METHOD FOR PRODUCING SLIDE FASTENER STRINGER HAVING COLORED METAL ELEMENT, METAL ELEMENT, SLIDE FASTENER STRINGER AND SLIDE FASTENER CHAIN

Abstract

This method for producing a slide fastener stringer having a colored metal element involves: forming a plurality of slide fastener elements fabricated from a metal material; preliminarily performing a surface-roughening treatment on the elements; forming one or more corrosion resistance layers on one or more roughened surfaces of the elements; forming one or more coating layers for covering the corrosion resistance layers; and attaching the teeth to a tape.

Claims

1. A method of manufacturing a slide fastener stringer with colored metal elements, the method comprising: forming a plurality of elements for a slide fastener from a metal material; subjecting the elements to a preliminary surface roughening process; applying at least one anti-corrosion layer on at least one roughened surface of the elements; applying at least one paint layer covering the anti-corrosion layer; and attaching the elements to a tape.

2. The method of manufacturing according to claim 1, wherein the preliminary surface roughening process includes a blasting step, and wherein the blasting step is or includes a step selected from a group comprising a shot peening, a sand blasting, a shot blasting, a steel ball shot blasting, and a wet blasting.

3. The method of manufacturing according to claim 1, wherein the plurality of elements are formed from a copper-zinc alloy.

4. The method of manufacturing according to claim 1, wherein the anti-corrosion layer is a plate layer including copper, tin, and zinc.

5. The method of manufacturing according to claim 1, wherein the step of applying the anti-corrosion layer is followed by a step of applying a coloring backing layer of finishing.

6. The method of manufacturing according to claim 5, wherein the coloring backing layer is a plate layer including tin and cobalt.

7. The method of manufacturing according to claim 5, wherein after the step of applying the coloring backing layer, the paint layer is applied and formed multiple times.

8. The method of manufacturing according to claim 1, wherein the paint layer is black.

9. The method of manufacturing according to claim 1, wherein a final step of applying at least one layer of lacquer may be applied to the elements.

10. A metal element for a slide fastener, the metal element comprising: a body made of a metal material; at least one roughened outer surface subjected to a preliminary surface roughening process; at least one anti-corrosion layer on the at least one roughened outer surface of the metal element; and at least one paint layer covering the anti-corrosion layer.

11. The metal element according to claim 10, wherein the metal element includes copper and zinc.

12. The metal element according to claim 10, wherein the anti-corrosion layer is a plate layer including copper, tin, and zinc.

13. The metal element according to claim 10, wherein at least one coloring backing layer is formed between the at least one anti-corrosion layer and the at least one paint layer.

14. The metal element according to claim 13, wherein the coloring backing layer is a plate layer including tin and cobalt.

15. The metal element according to claim 10, wherein the paint layer is black.

16. The metal element according to claim 13, wherein a plurality of recesses are formed on the roughened outer surface of the metal element by the preliminary surface roughening process, and wherein the at least one anti-corrosion layer, the at least one coloring backing layer, and the at least one paint layer are formed inside the plurality of recesses.

17. A slide fastener stringer comprising: a slide fastener tape; and a row of metal elements attached to an edge portion of the slide fastener tape, wherein the slide fastener stringer is manufactured through the method of manufacturing according to claim 1.

18. A slide fastener chain; comprising: the slide fastener stringer of claim 17, wherein: the slide fastener tape comprises: a left fastener tape extending in a longitudinal direction; a right fastener tape extending in a longitudinal direction; and the row of metal elements comprises: a left row of metal elements attached to an edge portion of the left fastener tape; and a right row of metal elements attached to an edge portion of the right fastener tape, the left row of metal elements and the right row of metal elements engageable with each other.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0038] FIG. 1 is a schematic elevational view of a slide fastener with stringers manufactured in accordance with the present invention.

[0039] FIG. 2 is a schematic perspective view of an exemplary element or fastener element included in a stringer according to the present invention.

[0040] FIG. 3 is a perspective view of an exemplary elongate metal wire member from which individual elements may be cut to be attached to a tape.

