Waterproof and breathable sole structure

Abstract

A waterproof and breathable sole structure having an inner face (2) intended to be facing inside a shoe and an outer face (3) intended to be facing the environment outside of the shoe is described, wherein the sole structure (1) comprises: a tread (4) having an upper surface (5) on the side of the inner face (2) and a lower surface (6) on the side of the outer surface (3), one or more ventilation channels (8), a functional region comprising its own breathable portion adapted for the passage of water vapor, a waterproof membrane (10) permeable to water vapor and a sealing region (9) surrounding the breathable portion and to which the membrane is sealed in a waterproof way, wherein the one or more ventilation channels (8) are adapted for directing water vapor towards the surface of the membrane facing the inner face (2), and wherein the breathable portion of the functional region is fully located outside of a forefoot portion corresponding to a region of maximum bending.

Description

[0001] WATERPROOF AND BREATHABLE SOLE STRUCTURE

[0002] ***

[0003] DESCRIPTION

[0004] Field of the invention

[0005] The present invention concerns the field of shoes and, in particular, refers to a waterproof and breathable sole structure.

[0006] Known art

[0007] Generally, a shoe item comprises a sole structure placed below with respect to the use arrangement of the shoe item and adapted for supporting the foot of a user, therefore allowing to release the weight of the same to the ground and to lessen stresses that the ground transmits to the foot, and an upper assembly placed above and enveloping the foot, joined to the sole structure which can in turn be monolithic, i.e. made in one piece, or which can comprise a tread joined to a midsole.

[0008] Nowadays, for the purpose of increasing comfort, the known art provides shoe items comprising waterproof and breathable sole structures which, in particular, are provided with a breathable region provided with through openings and a waterproof and breathable functional layer sealed in a waterproof way along the perimeter of the breathable region.

[0009] The through holes allow sweat in vapor phase produced by the foot of the user to escape through the sole structure, whereas the aforesaid waterproof and breathable functional layer, in practice a membrane, has the dual function of preventing water from entering from the outside towards the inside of the shoe item and to simultaneously allow the vapor to escape. In other words, the aforesaid membrane has a barrier effect which prevents water from entering the shoe through the through holes, which is why it is waterproof, but allows vapor produced by the user to escape outside, through the same through holes, which is why it is vapor permeable or breathable.

[0010] Sole structures of the aforesaid type are described, for example, in patents EP 0382904 B1 and EP 0858270 B1 and in the patent application WO 98 / 51177.

[0011] The aforesaid functional layer is generally constituted of polymer materials, such as for example polyurethane (PU), polyester, expanded polytetrafluoroethylene (e-PTFE), whose flexural strength is put to the test when using the shoe item.

[0012] The sole structure is actually subjected to repeated bending which is transmitted to all the components composing it and which mainly concern the forefoot region, which is the same region as the one where the aforesaid breathable region is arranged and where the membrane is therefore present. The foot region where most of the sweat glands of the sole of the foot are located and which is therefore most affected by sweating is precisely the forefoot region.

[0013] More precisely, there is a forefoot region of the sole structure most concerned by mechanical stresses, such as the aforesaid bending which substantially corresponds to a user's forefoot region most affected by sweat, which region is commonly referred to as the “region of maximum bending” and which region can be identified, for example, by known methods as set forth below.

[0014] The aforesaid stresses can therefore cause the membrane to break at the region of maximum bending due to its structural failure, for example because a given number of bending cycles, for example 2000000 cycles, has been exceeded, according to the method illustrated in chapter 8.4.2 of the ISO 20344:2011 standard. Disadvantageously, the breaking of the membrane corresponds to the loss of the sole structure’s impermeability.

[0015] Definitions

[0016] - The term midsole denotes an element or layer, of any nature, interposed between the sole and the insole, according to the general definition provided by the EN ISO 19952:2005 standard, item 106, page 18.

[0017] - A material, and therefore a component considered in isolation constituted of such material, is waterproof in the absence of water crossing points, when the material is subjected to a pressure of at least 1 bar for at least 30 seconds. In particular, impermeability is assessed as resistance by a specimen, which is substantially consisting of the material being tested, to the penetration of water under pressure, according to the method described in the EN1734 standard. According to this method, a sample of the aforesaid material is fastened to a receptacle and used to close the receptacle, wherein the receptacle, which is provided with an inlet of pressure water, is filled with water so that the face of the aforesaid sample facing the inside of the receptacle is subjected to a hydrostatic pressure of 1 bar, in which this condition is maintained for 30 seconds. In detail, the aforesaid sample is stuck between the opening mouth of the receptacle and a restraining ring, wherein the sample and the restraining ring are covered with silicone rubber sealing gaskets and wherein pressurization is achieved by forcing water into the receptacle from a tank by means of a flow of compressed air regulated by a valve with pressure gauge on which the reached pressure is shown. Then the face (surface) of the sample outside the receptacle is observed. The absence of crossing points consisting of the formation on this face or surface of drops with a diameter of between 1 mm and 1.5 mm denotes the impermeability of the sample, therefore of the aforesaid material. If it is necessary to prevent the deformation of the sample, a square-meshed grid of synthetic material, with a side of no more than 30 mm, made of threads with a diameter of between 1 mm and 1.2 mm, is fastened thereto.

[0018] - Vapor permeability is the amount of vapor that passes through a material due to a partial pressure gradient. ISO 20344-2004 standard related to the safety shoes, in chapter 6.6 "Determination of water vapor permeability", describes a test method consisting of fastening a specimen of the material being tested so as to close the opening of a bottle containing a certain amount of solid desiccant, i.e. silica gel, wherein the bottle is subjected to a strong air current in a conditioned atmosphere. The bottle is rotated so as to remix the solid desiccant and to optimize the drying action of the air contained in the bottle. The bottle is weighed before and after the test period to determine the moisture mass that has passed through the material and has been absorbed by the solid desiccant. The water vapor permeability expressed in milligrams per square centimeter per hour [mg / cm2 / h] is then calculated on the basis of the measured moisture mass, the area of the bottle opening and the test time.

[0019] - In the context of the present invention and in accordance with common practice, the expressions “permeable / vapor permeability,” “permeable / water vapor permeability” and the like are intended to be equivalent to each other and synonymous with “breathable”. Moreover, in the context of the present invention, the expressions “breathable region” and “breathable portion” means a region or portion permeable to water vapor, as stated above, and constituted of a breathable material, such as for example leather, skin, fabric, non-woven fabric, etc., but also a region or portion provided with at least one through opening.

[0020] - Water-repellent means a material capable of making a drop of water slide on its surface, as a very high contact angle is generated between surface and drop that does not allow absorption by the same material, in the absence of hydrostatic pressure. The contact angle between water droplet and surface, and the surface tension of the surface, are commonly used to measure the water repellency of a surface.

[0021] - In the following description, according to what was previously set forth and similar to the anatomy of the foot, the forefoot region A, the midfoot region M and the hindfoot region R of a sole structure and a shoe item, schematically depicted in the example of figure 1a, are defined as follows:

[0022] The forefoot region is in the front region of the foot, that of the midfoot in the plantar arch region and that of the hindfoot in the back region. In particular, the forefoot region generally comprises portions of a shoe item corresponding to the toes and the joints between the metatarsal bones and the proximal phalanges, whereas the hindfoot region generally comprises portions of a shoe item corresponding to the heel bone. A shoe item (or a sole structure) further comprises a portion at the outside of the foot (side portion) and a portion at the inside of the foot (medial portion), each of which extend through the hindfoot, midfoot and forefoot portions, generally corresponding to opposing portions of the shoe item, which are ideally separated by the Brannock axis which can be defined as the axis which divides the foot in half in the back-front direction (hindfoot-forefoot). The hindfoot, midfoot and forefoot regions do not intend to demarcate precise areas of a shoe item or of a sole structure, but rather intend to provide a general representation of the areas of a shoe item or a sole structure useful in describing the invention.

