IMPROVED SHOE SOLE AND SHOE INCLUDING SUCH A SHOE SOLE

DESCRIPTION Field of the invention

The present invention relates to the shoe industry and it relates, in particular, to an improved structure of shoe sole.

The invention relates to a shoe, which includes such a sole .

State of the art

The shoe sole that is fixed to the shoe upper, by gluing and/or sewing, must have determined properties in order to guarantee a correct posture of the foot of the person who puts on the shoe, and a correct loads distribution during the gait, in particular on the foot, and from the foot to the ground. An incorrect positioning on the ground, in fact, not only has a negative impact on the foot, but also on the other parts of the lower limbs, in particular on the ankles and the knees.

An incorrect posture can cause, over time, inflammations to the joints of the lower limbs, up to cause serious consequences, in particular for the muscles and the tendons, due to an incorrect load distribution on the feet and an incorrect discharge of the loads on the ground .

The shoes currently on the market, in particular those that have a very thin sole made of rubber, have many drawbacks .

Firstly, the thin shoes cause the arch of the foot sole to become flat up to obstruct the blood circulation. The flat shoes can, furthermore, cause tendon inflammations, in particular of the Achilles tendon, that is located just above the heel.

Another drawback of the shoes having a thin sole, is that, in the case of irregularities in the ground, as for example the presence of small stones, have repercussions on the user foot that, when it detects an obstacle, tends to incorrectly distribute the loads, thus, causing, over time, trauma to the muscles, to the tendons, and also to the spine of the user.

In recent years the soles made of plastic materials have had a wide circulation. Notwithstanding, also these soles have many drawbacks.

Among the soles made of plastic material, in recent years, the soles made of EVA, i.e. Ethylene-vinyl acetate, have achieved a large market share, mainly because the production process is extremely simple. These soles, in fact, are obtained by injection moulding carried out by injection of granules of material into moulds, which are appropriately measured in order to take into account the material properties. In particular, the material is introduced into the mould and heated up to a temperature higher than the softening temperature for causing its moulding. Once the semifinished product has been extracted from the mould, at first, it enlarges, then, it becomes cold and slightly contracts. At the end of this step a one-piece product is obtained having a shape corresponding to that of the mould that has been used.

However, all these soles, because of their material physical properties, are so soft that the soles can collapse when pressed by the heel of the user foot, therefore, in these soles it can be difficult to transfer the weight from the heel to the forefoot.

Therefore, at present, both the shoes provided with soles made of rubber, and the shoes having a sole made of plastic material, in particular EVA, or because they are too much stiff, or on the contrary, because they are too much soft, do not allow to correctly distribute the weight of the user on the foot and, therefore, to discharge the weight to the ground in such a way not to stress, in a wrong way, the lower limbs. This can cause, over time, inflammations to the tendons and the muscles of the lower limbs of the user who puts on the shoe up to require, in the most serious cases, a surgical intervention.

In US2013/0025167 and in WO87/07481 two examples of prior art shoes are described. A first drawback of the shoes that are described in these documents is that, in both cases, the foot of the user who puts on the shoe, is positioned on a horizontal plane. This causes, as above disclosed, an incorrect weight distribution on the lower limbs of the user, and in particular on his/her feet, and an incorrect loads discharge to the ground.

Furthermore, both the solutions disclosed in US2013/0025167 and WO87/07481, as well as the other known soles, provides a series of protruding elements and a series of recesses alternately arranged, at the side of the sole that, in use, is opposite to the side facing the ground. In particular, when subjected to a vertical load, the protruding elements deform sideway. In this way, the necessary flexibility is assured to the sole shoe, otherwise, it would not be comfortable for the user who is putting on the shoe.

However, carrying out the above disclosed protruding elements greatly complicates the production process of the sole, in particular because a very complex mould must be used.

Summary of the invention

It is, therefore, an object of the present invention to provide an improved structure of shoe sole that is able to overcome the above described drawbacks of the prior art soles . It is, in particular, an object of the present invention to provide a shoe sole that is able to guarantee to the user who puts on the shoe, which includes such a sole, to assume a correct posture of the foot during the gait, assisting the gait, in such a way to have a correct rest on the feet and a correct discharge of the weight from the feet to the ground.

