GB881784A - Improvements in the manufacture of packages, especially of the infusion bag type - Google Patents

Abstract

881,784. Tea &c. infuser bags; packaging. WELIN-BERGER, J. M. G. July 22, 1959 [Aug. 2, 1958; Oct. 29, 1958], No. 25131/59. Classes 94(1) and 94(2). A perforated tubular blank 1 of thermoplastic material, e.g. polythene, with flattened edges 2, Fig. 2, is reshaped to displace the edges 2 to the middle of the flat sides, Fig. 4. Then one end is closed by heat sealing. The reshaping creates a tension in the material which tends to part the edge portions, while the original edges 2 act as stiffeners and facilitate the filling of the bag with tea. The reshaping operation should be performed before the blank is cut off from the original length of tubing and may be done by a single arrangement of rollers. By reshaping, and folding, a perforated tubular blank of double length, a twin bag may be formed, Fig. 6, with the four end walls interconnected and closed by a common heat seal 11a 11c, Fig. 5, in which an opening 11b may be left between the bags. After each bag has been filled its remaining open end is closed by heat sealing. One end of a bag string 14 is fixed in the common seal and the tag and string introduced through the opening in to the space between the individual bags 10a, 10b. A V-shaped spacer 12 may be added. The blanks may be cut from a tube having unequal wall thicknesses so that, when reshaped, the original thin portions B, Fig. 9, are in the middle of the flat sides and the original thick portions A are at the edges. The stiffness of the material may also be varied by altering the distribution of the perforations.