[0023] - The portion of the forefoot region subjected to maximum bending, i.e. the aforesaid region of maximum bending, corresponds to a portion of the sole structure which extends near, or straddles, the bending line defined in ISO 20344:2004(E) standard, paragraph 8.4, page 64; in practice, the aforesaid bending line is about orthogonal to the longitudinal axis which, for simplicity, can be identified as the Brannock axis, and intersects it at one-third of the length of the latter, starting from the toe of the sole. Approximately, the region of maximum bending is therefore at about 1 / 3 of the overall length of the sole structure, starting from the toe, and is easily identifiable without equipment by simply holding the sole structure in the hands and bending it about 1 / 3 of its length.

[0024] In alternative to what was set forth above, the aforesaid region of maximum bending can be identified in greater detail by referring to construction lines, denoted by r, s, t, defined below considering the ground projection of the inner profile of a sole structure, illustrated in figure 1 together with the bones of the foot of a user, where it is denoted by P.

[0025] - - construction line r, which identifies the bending axis of the foot, which passes through point B which represents the end of the first metatarsal bone facing the proximal phalanx of the big toe, and in the front (towards the toe of the foot) of the distal phalanx of the fifth toe, preferably tangent to the upper end of the same, and which intersects the aforesaid projection towards the outside of the foot, at a point Y. In practice, the construction line r does not cross the fifth toe of the foot: actually, the latter is hardly affected by the bending of the foot during walking.

[0026] - - construction line s, which passes midway through the proximal phalanx of the big toe, in front of point B and at a distance from point B equal to about 15-20 mm for a man’s foot of size 42 with reference to the French sizes, measured parallel to a longitudinal axis b which, for simplicity, is similar to the aforesaid Brannock axis which divides the foot in half in the forefoot-hindfoot direction. The construction line s further intersects the distal phalanx of the fourth toe between the front end and the centre-line of the same. As constructed, the construction line s intersects the construction line r at a point O and the projection P at a point X. The point O lies on the plane containing the aforesaid ground projection of the inner profile of the sole structure.

[0027] - - construction line t which extends from the point O of intersection between the construction line r and the construction line s and intersects the projection P at a point Z, so that the arch YZ has a length equal to about half of the length of the arch XY.

[0028] The aforesaid ratio, expressible as:

[0029] LXY = 2»LYZ is obtained from experimental evidence, according to which: the arch XY extends along a portion where the bending stress of the foot and the sole structure is maximum, and the fourth toe of the foot, as seen previously for the fifth toe, is almost excluded from bending when walking, due to the anatomy of the human foot, and the arch YZ as sized therefore identifies a portion where the bending stress of the foot and of the sole structure, although assuming a lower value than the one observed at the arch XY, is anyhow a non-negligible stress for the membrane.

[0030] The construction lines s, t therefore delimit the aforesaid region of maximum bending of the sole structure.

[0031] Summary of the invention

[0032] The technical problem underlying the present invention was to provide a waterproof and breathable sole structure having characteristics such as to overcome one or more of the drawbacks mentioned above with reference to the known art.

[0033] According to the invention, the aforesaid problem is solved by a sole structure of a shoe, comprising at least one breathable portion adapted for the passage of water vapor and at which a waterproof membrane permeable to water vapor is arranged, wherein the aforesaid at least one breathable portion is arranged outside of a forefoot portion of the sole structure known as region of maximum bending.

[0034] In substance, the solution suggested consists in placing at least the membrane portion placed at the aforesaid at least one breathable portion, and preferably the whole membrane, relatively far from, and anyhow outside of, the region of maximum bending of the sole structure, while favoring the confluence of sweat in vapor phase towards the aforesaid breathable portion or breathable portions, whenever more than one are present.

[0035] In particular, the present waterproof and breathable sole structure, which has an inner face intended to be facing inside the shoe and an outer face intended to be facing the environment outside of the shoe, comprises: a tread having an upper surface on the side of the aforesaid inner face and a lower surface on the side of the aforesaid outer face, one or more ventilation channels a functional region comprising its own breathable portion adapted for the passage of water vapor, a waterproof membrane permeable to water vapor and a sealing region surrounding the aforesaid breathable portion to which the aforesaid membrane is sealed in a waterproof way, therefore by an appropriate seal, which is characterized in that the aforesaid one or more ventilation channels are adapted for directing water vapor towards the surface of the aforesaid membrane facing the aforesaid inner face, and in that the aforesaid breathable portion of the aforesaid functional region is fully arranged outside of a forefoot portion corresponding to the aforesaid region of maximum bending.

[0036] According to the above, it can therefore be said that the aforesaid functional region is waterproof and permeable to water vapor on the whole.

[0037] The aforesaid membrane is preferably fully arranged outside of the aforesaid region of maximum bending.

[0038] The aforesaid sealing region is preferably fully arranged outside of the aforesaid region of maximum bending.

[0039] The aforesaid sealing region is preferably substantially flat.

[0040] The aforesaid sealing region is preferably substantially smooth.

[0041] The aforesaid membrane is preferably sealed to the aforesaid sealing region in a waterproof way by gluing by means of a specific adhesive, by comolding or by a third element, for example a sealing ring made of waterproof material such as polyvinyl chloride - PVC, or ethylene vinyl acetate - EVA, which partly surmounts the membrane and partly the sealing region.

[0042] The aforesaid membrane is preferably made of Pll, polyester, polyethylene or ePTFE.

[0043] The aforesaid functional region is preferably provided with a cavity in which the aforesaid membrane is housed.

[0044] According to the invention, the aforesaid sealing region can be outside or inside of the aforesaid cavity, if present. In the event of a sealing region inside the cavity, the aforesaid membrane is preferably sealed by gluing or co-molding, whereas in the event of a sealing region outside of the cavity, the membrane is preferably sealed by means of the aforesaid third element, such as the aforesaid sealing ring glued so as to straddle the membrane itself and the sealing region which actually extends outside of the aforesaid cavity, surrounding it. It should be set out that, according to what is set forth above, a sealing ring can also be used in the absence of the aforesaid cavity.

[0045] The aforesaid sole structure preferably comprises a breathing element or a layer of breathable material arranged at the aforesaid membrane, above or below it, and / or a layer of material provided with channels facing, in use, the ground and arranged above the aforesaid membrane, which is preferably water- repellent and also generally referred to as protective element.

[0046] The aforesaid breathable element or layer of breathable material preferably is a polyester felt or a three-dimensional fabric.

[0047] The aforesaid one or more ventilation channels preferably have a mainly longitudinal direction, are for example directed from the hindfoot (or back region of the tread) or from the forefoot (or front region of the tread), towards the aforesaid breathable portion.

[0048] The aforesaid one or more ventilation channels can have a more or less rectilinear, wavy, curved or interrupted pattern or a combination of the same, but preferably always in a mainly longitudinal direction.

[0049] The aforesaid one or more ventilation channels preferably have a width of between 2 mm and 10 mm.

[0050] The aforesaid one or more ventilation channels preferably have a depth of between 1 mm and 5 mm.

[0051] The aforesaid one or more ventilation channels preferably have a bottom at the level of the aforesaid sealing region.

[0052] The aforesaid one or more ventilation channels are preferably delimited by ribs made in one piece with the aforesaid tread, for example by injection molding or compression molding of a polymer material, such as for example rubber, polyurethane (Pll), thermoplastic polyurethane (TPU), ethylene vinyl acetate (EVA), thermoplastic rubber (TR).

[0053] As previously set forth, the expression “breathable portion” (or breathable region) means a portion or region which can be permeable to water vapor as set forth above, since made of a breathable material, or can be a portion or region provided with at least one through opening which, as such, also allows the passage of water vapor.

[0054] In this regard, in the event of a through opening or through openings, it should be said that they preferably have circular or ellipsoidal shape, other shapes, for example quadrangular, not however being excluded.

[0055] The aforesaid at least one through opening preferably has a width of between 2 mm and 30 mm.

[0056] The aforesaid at least one through opening is preferably arranged at least at 14 mm from an inner edge of the sole structure, so as to leave a sufficiently large allowance devoid of openings to ensure the sealing of the membrane and gluing to any other components of the sole structure or to an upper assembly. In this regard, the aforesaid sealing region has a width preferably of between 4 mm and 12 mm.

