GB611652A - Bag making machine - Google Patents

Abstract

611,652. Bag-making machines. FITZPATRICK, H. J. (Richens, A. W.). May 2, 1946, No. 13435. [Class 94 (ii)] For bags made of heat-sealable material, or thermoplastically-coated. material, the material is formed into a tube, passed between rollers 31, 32 where the tube is heat-sealed and partially. severed, the tube then being fed at varying speeds between pairs of rollers 42, 46, the former pair holding a bag section while the rollers 46, moving faster than the rollers 42, exert a snatching effort on the tube and complete the severance of a bag from the tube. The tube is preferably preheated by passing it over an electrically or steam-heated foll 93 to within a few degrees of the sealing temperature at the rollers 31, 32. The tube may be folded around a former 20, or formed by two strips which are sealed together at the edges. Fig. 2 shows a roll 14 of strip material which is passed around guide rollers, over a former 20, through the pre-heating, heat-sealing and cutting and final snatch-severance stages. Guide bands 40, 39, are stretched over rollers, some loose; the others being driven through gears from a motor 60. Hand feeding mechanism may be operated by a wheel 81. The spacing between pairs of rollers 42, 46 may be varied to vary the sizes of the bags. A brake on the shaft 12 provides a slight resistance to the rotation of the roll 14, creating tension in the strip of material. Feeding rolls 29, 30 are preferably covered with, or formed, of a material such as rubber to grip the strip of material and draw it from the roll 14. The pressure between the rolls may be adjusted. Holding segments 42, 43 are preferably formed of corrugated rubber blocks. The speed ratios and temperatures at various stations in the machine are given in the Specification.