METHOD FOR THE PRODUCTION OF THE HOOK COMPONENT OF A HOOK OR CLASP FASTENER

Abstract: A method is proposed for the production of the hook component of a hook or clasp fastener, according to which at least two support layers (T1, T2) facing each other are linked together by means of lengths of monofilament (M), said monofilament lengths are shaped by Z- or S-bending, the so bent lengths are thermofixed and are finally cut in a central zone of them. At least two support layers provided with hooks on at least one of their faces are thus obtained.

Description: Ilethod for the production of the hook coaponnent of a hook or clas-o fastener The present invention relates to a method for the production of the hook component of a fastener of the so called hook or clasp type, with woven or not woven sup¬ port, serving for the grasping with the other component, provided with ring-shaped extensions. Fasteners provided with woven hooks are already known, wherein such hooks are accomplished by forming, during the weaving, with synthetic monofilament, rings of suitable section, protruding from the support fabric, which are then, cut, after prior thermofi xing, in a proper position, thus being transformed into the desired hooks. This method can only be implemented by means of the use of a particular textile pattern, denominated "English pattern" allowing the rings of monofilament to be formed around blades acting as forming mandrels, and which ex¬ tend longitud nally along the direction of the warp from a position on the loom rearwards to the heald frames, where the mandrels are fastened, up to a front position wherein the tape is already formed, and wherein the rows of rings come out from such mandrels, passing though the teeth of the reed and the point of fabric formation. In order to execute this English pattern, applying to the heals special stitches, designed to that purpose, is necessary, such stitches showing the drawback, because of a a series of reasons, deriving both from their shape, and from the implicit need of operating with very long heal strokes, of imposing operating at very reduced speeds. In the case of the modern needle looms for tapes, designed for production speeds of about 3000 rpm, this means reducing their production capability by at least 50%. The same product shows the appendices of the rings cut, which cannot be used, by not forming part of the hook: these appendices not only partly hinder a greater and more complete penetration of the same hooks into the rings of the conjugated compoirent, but result, on the end product, a useless material only conferring weight, and hence causing a greater cost. Purpose of the present invention is hence providing a production method which, while maintaining the good characteristics of the hereinabove mentioned method, eliminates on the contrary the inherent defects as for the product and the productivity limitations of the ma¬ chinery. The purpose " is achieved, according to the present invention, by a method which, by not providing the forma¬ tion of the rings, not only is not concerned by the speed limitations inherent in the "English pattern" system, but provides also the formation of a sandwich of two or more support elements linked by rows of lengthes of monofila- ment suitably shaped by bending which, after a preliminary thermofi xing, are subsequently cut in correspondence of their most suitable position thus providing, from one single production equipment, two or more hook fastener components . In particular, the method according to the invention is characterized in that it comprises the operations of linking to each other by means of rows of lengthes. of monofilament at least two support layers facing each other, of shaping said monofilament lengthes into Z- or S-shapes by bending, of thermofixing said so-shaped mono¬ filament lengthes and of cutting the so-shaped monofila- ment lengthes in correspondence of a central zone there¬ of, to obtain at least two separate support layers pro¬ vided with hooks on at least one of their faces. The said support layers can be constituted by one single layer folded on itself, or by a flattened tubular e lement . An exemplifying form of embodiment of the production method according to the invention uses, for its practical embodiment, a normal weaving loom, of the shuttle or of the needle type, preset, according to known techniques, for the production of two or more superimposed support fabrics, linked to each other, always by means of known techniques, such as, e.g., from the production of vel¬ vets, by the whole set of the lengthes of monofi laments destined to form the hooks, extending along the direction of the warp. The bending of the lengthes of monofilament recti- linearly extending between the one support fabric and the other, to the purpose of arri ing to a Z- or S-shaped configuration, necessary, after the preliminary cutting of the intermediate portion, to achieve from them the end hooks, can be obtained, in a possible form of embodiment of the method, by means of two blades or mandrels which extend, more or less as the blades or mandrels of the hereinabove described known method, from a rear point to a front point of the loom, remaining on both sides of each one of the rows of the same monofilament lengthes, up to at least the point immediately following that wherein the fabric is formed: from this point on, the blades of mandrels cross each other, and oblige, by being suitably shaped, thanks to the advancing motion of the same fabric, the rectilinear lengthes