Patent Description:
As is well known, there are surface coating processes traditionally used in various sectors as a quality alternative to common surface finishing techniques (e.g. electroplating, painting, etc.), compared to which they have much higher physical and aesthetic characteristics.

It is, however, well known that such surface coating processes are not generally used for the coating of small parts, e.g. zipper teeth, which are traditionally treated by means of painting or galvanic plants, but which not only suffer from a reduced production capacity in the face of a significant encumbrance, but also result in a coating with mechanical, physical and chemical properties that are not always adequate.

<CIT> discloses a method and an apparatus for plating parts like lug nuts or other metal parts; <CIT> shows a plating or anodizing rack with a supporting structure; <CIT> discloses an electroplating support of a chain belt and an electroplating apparatus with the support.

There is therefore a need to improve the process structure for coating and protecting zipper teeth. The technical task that the present invention proposes is, therefore, to realise an exposure unit for the coating and protection of zipper teeth that eliminates the complained of technical drawbacks of the known technique.

Within the scope of this technical task, one aim of the invention is to realise an exposure unit for the coating and protection of zipper teeth in which the teeth are individually held in certain positions.

Another purpose of the invention is to make an exposure unit for coating and protecting zipper teeth in which the teeth are exposed to coating and protection on surfaces of specific interest. Another purpose of the invention is to realise an exposure unit for coating and protecting zipper teeth in which the teeth are evenly distributed in the exposure to the coating.

The technical task, as well as these and other purposes, according to the present invention are achieved by making an exposure unit according to Claim <NUM>.

In one form of realisation, the metallic or metallised retaining means comprises at least one disc along the outer circumference of which elastically deformable finger pairs are extended in overhang.

Other features of the present invention are also defined in subsequent claims.

Further features and advantages of the invention will become more apparent from the description of a preferred but non-exclusive embodiment of the exposure unit of zipper teeth to a surface coating film deposition treatment according to the invention, illustrated by way of illustration and not limitation in the accompanying drawings, wherein:.

In drawings, similar reference numbers typically identify similar components, unless the context indicates otherwise.

The illustrative forms of realisation described in the detailed description and drawings are not intended in a limiting sense.

Other forms of realisation may be used, and other modifications may be made without departing from the scope of the subject matter depicted here and defined by the appended claims.

The aspects of this description, as generally described in this context and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and are part of this description.

With reference to the above-mentioned figures, a unit for exposure of zipper teeth to a deposition treatment is shown of a surface-coating film indicated overall by reference number <NUM>.

As depicted in <FIG>, the tooth <NUM> of a zipper has two opposite legs <NUM>, <NUM> A and <NUM> B respectively, connected by a bridge <NUM> that delimits between the opposite legs <NUM> a recess <NUM>. For the formation of the finished zipper, the teeth <NUM> are arranged at predetermined distances along a webbing, typically made of flexible textile material, which passes through the recess <NUM> and is permanently engaged by a plastic mechanical deformation of the opposite legs <NUM>.

The surfaces of tooth <NUM> inside the recess <NUM> therefore do not require mechanical and aesthetic surface treatment, as they are no longer visible and no longer operationally engaged in the finished zipper; all other surfaces, on the other hand, require surface treatment, both for the aesthetic quality of the zipper and for the continuous engagement in operation of opening/closing the zipper. Advantageously and innovatively, according to the present invention, the exposure unit <NUM> comprises means for retaining <NUM> of the teeth <NUM> in certain positions.

Advantageously and innovatively, the retaining means <NUM> is configured for a force connection by elastic mechanical engagement in the recess <NUM> between the opposing legs <NUM> of the single tooth <NUM>.

Appropriately, the retaining means <NUM> is metallic or metallised and is configured for an electrical connection of the teeth <NUM>.

Retaining means <NUM> is formed, as we shall see in detail below, by filiform elements <NUM>.

In a first form of execution depicted in <FIG>, the exposure unit <NUM> is configured as a cylindrical metal cage formed by two bases 1a, 1b connected by a series of parallel rectilinear rods 1c placed on the outer circumference of the two bases 1a, 1b.

The cylindrical cage is preferably arranged with a vertical axis.

The filiform elements <NUM> are formed in this case directly from the parallel straight metal rods 1c of the cylindrical cage placed on the outer circumference of the bases 1a, 1b of the cylindrical cage.

The teeth <NUM> are positioned on the metal filiform elements <NUM> at uniform and suitably predetermined distances d to ensure maximum exposure of the surfaces of the individual teeth to be coated; with mechanical engagement in the elastic field, the opposite legs <NUM> of the teeth <NUM> are fixed on the filiform element <NUM>.

In this case, the position of the teeth <NUM> along the filiform metal elements <NUM> and the distance d can be finely adjusted to optimise the number of treated teeth per unit length of the filiform metal elements <NUM>.