[0057] According to an embodiment of the invention, the aforesaid breathable portion is between the aforesaid upper surface and the aforesaid lower surface of the aforesaid tread, particularly extended from the upper surface to the lower surface of the tread. In this case, the breathable portion is preferably, but not exclusively, arranged at the midfoot of the sole structure or at the forefoot of the sole structure in front of the aforesaid region of maximum bending, the possibility of providing the breathable portion arranged at the hindfoot, precisely inside the latter or astride the midfoot and the hindfoot, not however being excluded. Two breathable portions of the aforesaid type can also be provided, in such case, the present sole structure comprises a second functional region arranged on the aforesaid tread and which comprises its own breathable portion (second breathable portion of the sole structure) adapted for the passage of water vapor, a second waterproof membrane permeable to water vapor and a second sealing region surrounding the aforesaid breathable portion to which the aforesaid membrane is sealed in a waterproof way, in which the aforesaid breathable portion of the aforesaid second functional region is fully located outside of the aforesaid region of maximum bending, wherein the aforesaid second membrane is preferably fully located outside of the aforesaid region of maximum bending, and wherein the aforesaid second sealing region is more preferably fully located outside of the aforesaid region of maximum bending. In the event of two breathable portions, one is preferably arranged at the midfoot of the sole structure, the other at the forefoot of the sole structure in front of the aforesaid region of maximum bending.

[0058] According to the aforesaid embodiment of the present invention, the aforesaid one or more ventilation channels are arranged on the aforesaid upper surface of the tread and are in fluid communication with the aforesaid functional region and possibly with the aforesaid second functional region.

[0059] According to an embodiment variant of the invention, the present sole structure comprises a shock-absorbing element, substantially a midsole, having an upper surface, a lower surface coupled to the aforesaid upper surface of the tread and a second breathable portion adapted for the passage of water vapor, wherein the aforesaid breathable portion of the aforesaid functional region (first breathable portion) is between the aforesaid upper surface and the aforesaid lower surface of the tread, wherein the aforesaid second breathable portion is between the aforesaid upper surface and the aforesaid lower surface of the midsole, wherein the aforesaid one or more ventilation channels are arranged on the aforesaid upper surface of the midsole and are in fluid communication with the aforesaid second breathable portion, which is preferably provided with at least one through opening, and wherein the aforesaid breathable portion and the aforesaid second breathable portion are substantially overlapping each other.

[0060] According to the aforesaid embodiment variant of the invention, the present sole structure can possibly comprise a cavity (second cavity) at the aforesaid second breathable portion.

[0061] The aforesaid sole structure preferably comprises a breathable element or a layer of breathable material, preferably water-repellent, arranged at the aforesaid second breathable portion and possibly housed inside the aforesaid second cavity.

[0062] According to a further embodiment variant of the invention, the present sole structure comprises a midsole having an upper surface and a lower surface coupled to the aforesaid upper surface of the tread, wherein the aforesaid breathable portion of the aforesaid functional region is between the aforesaid upper surface and the aforesaid lower surface of the midsole, wherein the sole structure comprises a second breathable portion adapted for the passage of water vapor between the aforesaid upper surface and the aforesaid lower surface of the tread, wherein the aforesaid one or more ventilation channels are arranged on the aforesaid upper surface of the midsole and are in fluid communication with the aforesaid breathable portion, which is preferably provided with at least one through opening, wherein the breathable portion of the aforesaid functional region (first breathable portion) and the aforesaid second breathable portion are substantially overlapping each other.

[0063] According to still another embodiment variant of the invention, the present sole structure comprises a midsole having an upper surface, a lower surface coupled to the aforesaid upper surface of the tread and a second breathable portion adapted for the passage of water vapor between the aforesaid upper surface and the aforesaid lower surface of the midsole, wherein the aforesaid one or more ventilation channels comprise a first series including one or more channels arranged on the aforesaid upper surface of the midsole and a second series including one or more channels arranged on the aforesaid lower surface of the midsole, wherein the channels of the aforesaid first series and the aforesaid second series are in fluid communication with the aforesaid second breathable portion, which is preferably provided with a through opening, wherein the aforesaid breathable portion of the aforesaid functional region (first breathable portion) is between the aforesaid upper surface and the aforesaid lower surface of the tread, and wherein the aforesaid breathable portion and the aforesaid second breathable portion are staggered and not overlapping each other.

[0064] In this latter case, the aforesaid breathable portion of the aforesaid functional region (first breathable portion) and the aforesaid second breathable portion are preferably extended at the hindfoot and, respectively, at the midfoot of the sole structure.

[0065] The aforesaid one or more channels of the aforesaid first series are preferably extended from the aforesaid second breathable portion to the forefoot and the aforesaid one or more channels of the aforesaid second series are extended from the aforesaid second breathable portion to the hindfoot.

[0066] The aforesaid region of maximum bending is preferably delimited by construction lines s, t as previously defined.

[0067] According to still another embodiment variant of the invention, the present sole structure comprises a midsole having an upper surface, a lower surface coupled to the aforesaid upper surface of the tread and a side edge between the aforesaid lower surface and the aforesaid upper surface, wherein the aforesaid breathable portion of the aforesaid functional region is between the aforesaid upper surface and the aforesaid lower surface of the midsole, wherein the aforesaid one or more ventilation channels are arranged on the aforesaid upper surface of the midsole and are in fluid communication with the aforesaid breathable portion, and wherein the aforesaid sole structure is provided with one or more transversal passages extended on the aforesaid lower surface of the midsole from the aforesaid breathable portion to the aforesaid side edge.

[0068] Brief description of the figures

[0069] Further characteristics and advantages of the invention will be more evident from the review of the following detailed description of some preferred, but not exclusive, embodiments depicted for illustration purposes only and without limitation, with the aid of the attached drawings, wherein:

[0070] - figure 1 schematically shows a projection on the ground of the inner profile of a generic sole structure with corresponding construction lines r, s, t adapted for defining, in a known way, a forefoot portion of the sole structure known as the region of maximum bending, together with the bones of the foot of a user;

[0071] - figure 1a schematically shows the aforesaid inner profile of a generic sole structure with respective forefoot, midfoot and hindfoot regions;

[0072] - figure 2 is a schematic plan and top view of a first embodiment of a sole structure comprising a tread, according to the present invention;

[0073] - figure 3 is a schematic longitudinal sectional view of the sole structure according to the present invention, taken along the plane A-A of figure 2;

[0074] - figure 4 is a schematic cross sectional view of the sole structure according to the present invention, taken along the plane B-B of figure 2;

[0075] - figure 5 is a schematic view, in perspective and separate parts, of a sole structure comprising a tread and a midsole, according to an embodiment variant of the invention, in which the midsole is shown both according to a bottom view with an upper assembly denoted by dotted lines and according to a top view;

[0076] - figure 6 shows a schematic perspective view of the sole structure of figure 5 with the aforesaid upper assembly denoted by dotted lines;

[0077] - figures 7a and 7b schematically show a cross sectional view of a detail of the sole structure of figure 5, taken along the plane C-C of figure 6; according to two embodiment variants of the invention;

[0078] - figure 7c is a schematic view of a detail of the sole structure of figure 5, precisely of the aforesaid midsole, according to an embodiment variant of the invention;

[0079] - figures 8a and 8b show respective schematic views of a detail of the present sole structure, precisely of the aforesaid midsole, according to two different configurations, in accordance with a further embodiment variant of the invention;

[0080] - figure 9 is a schematic view of the present sole structure comprising a tread and a midsole, according to a further embodiment variant of the invention, and in which the midsole is shown both according to a bottom view with an upper assembly denoted by dotted lines and according to a top view;

[0081] - figure 10 is a schematic view of a detail of the sole structure of figure 9, precisely of the aforesaid midsole, according to an embodiment variant of the invention;

[0082] - figure 11 is a schematic view of the present sole structure comprising a tread and a midsole, according to a further embodiment variant of the invention, in which the midsole is shown both according to a bottom view with an upper assembly denoted by dotted lines and according to a top view.

