| 摘要 |
PROBLEM TO BE SOLVED: To provide a knurl, in which, when a bottom of a paper cup is molded by folding a lower end part of a trunk member of a paper cup inward, then sandwiching a lower folding part of a bottom member, and pressing and caulking from inside for molding the bottom of the paper cup, when the knurl attached to a knurl rotary table rotates in offset rotation, pressure is hardly released even when the knurl is moved.SOLUTION: A knurl 10 folds a lower end part of a cylindrical trunk member, then sandwiches a lower folding part in which a peripheral edge part of a bottom member is downward folded, then presses and calks the lower folding part from inside. In the knurl, a step part B is formed so that a diameter on a tip end side is thicker.SELECTED DRAWING: Figure 1 |
