Patent GB-999451-A (GB)
Title: Process and device for the production of a multiply tube and bag manufactured from such tube
IPC: B31B39/00
Filed: 1962-05-22
Abstract: 999,451. Making non-metallic tubes. I. BOONE. May 22, 1962 [May 23, 1961; Oct. 2, 1961], No. 19656/62. Heading F2P. [Also in Division B8] In a process for the continuous production of a multiply tube of paper comprising an inner ply having a greater absolute length than its apparent length and one or more outer plies having a length corresponding to the apparent length of the inner ply, a preformed flat tube constituting the inner ply has imparted thereto a permanent undulation, i.e. a permanent deformation which gives the tube a smaller apparent length than the absolute length thereof, and is surrounded by outer plies which are longitudinally closed upon themselves around the undulated tube, the assembly of inner and outer plies of the so obtained multiply tube being moved forward simultaneously. As shown, a preformed tube 1 made from a web of plastic material or paper treated with plastic material, passes between rollers 2, 3, along a guide 4, between driving rolls 6, 7 and then fluted rolls R, 9 which impart a permanent undulation to the tube. The latter then passes over a guide roller 10, which may be fluted, and then into a hollow guide 11 of the cross-section shown in Fig. 2, lateral guides being provided to progressively open the pleats of the tube. To facilitate advance of the tube, nozzles S blow air under pressure between the tube and the inner wall of the guide 11, and the lower wall of the guide is inclined downwardly. One or more webs 12 of paper are fed through rollers 13, 14 and over a guide 15 so that the edges of the webs are raised, the longitudinal edges of the web previously coated with glue then being pushed into the lateral hollows of the guide 11 by rollers 16 to form pleats, and also folded over the guide. The assembly of plies in flattened condition pass between successive pairs of driving rollers 17, 18 and 19, 20 mounted so as to move vertically to and fro, such movement being obtained by cams 21, 22 fast with the rollers and co-operating with fixed rollers 23; in this way, the assembly of plies are driven alternately by the rollers 17, 18 and 19, 20 and pressure bars 24, 25 associated with these rollers follow the vertical movements of the rollers so that when the rollers are in the driving position the bar 24, or 25, exerts a pressure on the assembly of plies and, whilst holding them, repels the undulations of the inner ply to prevent the rollers crushing the undulations of the inner ply and produce incorrect folds. In a modification, the tube 1, which has been undulated by the fluted rollers 8, 9, passes through a converging guide 34 having an open upper wall and in which are arranged two flexible endless belts 37, 38 conducted, at one end, over fluted or plain rollers 39, 40. Between the belts are supports 41, 42 of U-shaped cross-section which terminate in mutually spaced-apart undulated edges and carry in slots 46, 47 the spindles of freely rotatable rollers 44, 45. The belts may be provided with transverse ribs, the spacing of which corresponds to the undulations of the tube 1.