It is also an object of the present invention to provide a shoe provided with the above described sole having the same advantages.

These and other objects are achieved by a shoe sole provided with:

a top surface arranged, in use, in contact with the foot of a user;

a bottom surface arranged at the opposite side of the sole with respect to the top surface and arranged, in use, in contact with the ground, the top surface being inclined of a predetermined angle with respect to the bottom surface, in such a way to form a raised portion arranged to house the heel of the user's foot, at a rear portion of the sole, and a lowered portion arranged to house, in use, the user forefoot, at a front portion;

whose main characteristic is that the sole has a cross section comprising a first segment, which belongs to the top surface, having a first length _lr and a second segment, which belongs to the bottom surface, having a second length L ₂ , shorter than _lr that the sole has a cross section of minimum width at an intermediate portion that is interposed between the front portion and the rear portion, and that the second length L ₂ of the cross section of minimum width is set between 3 mm and 16 mm, depending on the size of the shoe including the sole.

In this way a very comfortable sole is obtained that is, at the same time, easy to produce.

Advantageously, the length L ₂ of the second segment at the section of minimum width of the sole is set between 8 mm and 14 mm.

In particular, the second length L ₂ can vary within the above indicated range depending on the size of the shoe .

In particular, the cross section of the sole is substantially trapezoidal shaped. More precisely, the sole comprises a front portion, a rear portion and an intermediate portion. In other words, the width of the sole decreases in a very accentuated manner going towards an intermediate portion that is interposed between the front portion and the rear portion. More precisely, the minimum width value for the sole is reached both at the top surface, and at the bottom surface, where, due to the particular cross section, reaches the minimum width L _mln of the whole sole. This particular technical solution, together with the inclination of the top surface of the sole where the user places his/her foot, allow to assist the gait and, therefore, to overcome the drawbacks of the prior art shoes. More in detail, during the gait, the user heel is higher than the forefoot, thus facilitating to transfer the weight to the forefoot. Furthermore, the small width of the sole at the intermediate portion, allows to help the gait, because it make the sole more flexible even if, however, it maintains the needed stiffness at the other portions of the sole.

Advantageously, the distance hi between the top surface and the bottom surface of the sole, at the rear portion, is set between 2.8 and 3.5 cm, i.e. 2.8 cm≤hl≤3.5 cm.

Preferably, the distance hi between the top surface and the bottom surface of the sole, at the rear portion, is set between 2.9 and 3.1 cm, i.e. 2.9 cm≤hl≤3.1 cm, for example hl=3 cm.

Advantageously, the distance h2 between the top surface and the bottom surface, at the front portion of the sole, is set between 0.6 cm and 1.2 cm.

Preferably, the distance h2 between the top surface and the bottom surface at the front portion of the sole is set between 0.7 cm and 1 cm, for example h2= 0,8 cm.

According to the invention, the ratio between the length l _max of the sole and its minimum width L _mln is set between 20:1 and 40:1, advantageously between 25:1 and 35:1. Advantageously, the sole comprises an upper portion of higher size, and a lower portion of smaller size. Therefore, between the upper portion and the lower portion a connecting perimeter edge is provided.

Preferably, the sole, according to the invention is made of synthetic, or natural rubber.

In particular, the sole can be made in a single piece produced by injection moulding.

According to another aspect of the invention, a shoe comprises :

a sole as above described;

a shoe upper fixed to the sole.

Preferably, the sole is configured in such a way that it juts out laterally from the shoe upper. In particular, the sole is overlapped to the shoe upper at the upper portion.

Advantageously, the shoe upper is made in a single piece .