[0083] Detailed description of the invention

[0084] The so-named region of maximum bending of a sole structure or shoe structure, as well as that of a foot, is located at the forefoot and can be identified in various ways, among which that using the construction lines r, s, t previously described in detail and illustrated in figure 1 , to which reference will be made along with figure 1a which schematically shows the regions of the sole structure identified as forefoot A, midfoot M and hindfoot R.

[0085] In particular, in figure 1 , P denotes the projection on the ground of the inner profile of a generic sole structure which can therefore be a sole structure according to the known art or a sole structure according to the present invention, the aforesaid region of maximum bending being uniquely and equally delimited in both cases by the construction lines s, t.

[0086] Keeping in mind the above, the present invention provides a waterproof and breathable sole structure comprising a waterproof membrane permeable to water vapor arranged at a breathable portion adapted for the passage of water vapor and towards which the confluence of sweat in vapor phase is favored, wherein the aforesaid breathable portion is arranged outside of the aforesaid region of maximum bending. In practice, according to the invention, the aforesaid membrane is at least partly, and preferably integrally, positioned outside of the aforesaid region of maximum bending.

[0087] With reference to the example of figures 2-4, 1 denotes a sole structure of a shoe according to the present invention, which has an inner face 2 intended to be facing the inside of the shoe and an outer face 3 intended to be facing the environment outside of the shoe.

[0088] In detail, the sole structure 1 comprises: a tread 4 having an upper surface 5 on the side of the aforesaid inner face 2 and a lower surface 6 on the side of the aforesaid outer face 3 a functional region for preventing the entry of water from the aforesaid outer face 3 towards the aforesaid inner face 2, comprising its own breathable portion 7 adapted for the passage of water vapor and extended from the upper surface 5 to the lower surface 6, a waterproof membrane 10 permeable to water vapor and a sealing region 9 surrounding the breathable portion 7 and at which the membrane 10 is sealed in a waterproof way, therefore by means of an appropriate seal; a plurality of ventilation channels (but it should be said that, according to the invention, also only one ventilation channel can be provided) for directing, on the side of the aforesaid inner face 3, water vapor towards the surface of the membrane 10 facing the inner face 2, in this specific case towards the breathable portion 7, wherein each ventilation channel, denoted by 8, preferably has a mainly longitudinal direction, and wherein the breathable portion 7 is fully arranged outside of the aforesaid region of maximum bending.

[0089] In this regard, in the example of figure 2, an inner edge of the sole structure 1 is denoted by 11, which edge substantially corresponds to the projection P on the ground of the inner profile of the generic sole structure depicted in figure 1 and to the same inner profile of the generic sole structure depicted in figure 1a.

[0090] In the embodiment according to the example of figures 2-4, as mentioned, the sole structure according to the present invention substantially comprises a breathable portion which is provided with a plurality of through openings 12 (but it should be said that, according to the invention, also only one through opening can be provided) located in the back, i.e. towards the hindfoot of the sole structure, with respect to the region of maximum bending. More precisely, the through openings 12 actually define the breathable portion 7 of the sole structure 1, which is contained inside the midfoot. More rigorously, a breathable portion can generally be defined as the minimum area whose contour contains all the aforesaid through openings. It should be added that the aforesaid contour, which is a closed line, can appropriately be modified so as to make it convex, therefore facilitating the process of making the membrane and any protective elements, as described below, wherein “convex contour” means that the space delimited by such contour contains all the segments which join the aforesaid through openings. It should be added that, in all the embodiments according to the present invention, a breathable portion can be constituted of a breathable material, such as for example leather, skin, fabric, non-woven fabric, etc., in place of the through openings. In this case, the contour of a breathable portion substantially coincides with the contour of the breathable material (or the breathable materials, if more than one).

[0091] In the event of through openings, is should be said that they preferably have circular or ellipsoidal shape, other shapes, for example a quadrangular shape, not however being excluded.

[0092] Moreover, the through openings 12 have a width preferably of between 2 mm and 30 mm and are preferably arranged at least at 14 mm from the inner edge 11 of the sole structure 1, so as to leave a sufficiently large allowance devoid of openings to ensure the sealing of the membrane 10 and the gluing to any other components of the sole structure or to an upper assembly intended to be constrained to the present sole structure.

[0093] What is set forth above in the event of several through openings is also valid in the event only one through opening is provided or in the event a breathable material is used in place of the through openings.

[0094] As far as the sealing region 9 extending outside along the perimeter of the aforesaid breathable portion is concerned, it should be said that it preferably has a width of between 4 mm and 12 mm and that the through openings 12 are preferably located inside at 4 mm from the sealing region.

[0095] Moreover, the sealing region 9 is preferably fully arranged outside of the aforesaid region of maximum bending and is preferably substantially flat and / or smooth so as to make the seal between the membrane 10 and the tread 4 stronger.

[0096] The membrane 10 is constrained to the sealing region 9, which membrane, in addition to actually being waterproof and permeable to water vapor, is sealed in a waterproof way to the aforesaid sealing region by gluing by means of a dedicated adhesive, by co-molding or by a third element, for example a sealing ring made of waterproof material, such as polyvinyl chloride - PVC, or ethylene vinyl acetate - EVA, which partly surmounts the membrane and partly the sealing region, as will be illustrated more in detail below.

[0097] The membrane 10, which is practically a functional layer, is preferably made of polyurethane (Pll), polyester, polyethylene or ePTFE.

[0098] As shown in the example of figures 2-4, the sole structure 1 can further be equipped with a cavity 13, however optional for the sole structure according to the present invention, arranged at the aforesaid functional region in which the membrane 10 is housed.

[0099] Consequently, the aforesaid sealing region can be outside or inside of the aforesaid cavity, if present. In the event of a sealing region inside the cavity, the aforesaid membrane is preferably sealed by gluing or co-molding, whereas in the event of a sealing region outside of the cavity, the membrane, as mentioned above, is preferably sealed by means of a sealing ring glued so as to straddle the membrane itself and the sealing region actually extends outside of the aforesaid cavity, surrounding it, as illustrated in the examples of figures 2-4, where the aforesaid sealing ring is not shown.

[0100] It should be set out that, according to what is set forth above, a sealing ring can also be used in the absence of the aforesaid cavity.

[0101] The ventilation channels 8 converge and are interrupted in the sealing region 9, so as to not interfere with the sealing of the membrane 10 to the tread 4.

[0102] In particular, as far as the ventilation channels 8 are concerned, it should be added that they can have a more or less rectilinear, wavy, curved or interrupted pattern or a combination of the same, but always in a mainly longitudinal direction, and that they are defined by ribs 14 which, depending on the ventilation channels, can be mainly continuous or interrupted, for example when one or more ventilation channels cross each other, as in the example of figures 2-4.

[0103] The ribs 14 are preferably made in one piece with the tread 4, for example by injection molding or compression molding of a polymer material, such as for example rubber, polyurethane (PU), thermoplastic polyurethane (TPU), ethylene vinyl acetate (EVA), thermoplastic rubber (TR).

[0104] In particular, it is also possible to make the tread by direct injection on the shoe upper, through a preformed insert provided with ventilation channels and loaded into the mold. This way, the ventilation channels are already made on the insert, for example by compression molding, and are not therefore made during the molding process of the tread, which process can therefore be sped up and simplified. The making of the ventilation channels by direct injection on the shoe upper would actually require, if a preformed insert is not used, particular attention to temperature, pressure and duration of the process and could lead to possible defects: for example, closed channels, not visible from the outside because the inside of a sole structure made by direct injection on a shoe upper is practically inaccessible to sight.

[0105] The ventilation channels 8, which are directed from the hindfoot (or back region of the tread) and from the forefoot (or front region of the tread) towards the aforesaid breathable portion preferably have a width of between 2 mm and 10 mm and preferably a depth of between 1 mm and 5 mm.

[0106] Moreover, the ventilation channels 8 preferably have a bottom at the level of the sealing region 9. In practice, the ventilation channels 8 are smoothly connected to the sealing region 9, i.e. steps are practically avoided between the ventilation channels and the sealing region, which steps could cause undesired stagnation with the consequent risk of condensing sweat in vapor phase. Actually, the sweat in vapor phase coming from the ventilation channels 8 is collected at the sealing region 9 and the breathable portion 7.

