IL35335A - A sliding clasp fastener with knitted stringer tapes - Google Patents

Description

rm-no cpKcm ρ»¾ήρ ^ga PSTT A SLIDING CLASP FASTENER WITH KNITTED STRINGER TAPES The invention relates to a process for the manufacture of sliding clasp fastener, in which two rows of interlocking elements in the engaged or disengaged condition are attached to two textile stringer tapes.

In the usual course of manufacture of sliding clasp fasteners, the rows of interlocking elements are presented and attached to two stringer tapes or textile ribhons paid out from separate magazines. The textile ribhons or stringer tapes are separated into lengths as required, either before or after attaching the rows of interlocking elements. Since each sliding clasp fastener incorporates two stringe tapes, the known fasteners always contai stringer tapes- which have "been made at different times and in different places (on different machines). Since the sliding clasp factories buy the textile ribbons or stringer tapes ready-made, it is generally ■ impossible to he certain of the time and place of manufacture or to sort them into groups of like origin (i.e., made on the same machine). The siding clasp fasteners are consequently subject to manufacturing tolerances that have an adverse effect on performance.

The disadvantages, of the known- processes are many. In the first place, the manufacture of individually woven stringer tapes is relatively costly. Moreover, the mechanical properties (resilience, strength)of a long tape-like textile ribbon for use.- as a stringer tape are variable "both along its length and across. its width. Since the pitch of the rows of interlockin elements in a sliding clasp fastener, on which its resistance to tearing open is dependent, is wholly or partly determined "by the- stringer tapes to which the said rows are attached, the tolerances lead at once to a reduction in that resistance.

Furthermore, "because of the said tolerances sliding clasp fasteners incorporating stringer tapes that have "been made at different times and in different places in many cases are no longer mechanically symmetrical about their central axis (even though they may have been initially positioned symmetrically), v/ith a further adverse effect on resistance to tearing open. '~ These disadvantages are significantly increased by the fact that to make a sliding clasp fastener the sewing machine used to attach the rows of interlocking elements to the stringer tapes must be fed, under individual guidance and handling, v/ith two separate stringer' tapes, thereby occasioning additional manufacturing tolerances. In addition to these disadvantages, whic reflect directly on the performance of the finished sliding clasp fasteners., there is the manufacturing problem as such, viz., the cost of handling two textile ribbons or stringer tapes for the sewing process. By no means the le&st of the disadvantages is the consequent limitation on operating speeds during the sewing of the rows of interlocking elements to the stringer^ tapes. Constant production controls must be maintained, and efforts to automate the process are significant: thwarted.

The disadvantages just described, in relation to woven textile ribbons or the virtually identical stringer' tapes for sliding clasp fasteners, apply in even greater force to knitted textile ribbons or stringer tapes, because the resilience of the looped structure in knitted goods is influen ced by the tension maintained during manufacture and the tolerances already referred to become even wider. Moreover, such stringer tapes frequently and readily roll up transversel causing additional difficulties in the stage of sewing the rows of interlocking elements to them. This concatenation of circumstances probably explains the almost complete lack of sliding clasp fasteners with knitted stringer tapes in commerc despite the fact that knitted textile ribbons are usually cheaper to make than woven.

The object of the invention is to devise a process for the manufacture of sliding clasp fasteners, which process is less costly at the same or increased operating speeds and provides sliding clasp fasteners of better quality,, According to the present invention, a process for the manufacture of sliding clasp fasteners, in which two rows of interlocking elements in the engaged or disengaged condition are to be attached to two textile stringer tapes, comprises forming two textile stringer tapes side-by-side simultaneousl on one and the same loom or knitting machine to form a single correspondingly wider textile ribbon with separable, connectin threads between the tapes., r-g a ip .nni †,pe r.nnnBrdJjaa— iJ¾¥^& e- of being parted to separate the stringer tapes during or after the attachment of the rows of interlocking elements.

The above-mentioned tolerance problems are eliminated by manufact ring the interconnec ed stringer- tapes for a given sliding clasp fastener at the same, time and place, provided that after making the stringer tapes at the same time and place they are allowed to remain as a pair until suc time as the rows of interlocking elements are or have been attached to them. In other words, the inventio proposes maki the two textile stringer tapes corresponding to the rows of -interlocking elements together on one and the same loom o knitting machine. It is within the scope of the invention to make more than two stringer tapes together, side-by-side with connecting threads as described above. The process can readil be carried out on flat (warp or Raschel) knitting machines or circular knitting machines. The various stringer tapes united into a single textile ribbon in this way are joined together by connecting threads, which are parted as required to separate the individual stringer tapes.

