The present invention relates to slide fasteners. More specifically, the present invention relates to methods of manufacturing slide fastener stringers with colored metal element.
Slide fasteners provided with metal teeth, also known as metal zippers, include a plurality of teeth made for instance of brass, zinc, aluminum or nickel. These zippers exhibit higher strength and can withstand tougher washing with respect to zippers having plastic-molded teeth.
It is sometimes desired, for instance for application to a garment or the like, that the elements of a slide fastener or zipper have a particular color, for instance a color matching that of the surrounding fabric.
Plastic zipper elements can be easily manufactured in any color of plastic, because plastic used for the elements can be colored to ensure the different coloring required. Metal zipper elements can be colored through a painting process before or after being crimped to the fastener tapes.
Patent Literature 1 discloses a method for the manufacture of slide fastener elements including a substrate made of zinc, provided with a chromate conversion coating layer or chromate layer, and a clear coating layer of brown color superposed thereon.
Patent Literature 2 and Patent Literature 3 disclose a method for manufacturing a fastener tape with colored metal elements. The method includes forming a plurality of fastener elements made of a metal material, applying a coat made of a synthetic primer material onto the outer surface of the elements, and attaching the elements to a longitudinal edge portion of the tape, such that once the attached elements extend on both sides of the tape. A layer of hot-melting coloring material is thermally transferred from a carrier onto a respective surface portion of the elements which extends on one side of the tape so as to deposit a colored foil thereon.
Patent Literature 4 discloses a fastener stringer including a fastener tape and a plurality of elements attached to a side-edge portion of the fastener tape. Each of the elements includes: a metal base member, a single layered or multi layered surface resin layer formed on the metal base member; and one or more intermediate metal layers interposed between the metal base member and the surface resin layer. The one or more intermediate metal layers include an exposure metal layer that will be exposed by at least a partial removal of the surface resin layer. The surface resin layer and the exposure metal layer are made of material having the same color tone.
Patent Literature 5 discloses a fastener stringer or fastener chain in which the texture of metal elements is modified to an extent to which streak patterns disappear while minimizing decoloration, soiling, and damage in a fastener tape. The fastener stringer or the fastener chain is surface-treated using a wet blast process, whereby the surface roughness and the linear roughness of the elements are controlled to prescribed ranges.
The main problem to be solved with slide fasteners having painted metal elements is that the paint tends to chip little by little and wear away rather quickly under constant use, due to the inevitable friction and abrasion arising from the passing of the slider, with consequent deterioration of the aesthetic appearance of the slide fastener elements.
It is an object of the present invention to provide improved slide fasteners with colored metal elements and methods for the manufacture thereof, which on one hand overcome the above outlined inconveniences of the related art, and on the other hand make it possible to achieve new, attractive aesthetic effects.
The above and other objects are achieved, according to an aspect of the present invention, by a method of manufacturing a slide fastener stringer with colored metal elements, the method including:
According to another aspect, the present invention provides a metal element for a slide fastener, the element including:
According to a further aspect, the present invention provides a slide fastener stringer including:
According to a still further aspect, the present invention provides a slide fastener chain, including:
In accordance with a still further aspect, the present invention provides 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 attached to a tape, the wire member having at least one roughened outer surface subjected to a preliminary surface roughening process, in which the roughening process includes a step of blasting.
Additional advantageous features of the fastener stringers and their manufacturing methods are defined in the annexed dependent claims.
Features and advantages of the present invention will become apparent from the following description, provided merely by way of a non-limiting example with reference to the accompanying drawings.
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.
A slide fastener 100 shown in
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.
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.
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 (
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.
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.
The fastener tape 10 may be woven or knitted together fabric, for example, having a flexibility. The element 20 shown in
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.
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.
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.
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.
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.
(a) to (f) of
As shown in (b) of
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.
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.
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.
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.
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 μm prior to the roughening step, which increased to 1.22 μm after a shot peening step. Further, the average linear roughness Ra increased from an average value of 0.39 μm with no treatment to an average value of 0.93 μm after the shot peening step.
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.
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.
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.
As shown in (c) of
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.
As shown in (d) of
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.
As shown in (e) of
As shown in (f) of
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 (
The step of forming a clear coating film on the element as shown in (f) of
On the other hand, the processes as shown in (a) to (e) of
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.
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.
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.
The methods disclosed hereinabove allow the manufacturing of a more durable, long-lasting coloring on the metal elements of a slide fastener.
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.
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.
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.
Number | Date | Country | Kind |
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102021000007925 | Mar 2021 | IT | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2022/013757 | 3/23/2022 | WO |