Technical Field
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The present invention generally refers to footwear and particularly relates with a breathable shoe having a peculiar structure for comfort and above all for the ventilation of the feet and the reduction of sweat through air exchange with the outside by suction and expulsion of the air at the inside.
State of the art
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Several solutions are known for improving shoe breathability to prevent foot sweat, which, in addition to producing unpleasant odors, can lead to dermatitis, skin infections, and even fungal infections.
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Some patented solutions provide for micro-perforations in the outsole for airflow, with a fabric to protect against water infiltration. However, after a short time, these micro-perforations become clogged by dirt, mud, earth and sand.
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Other solutions involve an air exchange system of the air inside the shoe, by expelling it through holes made in the upper of the heel, which holes being necessarily placed at a lower position and too close to the outsole to be protected by the necessarily short tongue, which extends from the insole.
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This system leads to possible water infiltration if walking through puddles, also presenting a risk of eyelet breakage and outsole disassembling from the upper during production, upon the drilling and the eyeleting of the air vents, which are too close to the outsole, as this operation is carried out by an appropriate automatic machine, exerting excessive pressure that is risky for the assembly glue to hold.
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Another solution provides for an upward tongue or protrusion, extending from the edge of the insole near the heel, to create a conduit for channelling the air moving up to the vents in the heel upper; also for this reason, this version is also unsatisfactory, as when inserting the foot into the shoe, there is a risk that the above upwardly facing protrusion is completely folded over, thus creating a particularly uncomfortable thickness under the foot.
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Another patent provides for a foam bellows or pump in the heel, which pushes pressurized air inside the shoe to create a ventilation at the inside, which, brushing against the surface and skin of the feet, wicks away the sweat, creating a cooler and more hygienic environment; however, it creates excessive bulk inside the shoe, altering and reducing the inner space technically known as the "fit", causing confusion and discomfort for the end user, who is forced to wear a shoe of a larger size than usual.
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A second limitation or drawback in this solution is the change in the shoe's internal space over time, due to the obvious degradation of the materials over time, causing this foam bellows or pump to settle and reduce in thickness, with the consequence that, while initially the inner space is more limited and is adapted and measured precisely for the size of the user's foot, over time it increases excessively, creating discomfort for the wearer and risk of losing the shoe.
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In the latter case, the heel features a single, minimally thick counter stiffener, approximately 1 mm, and a soft bellows that can be compressed and expanded alternately, step by step.
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Other patents also provide for the movement of internal air, with relative intake and expulsion through one or more air chambers, but this is rarely achieved through eyelets working as vents in the heel upper, as they are difficult to create in this position, also being bulky and creating a bothersome obstacle for the machinery, especially the backpart moulding machine, which could break them.
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Furthermore, these holes, with the necessary metal eyelets, are exposed and slightly protruding from the lining, and, as the heel rubs against the foot during walking, they could cause nicks and abrasions in the particularly delicate skin of the foot.
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These well-known solutions also have in common the fact that they feature a single counter stiffener, glued to the upper.
Scope of the invention
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The object of the present invention is to overcome the above drawbacks by providing a breathable shoe that corrects and improves, with appropriate modifications, the defects and functional limitations of known solutions, improving functionality and also simplifying manufacturing and, therefore, increasing production yields, with obvious cost reductions, particularly by reducing the excessive number of molds required to remedy the variation of the dimensions of shoes for different sizes.
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A further object of the present invention is to improve breathability systems even in slightly different and seemingly secondary and insignificant aspects, which are, however, substantial and crucial for resolving certain construction defects and limitations, while also increasing the quality and functionality of the finished footwear. These objects, as well as others that will become more apparent hereinafter, are achieved by a breathable shoe according to claim 1, to which reference is made for a more concise explanation.
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The shoe according to the invention will be particularly breathable as it exchanges the humid, smelly, and unhealthy air inside the shoe by expelling it through one or more vents located in the heel upper, as well as using a special exchange system.
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The shoe, in fact, comprises:
- an upper made of material such as leather, fabric, or plastic;
- a outsole made of rubber, leather, or other material;
- an insole made of a soft, expanded plastic material, such as polyurethane, shaped with one or more air chambers positioned underneath, one under the heel, with a bulge at the top to increase air volume, and at least another one under the outsole of the foot, in such a manner as that, as the foot moves vertically while walking, these air chambers are compressed and expanded to return to their original configuration, thus creating internal movement of the air, that is drawn in from the outside as the chamber expands and expelled when the chamber compresses.
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The air chamber under the heel may have a channel converging posteriorly toward the heel to increase the speed of expulsion, as well as vertical holes in the insole and the lining above it to also create vertical air movement to brush the foot and take away sweat.
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The upper of the shoe will have at the rear one or more holes with corresponding eyelets, serving as external air intakes for the intake and expulsion of internal air moistened with sweat.
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Unlike previous solutions, the shoe according to the present invention does not include any bellows or foam pump in the heel, so as not to alter or reduce the inner space for a correct and precise fit, as well as there is not any recess in the rear edge of the insole near the heel for the vertical passage of air.
