Method of manufacturing slide fasteners

Abstract: A method is disclosed for manufacturing slide fasteners from a single homogeneous elongate stringer chain (F) or a stringer chain (F) comprising a plurality of interconnected stringer chains of different characteristics having first standard element-devoid space portions (S₁). The method comprises marking the stringer chain (F) at spaced apart locations by providing second element-devoid space portions (S₂) greater in length than the first standard space portions (S₁) and detecting the second space portions (S₂) to trigger operation of respective operative units in the manufacturing apparatus.

Description: This invention generally relates to a method of manufacturing slide fastener products from an elongate continuous stringer chain and more particularly such a method which enables selective production of slide fasteners of different types, lengths and/or colors during a continuous automatic cycle of operation. This invention particularly relates to a method of manufacturing slide fasteners which comprises the steps of gapping an elongate continuous stringer chain to provide first element-devoid space portions having a standard length at predetermined intervals therealong; selectively feeding and applying various slide fastener component parts onto said stringer chain; and cutting said stringer chain across said element-devoid space portions into individual slide fastener products. There are known certain methods of manufacturing slide fasteners from a continuous stringer chain without interrupting or shutting down the production line. A typical example of such method is disclosed in FR-A-2 634 990 which teaches marking a stringer chain at certain intervals or at defective portions by punching holes which serve as a means of controlling the operation of each of the parts applying units in a slide fastener manufacturing apparatus. Such prior art method has a difficulty in that the punched out holes in the stringer types are prone to get plugged up or otherwise marred by dusts, frayed yarns of the stringer tapes, or other foreign matters, resulting in inaccurate detection of the marks which is usually optically performed. A method of the type mentioned above is disclosed in EP-A-0 181 576. In this prior art method the element-devoid space portions having a standard length are detected by mechanical means associated with an optical sensor. By these detecting means it is detected when a leading end of one of the successive spaced pairs of coupling elements groups is in a separate detecting station fully upstream of the cutting station. In response to said detection the moving rate of the fastener chain is reduced from a high speed to a low speed until a preceding element-free gap section continuous to the leading end of said one pair of coupling element groups arrives at the cutting station. Upon said arrival of said preceding element-free gap section the movement of the fastener chain is terminated and the slide fastener chain is severed transverse across said preceding element-free gap section. With the foregoing difficulties of the prior art in view, the present invention seeks to provide an improved method of manufacturing slide fasteners which will make it possible to produce slide fastener products of different forms, sizes and/or colors from a single continuous elongate stringer chain or a plurality of interconnected stringer chains. The invention further seeks to provide an improved method of manufacturing slide fasteners of the character described in which there is provided a means of detecting the control marks without fail to trigger operation of the respective parts applying units. According to the invention a method satisfying these requirements is characterized in that it further comprises forming a control mark consisting of a second element-devoid space portion having a length greater than that of said first element-devoid space portion at locations spaced apart by predetermined distances along the length of said stringer chain; and detecting said control mark on said stringer chain in ad vance of each of said steps by means of a detector having an operating length corresponding to the length of said control mark. These and other objects and features of the invention will become manifest from reading the following detailed description with reference to the accompanying drawings. Figure 1 is a segmentary plan view of a single elongate stringer chain to be processed; Figure 2 is a view similar to Figure 1 but showing a plurality of interconnected stringers; Figure 3 is a diagrammatic perspective view of a marking means provided in accordance with the invention; Figures 4, 5 and 6 inclusive are segmentary views utilized to explain the operating relation of the detecting means relative to the stringer chain; Figure 7 is a diagrammatic perspective view utilized to illustrate the overall process steps involved in the manufacture of slide fasteners according to the invention; Figure 8 is a segmentary plan view of a stringer chain assembled with bottom end stops; and Figure 9 is a view similar to Figure 8 but showing the stringer chain further assembled with sliders and top end stops. Referring now to the drawings and Figure 1 in particular, there is shown a single continuous stringer chain F which comprises a pair of the same kind of stringer tapes T, T and a row of the same kind of coupling elements E mounted thereon and gapped to provide element-devoid space portions at predetermined intervals. A first space portion S₁, hereinafter referred to as a standard space portion, has a standard length ℓ₁ normally adopted for determining a given product length of an individual slide fastener. The first space portion S₁ is formed by removing a corresponding length of a row of interengaged coupling elements E from the tapes T, T at locations spaced apart by predetermined distances along the length of the chain F by means of a gapping device 11 shown in Figure 7 which essentially comprises a punch 11a and a die anvil 11b, the punch 11a having an operating length corresponding to the standard space portion S₁. A second space portion S₂, hereinafter referred to as a control mark, has a length ℓ₂ greater than that ℓ₁ of the standard space portion S₁ and hence can be formed by the same gapping device 11; that is, by actuating the punch 11a twice or thrice to provide the space length ℓ₂ at locations spaced a predetermined distance apart along the length of the chain F. In the embodiment shown in Figure 1, there are two neighboring control marks S₂, S₂ spaced apart from each other longitudinally of the stringer chain F across a demarcating element zone Ea formed by a predetermined length of a row of coupling elements E. In the embodiment shown in Figure 2, the two neighboring control marks S₂, S₂ are spaced apart across a connecting strip C spanning the width of the tapes T, T, and interconnecting adjoining stringer tapes T, T which are different in for instance color, size and/or material. When changing the lengths or styles of individual slide fasteners to be produced from a single homogeneous stringer chain, this may be done with a single control mark S₂ consisting of a space portion longer than the standard first space portion S₁ and located where such change is desired. Figure 3 shows a control mark detector 100 which comprises a pair of vertically disposed first and second levers 101 and 102 which are mounted on a carrier 103 in spaced apart relation longitudinally of the stringer chain F and pivotable about their respective pins 104 and 105. Each of the levers 101 and 102 has a shank 106, (107) at its lower end and a probing roll 108, (109) rotatably connected thereto. Springs 110 and 111 are connected to the upper portions of the respective levers 101 and 102 and adapted to normally urge the respective rolls 108 and 109 against the interengaged rows of coupling elements E. Designated at 112 and 113 are projecting lugs extending laterally from the upper ends of the respective levers 101 and 102 and adapted to engage respective microswitches 114 and 115 when the probing rolls 108 and 109 are brought into engagement with the second space portion or control mark S₂ in a manner hereinafter described. The levers 101 and 102 are spaced from each other by a distance corresponding to the length ℓ₂ of the control mark S₂ such that both of the microswitches 114 and 115 are actuated when both of the two rolls 108 and 109 are simultaneously located in and at the control mark S₂ as shown in Figure 4. With advancing movement of the chain F, the probing roll 108 of the first lever 101 reaches the control mark S₂, causing the lever 101 to make a pivotal movement about the pin 104 and hence the lug 112 to contact the microswitch 114. A similar action is followed by the second lever 102. And, as both of the rolls 108 and 109 come into engagement with the control mark S₂, both microswitches 114 and 115 are turned on simultaneously, whereupon a parts applying unit immediately downstream of the detector 100 is triggered to perform its work according to a computer program which has been compiled to effect a predetermined mode of operation of the apparatus. An optical detection means may be alternatively used to detect the control mark S₂. Figures 5 and 6 illustrate a stringer chain F having a standard space portion S₁ smaller in length than the control mark S₂. Due to the standard space portion S₁ being shorter, there is no instance in which the two rolls 108 and 109 are located simultaneously in and at the control mark S₂ to actuate the two microswitches 114 and 115 at the same time. Therefore, there is no risk of erroneous detection of the control mark S₂, or malfunction of the apparatus. Turning to Figure 7, there is shown an overall assembling apparatus 10 for manufacturing slide fasteners of different product characteristics from the stringer chain F. The apparatus 10 comprises a gapping unit 11, a bottom end stop applying unit 12, a slider applying unit 13, a top end stop applying unit 14, and a cutting unit 15. The starting stringer chain F supplied from a source not shown is metered by a metering roll assembly 16 which meters the length of the chain F by counting the number of revolutions for instance of a roll 16', and the feeding of the stringer chain F is arranged to stop upon completion of a predetermined number of revolutions of the roll 16'. A reserve vessel V is provided for storing a plurality of stringer chains F of different sizes and product characteristics which have been metered and fed from the metering assembly 16. The chain F is advanced by feed rolls 17 into the gapping unit 11, which essentially comprises a punch 11a and a die anvil 11b disposed in confronting relation to each other, and gapped at a predetermined position to remove a length of coupling elements E thereby providing the first or standard element-devoid space portion S₁ as well as the second space portion or control mark S₂ at predetermined intervals as already described. The control mark detector 100 is located upstream of the bottom end stop applying unit 12 and adapted to detect the control mark S₂ in a manner described hereinabove, thereby triggering operation of a bottom end stop feeder 19 to supply a new or selected set of end stops Be differring in form and/or color from a previous inventory of end stops. The stringer chain F, upon attachment with the end stop Be as shown in Figure 8, continues to advance until the control mark S₂ is detected by another detector 100' upstream of the cutting unit 15, whereupon the subsequent slider and top end stop applying units 13 and 14 are triggered to apply a new or selected slider D and top end stop Te from a slider feeder 20 and a top end stop feeder 21, respectively in a manner well known in the art and as shown in Figure 9. The stringer chain F thus assembled is cut by the cutter 15 across the standard space portion S₁ to provide an individual slide fastener product F' as shown in Figures 9 and 7.

