| 摘要 |
PURPOSE:To obtain a number of inexpensive square bottom bags with stable sizes and forms, by providing a joint line of a sheet, starting from the middle of respective opposite sides of an opening and separating to be two lines at the point of a half depth from the bottom to reach four corners of the bottom. CONSTITUTION:Sizes of a square bottom bag are made as follows: folded depth of a gazette 7 = b/2, where a shorter side of the bottom 3 = b, a triangle 11 separated by seal/cut 4 forms a right isosceles triangle and the cut depth = b/2 and hence, the cut width = b, and moreover a+b = constant distance, where a longer side of the bottom 3 = a, the length of seal/cut = (c-b/2), where the height of the square bottom bag = c. If the form of the triangle separated by seal/cut 4 is changed, several forms of square bottom bags are obtained. A composite sheet is folded by a half 6 to form the gazette 7 in the direction to recess the half-folded line and a heat resistant plate is inserted into the gazette and further the triangle is drawn out of seal/cut every certain distance and by seal/cut 4 on the line crossing the half-folded line, passing the top of the triangle, in order to make the square bottom bag. |
