The present invention relates to the field of finishing leather or leatherette products, such as belts, straps, laces, handles etc. In particular, the present invention relates to a machine and related method for sizing and colouring holes in leather or leatherette products.

In the scope of the present description, the term “sizing” refers to the action of superficially finishing the internal side walls of the holes and correcting their imperfections to make them more regular and cylindrical. The manufacturing of leather goods often involves punching leather or leatherette semi-finished products to make holes therein, for example suitable to allow length adjustment of belts, laces or straps.

The punching of holes, without subsequent working, entails the drawback of exposing the unprocessed lower layers of the leather or leatherette garment, which clash with the external processed or coloured surfaces of the same garment, thus creating an unpleasant aesthetic effect.

In addition, the punching operation has the further drawback of creating scraps and stretching at the edge of the holes.

A method currently in use for colouring the inner part of the hole consists in manually passing an ink-soaked stem or rod inside the hole.

Disadvantageously, this operation, although capable of achieving an aesthetically satisfying result, is highly inefficient in terms of time and costs and entails considerable increases in the sales prices of the related leather products.

Another method in use for colouring the inside of the holes of leather products is to automatically move a comb equipped with colour-soaked tips, inserting them from the top through the holes of the leather product. Disadvantageously, a drawback of this method is the possible dripping of the colour onto the leather or leatherette product, resulting in stains on the same, thus ruining the appearance thereof. A further major drawback of the method described above is the interference between the stretching and scraps due to the punching on the sides of the hole with the comb tips, which causes partial removal of the colour from the latter and does not allow satisfactory colouring of the walls of the hole.

The currently known hole colouring machines also have the drawback of having rigid parts that cannot be adapted to different shapes and patterns of the holes.

Other examples of the prior art and currently known and used machines are described in documents US 1062257 and US 4132190.

In this context, the technical task underlying the present invention is to propose a machine and related method for sizing and colouring holes in leather or leatherette products which overcome at least some of the above-mentioned drawbacks of the prior art.

In particular, it is an object of the present invention to provide a machine and related method for sizing and colouring holes in leather or leatherette products, which can preserve the product itself from the formation of unwanted colour stains.

A further object of the present invention is to provide a machine and related method for sizing and colouring holes in leather or leatherette products, which can apply the colour evenly inside the holes and at the same time finish off any imperfections caused by previous workings on the edges thereof.

Another object of the present invention is to provide a machine for sizing and colouring holes in leather or leatherette products, which is quickly adaptable to different sizes, shapes and patterns of the holes on the product itself.

The specified technical task and objects are substantially achieved by means of a machine and related method for sizing and colouring holes in leather or leatherette products comprising the technical features set forth in one or more of the accompanying claims. The dependent claims correspond to possible embodiments of the invention.

In accordance with a first aspect, the present invention relates to a machine for the sizing and colouring of holes in leather or leatherette products comprising a structure having a supporting surface for a leather or leatherette product having a plurality of holes, a movable base located below the supporting surface and supporting a plurality of heads, each equipped with a respective tool adapted to size and colour the holes, a movement unit configured to move the movable base between a colour dipping position, in which the heads interact with a containment volume containing the colour, and a hole sizing and colouring position, in which the tools protrude from the supporting surface for engaging, sizing and colouring the holes.

In accordance with a second aspect, the present invention relates to a method for the sizing and colouring of holes in leather or leatherette products, comprising the steps of arranging a plurality of tools in an initial position in which the tools have respective top apexes facing downwards, moving the plurality of tools downwards from the initial position to a colour dipping position for immersing the tools in a containment volume, moving the plurality of tools upwards from the colour dipping position to a first intermediate position for disengaging the containment volume, rotating the plurality of tools about an axis of rotation from the first intermediate position to a second intermediate position in which the tools are oriented upwards and face a plurality of respective holes formed in a leather or leatherette product, moving upwards the colour-soaked tools from the second intermediate position towards the plurality of respective holes up to a hole sizing and colouring position, in which the tools engage the holes, moving downwards the colour-soaked tools from the hole sizing and colouring position to a final position in which the tools disengage the respective holes, rotating the plurality of tools to bring them back to their initial position. In one or more of the aspects set forth, the present invention can comprise one or more of the following features.

Preferably, the movement unit is configured to rotate the movable base about an axis of rotation parallel to the supporting surface between a first intermediate position, in which the tools face the containment volume, and a second intermediate position, in which the tools are arranged below the supporting surface and face the supporting surface.

Preferably, the movement unit is configured to rotate the movable base by 180° around the axis of rotation.