Since the connecting threads are not parted until the rows of interlocking elements are being or have been 'attached, the two simultaneoulsy made stringer tapes remain united up to a certain point in time, i.e., they undergo the same handling throughout. In particular, the stringer tapes underg the same pulling action in a fedding device of equipment for attaching the rov/s of interlocking elements. The features of the invention ensure that "both the stringer tapes experience the same pull in the feeding device and are under the same tension when the rows of interlocking elements are attached.

This makes it possible to position the rows of interlocking elements and stringer tapes in the two halves of a sliding clasp fastener- very precisely and very uniformly, with a highly advantageous effect on the pitch, which substantially improves the quality of the sliding clasp fastener* If the stringer tapes are made on a knitting machine, they are formed from warp chain threads, transverse lapping threads, and inlaid lapping threads to form a waled texture. In this case it is possible, notably "by varying the thread gauge and the lays of the .warp chain, transverse lapping and inlaid lapping threads, to obtain better properties in the sliding clasp fasteners. According to one feature of the invention, both the strength and the elastic properties of sliding clasp fasteners is regulated at the early stage of making the knitted stringer tapes, by reinforcing the marginal threads of the stringer tapes in the warp chain threads and/or the transverse lapping' threads and/or the inlaid lapping threads. Reinforcement can be effected by doubling the threads concerned or including thicker threads. In any case, this offers the means of adapting the properties of the knitted stringer tapes to the functional and manufacturing requirements. Moreover, the same means contribute to the elimination of thickness variations across the width of the ... stringer tapes. According to a further feature of the invention, a similar adaptation of the thickness distribution can be achieved by means characterised in that some of the inlaid lapping threads near the middle are omitted to make the centre of the stringer tapes approximately the same thickness as their margins. This procedure is particularly preferred when there are no special requirements as to the strength and stretch properties of the stringer tapes. In any case, it is preferred that the inlaid lapping threads extend over at least three and preferably four wales, which brings the resilience of the knitted stringer tapes in the transverse direction to a particularly low level. When the inlaid lapping threads extend over less than three wales, the transverse resilience increases very substantially, to undesirably high levels for the stringer tapes used in sliding clasp fasteners.

Again, there are several possible ways of laying the connecting threads that unite the individual stringer tapes into a single broad textile ribbon. Thus, the connecting threads may be laid as inlaid lapping threads or loop-forming threads, fed to a lay-strip with individualised tension. The last feature is particularly significant in view of the scope it provides for different ways of attaching the rows of interlocking elements to the stringer tapes, as will emerge from the further descripti below.

The rows of interlocking elements are attached to the stringer tapes in equipment into which the. stringer tapes are fed in the united condition, the rows of interlocking elements "being attached to the stringer tapes "by sev/ing, insertion, adhesive "bonding, or welding. By adopting these ways and means the stringer tapes, still , united across their adjacent margins, can he fed exactly centrally and under the same tension to the rows of interlocking elements. The pair of interconnected united stringer tapes can he separated from a "broad textile rihhon containing more than one such pair, so that manufacturing tolerances in the transverse direction will have no adverse effect.

When;the rows of interlocking elements are attached to th stringer tapes "by sev/ing, various structural features can he introduced into the stringer tapes, especially when they are knitted, in order to simplify the subsequent attachment proces Knitted textile ribhons or stringer tapes in which different threads are knitted together at the ales display a distinctiv structure "because of the inter-wale grooves left "between the individual wales. The grooves are only covered on one side "by the transverse inlaid lapping threads and the transverse lappi threads, which are also transversely laid in these regions." Kence when sev/ing is used to attach the rows of interlocking elements to the stringer tapes, the attachment threads can he emhedded in the grooves and effectively protected from outside contact. The tape margins on which the rows of interlocking elements are laid can extend over one or more v/ales, according to the width of the rows. The sewing can then be protected in the grooves nearest the tape margins. However*, the "breadth of the grooves, in the very fine sliding clasp fasteners 'as now developed, with correspondingly finely knitted stringer tapes, is often less than the gauge of the sewing needle used. Accordingly, it is preferred to displace the wales forming one margin of the stringer tape in the direction: of the further margin, with strong tensioning of the connecting threads in the knittin machine, thereby extending the endmost groove and providing . . space fo insertion of the sewing needle into it. After parting of the connecting threads the wales the grooves move back into place and thereby cover the sewing thread.