Claims: A method of manufacturing slide fasteners (F') which comprises the steps of gapping an elongate continuous stringer chain (F) to provide first element-devoid space portions (S₁) having a standard length (l₁) at predetermined intervals therealong; selectively feeding and applying various slide fastener component parts onto said stringer chain (F); and cutting said stringer chain (F) across said element-devoid space portions (S₁) into individual slide fastener products (F') characterized in that the method further comprises: forming a control mark consisting of a second element-devoid space portion (S₂) having a length (l₂) greater than that (l₁) of said first element-devoid portion (S₁) at locations spaced apart by predetermined distances along the length of said stringer chain (F); and detecting said control mark (S₂) on said stringer chain (F) in advance of each of said steps by means of a detector (100, 100') having an operating length corresponding to the length (l₂) of said control mark (S₂). The method claimed in claim 1 characterized in that a plurality of said control marks (S₂) are spaced apart from each other across a demarcating element zone (Ea) formed by a predetermined length of a row of coupling elements (E). The method claimed in claim 1 characterized in that a plurality of said control marks (S₂) are spaced apart from each other across a connecting strip (C) interconnecting adjoining stringer chains (F). The method claimed in claim 1 characterized in that said stringer chain (F) is a single continuous elongate stringer chain of the same characteristics. The method claimed in claim 1 characterized in that said stringer chain (F) comprises a plurality of interconnected stringer chains of different characteristics.

Inventors: ITO TATSUO, KUSE KAZUKI, YAMAZAKI MAKOTO, ITO, TATSUO, KUSE, KAZUKI, YAMAZAKI, MAKOTO
Applicants: YKK CORP, YKK CORPORATION
Application year: 1991
Main classification: A44B19
IPC codes: A44B19