Patent GB-1092680-A (GB)
Title: Improvements in edging formed of a band of flexible, air impervious thermoplastic material
IPC: B29C53/36
Filed: 1965-11-22
Abstract: 1,092,680. Seaming and finishing edges of non-metallic sheet material. S. H. MAGID. Nov. 22, 1965, No. 49547/65. Heading B5K. An edging 37 formed of a band of flexible air impervious thermoplastic material is characterized in that the thermoplastic material is folded upon itself to form two flaps 42, 43 and a bight 44 therebetween, the flaps 42, 43 being secured to each other at 45, 46, e.g. by heat sealing or cementing, and defining a hermetically sealed tunnel 38 with air entrapped therein, the tunnel 38 also having enclosed therein an elastic constricting element 39, said air being of sufficient quantity to maintain the confronting walls of the tunnel 38 free to move relative to each other when the element 39 is in a contracted state. In one embodiment, Fig. 3, the edging 37, e.g. of polyethylene or polyvinyl chloride, is secured by heat-sealing or cementing to the walls 21 (not shown), 22 surrounding a leg opening 35, Fig. 1 (not shown), of a pair of baby pants 20. The waist opening is bounded by a hem 26, Fig. 2 (not shown), having its edge portion 28 secured by heat sealing or cementing to the walls 21, 22 with an elastic constricting element 29 therein. Apparatus for attaching the edging to the leg opening of baby pants comprises a fabricating assembly 65, Fig. 4 (not shown), supported on a column 52. A vertically movable platen 66 is situated above the assembly 65. The assembly 65 and the platen 66 are provided with electrical connections 71, 72, respectively, to effect heat sealing. The leg opening 35a is disposed over the assembly 65. The assembly 65, Figs. 5 and 6 (not shown), comprises three cupped elements 75, 85, 82 slidable within each other, the elements 82, 85 being slidable on the column 52. A lower tubular spacer 90 slides through an aperture in the element 85 and an upper spacer 91 slides through an aperture in the element 75. A compression spring 93 urges the element 85 into engagement with the lower end of the spacer 91. In operation, an endless band 95 of thermoplastic material is circumposed upon the element 75 with the upper edge 98 thereof extending over the upper edge 80 of the element 75. A resilient constricting element 100 is engaged about the band 95 in the region of an annular groove 77 formed between two ribs 78, 79 on the element 75. The elements 82, 85 are then moved upwards so that the upper edge 87 of the element 85 clamps a portion 101 of the band 95 against the rib 79. The element 82 then folds the band portion 97 upward to overlie the band portion 96, the constricted band portion in the groove 77 ensuring that a quantity of air is trapped between the portions 96, 97. The overlying edges are then heat sealed and simultaneously applied to the leg opening. The upper edge 80 of the element 75 may be sharp to cut excess material. In a modification, Fig. 7 (not shown), the portion 101a of the band 95a is clamped against the rib 79a by the element 85a and the lower band portion 97a is swung upwardly manually or otherwise. Heat sealing is then effected.