| 摘要 |
568,623. Paper sacks. ROBINSON, F. G., and PAPER SACKS, Ltd. Oct. 29, 1943, No. 17930. [Class 94 (ii)] In a multi-ply paper sack made on a tube-making machine, portions of a pasted area of a seam on a web are exposed while wet to the next web, through perforations in the unpasted seam of the first tube. The adhesion of only small spaced areas of adjacent webs prevents the cockling of the paper caused by the normal practice of pasting the whole areas of one web. The invention is applied to a machine such as described in Specification 459,377, in which a multi-ply, staggered-mouth, sack tube is formed and divided into lengths for presentation to block-bottoming or like closure means. Webs 1, 2, 3 are supplied from rolls 1a, 2a, 3a, 3 being the outermost web. Prior to folding, perforating means 4, 5 make incisions in the unpasted margins of webs 1, 2, and means, such as a bar 16 or roller cause the protruding flaps 14 to be folded back on the web, leaving holes to expose the pasted seam, A rotary arm 6 coacts with a grooved roller 11. a cutter 7 protruding through the web 1, the arm mounting 8 and roller 11 being adjustable. The peripheral speed of the cutter 7 is equal to, or slightly less than the linear velocity of the web. An alternative form of cutter 21, for the web 2, co-operates with a fixed grooved plate 18 which deflects the web to cause it to be under slight tension. Reciprocating cutters may be used in place of the rotary cutters. Specifications 443,950 and 526,676 also are referred to. |