[0041] FIGS. 4 (a) to (f) of FIG. 4 are schematic diagrams for illustrating the processes applied to a surface of the element.

DESCRIPTION OF EMBODIMENTS

[0042] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is however not limited to the embodiments disclosed in the following, and various changes can be made as long as substantially the same or similar configuration and the same function and effects as the present invention are provided, within the scope of the annexed claims.

[0043] A slide fastener 100 shown in FIG. 1 has a left and right pair of fastener stringers 30, and a slider 40 for opening and closing the left-right pair of fastener stringers 30. Frontward movement of the slider 40 opens the left-right fastener stringers 30, and rearward movement of the slider 40 closes the left-right fastener stringers 30. A front-rear direction corresponds to a direction of movement of the slider 40. A left-right direction indicates a direction of side-by side arrangement of fastener stringers 30. The left-right direction is orthogonal to the front-rear direction. Up-down direction is orthogonal to the front-rear direction and the left-right direction.

[0044] Each fastener stringer 30 has a fastener tape 10, and a plurality of elements (or fastener elements) 20 attached to a side-edge portion of the fastener tape 10. The fastener tape 10 of each one of the left-right fastener stringers 30 has a side-edge portion that is opposed to the fastener tape 10 of the other one of the left-right fastener stringers 30. The plurality of elements 20 are attached to this side-edge portion.

[0045] In some embodiments, the elements 20 may be manufactured through a step of die-cutting a metal plate. The die-cutting step is performed by using a punch having an outer shape corresponding to the outer shape of an element 20.

[0046] In other embodiments, the elements 20 may be manufactured through a step of cutting, by a cutter at a length corresponding to a thickness of an element 20, a metal wire or profile 70 (FIG. 3) that has a transversal cross-sectional shape corresponding to the cross-sectional shape of an element.

[0047] Subsequently, each element obtained by the die-cutting of metal plate or the cutting of the metal wire 70 may be pressed, if necessary. Then, after passing through at least steps of plating and coating, the elements 20 may be attached to the side-edge portion of the fastener tape 10 by a crimping apparatus. At the time of this attachment, the elements 20 will be plastically deformed.

[0048] In still other cases, the elements 20 may be attached to the fastener tape 10 in arbitrary way, then the elements 20 are plated and coated.

[0049] The fastener tape 10 may be woven or knitted together fabric, for example, having a flexibility. The element 20 shown in FIG. 2 is exemplary. The element 20 has a pair of legs 211, 212, which sandwich the side-edge portion of the fastener tape 10 or a cord provided there or both of them, as schematically shown in FIG. 2, and an engagement head portion 213 coupled to the pair of legs 211, 212. The above-mentioned crimping apparatus operates so as to reduce a spacing between the pair of legs 211, 212, thereby an element 20 may be attached to the side-edge portion of the fastener tape. The engagement head 213 is provided outwardly of fastener tape relative to the pair of legs 211, 212. Outwardly of fastener tape indicates a left-right direction directed from a point or position on the side-edge portion of a fastener tape to a point or position external of the fastener tape in a plane where the fastener tape exists. Inwardly of fastener tape indicates a direction opposite to the left-right outward direction.

[0050] In a per se known manner, the edge of the tape onto which the elements are attached may incorporate, for instance by weaving, a cord (not shown) which protrudes substantially out of the plane of the tape and also providing a transverse protrusion, which enables the elements to obtain a firm grip when crimped to the side-edge portion of the tape and the cord.

[0051] The engagement head 213 of the element 20 has at least one engaging projection 214 being projected frontward and/or rearward and at least one correspondingly sized recess 216 adapted to receive an engaging projection 214 of an element mounted to the opposite stringer. As known, in the closed condition of a slide fastener, an element of one of the left-right fastener stringers is inserted into a space between adjacent elements in front-rear direction of the other one of the left-right fastener stringers. The engaging projection 214 of a certain element is fitted to a recess 216 of a first element on the opposite stringer, and the recess 216 of that certain element receives an engaging projection 214 of a second element, which is on the opposite stringer and is adjacent to the first element on that opposite stringer in a front-rear direction.

