EP3618658A1

EP3618658A1 - Shoe sole

Info

Publication number: EP3618658A1
Application number: EP18727431.1A
Authority: EP
Inventors: Alessio Rizzi; Alberto Del Biondi
Original assignee: Alberto Del Biondi SpA
Current assignee: Alberto Del Biondi SpA
Priority date: 2017-05-03
Filing date: 2018-05-03
Publication date: 2020-03-11
Also published as: MA50602A; IT201700047621A1; WO2018203267A1

Abstract

Shoe sole (1) comprising a main part (4) developed along a longitudinal axis (X), which is to be found in a toe-to-heel direction, comprising respective forefoot (2), midfoot (3) and hindfoot (3b) regions which are contiguous along the longitudinal axis (X), said forefoot (2), midfoot (3) and hindfoot (3b) regions bearing respective tread surfaces (5, 6, 6b) each delimited perimetrically by a respective inner and outer flank (7, 8) of the sole (1). The sole (1) being affected in at least one of the forefoot (2) and/or midfoot (3) regions by at least one recess (9) extending transverse to the longitudinal axis (X), at least one insert (10) at least partially housed in the at least one recess (9), the insert (10) comprises at least one elongated extension (11) having a main development along a first extension axis (E1) and the first extension axis (E1) being transverse to the longitudinal axis (X). The insert (10) is formed from a first material (P1), and the forefoot (2) and/or midfoot (3) region of the main part (4) are formed from a second material (P2), with the first material (P1) having a higher modulus of elasticity and/or a greater hardness than the second material (P2) and the at least one elongated extension (11) comprising a support end (11a1) being perpendicular to the longitudinal axis (X).

Description

Shoe sole

DESCRIPTION Technical scope

The invention refers to a shoe sole of the type including the features mentioned in the introduction of the main claim.

Technological background

It is known that the human foot is subjected to multiple and complex forces while carrying out the movements foreseen during the phases of the gait.

In particular, during the phases of loading and unloading of body weight on the foot, a torsional movement can be identified which derives from the superposition of bending forces that act in parallel, transversal and orthogonal directions to the toe-to-heel longitudinal axis of the foot.

This type of torsional movement, defined in the technical sector as the "propeller effect", is particularly complex and its spatial movements are not easy to follow for footwear that tries to support the movement of the foot in a natural manner.

Within the footwear sector, there are soles that include internal cut-outs or inserts; however, none of them is capable of addressing or limiting the complex torsion and bending forces that are produced during the "propeller effect".

US2005/246922 describes an insert having a high modulus of elasticity, having at least one extension that is transversal to its longitudinal axis.

For the purpose of identifying the technical solutions of the sole that are most appropriate for the optimisation of the behaviour and the comfort of the sole during the various phases of the gait, the Applicant has found that it is necessary to carry out an in-depth study dedicated to the identification of the parts of the sole where such forces are most heavily applied and to the specific directions of application of the different torsional forces developed. Furthermore, the Applicant has found that it is useful to confine the torsional forces that occur during the propeller effect for the purpose of optimising the response of the sole when walking.

Description of the invention

The purpose of this invention is that of supplying a shoe sole that overcomes the disadvantages of the identified prior art.

Within this purpose, one of the objectives of the invention is that of improving the energy return and the torsional control of the sole when walking, while optimally following the propeller effect that is produced, in particular in line with the metatarsophalangeal joint.

The finding made according to this invention is a shoe sole 1 comprising a main part developed along a longitudinal axis, which is to be found in a toe-to-heel direction, comprising respective forefoot, midfoot and hindfoot regions which are contiguous along the longitudinal axis, the forefoot, midfoot and hindfoot regions bearing respective tread surfaces each delimited perimetrically by a respective inner and outer flank of the sole. The sole is affected in at least one of the forefoot and/or midfoot regions by at least one recess extending transverse to the longitudinal axis, the at least one insert being at least partially housed in the at least one recess and the insert comprises at least one elongated extension having a main development along a first extension axis, with the first extension axis being transverse to the longitudinal axis.

Preferably, the insert is formed from a first material, and the forefoot and/or midfoot regions of the main part are formed from a second material, with the first material having a higher modulus of elasticity and/or a greater hardness than the second material.

According to one embodiment, the at least one elongated extension comprises a support end perpendicular to the longitudinal axis.

The Applicant has verified that these features correlated to the modulus of elasticity and/or the hardness of the first material in relation to the second material allow for the production of a greater energy return and optimized torsion control during the phases of the gait.

