| 摘要 |
PURPOSE:To form the wall thickness on an outer face of a bending section not being too thin by forming a projected circular shaped crest section on an outer peripheral section of a bending section of a cement mortar plate with its wall thickness thicker than those of other non-bending sections. CONSTITUTION:When a cement mortar plate 1 is formed, a projected circular crest section 2 with the wall thickness of a section forming the outer face in the bending direction of a flat plate is formed, and a corner circular shape 5 of an inner frame 4 for bending is made corresponding to the projected circular crest section 2 and one side of the cement mortar plate 1 is rotated in the direction of arrow mark (a) to stretch the outer peripheral face of the projected circular crest section 2 and make the wall thickness of said section thinner gradually. As the wall thickness of said section is formed thicker than those of other sections preliminarily, the thickness is almost same when the bending of the frame plate is completed. Said arrangement of making the plate thickness of the bending section thicker preliminarily prevents the reduction of wall thickness at the time of processing and avoids the lowering of strength of a product, and further its increase is also possible. |
