| 摘要 |
PROBLEM TO BE SOLVED: To form a paper bag without any folding line efficiently and improve the accuracy of setting of the forming position of side line of the bottom of the bag by a method wherein a paper tube is turned and transferred by the rotation of a bottom folding drum while a rear pressing pawl as well as a rear raising pawl are positioned near the bottom folding line of a surface side flap. SOLUTION: The folding part of a paper tube is pinched by the opening and closing pawl of a bottom opening device and the opening and closing pawl 643 of a bottom folding drum 640 while the rear surface paper side tip end of the paper tube, whose bag bottom is opened by a catching pawl 641 provided on the bottom folding drum 640 arranged near the bottom opening device, or a rear side folding flap is pinched. Thereafter, the paper tube is transferred by the rotation of the bottom folding drum 640. A rear pressing pawl 644 as well as a rear raising pawl 645 are positioned near the bottom folding line of a front side folding flap. The rear raising pawl 645 is rotated toward upward in accordance with the pivoting operation of a pivotable shaft 645B whereby the fore side of the bottom folding line in the front side folding flap is pushed by the rear pressing pawl 644 and the rear side of the bottom folding line is raised by the rear raising pawl 645. |
