONSTITUTION: After forming an insert part 3 for inserting a straight pipe end part and a fitting part 2 having small outer diameter to the one end of a pipe stock 1 by a reduction work, a step-down working for forming a small R part between a step part 6 between a fitting part 2 and the straight pipe part. The step part 6 is provided with an inside roll 22 inserted in the fitting part 2, an outside roll 21 faced to the inside roll 22 through the pipe wall, a rotary head 23 fitting the inside roll 22 and the outside roll 21 so as to be rotatable. Since the vertical troughs are mutually connected through a joint part 4 having small R, a recessed part and a projecting part are not developed at the connecting part, and the vertical trough is constructed in good finishing state.;COPYRIGHT: (C)1996,JPO