Appropriately, the metal filiform elements <NUM> and the bases 1a, 1b of the metal cylindrical cage electrically connect the teeth <NUM> , which are thus all at the same electrical potential in the deposition chamber of the surface coating film: all surfaces of the teeth <NUM>, except those inside the recess <NUM> for which no treatment is required, remain exposed for coating.

In a second form of execution, the filiform elements <NUM> are formed this time from electrically conductive flexible cords <NUM> of a cross-section and consistency appropriate to the elastic mechanical engagement in the recess <NUM> of the tooth <NUM>.

The teeth <NUM> are positioned on the electrically conductive flexible cords <NUM> at uniform and suitably predetermined distances d to ensure maximum exposure of the surfaces of the individual teeth to be coated, and with a mechanical engagement in the elastic field the opposite legs <NUM> of the tooth <NUM> are fixed on the conductive flexible cord <NUM>.

In this case, the flexible cords <NUM> can be stretched between two opposing tensile supports and can be arranged parallel and straight.

Alternatively, as illustrated in <FIG>, the flexible cords <NUM> may be supported in an exposure unit <NUM> again configured as a cylindrical cage where each flexible cord <NUM> is spirally wound with pitch p1 around a corresponding rod <NUM> of the cylindrical cage and where, in order to hold each flexible cord <NUM> in position, it may be subjected to a certain tension and possibly arranged along a helical guide groove (not shown) provided on the surface of the rod <NUM>.

Again, the cylindrical cage is metallic to simplify the electrical connection between all the teeth. In a more complex design variant, the cylindrical cage may be non-metallic, as the electrical connection between the teeth <NUM> may also be provided by connecting the ends of various flexible cords <NUM>.

The flexible cords <NUM> can in fact be connected in series or in parallel and are thus all at the same electrical potential in the deposition chamber of the surface coating film: again, all surfaces of the tooth <NUM>, except those inside recess <NUM> for which treatment is not required, remain exposed for coating.

Again, the position of the teeth <NUM> along the filiform metal elements <NUM> and the distance d can be finely adjusted as desired to optimise the number of treated teeth per unit length of the filiform metal elements <NUM>.

In a third embodiment, the filiform elements <NUM> are formed of electrically conductive flexible cords <NUM> supported by electrically conductive flexible webs <NUM> of fabric, wherein the flexible cords <NUM> have a cross-section and consistency appropriate to the elastic mechanical engagement in the recess <NUM> of the tooth <NUM>.

More precisely, cords <NUM> are applied along one longitudinal edge of webs <NUM>.

The webs <NUM> can already be configured in length and width as the final load-bearing elements of the finished zipper.

The teeth <NUM> are positioned and fixed on the flexible cords <NUM> at uniform distances d1 and already definitive of the position of the tooth <NUM> in the finished zipper, on a section of length D2 of a section of length D1 of the flexible web <NUM>; the greater total length D1 has end sections D3 and D4 free of teeth <NUM> and suitable for completing the finished zipper with other accessory and functional elements.

Favourably, flexible web <NUM> has a plurality of sections of length D1.

In this case, the flexible webs <NUM> can be stretched between two opposing tension supports and can be arranged parallel and straight.

Alternatively, as illustrated in <FIG>, the flexible webs <NUM> may be supported in an exposure unit <NUM> again configured as a cylindrical cage wherein each flexible web <NUM> is spirally wound with pitch p2 around a corresponding rod <NUM> of the cylindrical cage and wherein, in order to hold each flexible web <NUM> in position, the latter is arranged along a helical guide groove <NUM> provided on the surface of the rod <NUM>.

Again, the cylindrical cage is metallic to simplify the electrical connection between all the teeth. In a more complex design variant, the cylindrical cage may be non-metallic, as the electrical connection between the teeth <NUM> may also be provided by connecting the ends of various flexible webs <NUM>.

The flexible cords <NUM> and/or flexible webs <NUM> can thus be connected in series or in parallel and are thus all at the same electrical potential in the deposition chamber of the surface coating film: again, all surfaces of the teeth <NUM>, except those inside the recess <NUM> for which no treatment is required, remain exposed for coating.

In a fourth form of execution, the filiform elements <NUM> are formed by elastically deformable finger pairs <NUM>, where each finger pair <NUM> holds a single tooth <NUM>.

Finger pairs <NUM> are supported by rods <NUM>.

Innovatively, according to the present invention, each rod <NUM> is metallic and straight and supports pairs of fingers <NUM>, also metallic.

The pairs of fingers <NUM> are distributed with step g longitudinally along the rectilinear rod <NUM> from which they extend in overhang.

In this case, as is evident from <FIG>, the exposure unit <NUM> is always configured as a metal cylindrical cage formed by two bases 1a, 1b connected by a series of parallel rectilinear rods 1c placed on the outer circumference of the two bases, and the rods <NUM> supporting the pairs of fingers <NUM> coincide with the rods 1c of the cylindrical cage.

The rods <NUM> are particularly flat and the finger pairs <NUM> project from a longitudinal edge of the rods <NUM>.