Preferably, the movement unit is configured to vertically translate the movable base between the first intermediate position and the colour dipping position.

Preferably, the movement unit is configured to vertically translate the movable base between the second intermediate position and the hole sizing and colouring position.

Preferably, the heads are rotatable about respective extending longitudinal axes.

Preferably, the plurality of heads are connected to the movable base and distributed along an alignment axis.

Preferably, the movement unit is configured to bring about an alternate translational movement of the movable base in a direction parallel to the alignment axis so as to favour the contact between the tools and respective inner walls of the holes to be coloured and sized.

Preferably, the movement unit comprises adjustment means configured to allow amplitude adjustment of the alternate translational movement.

Preferably, each head comprises an elastic element interposed between the respective tool and the movable base; a stretchiness of the elastic element allows a positional adjustment of the tool with respect to the movable base.

Preferably, the heads each comprise a collar located at the base of the respective tool and defining a tray for collecting the excess colour, and the movement unit is configured to orient the movable base, so as to arrange the collars vertically below the respective applicators when the movable base is in the sizing and colouring position.

Preferably, each tool has a substantially ogival shape with a tapered top apex and a convex central portion; the central portion has a plurality of side facets defined by a respective absence of material with respect to a perfectly ogival or circular plan shape.

Preferably, the side facets are circumferential flat or concave surfaces equally spaced on a side surface of the central portion, mutually connected by rounded surfaces in accordance with side portions of the perfectly ogival shape.

Preferably, each tool has a narrowing at the base of the convex central portion, the narrowing being defined by a flared portion of the tool.

Preferably, the movable base comprises a mechanism configured to adjust the mutual distance of the heads.

Preferably, the method comprises a step of rotating each tool about its own extending longitudinal axis while the tool is inserted in the respective hole.

Preferably, the method comprises a step of applying an alternate translational movement to the tools along a direction parallel to a line along which the holes lie, the alternate translational movement or oscillation being applied while the tools are in the sizing and colouring position, in order to facilitate the contact between the tools and respective inner walls of the corresponding holes.

Further features and advantages of the present invention will become more apparent from the indicative, and therefore non-limiting description of a preferred, but not exclusive, embodiment of a machine and related method for sizing and colouring holes in leather or leatherette products. This description will be set forth hereinafter with reference to the accompanying drawings, which are provided for illustration purposes only, therefore not for limiting purposes, in which: - Figure 1 A shows a schematic front view of a machine for sizing and colouring holes in leather or leatherette products in accordance with the present invention, with some parts removed to highlight others;

- Figure 1 B shows a schematic front view of the machine in Figure 1 A in a different operating configuration;

- Figure 2A shows a simplified perspective view of an implementation detail of the machine in Figure 1 A;

- Figure 2B shows a simplified perspective view of the implementation detail in Figure 2A in a different operating configuration;

- Figure 3A shows a front view of an implementation detail of the machine in Figure 1 A;

- Figure 3B shows a top view of the detail in Figure 3A;

- Figures 4A - 4D show a schematic side view of the machine in Figure 1 in different respective operating configurations in accordance with a method for the sizing and colouring of holes in leather or leatherette products according to the present invention.

With reference to the accompanying figures, a machine for the sizing and colouring of holes“F” in leather or leatherette products“P” is indicated as a whole by the numeral 1 , and it will be hereinafter referred to by the simplified term“machine 1”.

The machine 1 comprises a structure 10 defining a base 1 1 for supporting it on a floor and having an upper supporting surface 12 preferably oriented horizontally with respect to the floor.

The supporting surface 12 is configured to accommodate a leather or leatherette product“P” having a plurality of holes“F”, for example a leather belt or a shoulder strap of a bag, coming from an upstream conveyor or positioned by hand on the same by an operator, in a predetermined position.

Preferably, the supporting surface 12 has an elongated strip plan shape and is provided with a central slit arranged along an extension axis of the same, so as to be arranged beneath the holes “F” of the leather or leatherette product “P”, the holes “F” being mutually aligned in the predetermined position, and to define a window where the holes are located for the passage of working tools.

The machine 1 further comprises a movable base 20, shown in Figures 2A and 2B, placed vertically below the supporting surface 12 within the base 1 1 .

The movable base 20 supports a plurality of heads 22 for the sizing and colouring of respective holes, with the heads preferably distributed on the base 20 along an alignment axis “A” coinciding with a main axis of extension of said movable base 20; this alignment axis“A” is parallel to the main direction of extension of the aforementioned slit.