of monofilament extending between the two fabrics, to assume a Z- or S- shape, said two fabrics being kept at mutual proper distance by guide plates. More particularly, a possible embodiment of the method envisages the use of an equipment comprising a weaving loom suitable to manufacture tapes or wide fab¬ rics (these latter could be later on advantageously cut lengthwise to obtain from them tapes of the desired width), provided with means for the supply of synthetic monofi laments intended to form the hooks, with blades or mandrels, in a number of two pieces for each synthetic monofilament used to form the hooks, extending parallely to the direction of the warp yarns at least over a cer- tain length above the loom weaving rail, with guide plates to keep said tapes or fabrics pressed against said blades and with means suitable (according already known systems) to bring said synthetic monofi laments alternati¬ vely to opposite sides of the warp mouth, accordin-g to predetermined sequences. The blades or mandrels, thanks to whose action, coadiuvated by said guide plates, the rectilinear mono¬ filament turn into the Z- or S-shape, can be made from any materials having the necessary stiffness to oblige the monofi laments to assume the desired shape, and the necessary wear strength, which allows the rubbing, on their surface, of the monofi laments, without that they are damaged within too short time. To exemplifying pur¬ poses, they can be constituted by steel blades of suita- ble thickness. The equipment can finally be provided with means suitable to heat the fi lament lengthes already bent to the Z- or S-shape, while they are still located between the guide plates and the bending mandrels, to the proper temperature and for the time necessary for a good thermo- fixing. Other possible forms of embodiment of the production method according to the invention may envisage individual and separate equipment pieces for the implementing of the individual operating steps, and namely, the production of the supports, their linking by means of monofi lament lengthes, the shaping of these latter into Z- or S-shape, the related thermofixing and the end cutting. The invention shall be disclosed hereunder in great¬ er detail, with reference to the attached drawings, i l- lustrating, to exemplifying and not limitative purpose, in a schematic form, elements of a component of hook fastener produced according to the invention, and various steps of the production method and part of a machinery piece for the accomplishment thereof. Fig. 1 is a schematic view of two conjugated ele¬ ments of a hook fastener of known type. Fig. 2 is on the contrary the schematic view of two conjugated elements of a hook fastener, whose hook compo¬ nent is produced according to the present invention. Fig. 3 is a side view of a length of a form of embodiment of a blade or mandrel for the bending of the monofi lament lengthes. Fig. 4 is a perspective view of a couple of layers or mandrels according to Fig. 3, cooperating to the purpose of bending the monofilament lengthes. Fig. 5 is a schematic view of the couple of blades or mandrels of Fig. 4, during the bending operation: Fig. 6 shows the bending operation in side view. Fig. 7 is a sectional view taken along the path VII- VII of Fig. 6. Figs. from 8 to 11 are sectional views respectively taken along the paths VIII-VIII, IX-IX, X-X and XI-XI of Fig. 6. Fig. 12 is a perspective view of a couple of blades or mandrels for the bending of the monofilament lengthes in a second form of embodiment. Fig. 13 shows, in side view, the operation of bend¬ ing as carried out by a couple of blades such as that of Fig. 12. Figs. 14, 15 and 16 are sectional views respectively taken along the lines XIV-XIV, XV-XV and XVI-XVI of Fig. 13. Fig. 17 represents the sequence relating to the cutting of a length of monofilament bent into vertical Z- or S-shape for the obtainment of two hook elements. Referring to Figs. 1 and 2, in them the difference is shown between two conjuagted elements of a hook fas¬ tener of known type, wherein the hooks are obtained from cut rings (Fig. 1), and those of a fastener, the hooks of which are obtained according to the invention (Fig. 2): by comparing the two figures, it can be noticed how from an analogous woven or non-woven support 1 and 1*, hook- shaped monofilament lengthes 3 and 3'protrude outward, but in Fig. 2 the appendix 2, not used and completely useless to the purpose of the functionality of the same fastener, present in Fig. 1, is on the contrary totally absent. The dimensions and the structure of the support 1' and the number, the density and the mutual positioning of the rows of hook elements 3' can be varied as desired. It results however clear, always from the comparison of Fig. 1 and of Fig. 2, how, due to the fact that the hook elements 3 and 3' have to clasp to the rings 4 and 4' of another fabric or support, a hook like that of Fig. 2, without the appendix 2, shall be much more facilitated in such an operation, apart from considering that the appendix 2, with the portion interlaced in the fabric corresponding to it, constitutes a weight, and hence a totally useless monofilament cost. The following figures disclose more specifically the method and an equipment necessary to achieve the product of fig. 2. Fig. 3 shows a portion of blade or mandrel A, ac¬ cording to a possible profile thereof. In Figs. 4, 5, 6 and 7, two mandrels A and A', having a profile according to Fig. 3, are conjugated to provide an equipment which, according to the