Patent GB-605899-A (GB)
Title: An improved method of sealing wrappers
IPC: B65B51/14
Filed: 1945-12-19
Abstract: 605,899. Packing by wrapping-up. HARVEY, V. P., and MOLINS MACHINE CO., Ltd. Dec. 19, 1945, Nos. 34383/45, 21150/46 and 24325/46. [Class 94(i)] A wrapper of heat-sealing cellulose material is sealed about a rectangular block-shaped article, where laps occur comprising two over-lapping folds from opposite faces of the articles and a further fold from a side perpendicular to said faces, by forming conjoined seams transverse to one another by the application of heat along lines narrower than the overlap in order to avoid increasing substantially the permeability of the wrapper as a whole. The blank 2, Fig. 1, is folded about the article in the form of a tube with projecting ends, the ends of the wrapping lying on the wood face of the packet at 1. End tucks 3 are first formed, and side folds 4, 5 thereover. Heat is applied to form narrow seams 6, 7, 8, only where at least two layers of material overlap. For a block-ended packet, Fig. 2, seams 9, 10, 11, 12 are formed, and the packets may be stacked so that the seams 11, 12 of all the packets form continuous lines. One side flap may be extended to form a tab 13. The shape and size of the end tucks, may vary considerably. A narrow piece of the wrapper may be folded back at an overlap, or an extra strip of material, which may also be used as a rear strip, may be inserted in order to provide three thicknesses of material at a seam. One or more heaters, each with one or more heating elements, may be used, and the elements and packets may be stationary or move together. For sealing packets of the kind shown in Fig. 2, the packets may be formed into a stack and moved upwards intermittently by a platform 21, Fig. 3, operated by cams 36, 37 on a driving shaft 35 and actuating cam rollers 33, 34 on one lever 27 of a parallel lever system 27, 28 pivoted on the machine frame at 29. 30. The packets are passed up through a stacker 20 comprising two guide plates 55, Figs. 3 and 5, each having a guide strip 56, and each step of motion is through a distance equal to the depth of a packet. Three heaters 22, 23, 24 are provided to act on the three requisite sides of the stack, the fourth side being supported by a wall 43 operated by links 32, 38, 41 from the lever 27, and retracted while the stack is moving upwards. Each heater comprises horizontal and vertical electrical heating elements or bars 25, 26 for forming the seams, the bars 25 of the heaters 22, 24 being recessed to receive the strips' 56, which are arranged obliquely so that a part of any seam not heated at one level will be heated at another level. Brushes 54 are provided on the heater 23 to press the overlapping flaps 13 against the side of the stack. The heaters 22, 24 are mounted on levers 44 pivoted to a bracket 45 on the machine frame, and are reciprocated in timed relationship to the table 21 by cams on vertical spindles 48 engaging cam rollers attached to the heaters. The heater 23 is fixed to a slide 49 reciprocating, also in timed relationship to the table 21, on a fixed guide 50 by means of a cam 51 on the shaft 48 and a roller 52, and a compression spring 53. The stack moves up while the heaters are out of contact therewith. For pressing the slide of slide and shell cigarette cartons towards the heater 23 during sealing, springs 57 are provided on the wall 43. The heating bars may be two to three millimetres wide and engage the wrappers for four seconds at 130‹F. Each packet is thus subjected to a series of heating operations as it moves upwards, and on reaching the top is removed. Specifications 275,893, [Class 94(i)], 528,784, 528,785, [both in Group VI], and U.S.A. Specification 2,036,873 are referred to. According to the first and second Provisional Specifications the overlapping ends 1 of the wrapper lie on the top narrow end face of the packet, and the seam 6 is formed thereon, and according to the second Provisional Specification the seams 7 are continued to the ends of the side faces adjoining the top narrow end face. The third Provisional Specification refers to Specifications 259,165 and 285,326, [both in Class 94(i)]