[0107] In particular, according to the example of figures 2-4, the sealing region 9 is in low relief by a quantity H preferably of between 1 and 5 mm with respect to the upper surface of the ribs 14, so as to create a gap which accommodates the sweat in vapor phase coming from the ventilation channels 8. In particular, the aforesaid gap is defined below by the sealing region 9 and by the membrane 10, and above by the aforesaid upper assembly.

[0108] A breathable material, for example polyester felt, a three-dimensional fabric, etc., which provides support to the upper assembly without blocking sweat, or a non-breathable material however provided with channels facing, in use, the ground and guiding the sweat in vapor phase coming from the ventilation channels 8 towards the through openings 12, is located inside the gap.

[0109] More generally, it can be said that, according to the invention, the present sole structure can comprise a breathable element or a layer of breathable material arranged at the membrane, above or below it, and / or a layer of material provided with channels facing, in use, the ground and arranged above the membrane, which is preferably water-repellent and also generally referred to as protective element.

[0110] Keeping in mind what is set forth above, it should be said that the depth of the cavity 13 is preferably equal to that of the total thickness of the membrane 10 and of any materials or protective elements, whenever present. The template of the cavity 10 is therefore formed as a negative offset of the inner edge 11 of the sole structure 1, so as to leave at least a 10 mm allowance for gluing between the tread 4 and the upper assembly, the cavity 13 preferably having a longitudinal extent of between 5% and 50% of the length of the tread 4 and appropriately connecting the edges thus obtained with a radius of curvature preferably of between 2 and 10 mm.

[0111] In the example of figures 2-4, the aforesaid breathable portion or breathable region containing the through openings 12, for which it can be said that it is not physically, but only ideally, demarcated and which is designed with sharp angles for convenience only, is arranged at the midfoot of the sole structure 1. Although the aforesaid breathable portion is not physically demarcated in the example of figures 2-4, a longitudinal extent of between 5% and 50% of the length of the tread can also be provided for it.

[0112] In this regard, recalling that the aforesaid ventilation channels have the task of favoring the flow of the sweat in vapor phase coming from the upper assembly through a respective insole, towards the breathable portion, the following is observed.

[0113] After having crossed the insole and reached the ventilation channels, the sweat in vapor phase naturally tends to escape through the through openings of the breathable portion due to the partial vapor pressure which is greater inside the ventilation channels than that in the outer environment.

[0114] A further boost to the escape of the sweat in vapor phase through the through openings comes from the compression acting on the ventilation channels, which occurs due to walking.

[0115] As mentioned, according to the example of figures 2-4, the sweat in vapor phase can escape towards the outer environment from the through openings 12 placed on the tread 4 at the midfoot of the present sole structure. In this regard, the breathable portion is located at about the region of the sole structure where the intermediate heel-to-toe motion step occurs, i.e. the movement performed by the foot of a user (therefore also performed by the sole structure according to the present invention) which lands starting from the hindfoot to then lean on the midfoot and finally on the forefoot. In practice, the thrust of the sweat in vapor phase is exerted for a first period substantially coinciding with the first heel-to-toe motion step, i.e. assuming the maximum value in a region around the sole structure which progressively moves from the hindfoot up to reaching the breathable portion in the midfoot. The thrust of the sweat in vapor phase due to compression is then exerted, as the heel-to-toe motion progresses, for a second period substantially coinciding with the final part of the heel-to-toe motion, i.e. assuming the maximum value in a region around the sole structure which can progressively move from the breathable portion of the midfoot up to reaching the forefoot. During this second period, the sweat in vapor phase, which is located right after the breathable portion, is pushed towards the breathable portion and, gradually, that which is located farther away from the latter, i.e. at the toe of the sole structure.

[0116] As previously set forth, the present sole structure is intended to be joined to an upper assembly (not shown in the example of figures 2-4) on the part of the inner face 2 of the sole structure 1, i.e. at the upper surface 5 of the tread 4, according to known arts, such as for example gluing. In detail, the joining of the upper assembly and the sole structure occurs at the aforesaid insole, which is placed on the lower part of the upper assembly, between the lower surface of the insole and the upper surface of the sole structure.

[0117] In particular, the insole is made of a breathable or pierced material preferably at least at the forefoot and / or at the aforesaid breathable portion of the functional region of the sole structure. This way, the sweat in vapor phase, which is produced by the foot of the user inside the upper assembly, can cross the insole and reach the breathable portion of the sole structure in a so-named “direct” way, through the holes present in the insole (or by crossing the breathable material), and / or in a so-named “indirect” way, through the holes present at the forefoot (or by crossing the breathable material), therefore reaching the aforesaid ventilation channels and reaching, from the same, the breathable portion of the sole structure.

[0118] Advantageously, according to the invention, by locating at least the membrane portion placed at the breathable portion outside of the region of maximum bending of the sole structure, the risk of breaking the same is removed and the range of usable membranes is further increased, also comprising, for example, membranes with a relatively low flexural strength but which are particularly inexpensive.

[0119] It should be added that the embodiment according to the example of figures 2-4 is also particularly adapted for women’s shoes which use a sole structure comprising a tread and a relatively high heel, the latter applied in the hindfoot region. Generally, the thickness of the tread for this type of shoes ranges from 2.5 mm and 5 mm and the aforesaid ventilation channels therefore preferably have a depth of between 1 mm and 3 mm. It should be noted that in such types of women’s shoes, it would almost be impossible to form a breathable portion at the hindfoot.

[0120] Anyway, if the breathable portion is located at the midfoot in the example of figures 2-4, it should be said that according to embodiment variants of the present invention, it can be provided, as an alternative, at the forefoot of the sole structure, in front of the region of maximum bending. In such case, the region of the sole structure where the final heel-to-toe motion step occurs substantially coincides with the breathable portion. In practice, the thrust of the sweat in vapor phase is practically exerted continuously from the hindfoot up to the forefoot before reaching the breathable portion.

[0121] Moreover, according to the invention, it should be said that the possibility of providing a breathable portion of the aforesaid type arranged at the hindfoot, precisely inside the latter or placed astride the midfoot and hindfoot, is not excluded. In the event of breathable portion at the hindfoot, the present sole structure advantageously offers additional freedom of implementation and can be useful in implementations comprising, for example, special safety devices which would make the implementation of a breathable portion more difficult at the midfoot and / or forefoot.

[0122] Two breathable portions of the aforesaid type can also be provided, in such case, the present sole structure comprises a second functional region arranged on the aforesaid tread, which comprises a second breathable portion adapted for the passage of water vapor, a second sealing region surrounding the aforesaid second breathable portion and a second waterproof membrane permeable to water vapor and sealed in a waterproof way to the aforesaid second sealing region, wherein the aforesaid second breathable portion of the aforesaid second functional region is fully located outside of the aforesaid region of maximum bending, and wherein the aforesaid second sealing region is preferably fully located outside of the aforesaid region of maximum bending, wherein the aforesaid second membrane is therefore preferably located outside of the aforesaid region of maximum bending. In the event of two breathable portions, one is preferably arranged at the midfoot of the sole structure, the other at the forefoot of the sole structure in front of the aforesaid region of maximum bending. Such solution is advantageous because it allows to increase the overall breathable area of the sole structure.

[0123] With reference to the example of figures 2-4, it should be added that the aforesaid tread extends in length along a longitudinal axis in the forefoothindfoot direction (axis A-A). In this case, the tread is therefore continuous in the sole structure. According to the present invention, it is however possible to provide a discontinuous tread, i.e. comprising two or more portions not in contact with each other and i.e. isolated from each other. In the event of a discontinuous tread, the sole structure according to the present invention further comprises a midsole, as in the embodiments described below.

[0124] With reference to figures 5, 6, 7a and 7b, an embodiment variant of the present invention is now described in detail.

