High-frequency zig-zag welding

1,066,907. Finishing edges and. seaming non- metallic sheet material. BRITISH ENKALON Ltd. March 18, 1965 [March 18, 1964], No. 11621/65. Heading B5K. [Also in Division D1] Knitted fabrics which are at least partially derived from a thermoplastic yarn 2, e.g. polyamide, are welded by forming at least two rows 5, 6 of stitch welds 4 each row extending along a course of the fabric and being spaced apart from an adjacent row, each stitch weld 4 extending over at least two stitches of the knitted fabric and the stitch welds 4 of each row overlapping the stitch welds 4 of the adjacent row. The invention is applicable to joining fabrics or finishing the edges thereof. In the embodiment shown, a polyamide knitted fabric 1 is welded to another knitted fabric (not shown) and the distance between the rows 5, 6 is about twice the distance between two adjacent courses. In the longitudinal direction of the seam the welds 4 each extend over four stitches of the fabric 1. Preferably, the seam 3 is welded by high-frequency current by dash-like parallel electrodes (7), Fig. 2 (not shown).