In the case of sliding clasp fasteners in which the rows of interlocking elements are attached to knitted stringer tapes by inserting them in holes, a pre-determined disposition of hol can be made during knitting. Thus-, holes may be made in ladder-like formation in a loop-free zone that only contains the transverse threads connecting one broad and one narrow side, of the stringer tape. In order not to weaken the stringer tape, with a'.- ladder of excessively large holes, which must be large enough to accommodate the rows of interlocking elements, and at the same time to facilitate insertion of the said rows, it is preferred to displace the loop-forming threads to either side of the loop-free zones in the direction of the nearer stringer tape margin, so as to "broaden the holes with strong tensioning of the connecting threads. After parting of the connecting threads holding the individual stringer tapes together the ladders of holes in the loop-free zones close up, wholly or in part, and thus; more firmly secure the rows of interlocking elements.

By means of the invention, the manufacture of stringer tapes united into bripd textile ribbons promotes a substantially better utilisation of the looms or knitting machines used for the-, process, with manufacturing tolerances arising from the manufacture of stringer tapes for the same sliding clasp fastene at different times and places largely eliminated. This leads to substantially more rational production techniques for the further1 important reason .that additional production controls can be abandoned, thereby greatly facilitating the problems of automation in sliding clasp fastener manufacture and in the final analysis, permitting the use of higher?' operating speeds. Moreover, the performance: of the sliding clasp fasteners made by the process of the invention is substantially improved.

The invention will now be further described v/ith reference 'to the accompanying drawings, in which: - Figure 1 shows the thread lay in a textile ribbon providing two stringer tapes for a sliding clasp fastene connected side-by-side; Figure 2 is a modification of Figure 1 , the ribbon moreover embracing more than two tapes; Figure 3 is another modification of Figure 1 ; Figure h shows details of the thread lays in the tapes of Figures 1 to 3, and likewise Figures 6, 8 and 9; Figure 5 corresponds to.-Figure 2, but shows a ribbon with reinforcements near the stringer tape margins; Figure 6 shows the thread lay of a single tape with a reduced number of inlaid lapping threads, the connection to an adjoining tape being omitted; .. Figure 7 is a perspective view of equipment for attaching rows- of interlocking elements to interconnected pairs of tapes; Figure 8 is a transverse section through a sliding clasp fastener complete with the rows of interlocking elements; Figure 9 is another modification of Figure 1 with loop-fre zones in the tapes-; and insertion Figure 10 is a perspective view showing the progressive/ of the rows of interlocking elements- in holes in the stringer tapes. - The textile ribbons 1 provide interconnected pairs of stringer tapes for sliding clasp fasteners, for the attachment of rows 2 of plastics monofilament interlocking elements (Figures, 7, 8 and 10). Each ribbon is a texture, of threads and weft . threads, with wales 3, and is formed from warp chain . threads k, transverse lapping threads 5, and inlaid lapping threads 6. Each' ribbon 1 consists of at least one pair of stringer tapes 7, to he used in one and the same sliding clasp fastener, made simultaneously on one and the same loom or knitting machine and united "by separable connecting threads 8. By parting the connecting threads 8, the textile ribbon 1 can be separated into the independent stringer tapes 7 with strong margins. The connecting threads 8 are not parted until the row 2 of interlocking elements are being or have been attached to the corresponding stringer- tapes 7. Whereas the warp chain thr 1+, the transverse lapping threads 5, and the inlaid lapping threads 6 forming the texture could be all of the same gauge,, some or all of the various threads i, 5 and 6 could.be reinfor Thus, the threads l and 5- hordering the margins 9 of the strin tapes 7 in Figure 2 are shown reinforced. This may be by the use of thicker threads, as indicated by the thicker lines, or it may be effected by providing two or more threads. On the on hand, reinforcement improves the strength and elastic propertie of the stringer tapes 7» hut on the other hand it also thicken the stringer- tapes 7 near the margins 9? so as to attain an almost uniform thickness over the entire width of the stringer tapes 7. Alternatively, uniform thickness over the entire widt can be obtained by omitting some of the inlaid lapping threads near the middles of the stringer tapes 7, as indicated in Figure 6, In knitting the textile ribbon 1 the individual threads are. laid in accordance with a definite pattern, as shown "by Figure 2+. The code used to describe the lays is interpreted as follows: The combination of digits describes the repeat pattern for each thread lay, which repeats periodically. In the example given, the pattern covers two courses o loops.

The pair of digits, before the oblique stroke specifies how many wales 3 are subtended by the thread in the direction across the textile ribbon 1, moving in both direction within one course of loops; the pair of digits after the oblique stroke specifies the corresponding thread lay in the next ■course of loops along the textile ribbon 1. Figure k- also gives the threading pattern for the lay-strips. The knitted textile -ribbons 1 are preferbaly made with four lay-strips.

