GB860803A - Methods of and apparatus for cutting tubular stock of thermoplastic material in the manufacture of bags or like containers - Google Patents

Abstract

860,803. Cutting tubular thermoplastic stock. LUETZOW, A. E. July 8, 1957, No. 21583/57. Class 87(2). [Also in Group XVII] Tubular thermoplastic stock is gripped under tension in a flattened condition and a hot wire is brought into melting contact first with one layer and then with the other layer of the tensioned stock to successively separate the layers from the remainder of the stock while leaving this remainder unsealed. In apparatus for forming a bag for covering garments using this method, a garment is mounted on a hanger beneath a roll of the tubular thermoplastic stock, a length of which is pulled down over the garment and separated from the roll by a cutting device. This device includes a stationary part, Figs. 6, 14, which comprises a metal base member 38, a pair of spaced metal channels 39 having their outer sides 40 of less length than their inner sides, and a pair of yieldable rubber pads 41 mounted in the channels. It also comprises metal base members 42, each having a metal channel 43 forming a mounting for a yieldable rubber pad 44 with a top face 45 of glass or other suitable heat insulating material and a heat insulating coating or tape 45a. Referring to Figs. 7 and 14, the movable part of the device, which is pivoted so as to enable it to be swung by means of a compressed air-operated device towards the stationary part, has base members 46 and 47, the forming having a metal channel member 48 in which is mounted a heated cutting wire 49. When the edges of channel 48 engage the double thickness of the stock and force it towards the stationary part, the stock is drawn over the edges of the inner sides of channels 39 and at the same time pressed into the pads 41 so as to be tensioned as it bridges these channels. The wire 49 is so positioned as not to engage the stock until this has been tensioned. The base members 47 which are arranged to coincide with the base members 42, have metal channels 54 in which are mounted rubber pads 55 with top glass faces 55a. A heated cutting wire 56 extends lengthwise of the outer surface of each glass face 55a, and each wire 56 has a neck extension 67, Fig. 7. The wires 56 and extensions 67 engage and cut through the plies of stock and melt their edge portions together. After removal from the apparatus ,a cord or ribbon may be tied about the neck portion of the bag and the projecting hanger hook.