Patent GB-1299913-A (GB)
Title: A sliding clasp fastener with knitted stringer tapes
IPC: D04B21/20
Filed: 1970-05-26
Abstract: 1299913 Sliding clasp fasteners LIGHTNING FASTENERS Ltd 26 May 1970 [4 May 1970] 25057/70 Heading E2S [Also in Division D1] A process for manufacturing sliding clasp fasteners comprises forming two textile stringer tapes 7 simultaneously on a loom or knitting machine and joined in side-by-side relationship by separable connecting threads 8 which can be parted to separate the tapes during or after attachment to the rows of interlocking elements. As shown in Fig. 7 stringer tapes 7 formed in two connected pairs are fed to a feeding device 10 together with two pairs of plastics monofilament interlocking elements 2, the tape pairs are then separated by a separator 14 for presentation to an attachment device 11 comprising a sewing machine 13 as shown after which the remaining connecting threads 8 between the stringer tapes 7 of each fastener are separated in a take-off device 12. Stringer tape. The textile ribbon 1, preferably knitted, having stringer tapes connected together in side-by-side arrangement comprises warp chain threads 4, and transverse lapping threads 5 and in-laid lapping threads 6 such that the loops form wales 3 longitudinal to the tape length and separated by grooves 15 in which there are only transverse threads, with connecting threads 8 between the tapes 7 encompassing at least one margin wale of each tape 7. The threads used in the knitting process are shown in Fig. 4 where the coded digits represent each periodically repeated thread pattern with the oblique representing the starting point on the pattern; the digits to the left representing the number of wales subtended by each loop as the pattern is traced through two loops in one direction; and the digits to the right representing the number of wales subtended in the opposite direction along the pattern with the same starting convention for each pattern. Thus, in examples 1 and 2, two loops complete the periodically repeated pattern and 44/00 represents the inlaid lapping threads 6 and 22/00 represents the connecting threads 8 while examples 3 and 4 represent respectively the transverse lapping threads 5 and the warp chain threads 4 each as used in Fig. 1. The threads bordering the margins 9 of the stringer tape 7 may be reinforced by thickening the gauge or by additional threads. A uniform thickness over the entire width of the tape can be obtained by omitting some of the transverse lapping threads 5 (Fig. 6), and holes 20 (Fig. 9) formed in a loop-free zone 17 parallel to the tape edge by omitting the second warp chain thread 4 and the first transverse lapping thread 5 on opposing tape margins 9 may be provided for inserting the rows 2 of interlocking elements. Attachment of interlocking elements. During manufacture of the ribbon 1, the connecting threads 8 may be strongly tensioned so as to enlarge the holes 20 such that after insertion of the interlocking elements, the holes close up on severing the threads 8. The rows of interlocking elements 2 may alternatively be attached to the tapes by sewing when they are attached to the plane side of the tape as in Fig. 8 or by adhesive bonding or welding. For attachment by sewing, tension in the connecting threads 8 is provided so as to produce sufficient space for the sewing needles to pass through the inter-wale grooves 15 and the sewing thread 16 is embedded in the groove.