Brief description of the drawings

The invention will be now shown with the following description of its exemplary embodiments, exemplifying but not limitative, with reference to the attached drawings in which :

Fig. 1 shows a view from below of a shoe sole, according to the present invention;

Fig. 2 shows a cross section of a shoe that includes the sole of Fig. 1 according to the arrows II-II, i.e. at the section of minimum width;

Fig. 3A diagrammatically shows, in a longitudinal section view, a shoe that includes the sole, according to the invention;

Fig. 3B diagrammatically shows in a longitudinal section view, a shoe that includes an alternative embodiment of the sole of Fig. 3A;

Fig. 4 shows an elevational side view of a shoe that includes the sole, according to the invention;

Fig. 5 shows a frontal view of the shoe that includes the sole of Fig. 4;

Fig. 6 shows a rear view of the shoe that includes the sole of Fig. 4.

Description of some embodiments of the invention

As it is diagrammatically shown in the figures 1 to 6, a sole 10, in particular a sole made of rubber, for shoes 1, according to the invention, provides a top surface 11 arranged, in use, in contact with the foot 50 of a user and a bottom surface 12 arranged at the opposite side with respect to the top surface 11 and arranged, in use, in contact with the ground.

More in detail, as diagrammatically shown in the Fig. 3A and 3B, the top surface 11 is inclined of a predetermined angle a, whose magnitude is, in particular, set between 2° (Fig. 3A) and 6° (Fig. 3B) , advantageously between 2° and 4°, for example about 3°, with respect to the bottom surface 12.

Still as diagrammatically shown in the figures 3A and 3B, at a rear portion 15 of the sole 10, the top surface 11 provides a raised portion 11a that, in use, houses the heel 52 of the user foot 50. At a front portion 14 of the sole 10, the top surface 11, therefore, provides a lowered portion lib arranged to house, in use, the forefoot 51 of user 50. Therefore, the user foot 50 is inclined of a corresponding angle. This assists the gait and, in particular, the passage of the load from the heel 52 to the forefoot 51.

As shown in detail in Fig. 2, the main characteristic of the sole 10, according to the invention, is to have a cross section 100 where a first segment 101, which belongs to the top surface 11 that has a first length LI, and a second segment 102, which belongs to the bottom surface 12 that has a second length L ₂ , and wherein the second length L ₂ is shorter than the first length Li. More precisely, the second length L ₂ at the section 18 of the sole 10 having the minimum width, is set between 3 mm and 16 mm, depending on the size of the shoe 1 that includes such a sole.

More precisely, the width L ₂ can be set between 3 mm and 6 mm in the case of shoes for children, i.e. with soles, having a length between 70 mm and 215 mm. Instead, in the case of shoes for adults, i.e. having a length longer than 215 mm, and in particular between 215 and 430 mm, the section of minimum width 18 has a length L ₂ set between 6 mm and 16 mm, advantageously between 8 mm and 14 mm.

In particular, the ratio between the first length LI and the length L ₂ can be set between 2:1 and 10:1, in particular between 3:1 and 8:1, for example between 4:1 and 7:1. The ratio between the length l _max of the sole 10 and the minimum width L _m i _n of the sole 10 can be set between 20:1 and 40:1, advantageously between 25:1 and 35:1.

In light of the above, the width of the sole 10, therefore, decreases in an accentuated manner going from the front portion 14, or the rear portion 15, towards the intermediate portion 16, up to reach a minimum value at the cross section 18, beyond which the width of the sole 10 starts again to increase. This technical solution, together with the inclination of the top surface 11, assists the gait of the user, because it makes the sole 10 more flexible at the intermediate portion, but at the same time, the other portions of the sole 10 have the necessary stiffness. The above described technical characteristics have the further advantage to make very comfortable shoe 1 including sole 10.

In an embodiment of the invention, the rear portion 15 and at least the intermediate portion 16 are arranged on the same plane that, in use, is horizontal. More in detail, when the user puts on shoe 1, at least rear portion 15 and intermediate portion 16, in a rest configuration, are both adjacent to the ground 200. The front portion 14, instead, is preferably tilted upward with respect both to rear portion 15 and to intermediate portion 16. However, it is also foreseen the possibility that a part of front portion 14 is coplanar to the above described portions 15 and 16 of sole 10.

More precisely, at section 18, sole 10 has the minimum value of its width, both at the top surface 11, and at the bottom surface 12, where, thanks to the particular shaped section provided by the invention, it reaches the minimum width L _mln of all the sole.

