| 摘要 |
PURPOSE:To obtain a seam part provided with ample fitting part for flange tips of top and bottom plates and shell plate at the center by forming a bent part of flange tip having a specified curved part and a nearly straight part on the flanges of top and bottom plates prior to fastening. CONSTITUTION:Flange parts of a top plate or bottom plate 1 and shell plate 2 are temporarily fitted at a projection difference L, and after being bent by a forming groove 6 of a bending roll 5 which moves in the direction of the arrow, the tip is bent by forming grooves 7-9. In the cross section of this part, the bent part shows a curve similar to that of a fastening groove 11 of a fastening roll 10. The bent part 3 is bent with a curvature less than 2.5 times the thickness of the plate, after bending of specified bending angle alpha (>=90 deg.) determined by the quality and thickness of the plate and length of bending (the length from intersection of bisector of interior angle of the bending to the tip of the plate) l, forms nearly a straight line. l is given by expressionsI, II. By fastening the flange part having both of parts 4, 3 or the latter by the roll 10, required seam part can be obtained. |