proposed method, shall form the monofi laments M into a vertical Z- or S-shape. By the fabric being formed moving to the direction of the arrow, the following steps can be noticed: 1) The fabric is formed in the portion where the mandrels A and A* are wider and the distance h between the two fabrics T. and T_ determines the length of the 1 2 vertical lengthes of monofilament M linking the said fabri cs. 2) From the point 5 and respectively 5' of the mandrels A and A', the distance between the fabrics shall start decreasing, to allow the lengthes of monofilament M to bend, helped in that by the action of the stationary guide plates P and P along whose profile the fabrics T and T are obliged to slide. The surfaces of the mandrels A and A', forcing the monofilament to bend, are those from 8 to 10 and from 8" to 10' : such inclined-plane surfaces, combined with the crossing of mandrels A and A', force indeed the monofi lament lengthes to slide along them during their forwards running, arriving to their maximum bending at the points 10 and 10' . On the outer surfaces, to these points the points 6 and 6' correspond, which are the beginning of the step in which the fabrics J _ and T„ are at their minimum mutual distance h _ . From 1 2 1 this point, the necessary thermofixing step can begin of the lengthes of monofi lament M in their end vertical Z- or S-shape. In Figs. from 8 to 11, the various steps can be clearly seen, in orthogonal section, through which a length of monofilament passes to reach its end shape. Figs. 12 and 13 show another form of embodiment of an equipment to achieve the same results of the method according to the present invention: it can be clearly seen how the coupling of two mandrels B and C of differ¬ ent shape can lead to the same results, very clearly evidenced by the three orthogonal sections of figs. 14, 15 and 16. In this case, to the mandrel C, provided with a side flange D, the very bending task is committed, whi lst the mandrel B, which from a certain point on runs under the flange D, acts mainly as a guide for the monofi lament lengthes. The bending operation begins at the point 12, which is the beginning of the inclined plane of the flange D of mandrel C, and ends at the point 13, wherein the monofilament length reaches its end vertical Z- or S- shaped configuration. This operation is still helped by the two stationary guide plates P, and P_, which force 1 2 the fabrics T and T to come from their mutual initial distance h to their end distance h„. 1 From the examination of all figures, it can be seen how a possible equipment for the implementing of the proposed method may consist of a loom, or of any machine suitable to produce two supports linked by lengthes of monofilament of a material suitable to be formed into a vertical Z- or S- shape in a subsequent step. Such machine or loom shall be provided with means suitable to support the blades or mandrels around which the monofilament is being shaped. Such mandrels shall remain stationary, while the fabric or support with the related monofi laments shall run to the direction as indi¬ cated by the arrows. The equipment shall hence envisage, until the man¬ drel remain inside the interior of the sandwich and around them the monofilament remains shaped, a system suitable to thermofix the monofi laments in their posi¬ tion as reached. Only when such a thermofixing shall have occurred, indeed, even with the mandrels being slipped away, the vertical Z- or S-shape of the monofilament shall be maintained. From this moment, by cutting the so shaped monofi laments in the central portion of their length, either on the same equipment, or on another piece of machinery separated from it, two supports shall be obtained, so as it is schematically evidenced in the sequence of Fig. 17, each one provided with the desired hook elements. This latter cutting operation does not pose any particular problems: the same monofilament used for such hook or clasp fastener type is by definition provided with great elasticity and hence with the capability of returning, after the deformation, to its initial shape. It shall hence be enough to stretch the monofi laments, to render them more or less rectilinear, by moving away the tapes, and cut them at their intermediate point. By they returning to their shape given them by thermofixing, the two supports provided with the desired hook-shaped ele¬ ments shall be obtained.

Claims: £_._.__.__.______§ 1. Method for the production of the hook component of a hook or clasp fastener, characterized in that it comprises the operations of linking to each other by means of rows of lengthes of monofilament, at least two support layers facing each other, of shaping said mono¬ filament lengthes into Z- or S-shapes by bending, of thermofixing said so-shaped monofilament lengthes and of cutting the said lengthes in a central zone thereof to obtain at least two separate support layers provided with hooks on at least one of their faces. 2. Method according to claim 1, characterized in that there are linked to each other, by means of rows of lengthes of * monofi lament, at least two support layers constituted by one single layer folded on itself. 3. Method according to claim 1, characterized in that there are linked to each other, by means of rows of lengthes of monofilament, at least two support layers constituted by a flattened tubular element.

Inventors: MOTTA CARMELO, MOTTA, CARMELO
Applicants: MOTTA CARMELO, MOTTA, CARMELO
Application year: 1986
Main classification: A44B18
IPC codes: A44B18