In the preferred embodiment, the movable base 20 comprises a plurality of gears defining a mechanism configured to adjust the mutual distance of the heads 22 along the alignment axis“A”, so as to adapt the arrangement thereof to different mutual distances of the holes along the leather or leatherette product to be worked.

Furthermore, the heads 22 are rotatable about respective extending longitudinal axes“T” oriented perpendicular to the alignment axis“A”. In the embodiment shown herein, the rotation of the heads 22 is driven by a single rotary motor mounted externally to the movable base 20 and connected thereto by a rotatable shaft which, through suitable transmission members, transmits the rotary motion to the individual heads 22.

Each head 22 is equipped with a respective, preferably rigid tool 24, shown in Figures 3A and 3B, dimensioned to pass through a respective hole to be sized and coloured, so as to interfere with the inner wall of the hole.

Each tool 24 shares the same longitudinal axis“T” as the head 22 to which it belongs.

In particular, each tool 24 is configured to be dipped in a liquid colour for leather or leatherette, and subsequently to pass through a hole“F” of the product“P”, abutting against its inner walls, so as to compress them in order to size them, and at the same time distribute the colour on these walls.

In the preferred embodiment, each tool 24 has a substantially ogival shape with a tapered top apex 25 and a pointed, rounded or flat end, a convex central portion 27 and a narrowing 29 at its base defined by a flared portion which causes a narrowing of the section of the tool 24 with respect to the maximum section of the central portion 27.

The central portion 27 has a plurality of concave, or preferably flat side facets 28 circumferentially equally spaced apart with respect to the longitudinal axis“T” of each tool 24.

The side facets 28 are defined by a respective absence of material with respect to a perfectly ogival or circular plan shape of the tool 24 in the central portion 27.

More specifically, these side facets 28 are circumferential flat or concave surfaces equally spaced apart on the side surface of the central portion 27, mutually connected by rounded surfaces defining the perfectly ogival shape.

Preferably, but without limitation, the central portion 27 has at least two, advantageously three - as in the illustrated embodiment - side facets 28.

In other words, each tool 24, seen in a section perpendicular to the respective longitudinal axis“T”, has a circular plan shape at the top apex 25 and at the narrowing 29 at the base, while in the central portion 27, the tool 24 has a perimeter defined by arcs of a circle centred on the longitudinal axis“T” and mutually connected by segments defining the side facets 28, as shown in Figure 3B.

Preferably, each head 22 comprises a respective collar 31 located at the base of the respective tool 24, so as to define a colour collecting tray; in fact, when the head 22 is arranged in the vertical position, with the tool 24 facing upwards, any excess colour may drip downwards and collect inside the collar 31. Moreover, each head 22 comprises an elastic element 33, such as a spring or an elastomer, interposed between the respective tool 24 and the movable base 20, so as to determine a degree of flexibility of the tool 24 with respect to the movable base 20.

In particular, the greater stretchiness of the elastic elements 33 compared to the rest of the structure of the heads 22 allows greater freedom of movement to the elastic elements 33 with respect to the movable base 20, for example, allowing them to adapt to tolerances or manufacturing errors in the shape or arrangement of the holes“F” on the product“P”. In other words, the greater stretchiness of the elastic elements 33 compared to the rest of the structure of the heads 22 brings about a degree of flexibility of the centre distances between the holes to be machined which may not be exactly equidistant.

The machine 1 further comprises a movement unit 40 configured to move the movable base 20 in accordance with successive steps of a method for sizing and colouring holes“F” in leather or leatherette products“P”, which is a further object of the present invention.

The movement unit 40 comprises a plurality of vertical guides 41 oriented perpendicular to the supporting surface 12, a translational support 42 slidably movable along them, and a dedicated motor configured to translate the translational support 42 along the vertical guides 41.

The movable base 20 is connected to the translational support 42 and rotatable with respect to it around an axis of rotation“R” parallel to the supporting surface 12 for the leather product, and more particularly oriented perpendicular to the aforesaid slit and to the alignment axis“A”. The movement unit 40 comprises a further motor configured to rotate the movable base 20 with respect to the rotational support 42.

In addition, the movement unit 40 is configured to bring about an alternate translational or oscillatory movement of the movable base 20 in a direction parallel to the alignment axis“A” (and to the axis of rotation“R”).

The movement unit 40 described herein is configured to move the movable base 20 between a colour dipping position, arranged in a lower containment volume“V”, for example defined by a tray, and a hole“F” sizing and colouring position, in which the tools 24 protrude from the supporting surface 12 through the central slit to engage, size and colour the holes“F” of the leather or leatherette product“P”.