[0125] In particular, in the aforesaid figures, there is shown a sole structure 100 similar to the sole structure 1 illustrated with reference to the example of figures 2-4 to whose description reference is made and from which it differs essentially in that it comprises a shock-absorbing element, practically a midsole denoted by 115 and on which ventilation channels 108 are provided in fluid communication with a respective breathable portion of the midsole (second breathable portion), whereas the tread does not have ventilation channels.

[0126] In detail, the sole structure 100 comprises a tread 104 provided with through openings 112 which define a breathable portion 107 which is surrounded by a sealing region 109 to which a membrane 110, fully similar to the membrane 10 previously described and to which reference is made, is constrained in a waterproof way.

[0127] The aforesaid membrane, the breathable portion 107 and the sealing region 109 define a functional region waterproof and permeable to water vapor on the whole.

[0128] The aforesaid midsole, denoted by the numerical reference 115, which comprises an upper surface 116 and a lower surface 117 that is coupled to the tread 104 at the upper surface 105 of the latter, is constrained to the tread 104.

[0129] The midsole 115 preferably extends throughout the surface of the tread 104.

[0130] As mentioned above, the midsole 115 is further provided with a breathable portion, also identified as second breathable portion and denoted by 118, adapted for the passage of water vapor and extended from the upper surface 116 to the lower surface 117 of the midsole.

[0131] The ventilation channels 108 are arranged on the upper surface 116 of the midsole 115 and are in fluid communication with the second breathable portion 118 which, as illustrated in the examples of the figures, is preferably provided with through openings 112a, wherein the breathable portion 107 of the functional region, therefore of the tread (first breathable portion), and the second breathable portion 118 of the midsole are substantially overlapping each other and preferably arranged at the midfoot, as illustrated in figure 5, the possibility of providing them at the hindfoot or astride the midfoot and the hindfoot or in the forefoot outside of the region of maximum bending not however being excluded.

[0132] The ventilation channels 108 have substantially longitudinal extent and preferably a nearly rectilinear pattern.

[0133] Moreover, substantially transversal channels, not illustrated in the examples of the figures, can optionally be provided, also with a nearly rectilinear pattern from the outside of the foot to the inside of the foot and preferably oriented along the aforesaid construction lines r, s, t described previously. This is advantageous because it allows the sole structure to bend in accordance with the movement of the foot during the various heel-to-toe motion steps.

[0134] In practice, the ventilation channels 108 of the midsole 115 of the sole structure 100 substantially perform the same function as the ventilation channels 8 of the tread 4 of the sole structure 1.

[0135] The use of the midsole 115 advantageously allows to lighten the sole structure because, since the aforesaid channels are no longer provided on the tread, the same tread can be made with a reduced thickness: this results in a lightening of the sole structure because the tread is usually made of materials having a density which can also be equal to two or three times that of the materials used for the midsole.

[0136] In the example of figure 5, the ventilation channels 108 are depicted at the forefoot but, in accordance with the invention, they can be provided, as an alternative or in addition, at the hindfoot, they can moreover also have a similar pattern as that of the ventilation channels 8 of the sole structure 1 previously described.

[0137] Also in this case, the present sole structure can possibly comprise a cavity 113 (first cavity) arranged on the upper surface 105 of the tread 104 in which the membrane 110 is housed, and can optionally comprise a cavity 120 (second cavity) arranged at the midsole 115, in particular at the aforesaid second breathable portion.

[0138] The sole structure according to the present invention can therefore comprise two, one or no cavities.

[0139] In particular, as far as the cavity 113 provided on the tread 104 and inside which the membrane 110 is arranged is concerned, it should be said that the seal of the latter at the sealing region 109 can occur by gluing, or by means of a sealing element 122, as shown in the example respectively of figure 7a and 7b where the sole structure 100 is illustrated without a midsole, wherein the sealing element 122 can be, for example, a PVC or EVA sealing ring.

[0140] A protective element, such as for example a water-repellent polyester felt, can further be located below or above the membrane 110.

[0141] The protective element, which is therefore optional, can also be defined as breathable element or layer of breathable material and is denoted by the numerical reference 121 in the example of figure 5.

[0142] In particular, a protective element placed above the membrane can be used to “level off” the difference in level possibly created by the sealing element and which can be perceived by a user, and is generally used to provide further protection to the membrane which comes into contact with the upper assembly.

[0143] A protective element placed below the membrane protects it from any roughness on the surface of the tread with which it comes into contact. The roughness can mostly be present at the through openings due to leakages of the material with which the tread is molded and / or due to an imperfect carding operation necessary for removing residues of material to make the aforesaid openings through openings, which would otherwise be blind in the case of tread made, for example, of Pll or compressed EVA (where such residues of materials cannot be avoided, due to the molding process).

[0144] When the protective element is placed below the membrane and the latter is sealed directly to the tread, i.e. without the aforesaid sealing element, the protective element has smaller dimensions than those of the membrane, being obtained for example with a negative offset of 4-6 mm with respect to the membrane template so as to not preclude the seal.

[0145] As far as the cavity 120 arranged at the midsole 115 is concerned, it should be said that it almost has the same template as the cavity 113 arranged on the tread 104.

[0146] The sole structure 100 can further comprise a breathable element or a layer of breathable material, preferably water-repellent, arranged at the second breathable portion 118 and possibly housed in the cavity 120 of the midsole, above or below the through openings 112a, depending on the position of the cavity 120: arranged on the upper or lower surface of the midsole. It should be added that the cavity 120 can be a fully through cavity and fully filled by the aforesaid breathable element or layer of breathable material. In practice, in the latter case, it is like having a single through opening filled with the breathable element or layer of breathable material.

[0147] The breathable element or layer of breathable material is shaped according to the template of the cavity 120 and can be made, for example, of three-dimensional fabric.

[0148] The aforesaid breathable element or layer of breathable material at the midsole contributes to further lighten the sole structure, simultaneously ensuring the flow of the sweat in vapor phase coming from the through openings 112a of the midsole 115 towards the membrane 110, and from there out towards the outer environment through the through openings 112 of the tread 104.

[0149] According to the invention, also in this embodiment, the drainage of the sweat in vapor phase occurs far from the region of greatest sweating and maximum bending of the foot, thanks to the combined action of the ventilation channels 108 of the midsole and of the through openings 112a and 112 provided on the midsole 115 and respectively on the tread 104.

[0150] As far as still concerns the aforesaid ventilation channels, it should be added that, as an alternative to what is set forth above, they can have a curvilinear pattern which mainly concerns the regions mostly concerned by the heel-to-toe motion, in particular the forefoot portion closest to the outside of the foot, as shown in figure 7c where a left midsole 115 is depicted, which is a shock-absorbing element, provided with ventilation channels 108a with convexity facing the outer portion of the foot. This embodiment allows to better exploit the compression deriving from the heel-to-toe motion because it follows its pattern more closely.

[0151] For the embodiments described with reference to figures 5, 6, 7a, 7b and 7c, unless otherwise stated, the same as set forth above for the sole structure 1 applies, with the respective variants described with reference to figures 2-4. With reference to figures 8a and 8b, a further embodiment variant of the present invention according to two different configurations is now described.

[0152] In detail, in the examples of figures 8a and 8b, a detail of the present invention is schematically illustrated, namely a midsole 225 of a sole structure similar to the sole structure 100 described with reference to the example of figures 5, 6, 7a, 7b and 7c to which reference is made and from which it differs essentially in that it comprises a membrane 210 constrained to the midsole 225, at a sealing region 209 instead of at the tread, the latter not being illustrated in the example of figures 8a and 8b.

[0153] The midsole 225 is therefore intended to be constrained to a tread which has no ventilation channels and no sealing region, whereas it has a second breathable portion.

[0154] In practice, in the embodiment of the example of figures 8a and 8b, the functional region with its own breathable portion (first breathable portion) of the sole structure is arranged at the midsole and not at the tread, as occurs in the embodiments previously described.

[0155] In detail, the midsole 225 comprises an upper surface 226, a lower surface 227 intended to be coupled to the upper surface of the aforesaid tread and the aforesaid breathable portion 207 adapted for the passage of water vapor and extended from the upper surface 226 to the lower surface 227.