[0052] The specific design of the element should not be construed as limiting the scope of the patent, as metal elements of any design may be treated in accordance with the method described herein.

[0053] The element has a body made of metal, preferably a metal or a metal alloy being relatively soft from a view point of workability. In some cases, the body of the element may be made out of a single metal. The exemplary single metal may be iron (Fe), or zinc (Zn) or aluminum (Al). In some other cases, the body of the element may be made of an alloy that includes a plurality of metal teeth, for example copper-zinc or brass alloys (CuZn), copper-zinc-nickel alloys (CuZnNi), red brass (CuZnSnPb) or copper-zinc-manganese alloys (CuZnMn). In a case where the body (base material) of the element 20 is made of a copper-zinc alloys including copper and zinc, the appearance thereof is made gold.

[0054] According to an aspect of the present invention, prior to treating the elements with a series of finishings, as describer hereinafter, the elements are subjected to a preliminary surface roughening process which includes a step of blasting, that roughens smooth surfaces of the element in order for it to better retain finishing layers applied to the element in subsequent finishing steps. Owing to this preliminary roughening treatment, the element provides more surface area having very small recesses, created by the blasting step, on which various subsequent treatments can be applied and, as a result, more color bearing material can be applied to the element.

[0055] (a) to (f) of FIG. 4 are schematic diagrams for illustrating the processes applied to a surface of the element. As shown in (a) of FIG. 4, the surface 21 of the element 20 before the roughening treatment is applied thereto has a smooth flat shape.

[0056] As shown in (b) of FIG. 4, by applying the roughening treatment to the surface 21 of the element 20, the surface 21 becomes a roughened outer surface 23. The roughened outer surface 23 has a plurality of recesses 25 formed by the blasting step, and a protrusion 27 formed between the adjacent recesses 25.

[0057] Preferably, the blasting step is or includes a shot peening step, which entails striking the outer surfaces of the element with a stream of metallic, glass, or ceramic particles, balls or pellets, with a force sufficient to create plastic deformation in the outer surfaces of the elements. Round metallic balls, for example made of lead (and known as shot), may be used.

[0058] Shot peening, which is a cold working process conventionally used to produce a compressive residual stress layer and modify the mechanical properties of metals and composites, is particularly preferred. Experimental tests carried out by the applicant have revealed that shot peening does not encourage surface cracks, while roughening the surfaces.

[0059] As an alternative, or in addition to shot peening, the blasting step may include a sand blasting step, which includes the operation of forcibly propelling a stream of abrasive material against surfaces of the element under high pressure. The blasting step may include shot blasting, or steel ball shot blasting, or wet blasting.

[0060] Embodiments of the present invention may provide that the elements are made and then subjected to the preliminary roughening process individually. In these cases, the elements are made by pressing from a metal sheet, die casting or other convenient method and then subjecting them to the preliminary roughening step. According to these embodiments, the blasting step will roughen the whole of the outer surfaces of each element.

[0061] Excellent results, in terms of durability of colored paint applied over the elements after subjecting them to the finishing steps discussed herein after, have been accomplished by the applicant through experimental tests carried out on five samples of elements that had an average surface roughness Sa of 1.00 ?m prior to the roughening step, which increased to 1.22 ?m after a shot peening step. Further, the average linear roughness Ra increased from an average value of 0.39 ?m with no treatment to an average value of 0.93 ?m after the shot peening step.

[0062] After the roughening treatment, the element may then be cleansed from any debris that might remain from the surface roughening process via washing and drying or other appropriate method and the element is then treated with a series of finishings.

[0063] A first finishing treatment includes the application of at least one anti-corrosion layer at least on the roughened surface of the element. Preferably, the anti-corrosion layer is a plate layer of a copper, tin and zinc alloy, often know as white bronze, which has the primary purpose of resisting corrosion and strengthening the surface of the element. This anti-corrosion layer also hides the original surface color of the elements which may be more reflective or otherwise visible if paint is scratched off.

