GB484263A - Improvements in the manufacture of paper bags - Google Patents

Abstract

484,263. Making paper-bags. ROHRBACHER, H. July 13, 1937, No. 19340. Convention date, July 18, 1936. [Class 94 (ii)] A method of forming a block bottom on a transversely-guided paper leaf tube p, during feeding, comprises drawing apart the leading edges of the end portion of the tube to form a right-angled isosceles triangular pocket t<1> disposed at right-angles to the tube, fixing the pocket by rolling it out at the moment of its completion and then forming, by continued rolling, a similar pocket t<2> between the rear edges of the tube end. The free edge of each transversely fed tubular blank, overlapping the feed rollers r', r<2>, is opened partly by suction members s<1>, s<2>, attached thereto, and preliminary grippers v<1>, v2, rotating about axis disposed parallel to the direction of feed, further open the tube end, until the main grippers h<1>, h<2> complete the opening and form the front triangular pocket t<1>. This is immediately pressed by rollers a<1>, a<2>, the roller a<2> being in two parts and the roller a<1> being gapped to avoid rolling the corner of the pocket t<1> too sharply. The following pocket t<2> is formed during the rolling operation and rolled also by rollers a<1>, a<2>. The main grippers h<1>, h<2> are mounted on shafts el, e<2> at 45‹ which intersect in a plane which passes through the axis of the two rollers a<1>, a<2>, and can be adjusted, along with the preliminary grippers v<1>, v<2> and the interconnected suction members s<1>, s<2>, to accommodate different sizes of bags. The rolls a<1>, a<2> are provided with adjustable ribs or depression whereby creases b<1>, b<2> are formed, during the rolling operation, about which the side flaps may be folded in and subsequently adhered together to complete the bag bottom. A valve may be incorporated in known manner.