[0156] Moreover, the midsole 225 has ventilation channels 208 arranged on its own upper surface 226, which are in fluid communication with the breathable portion 207 which is preferably provided with through openings 212a.

[0157] According to the invention, the aforesaid breathable portion of the midsole (first breathable portion) and the aforesaid breathable portion of the tread (second breathable portion) are substantially overlapping each other, in particular at the midfoot, the possibility of providing them at the hindfoot or astride the midfoot and hindfoot or in the forefoot outside of the region of maximum bending not however being excluded.

[0158] In the example of figure 8a, the sealing region 209 to which the membrane 210 is sealed is arranged on the upper surface 226 of the midsole. Moreover, there may be a cavity 213, in which the membrane 210 is housed, on the upper surface 226.

[0159] As an alternative, as shown in the example of figure 8b, the membrane 210 can be sealed on the lower surface 227 of the midsole 225 on which the sealing region 209 is therefore also arranged and on which there may be a cavity 213 which accommodates the membrane 210.

[0160] By keeping in mind what was previously set forth above, it is observed that, in particular with reference to the example of figure 8a, depending on the type of sealing, the sealing region 209 can be provided outside of the cavity 213 or inside the cavity 213. If the membrane is sealed directly to the midsole and inside the cavity, then the seal is made, for example, by glue at least along an outer strip of the cavity between about 4 mm and about 6 mm wide. If the membrane is sealed indirectly to the midsole through a sealing element of the type previously considered, then the latter is placed astride the membrane and sealing region, and the sealing element is sealingly joined to the midsole at the sealing region.

[0161] With reference to the example of figure 8b, it should be said that the membrane is practically always sealed at a sealing region contained inside the cavity. In this case, the membrane is always sealed directly to the midsole without requiring a sealing element.

[0162] Similarly to what was set forth for the previous embodiments to which reference is made, a breathable element or a layer of breathable material not illustrated in the examples of figures 8a and 8b, can be located below or above the membrane, depending on the position of the membrane, throughout all or part of the thickness of the midsole, by taking care to maintain the sealing region for the membrane. This means that the template of the aforesaid breathable element or layer of breathable material is smaller than the template of the membrane, since practically formed as a negative offset of a value of between 4 mm and 10 mm of the latter. The aforesaid breathable element or layer of breathable material is advantageous because it further reduces the weight of the present sole structure.

[0163] Generally, the use of the aforesaid breathable element or layer of breathable material is advantageous because it also allows to use materials also characterized by, in addition to high breathability, elasticity (i.e. the ability of a material to be reversibly deformed upon shock) and / or resilience (i.e. the ability of a material to absorb the energy resulting from stress, typically a shock) that are different from those of the material constituting the midsole. Being able to place the membrane not only in the midfoot but also in the hindfoot, the use of a particularly elastic breathable element or layer of breathable material can increase the elastic response of the sole structure, therefore returning part of the stress suffered as an upward thrust and making walking less tiring.

[0164] For the embodiments of figures 8a and 8b, unless otherwise specified, the same as set forth above for the sole structures 1 and 100, with the respective variants illustrated with reference to the respective figures to whose description we refer, applies.

[0165] With reference to figure 9, a further embodiment of the present invention is now described.

[0166] In detail, in the example of figure 9, there is described a sole structure 300 similar to the sole structure 100 described with reference to figures 5, 6, 7a, 7b and 7c to which reference is made and from which it differs essentially in that the breathable portion of the functional region provided on the tread (first breathable portion) and the breathable portion of the midsole (second breathable portion) are not overlapping each other, and in that it comprises ventilation channels both on the upper surface of the midsole and on the lower surface of the midsole.

[0167] The sole structure 300 namely comprises a midsole 325 constrained to a tread 304 which has no ventilation channels, whereas it has a sealing region 309 surrounding a breathable portion 318 (first breathable portion) preferably comprising through openings 312 and to which a membrane 310 arranged in a cavity 313 is sealed.

[0168] In the example of figure 9, the sealing region 309 is inside the cavity 313, it is however possible to provide a sealing region outside of the cavity and which surrounds the latter if the aforesaid membrane is sealed to the tread through a sealing element similar to the one described previously.

[0169] In particular, the midsole 325 comprises an upper surface 326 and a lower surface 327 coupled to the upper surface of the tread 304 and on which there are ventilation channels 308, and a breathable portion 318a (second breathable portion) adapted for the passage of water vapor and extended from the upper surface 326 to the lower surface 327 of the midsole, wherein the ventilation channels 308 comprises a first series of channels 308a arranged on the upper surface 326 of the midsole and a second series of channels 308b arranged on the lower surface 327 of the midsole, wherein the channels of the aforesaid first series and the aforesaid second series are in fluid communication with the second breathable portion 318a of the midsole 325, which is preferably provided with through openings 312a.

[0170] In particular, the aforesaid ventilation channels converge in the through openings 312a.

[0171] It should be added that the channels 308a of the first series are extended from the second breathable portion 318a to the forefoot and the channels 318b of the second series are extended from the second breathable portion 318a to the hindfoot.

[0172] As mentioned above, the breathable portion 318 of the tread and the breathable portion 318a of the midsole are not overlapping with each other and, in particular, the first is provided at the hindfoot and the second at the midfoot.

[0173] Each channel 308b of the aforesaid second series converges, at the opposite end of the one which converges in the corresponding through opening 312a, in the breathable portion 318 of the tread 304. This way, the sweat in vapor phase, produced mainly at the forefoot, reaches the channels 308a of the first series of ventilation channels, crosses the through openings 312a thus reaching the channels 308b of the second series of ventilation channels and from there reaches the openings 312 provided on the tread 304 (after having crossed the membrane 310), then it reaches the outer environment from them.

[0174] This embodiment is advantageous because it allows greater freedom of execution, in particular by allowing to locate the through openings provided on the tread for the escape of the sweat in vapor phase at the hindfoot, where the surface useful for breathability can be in some cases greater than the one available at the midfoot, and to use, at the hindfoot region of the midsole, components, such as pads filled with fluids, lighting devices, sensors or the like, which would prevent to locate the aforesaid through openings at the hindfoot.

[0175] Still as far as the aforesaid ventilation channels are concerned, it should be added that they can be substantially longitudinal, as illustrated in the example of figure 9. As an alternative, the channels 308a of the first series of channels can have convexity facing the outer portion of the foot, similarly to what is illustrated in the example of figure 7c, and / or the channels 308b of the second series of channels can have convexity facing the outside of the foot, as in the example of figure 10, so as to follow the heel-to-toe motion more closely, therefore nearly maximizing the compression acting on the sweat in vapor phase present inside the same ventilation channels at each point.

[0176] For the embodiments illustrated with reference to figures 9 and 10, unless otherwise specified, the same as set forth above for the sole structures described previously, with the respective variants, to whose description we refer, applies.

[0177] With reference to figure 11 , a further embodiment of the present invention is now described.

[0178] In detail, a sole structure 400 similar to the sole structure described with reference to the example of figures 8a and 8b, to which reference is made and from which it differs essentially in that the tread is devoid of a breathable portion, is schematically illustrated in the example of figure 11. That is, the sole structure 400 comprises a midsole 425 constrained to a tread 404, wherein the tread neither has ventilation channels nor a breathable portion, whereas the midsole 425, which comprises an upper surface 426, a lower surface 427 coupled to the upper surface 405 of the tread and a side edge 450 extended between the lower surface 427 and the upper surface 426, is provided with a breathable portion 407 comprised between the upper surface 426 and the lower surface 427.

[0179] The sole structure 400 also comprises ventilation channels 408 arranged on the upper surface 426 of the midsole, which are in fluid communication with the breathable portion 407, which is preferably provided with through openings 412.

[0180] In this embodiment, the respective sole structure therefore comprises a functional region comprising the aforesaid breathable portion 407 adapted for the passage of water vapor, a waterproof membrane 410 permeable to water vapor and a sealing region 409 surrounding the breathable portion 407 and at which the membrane 410 is sealed in a waterproof way.