With reference, in particular, to the figures 3A and 3B, the height of the sole 10 gradually decreases, in particular substantially linearly, going from the rear portion 15 to the front portion 14 of the sole 10. This expedient allows, on the one hand, to raise the user foot and, in particular, to maintain the heel higher than the forefoot and, therefore, raised from the ground, thus avoiding that irregularities of the ground can cause the user to assume an incorrect body posture, and on the other hand, to assist the gait, in particular when the weight is transferred from the heel to the forefoot of the foot as above described.

The distance hi between the top surface 11 and the bottom surface 12 of the sole 10 at the rear portion 15 is set between 2.8 and 3.5 cm, i.e. 2.8<hl<3.5 cm. Preferably, the distance hi between the top surface 11 and the bottom surface 11 of the sole 10 at the rear portion 15 is set between 2.9 and 3.1 cm, i.e. 2.9≤hl≤3.1 cm, for example hl=3 cm.

The distance h2 between the top surface 11 and the bottom surface 12 at the front portion 14 of the sole 10 is, instead, preferably set between 0.7 cm and 1 cm, for example h2=0.8 cm.

Although the sole 10 is made in a single piece by injection moulding of plastic material, it can be, however, ideally divided into two portions and precisely, an upper portion 10a of higher size, and a lower portion 10b of smaller size. More in detail, between the two portions 10a and 10b a connection perimeter edge 17 can be identified.

According to another aspect of the invention that is shown in the figures from 4 to 6, a shoe 1 comprises a sole 10 as above described with reference to the figures 1 to 3B and a shoe upper 20 that is fixed to the sole, for example by gluing and/or sewing.

The sole 10, according to the present invention, is, in particular, destined to be adopted from a shoe 1 of the type without supplemental heel, that means of the type having the whole sole 10 arranged in contact with the ground 200. As it is shown in the figures 2 and from 4 to 6, the upper portion 10a of the sole 10 is configured in such a way to laterally contain the shoe upper 20 forming a perimeter containing edge 19. More in detail, the upper portion 10a of the sole 10 substantially forms a containing side wall for the shoe upper 20. More in detail the upper portion 10a is, in use, overlapped to the shoe upper 20. This technical solution allows, in particular, to simplify the fixing of the sole 10 to the shoe upper 20, because it increases the available surface for the overlapping of the two components of the shoe 1.

As diagrammatically shown in Fig. 6, the lower portion 10b of the sole 10, going from below to the above, can comprise a first portion 10b' made of a first material and provided with the bottom surface 12 that, in use, is arranged in contact with the ground 200, and a second portion 10b" integral to the first portion 10b' and made of a second material that is different from the first material. In particular, the density of the first material is high and, in particular, higher than the density of the second material that, instead, has a low density. For example the first material can be a hard rubber, or a Thermoplastic polyurethane (TPU) , or similar materials. Concerning the second material, instead, this can be EVA, or a foam rubber, or similar materials. In this way it is guaranteed that the first portion 10', i.e. the one that, in use, is arranged in contact with the ground 200, has a high friction resistance, instead, the second layer is light in such a way to have, on the whole, a sole that is able to last a long time, but, at the same time, that is light and, therefore, comfortable for the user who puts on it.

The upper portion 10a can be made of a third material. In an alternative embodiment, the density of the first material is higher than, or equal to, the density of the third material whose density is higher than the density of the second material. This because the third material, i.e. the one that is fixed to the shoe upper 20 of the shoe, must have, however, a certain mechanical resistance and stiffness in order to avoid that it can give away and can be torn at the sewing, or gluing, points necessary to fix the sole to the shoe upper 20.

According to the invention, the shoe upper 20 made in a single piece, in particular a textile material, is obtained, for example, through the process described in WO2005123998 in the name of the same Applicant.

The foregoing description of specific exemplary embodiments will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt in various applications the specific exemplary embodiments without further research and without parting from the invention, and, then it is meant that such adaptations and modifications will have to be considered as equivalent to the specific embodiments. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology that is employed herein is for the purpose of description and not of limitation.