The pairs of fingers <NUM> more precisely jut out diverging from each other orthogonally to the longitudinal direction of the rods <NUM>.

As mentioned, the teeth <NUM> are individually positioned and fixed on a pair of fingers <NUM>, for a mechanically engaged force connection by elastically deforming the fingers of the pair as they approach the recess <NUM> of the tooth <NUM>.

Fingers <NUM> and rods <NUM> electrically connect tooth <NUM>, which are then all at the same electrical potential in the surface coating film deposition chamber: again, all surfaces of tooth <NUM>, except those inside recess <NUM> for which no treatment is required, remain exposed for coating.

In a fifth form of execution depicted in <FIG>, the filiform elements <NUM> are still formed by elastically deformable finger pairs <NUM>, where each finger pair <NUM> holds a single tooth <NUM>.

In this case, however, unlike the previous one, the elastically deformable, metallic finger pairs <NUM> are supported in overhang by the circumference outside of a metal disc <NUM>.

The finger pairs <NUM> are distributed with step s along the outer circumference of the metal disc <NUM>. The pairs of fingers <NUM> more precisely project radially from disc <NUM> diverging from each other. The teeth <NUM> are individually positioned and fixed on a pair of fingers <NUM>, for a mechanically engaged force connection by elastically deforming the fingers of the pair as they approach each other within the recess <NUM> of the teeth <NUM>.

Appropriately, the fingers <NUM> and metal disc <NUM> electrically connect the teeth <NUM>, which are then all at the same electrical potential in the deposition chamber of the surface coating film Innovatively and advantageously according to the present invention, the exposure unit <NUM> is configured as a plurality of coaxial metal discs <NUM>, spaced and stacked along a Z axis, and electrically connected.

Innovatively and advantageously, the exposure unit <NUM> for the exposure of zipper teeth <NUM> to a surface coating film deposition treatment includes means of moving said teeth <NUM> with planetary motion.

As illustrated in <FIG>, a plurality of exposure units <NUM> are circumferentially placed on a turntable <NUM>, rotating about its own central axis Z1, within the deposition chamber: each exposure unit <NUM> is equipped with its own means of movement, not shown in the figures, which activate a rotation of exposure unit <NUM> about its own vertical axis Z, parallel to the axis Z1.

A law of motion superintends and determines the rotations of the plurality of exposure units <NUM> and turntable <NUM>, giving the teeth <NUM> an epicyclic motion in the deposition chamber for continuous and effective exposure to surface treatment.

The present invention also discloses and protects a method for deposition of a surface coating film on teeth <NUM> for zippers, comprising arranging an exposure unit having metallic or metallised retaining means <NUM> of individual teeth <NUM> in specified positions, arranging the teeth <NUM> on the exposure unit <NUM> by means of a force connection engagement of the metallic or metallised retaining means <NUM> in the recess <NUM> between the legs <NUM> of the teeth <NUM>, placing the exposure unit <NUM> in a deposition chamber, applying the surface coating film on the teeth <NUM> while the exposure unit <NUM> is moved with a determined law of motion.

The operation of the exposure unit for exposing zipper teeth to a surface coating film deposition treatment according to the invention is apparent from what is described and illustrated.

In practice, it has been found that a exposure unit for exposing zipper teeth to a surface coating film deposition treatment according to the invention is particularly advantageous for retaining the teeth individually in certain positions.

Another advantage of the invention is that it exposes the teeth to coating and protection on surfaces of specific interest.

Another advantage of the invention is to evenly distribute the teeth in the coating exposure.

Claim 1:
An exposure unit (<NUM>) comprising zipper teeth (<NUM>) to be exposed to a treatment of depositing a surface coating film, wherein said zipper teeth (<NUM>) have two opposite legs (<NUM>), respectively (<NUM> A, <NUM> B) connected by a bridge (<NUM>) which delimits a recess (<NUM>) between said legs (<NUM>), characterised in that it comprises a metallic or metallised retaining means (<NUM>) for retaining said zipper teeth (<NUM>) in specific positions, wherein said metallic or metallised retaining means (<NUM>) is configured for a force connection by elastic mechanical engagement in said recess (<NUM>) between said legs (<NUM>) of said zipper teeth (<NUM>), and in that said metallic or metallised retaining means (<NUM>) is configured for an electrical connection of said zipper teeth (<NUM>) and comprises at least one filiform element (<NUM>), said at least one filiform element (<NUM>) is formed by at least one rod for retaining a plurality of teeth (<NUM>), or said at least one filiform element (<NUM>) is formed by at least one flexible cord (<NUM>) for retaining a plurality of teeth (<NUM>), or said at least one filiform element (<NUM>) is formed by a plurality of pairs of elastically deformable fingers (<NUM>), wherein each pair of fingers (<NUM>) is configured to retain a single tooth (<NUM>), said finger pairs (<NUM>) being supported by rods (<NUM>) particularly flat and projecting from a longitudinal edge of said rods (<NUM>).