[0181] In the example of figure 11 , the sealing region 409 to which the membrane 410 is sealed is arranged on the upper surface 426 of the midsole and surrounds a cavity 413 at which the through openings 412 are arranged.

[0182] According to the invention, the sole structure 400 is further provided with one or more passages 460, three passages in the example of figure 11 , extending transversely on the lower surface 427 of the midsole 425, from the breathable portion 407 to the side edge 450.

[0183] For the embodiment of figure 11 , unless otherwise specified, the same as set forth above for the sole structures illustrated with reference to figures 8a and 8b, with the respective variants, to which the description we refer, applies.

[0184] The advantages of the present invention, which have become apparent throughout the description set forth above, can be summarized by pointing out that a waterproof and breathable sole structure, particularly resistant and durable and therefore able to prevent breaking following repeated bending cycles, is provided.

[0185] Moreover, the present sole structure advantageously ensures a high level of comfort when walking.

[0186] Moreover, the present sole structure can advantageously be made at a low cost.

[0187] The sole structure according to the present invention is therefore economical and reliable.

[0188] What above is due to the moving away at least of the breathable portion to which the waterproof and breathable membrane is combined, from the so- named region of maximum bending of the sole structure at which there is also most of the sweat glands of the foot, simultaneously favoring the confluence of the sweat in vapor phase towards the breathable portion of the tread and possibly of the midsole, for its expulsion outside of the shoe.

[0189] In this regard, it should be recalled that the purpose of the invention is to preserve the functionality of the aforesaid functional region for a long time, to prevent water from entering from the outside to the inside of the shoe comprising this sole structure. Recalling that the contour of the aforesaid sealing region of the tread or sole, by construction, contains the contour of the aforesaid breathable portion of the tread or midsole, and that the membrane extends both into the breathable portion and the sealing region, it should be emphasized that the aforesaid functionality can also be preserved in the event the membrane should break in the sealing region of the tread or midsole, since the impermeability would anyhow be guaranteed, in this case, by the presence of the seal. According to the invention, it is therefore sufficient that the aforesaid breathable portion of the functional region is outside of the region of maximum bending, while the sealing region and the whole membrane are also preferably outside of the region of maximum bending.

[0190] In order to meet contingent and specific needs, a technician of the field can make numerous changes and modifications to the present invention in the embodiments shown and described, all thereby comprised in the protection scope of the invention as defined in the following claims.

Claims

CLAIMS1. Waterproof and breathable sole structure having an inner face (2) intended to be facing inside a shoe and an outer face (3) intended to be facing the environment outside of the shoe, wherein said sole structure (1 ) comprises: a tread (4) having an upper surface (5) on the side of said inner face (2) and a lower surface (6) on the side of said outer face (3), one or more ventilation channels (8), a functional region comprising its own breathable portion adapted for the passage of water vapor, a waterproof membrane (10) permeable to water vapor and a sealing region (9) surrounding said breathable portion to which said membrane is sealed in a waterproof way, characterized in that said one or more ventilation channels (8) are adapted for directing water vapor towards the surface of said membrane facing said inner face and in that said breathable portion of said functional region is fully located outside of a forefoot portion corresponding to a region of maximum bending.

2. Sole structure according to claim 1 , wherein said membrane (10) is fully located outside of said region of maximum bending and / or wherein said sealing region (9) is fully located outside of said region of maximum bending.

3. Sole structure according to claim 1 or 2, wherein said sealing region(9) is substantially flat, wherein preferably said sealing region is essentially smooth.

4. Sole structure according to any one of the preceding claims, wherein said functional region is provided with a cavity (13) in which said membrane(10) is housed.

5. Sole structure according to any one of the preceding claims, comprising a breathable element or a layer of breathable material (121 ), preferably water-repellent and arranged at, above or below, said membrane,and / or a layer of material provided with channels facing the ground, in use arrangement, and arranged above said membrane.

6. Sole structure according to any one of the preceding claims, wherein said breathable portion is between said upper surface (5) and said lower surface (6) of said tread, wherein said breathable portion is preferably arranged at the midfoot or at the forefoot in front of said region of maximum bending.

7. Sole structure according to claim 6, comprising a second functional region arranged on said tread and comprising its own breathable portion adapted for the passage of water vapor, a second sealing region surrounding said breathable portion and a second waterproof membrane permeable to water vapor and sealed to said second sealing region in waterproof way, wherein said breathable portion of said second functional region is fully located outside of said region of maximum bending, wherein said second sealing region is preferably fully located outside of said region of maximum bending and / or wherein said second membrane is fully located outside of said region of maximum bending.

8. Sole structure according to claim 6 or 7, wherein said one or more ventilation channels (8) are arranged on said upper surface (5) of said tread (4) and are in fluid communication with said functional region and possibly with said second functional region.

9. Sole structure according to claim 6, comprising a midsole (115) having an upper surface (116), a lower surface (117) coupled to said upper surface (105) of said tread (104) and a second breathable portion (118) adapted for the passage of water vapor and between said upper surface (116) and said lower surface (117) of said midsole (115), wherein said one or more ventilation channels (108) are arranged on said upper surface (116) of said midsole (115) and are in fluid communication with said second breathable portion (118), and wherein said breathable portion (107) and said second breathable portion (118) are substantially overlapping each other.

10. Sole structure according to claim 9, comprising a breathable elementor a layer of breathable material (121 ), preferably water-repellent and arranged at said second breathable portion (118).

11. Sole structure according to any one of claims 1-5, comprising a midsole (225) having an upper surface (226) and a lower surface (227) coupled to said upper surface of said tread, wherein said breathable portion (207) of said functional region is between said upper surface (226) and said lower surface (227) of said midsole (225), said sole structure comprising a second breathable portion between said upper surface (5) and said lower surface (6) of said tread, wherein said one or more ventilation channels (208) are arranged on said upper surface (226) of said midsole (225) and are in fluid communication with said breathable portion (207), wherein said breathable portion (207) and said second breathable portion are substantially overlapping each other.

12. Sole structure (300) according to claim 6, comprising a midsole (325) having an upper surface (326), a lower surface (327) coupled to said upper surface of said tread (304) and a second breathable portion (318a) adapted for the passage of water vapor and between said upper surface (326) and said lower surface (327) of said midsole (325), wherein said one or more ventilation channels (308) comprise a first series including one or more channels (308a) arranged on said upper surface (326) of said midsole and a second series including one or more channels (308b) arranged on said lower surface (327) of said midsole, wherein the channels (308a, 308b) of said first series and said second series are in fluid communication with said second breathable portion (318a), wherein said breathable portion (318) and said second breathable portion (318a) are staggered and not overlapping.

13. Sole structure (300) according to claim 12, wherein said breathable portion (318) of said functional region and said second breathable portion (318a) are extended at the hindfoot and the midfoot, respectively, wherein said one or more channels (308a) of said first series are preferably extended from said second breathable portion (318a) to the forefoot and said one or more channels (308b) of said second series are extended from said secondbreathable portion (318a) to the hindfoot.

14. Sole structure according to any one of claims 1-5, comprising a midsole (425) having an upper surface (426), a lower surface (427) coupled to said upper surface (405) of said tread (404) and a side edge (450) between said lower surface (427) and said upper surface (426), wherein said breathable portion (407) of said functional region is between said upper surface (426) and said lower surface (427) of said midsole (425), wherein said one or more ventilation channels (408) are arranged on said upper surface (426) of said midsole and are in fluid communication with said breathable portion (407), and wherein said sole structure is provided with one or more transversal passages (460) extended on said lower surface (427) of said midsole from said breathable portion (407) to said side edge (450).

15. Sole structure according to any one of the preceding claims, wherein said one or more ventilation channels (8) have a width of between 2 mm and 10 mm, wherein said one or more ventilation channels (8) preferably have a depth of between 1 mm and 5 mm.

16. Sole structure according to any one of the preceding claims, wherein said one or more ventilation channels (8) have a bottom at the level of said sealing region (9).

17. Sole structure according to any one of the preceding claims, wherein said region of maximum bending is delimited by construction lines s, t.

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