In particular, the present method, which can be implemented by means of the machine 1 described above, provides an initial position of the movable base 20, shown in Figure 4A, in which the heads 22 and hence the tools 24 face downwards, so that the respective longitudinal axes “T” are preferably oriented vertically.

A first step of the method comprises the downward vertical translation of the movable base 20 driven by the movement unit 40, from the initial position to a colour dipping position, shown in Figure 4B, in which the tools 24 are immersed in the containment volume“V” to collect the colour on its own outer surface.

Subsequently, the method comprises an upward vertical translation of the movable base 20 driven by the movement unit 40, from the colour dipping position to a first intermediate position in which the tools 24, still remaining oriented downwards, protrude from the containment volume“V”; this first intermediate position preferably coincides with the initial position described above.

Subsequently, the method comprises a rotation of the movable base 20, preferably by 180°, driven by the movement unit 40, about the axis of rotation“R” from the first intermediate position to a second intermediate position, shown in Figure 4C, in which the tools 24 are oriented upwards and face the plurality of respective holes“F” formed in the leather or leatherette product“P” to be machined.

Subsequently, the method comprises an upward vertical translation of the movable base 20 driven by the movement unit 40, from the second intermediate position up to a hole“F” sizing and colouring position, shown in Figure 4D, in which the colour-soaked tools 24 protrude from the slit of the supporting surface 12 and engage the holes“F” of the leather or leatherette product“P”.

While the tools 24 are engaging the holes“F” of the product“P”, the method comprises a step of rotating each head 22 around the respective longitudinal axis “T”; preferably, this rotation can be implemented simultaneously with an alternating upward and downward vertical movement of the movable base 20, along the same longitudinal axis“T”, to cause, in synergy with the rotary movement of the tools 24, a compression of the inner walls of the holes by the respective tools 24, which allows them to be sized.

Advantageously, during this step, the side facets 28 define a volume between the inner walls of each hole "F" and the outer surface of the respective tool 24, which allows the colour to penetrate inside the hole without being expelled by the interference between the tool 24 and the respective hole “F”, which would have occurred if they had matching shapes.

In this step, due to the upward vertical orientation of the heads 22, any excess colour drips downwards, without risking to stain the product being machined, and is collected by the collars 31 of the heads 22.

Preferably, during the rotation of the individual heads 22, the method comprises a step of moving, by means of the movement unit 40, the movable base 20 with an alternate translational movement having an amplitude that is preferably adjustable along a direction parallel to a line along which the holes“F” of the product“P” lie during the machining, or according to the supporting surface 12, and in particular parallel to its central slit and to the alignment axis“A”.

In the preferred embodiment, the machine 1 has a knob 45 adjustable by a user to determine the maximum amplitude of the alternate translational movement.

Advantageously, this step favours the contact between the tools 24 and the respective inner walls of the holes, especially when the latter have an ovaloid, elliptical or not perfectly circular shape.

During this step of implementing the alternate translational movement, the elastic elements 33 are configured to allow adaptation of the mutual position between the colour applicators 24 and the movable base 20, especially when the size of the respective hole prevents the tool 24 from moving with the same translational amplitude as the movable base 20. After the steps described above, the method provides a downward vertical translation of the movable base 20, driven by the movement unit 40, from the hole sizing and colouring position to a final position in which the tools 24 disengage the respective holes; preferably, this final position coincides with the second intermediate position described above.

Lastly, the method comprises a rotation of the movable base 20, preferably by 180°, driven by the movement unit 40, about the axis of rotation “R” to bring the movable base 20 back to the initial position described above.

The present invention achieves the intended object, overcoming the drawbacks of the prior art.

Advantageously, the steps of moving the movable base allow the tools to pass through the holes from the bottom upwards, avoiding the risk of accidental dripping of the colour from the tool onto the product, which could stain it.

Furthermore, the faceted conformation of the colour applicators and the rotation of the heads around their own axis of extension allow the described machine to finish the inner side surface of the holes, compressing any scraps or imperfections against the inner wall and giving the hole a more cylindrical shape.

At the same time, the facets on the tools define empty spaces between them and the respective holes, allowing an adequate amount of colour to penetrate inside the hole, and therefore an even colouring of the inner surface of the same. Finally, thanks to the alternate translational movement of the tools along the line along which the holes lie and thanks to the mechanism described for adjusting the mutual distance between the heads, the aforesaid machine is capable of effectively machining leather products having different shapes and distances between the holes. This allows greater flexibility of the machine and faster management and manufacturing of different products.