[0064] If the body of the element is made of an alloy including copper and zinc and is gold, and the paint layer described later is black, the anti-corrosion layer is preferably a white bronze, intermediate between the gold and black. Therefore, the anti-corrosion layer is preferably a plating layer including copper, tin, and zinc to be a white bronze in appearance. This configuration can make the gold of the body of the element less noticeable.

[0065] As shown in (c) of FIG. 4, by applying the anti-corrosion layer 50 to the roughened outer surface 23 of the element 20, the entire roughened outer surface 23, i.e., the plurality of recesses 25 and the protrusion 27, is covered by the anti-corrosion layer 50. In particular, because the anti-corrosion layer 50 is formed inside the recesses 25, which are located deep from the outside, wear of the anti-corrosion layer 50 inside the recesses 25 is suppressed even when the slider passes through. Therefore, even if the anti-corrosion layer 50 on the protrusion 27 is peeled off due to wear, the anti-corrosion layer 50 inside the recess 25 will not peel off.

[0066] Next, a second, optional coloring backing layer of finishing may be applied which may contribute to the desired final color. If, for example, it is desired to create elements colored black (the paint layer described later is black), a black plating layer (coloring backing layer) of a tin-cobalt alloy may be applied. If the coloring backing layer is black, the appearance of the element can be maintained in black even if the black paint layer described later peels off. Other options are well known to those skilled in the art. The shades of this backing layer may also contribute to darkening or lightening a top color.

[0067] As shown in (d) of FIG. 4, by applying the backing layer 60 to the element 20, the entire anti-corrosion layer 50 on the roughened outer surface 23 (on the recess 25 and the protrusion 27) is covered by the backing layer 60. In particular, since not only the anti-corrosion layer 50 but also the backing layer 60 is formed inside the recess 25, which is located deep from the outside, wear of the anti-corrosion layer 50 and backing layer 60 inside the recess 25 is suppressed even when the slider passes through. Therefore, even if the anti-corrosion layer 50 and the backing layer 60 on the protrusion 27 are peeled off due to wear, the anti-corrosion layer 50 and the backing layer 60 inside the recess 25 will not peel off.

[0068] Subsequently, at least one paint layer, preferably a plurality of colored coatings, for example five or more coatings is applied to cover the anti-corrosion layer. The paint layer bears the color. Any appropriate paint or combination of paints such as natural or synthetic resin-based paints may be selected and applied according to the desired color and finish. For example, lacquer, fluoropolymer or ceramic based paints may be selected. Needless to say, if it is desirable to create elements with a black appearance, a black paint layer is applied.

[0069] As shown in (e) of FIG. 4, the paint layer 80 is applied and formed on the element 20 multiple times, so that the entire anti-corrosion layer 50 and the backing layer 60 on the roughened outer surface 23 (on the recess 25 and the protrusion 27) are covered by the paint layer 80. By providing such a paint layer 80, the anti-corrosion layer 50 and the backing layer 60 on the inner side with respect to the paint layer 80 are protected and abrasion is suppressed. In particular, since not only the anti-corrosion layer 50 and the backing layer 60 but also the paint layer 80 is formed inside the recess 25, wear of the anti-corrosion layer 50, the backing layer 60, and the paint layer 80 inside the recess 25 is also suppressed when the slider passes through. Therefore, even if the anti-corrosion layer 50, backing layer 60, and paint layer 80 on the protrusion 27 are peeled off due to wear, the anti-corrosion layer 50, backing layer 60, and paint layer 80 inside the recess 25 will not peel off.

