Patent GB-667891-A (GB)
Title: Glued bag and method of making the same
Inventor: BILLEB CLYDE KENNEDY
IPC: B31B23/00
Filed: 1950-03-14
Abstract: 667,891. Making paper bags. MILPRINT, Inc. March 14, 1950, No. 6302/50. Class 94(ii) In forming the bottom of a bag which is made from a substantially rectangular flat tubular blank with one end provided with substantially coincident free edges a transverse fold 33, Fig. 5, is made at a short distance from the coincident edges and the end portion is glued to the outer surface of the tubular body, after which the initially folded portion is refolded in the same direction along a fold line 36 located between the transverse centre line of the first folded portion and the free edges thereof, and the folded portion 34 is glued against the part 38 of the initially folded portion and also against the outer wall 35 of the blank. The blank is formed from a thin flexible ribbon or web of impervious sheet stock such as regenerated cellulose which is drawn from a reel in known manner and supplied along one edge with glue or other adhesive from a contacting wheel, after which it passes through a tubeforming unit wherein the edges are overlapped to form a tube with a central longitudinal seam and, if required, an inwardly extending pleat 15 down each side. Rotary cutters sever the continuous tube into successive lengths or bag sections, and these are fed to a bottom-forming cylinder or rotor 20, Fig. 2, associated with two revolving cylindrical tuckers 21 mounted adjacent to it. The rotor 20 is provided with a series of equally spaced peripheral gaps 22 (of which only two are shown), within each of which a plate 23 is pivoted for oscillation about a carrier pivot 24 under the control of a rocking-lever 25 clamped upon the pivot and actuated by a stationary cam 27; a roller 26 on the lever 25 being held against the cam by a tensioned spring 28. The cylindrical tuckers 21 rotate in unison with the rotor 20 but in the opposite direction thereto, and each is provided with a pair of diametrically opposite radial tucking-blades 30 co-operating with a glue-transfer roller 31. The sequence of operations is shown diagrammatically in Fig. 3. At step I the transverse fold or tuck 33 at some distance from the leading-end of an advancing bag-section is formed by the glue-coated tucking-blade 30 of the upper tucker 21 entering the part of the adjacent gap 22 of the rotor, to the left of the clamping-blade 23. Glue is thus. deposited in the tuck, whereupon the blade 30 is withdrawn from the gap 22 and the clamping blade 23 is swung to the left and compresses the tuck. This causes the end portion 34 of the blank to project outwardly, as shown at II, whereupon it is engaged by an adjacent part of a frame member and folded back on to the part 35. A second transverse tuck 36 accompanied by application of glue is provided at step IV, the tuck being compressed by the clamping blade 23 swinging to the right (step V), and causing the folded portion 37 to project outwardly. While the final tuck 36 is held clamped the portion 37 is folded back by a frame member adjacent to the periphery of the cylinder 20 and pressed and glued against the end part 38 and seamed outer wall 35 of the bag.