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The shoe according to the present invention has a hollow chamber in the heel for the passage of air, such a chamber being made up by the peculiar shape of two joined counter stiffeners, an outer one, in contact with the upper, and an inner one, with a slight upward inclination, to form this cavity or air chamber a few millimeters wide, through which the air is drawn in and expelled.
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Therefore, the shoe according to the invention does not feature a single, thick, and particularly heavy and bulky counter stiffener, as in known solutions, but it features two joined counter stiffeners, the outer one of which is coupled to the outer upper and provides support to prevent undulations during the shaping process.
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This solution solves the defect of the previous solutions, where, without an outer support counter stiffener, during the shaping or final bending process by heating, the upper, not sufficiently strong and rigid, presented undulations that reduced or even completely obstructed the passage of air through the vertical channels, in addition to being aesthetically unacceptable.
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These counter stiffeners, usually made of plastic or salpa, are different from the usual standard ones, which are heat-sealed on both sides; conversely, the outer counter stiffener is thermo-adhesive on the outside, while the inner counter stiffener is thermo-adhesive on the inner face, to avoid total gluing therebetween, which would eliminate the cavity or chamber between the two counter stiffener.
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Two or more reinforcements may be inserted between the two counter stiffeners, depending on the pressure of the backpart moulding machine.
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This solution allows to reduce the weight of the shoe, to reduce the manufacturing times, to avoid the costs for different molds required in the previous solutions for the different sizes of men's, women's, and children's footwear.
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The theoretical design of the shoe will subsequently require even minor modifications and some improvements for the practical implementation during production, both to adapt to the characteristics and limitations of the used machinery and to improve quality and for using production processes that are satisfactory from all technical and economic perspectives.
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Advantageous embodiments of the invention are obtained in accordance with the dependent claims.
Brief disclosure of the drawings
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Further features and advantages of the invention will become more apparent from the detailed description of a preferred but non-exclusive embodiment of the shoe according to the invention, illustrated by way of non-limiting example with the aid of the attached drawings, wherein:
- FIG. 1 is a cross-sectional view of the shoe;
- FIG. 2 is a perspective view of the two coupled counters belonging to the shoe of the FIG. 1;
- FIG. 3 is a horizontal sectional view of the two counters of FIG. 2;
- FIG. 4 is a median vertical cross view of the two counters of FIG. 2;
- FIG. 5 is a rear perspective view of the shoe of FIG. 1.
Best mode of carrying out the invention
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FIG. 1 shows a vertical cross section of the shoe comprising a rear upper 13, or heel upper, having one or more holes 5 for the expulsion of internal air, a front upper 14, a outsole 6, an insole 7, made of open-cell expanded plastic material and equipped with vertical holes 9, an upper lining 8, and two air chambers 10 and 12 underneath the insole 7.
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The shoe, at the rear of the heel, comprises an inner counter stiffener 2 provided with a window 3 for the passage of air and an outer counter stiffener 1 supporting and glued to the rear upper 13 and having one or more holes 4 for the passage of expelled air. The two counter stiffeners 1, 2 are joined together at the top 15 and at an angle to made up a cavity 11 for the passage of air to be expelled.
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The cavity 11 will be connected on one side to the air chambers 10, 12 located under the insole 7, through the window 3, and on the other side it will be connected to the outside through the holes 4 and 5 made on the outer counter stiffener 1 and on the rear upper 13, respectively.
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FIG. 2 shows in more detail a view of the two joined counter stiffeners 1, 2, wherein the inner counter stiffener 2 is provided with the window 3 and is joined to the outer counter stiffener 1 provided with the tabs 16 to be folded under the last of the shoe during manufacturing.
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FIG. 3 shows the horizontal cross section seen from below of the two counter stiffeners 1, 2 joined together, wherein the outer counter stiffener 1 is joined to the inner counter stiffener 2 provided with the window 3.
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Two reinforcements 18 may be inserted between the two counter stiffeners 1, 2, depending on the pressure, if excessive, applied by the backpart moulding machine, to ensure sufficient space for the cavity 11.
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A 3D reinforcing fabric, preferably in the form of a mesh, may also be inserted in the cavity 11, between the two counter stiffeners 1, 2.
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FIG. 4 shows a vertical cross section of the two counter stiffeners 1, 2, wherein the outer counter stiffener 1 is provided with the hole 4 and the tabs 16 to be folded under the last during manufacturing, and is joined to the inner counter stiffener 2 provided with the window 3 for the passage of expelled air.
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The two counter stiffeners 1, 2 are joined at an angle to make the cavity 11.
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FIG. 5 shows a rear view of the shoe, with the rear upper 13, the front upper 14, the outsole 6, and the hole 5 for the intake and expulsion of internal air.
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Operatively, the alternating movement of the foot will cause compression and expansion of the elastic insole 7 and the air chambers 10, 12 underneath, so that air and sweat under the foot are drawn in through the respective vertical holes 9, then passing through the window 3 and reaching the cavity 11 defined between the two counter stiffeners 1, 2, from which the air will then be expelled through holes 4 and 5. The expansion movement will then draw a flow of air into the shoe with the opposite path to that of the expulsion flow.