Patent GB-991655-A (GB)
Title: Method of connecting the ends of screen fabrics for producing endless forming wires for paper machines
IPC: D21F1/12
Filed: 1963-06-21
Abstract: 991,655. Seaming non-metallic sheet material. K. U. SCHUSTER. June 21, 1963 [June 22, 1962], No. 24755/63. Heading B5K. The end portions of a woven screen fabric strip having synthetic plastic warp wires 3, 4 are interconnected to produce an endless forming wire for a paper-making machine by heatsetting the corrugated ends 9, 10 of the wires 3, 4 in both edge portions 1, 2 of the strip; cutting the ends 9, 10 of adjacent wires 3, 4 in each portion 1, 2 to different lengths and complementary to the lengths of the ends 9, 10 of the wires 3, 4 in the other portion 1, 2; removing the cut-off parts of the wires 3, 4; removing at least some of the weft wires 5, 6 from the marginal areas between the shortest and longest ends 9, 10 so as to expose these ends; and inserting new weft wires 11 to connect the projecting ends 9, 10 of both portions 1, 2 with each other. In one embodiment, Figs. 1, 3 and 4, the synthetic plastic warp wires 4 of the portion 2 are graphically distinguished from the synthetic plastic warp wires 3 of the portion 1 by an addi.- tional centre line. Metal weft wires 5 and synthetic plastic weft wires 6 alternate. After cutting, all of the weft wires 5, 6 are removed from the areas between the shortest and longest ends 9, 10. The portions 1, 2 are fitted together so that the ends of the wires 3, 4 abut. New weft wires 11, preferably of metal or alternating wires of metal and synthetic plastic, are threaded laterally through the corrugations in the exposed ends 9, 10. Preferably each of the wires 11 has an angular cross-section, see Fig. 3, to grip the warp wires 3, 4. Each wire 11 may be formed with a portion 12, Fig. 4, of smaller diameter than the actual weft wire. The portion 12 is first threaded through the ends 9, 10 and the full-size weft wire 11 is then drawn into the fabric. In an alternative embodiment, Figs. 5 and 10, alternate warp wires 3 of the portions 1, 2 are cut off to short lengths 9a, 9c, 10a, 10cwhich differ from each other preferably by the length of only one screen aperture and the remainder of the wires 3 have lengths 9b, 9d, 10b, 10d The weft wires 5, except for the last weft wire 5a in front of the shortest warp wire end 9a, 10a, are removed from the area in which the warp wires have been cut off. Weft wires 11, preferably those previously removed, are laid into the upwardly open corrugations of the ends 10b, 10d of the portion 2 and the ends 9b, 9d of the portion 1 are placed over the weft wires 11 and between the ends 10b, 10d so that corresponding warp wire ends abut. Small diameter auxiliary weft wires 13, Fig. 10, are first threaded through the open apertures in the warp wire ends and then replaced by normal weft wires or normal weft wires are immediately threaded therethrough. The inserted weft wires may each comprise a thin metal wire core coated with a weldable thermoplastic material. The metal core is heated by an electric current after the weft wires have been positioned so that the plastic coating is fused together with the warp wires.