[0070] As shown in (f) of FIG. 4, a clear coating film 90 is applied and formed on element 20, so that the entire anti-corrosion layer 50, backing layer 60, and paint layer 80 on the roughened outer surface 23 (on the recess 25 and the protrusion 27) are covered by the clear coating film 90. The clear coating film 90 protects the anti-corrosion layer 50, the backing layer 60, and the paint layer 80 below the clear coating film 90 and suppresses abrasion. The clear coating film 90 is a transparent coating film, and its composition is not limited and known materials can be used. For example, the clear coating film 90 may be made of epoxy, acrylic, urethane, alkyd, or other known resin materials. Since the clear coating film 90 is transparent, the appearance of the element 20 presents the color of the paint layer 80 (e.g., black).

[0071] Then the elements may be attached to a tape in a row to form a slide fastener stringer. If the elements are manufactured by an elongate wire member (FIG. 3), this needs to be cut, separating individual elements to be attached to the tape.

[0072] The step of forming a clear coating film on the element as shown in (f) of FIG. 4, does not necessarily have to be done before the element is attached to the tape, but may be done after the element is attached to the tape.

[0073] On the other hand, the processes as shown in (a) to (e) of FIG. 4 for roughening and forming the anti-corrosion layer, the coloring backing layer, and the paint layer are all performed before the element is crimped to the fastener tape. In other words, the above treatment (surface) layers are treated uniformly over the entire element, including the inner side of the leg that is in contact with the fastener tape.

[0074] Optionally, after attaching the elements to a tape, the elements of the resulting stringer may receive one or more layers of a hot-melting coloring material, as disclosed in the specification of CN105831899A and the specification of IT2015TO00072A, which are incorporated herein by reference. Specifically, at least one layer of a hot-melting coloring material may be thermally transferred from a carrier onto a respective surface portion of the elements, which extends on one side of the tape, thereby leaving a further layer of color on either the upper surface, the lower surface or the upper and lower surface of the attached elements.

[0075] Finally, and preferably, a layer of lacquer may be applied to the elements, after attaching the elements to the tape, to protect the color and aid the running of the slider. The layer of lacquer is preferably transparent.

[0076] According to other embodiments, the elements may be cut from an elongate metal wire member having a transversal cross-sectional shape corresponding to a cross-sectional shape of an element for a slide fastener and being configured to be separated into individual elements to be later attached to a tape. At least one outer surface of the elongate metal wire member is subjected to the preliminary roughening process and to one or more of the subsequent finishing steps as described herein above, prior to being cut into individual elements which are finally attached to a tape in a row to form a slide fastener stringer. With the preliminary roughening process being applied to the wire, when it is subsequently cut, the cut sides do not have roughened surfaces, as the side surfaces will not have existed during the roughening process. The cut sides will form the sides of the elements, that is the parts of the element that face the surface of a neighboring element on the same tape. It will be appreciated that the effects of the roughening treatment will be provided on at least the surfaces of the elements that are more visible once the elements are applied to a tape to form a chain, that including a side that will face the outside of the article to which the elements will be attached.

[0077] The methods disclosed hereinabove allow the manufacturing of a more durable, long-lasting coloring on the metal elements of a slide fastener.

[0078] The present invention is however not limited to the above-disclosed innovative method and the fastener tapes obtained thereby, and also includes metal elements and metal wire members to be cut into individual elements, as well as slide fastener stringers and chains with metal elements having the features defined in the attached method claims.

[0079] The principle underlying the present invention itself, various variants and modifications can be envisaged by those skilled in this art, without departing from the scope of the present invention, as defined in the appended claims.

[0080] This application is based on Italian Patent Application No. 102021000007925 filed on Mar. 31, 2021, the contents of which are incorporated herein by way of reference.

REFERENCE SIGNS LIST

[0081] 10 fastener tape [0082] 20 element [0083] 21 surface [0084] 23 roughened outer surface [0085] 25 recess [0086] 27 protrusion [0087] 30 fastener stringer [0088] 40 slider [0089] 50 anti-corrosion layer [0090] 60 backing layer [0091] 80 paint layer [0092] 90 clear coating film [0093] 70 profile, metal wire [0094] 100 slide fastener [0095] 211, 212 leg [0096] 213 engagement head portion [0097] 214 engaging projection