The 1st lay-strip works on the U-h/O-0 lay and carries the inlaid lapping threads 6, while the 2nd works on the 2-2/0-0 lay and carries the connecting threads 8. The 3rd lay-strip works on the lay 2-0/0-2, carrying the transverse lapping thread 5» and the th forms the warp chain thread k in the lay 0-1/1-0. The scope for varying the lay of the various threads can be seen by. comparing Figures 1,2,3,5,6 and 9, in which reinforcements are throughout indicated by thicker lines. The, lay 2-2/0-0 or -U/O-Q preferred for the connecting threads 8, because they then run so to speak parallel to the inlaid lapping threads k and are incorporated without difficulty in the fabric. It is however also possible to proceed as in Figure 2, where the connecting threads 9 are adapted as loop-forming transverse lapping threads in the lay 2-0/0-2.

Figure 7 shows; equipment for attaching rov/s of interlocking elements to the interconnected stringer tapes. A feeding device 10 receives "both the rows- 2 of interlocking elements and the . stringer tapes 7, an attachment device 11 in the form of a sewing machine 13, and a take-off device 12.. Two pairs of tapes- 7, all united together "by connecting threads 8 (not shown in the Figure) , are fed simultaneously to the sewing machine 13 "by the feeding device 0, the textile ribbon 1 consisting of the four tapes 7 "being however split by a separato m into the two independent pairs of tapes "before reaching the sewing machine 13. This is necessary in order to prevent the manufacturing- variations across the stringer tapes 7 from havin any adverse effect. In other words, the equipment shown feeds united pairs of the stringer tapes 7 together with the corresponding rov/s 2 of interlocking elements to the respective pairs of neddles of the sewing machine 13y where they are sevm. After sewing, the connecting threads 8 between the stringer tapes 7 are parted and the two stringer tapes 7 in each sliding clasp fastener are separated.

In the transverse, section through a sliding clasp fastener complete with the rows 2 of interlocking elements, shown in Figure.8, the profiled structure of the knitted stringer tapes is shown the individual wales 3 being separated one from the next by inter- ale grooves 15. The sewing threads pass through the grooves- 15 nearest the.' tape margins 9. In this case, the wales- 3 forming the tape margins 9 are displaced, with the tension in the connecting threads 8 increased when the stringer tapes- 7 are knitted, GO that sufficient space is provided in the grooves 15 for insertion of a sewing needle. After sewing, the sewing thread 1-6 is embedded ira the groove 15, effectively out of external contact. After parting of the connecting threads 8, the wales: 3 forming the tape margins 9 move back into place, thereby at least partially covering and protecting the sewing thread 16.

Figure 9 shows the lay pattern for a textile ribbon, in which the stringer tapes comprises holes 20 for securing the rov/s 2 of interlocking elements by insertion, the holes being in ladder-like formation in a loop-free zone 7 that only contains the transverse threads connecting one broad side 18 and one narrow side 19 of the stringer tape. These ladder-like holes 20 are formed by omitting the second warp chain thread k and the first transverse lapping thread 5 on opposing tape margins 9. By strongly tensioning the connecting threads 8, the loop-forming threads are displaced towards the tape sides 18 and 19, broadening the holes. 20 so that the rows. 2 of interlocking elements can be inserted more easily into them. After parting of the sly connecting threads 8 »ηά the holes 20 close up spontaneoui&y and secure the inserted rows; 2 of interlocking elements. This is indicated in Figure 10o .

Claims (3)

P.A. 35.335/11 WHAT WE CLAIM IS:

1. A process for the manufacture of sliding clasp fasteners, in which two rows of interlocking elements in the engaged or disengaged condition are to be attached to two textile stringer tapes, produced simultaneously on one and the same knitting machine to form a single correspondingly wider textile ribbon with separable connecting threads between the tapes, capable of being parted to separate the stringer tapes during or after the attachment of the rows of interlocking elements, characterised thereby that at the margins of the knitted stringers grooves of increased width are produced between two walQs by tensioning sewing the connecting threads and the wi g stitches connectin the sliding clasp elements to the stringers are passed through said widened grooves*

2. * A process as in. Claim 1, characterised thereby that for making stringer tapes on a knitting machine, the stringer tapes being formed from warp chain threads transverse lapping threads, and inlaid lapping threads, the connecting threads are laid as inlaid lapping threads or loop- forming threads, and are fed to a lay-strip with individualised tension*

3. * A process as in Claim 2, wherein the marginal threads of the stringer tapes are reinforced in the warp chain threads, and/or the transverse lapping threads* and /or the inlaid lapping threads. h. A process as in any one of Claims 1 to 3, wherein the inlaid lapping threads extend over at least three and preferably four wales.