In this context, the higher modulus of elasticity and/or greater hardness of the first material in comparison to the second material identify a circumstance of lesser deformability of the first material when compared to the second, as regards local elasticity and/or plasticity, under the same applied force. This allows the sole to have a response region, the behaviour of which is more rigid when compared to the entirety of the sole which, therefore, by limiting the deformations that can be achieved by the insert, allows for a control and a return of energy, all the while offering a greater elastic behaviour.

In this way, one can achieve a more efficient and comfortable gait for the user and optimise the torsional propeller effect that is created during the changes in loads applied to the feet.

Furthermore, the Applicant has found that, by creating the support end having a main development perpendicular to the longitudinal axis X, one can limit the forces applied to the foot to a desired region during the gait, thus further optimising the torsional propeller effect which is present.

Preferably, the first material has hardness and/or modulus of elasticity values which are 20-30% greater than those of the second material. Moreover, the fact that the insert is formed from the first material and having a modulus of elasticity and/or hardness values 20-30% greater than those of the second material allows the insert to more efficiently return to the initial shape, which is to say, to have a more effective elastic behaviour and with reduced plastic contributions, thus providing a further improvement in the return of the energy accumulated by the insert during the phases of the gait.

Preferably, the elongated extension of the insert has a substantially constant section perpendicular to said first extension axis.

In this manner, it is possible to obtain an optimum torsional control during the gait inasmuch as the constant section of the elongated extension can rotate in a uniform and easy manner around the first extension axis. Indeed, a constant section avoids edges or protrusions which can act as obstacles during a rotation of the insert along the first extension axis.

In this context, by torsion axis, one means an axis which is to be found in the sole wherein, during the phases of the gait, the torsion forces are applied with greater intensity, when compared to the remaining parts of the sole. Furthermore, in this context, the torsion axis is not to be understood as an axis on which only purely torsional forces can act, but rather also bending forces linked to the complex nature of the movement induced by the propeller effect.

It must therefore be understood that this torsion axis is a straight line which is to be found in the sole and around which pairs of opposing forces apply as per twisting moments that are parallel to the axis and opposite to each other.

According to one embodiment, the insert has the first extension axis that is substantially coincident with a first torsion axis or with a second torsion axis of the sole.

In this context, as shown in Figures 1 , 2, and 4a, the torsion axis of the sole is preferably to be identified by an axis comprised in the sole and substantially coplanar to the longitudinal axis and to the first extension axis (and, thus substantially coplanar to the transverse extension of the sole). Furthermore, the torsion axis comprises one of its parts included in a torsion area which is to be found in a region of the forefoot and/or midfoot where the torsion axes are concentrated.

The Applicant has verified that when the first extension axis of the at least one elongated extension coincides with the first or second torsion axis, said technical feature improves the return of energy and torsional control.

This effect is further improved in the case wherein, in addition to the torsion effect, a bending force is also applied.

Preferably, the first torsion axis and/or the second torsion axis are inclined at an angle of between 10° and 60° to the longitudinal axis.

In this manner, there is a more efficient response of the insert in function of the complex torsional movements applied to the sole.

In particular, the first torsion axis and/or the second torsion axis are inclined at an angle of 45° to the longitudinal axis.

In this manner, it is furthermore possible to optimise the return of energy and torsional control.

Preferably, the insert extends to affect substantially the entirety of the transverse extension of the tread surfaces of the sole. It is important to point out that, in this way, the response of the sole to the propeller effect is distributed and effective over the entire extension of the sole, thus producing a more uniform behaviour. Advantageously, the insert extends to also substantially affect a lateral portion of the sole.

According to one embodiment, the at least one elongated extension consists of two elongated extensions, one having a main development along the first extension axis and the other along a second extension axis, with the first and second extension axes being transverse to the longitudinal axis. Preferably, the two elongated extensions intersect with one another in at least one intersection point and substantially coincide, one with the first torsion axis and the other with the second torsion axis.

According to another embodiment, the insert comprises four elongated extensions, a first and a third elongated extension of the four elongated extensions having a main development along the first extension axis that coincides with the first torsion axis, a second and a fourth elongated extensions of the four elongated extensions having a main development along the second extension axis that coincides with the second torsion axis.

The Applicant has verified that the applied tension forces tend to develop mainly along two torsion axes that intersect and are at least partially included in the torsion area: by means of this technical solution, it is possible for the insert to more effectively follow the complex developments of the applied torsional forces.

According to one embodiment, the four elongated extensions intersect with one another in at least one intersection point belonging to said longitudinal axis.

In this manner, the intersection point allows optimal following of the bending imposed according to at least two torsion axes at the same time, and this occurs at the point which mirrors the torsion behaviours of the sole in relation to the longitudinal axis. This allows for further improvement of the directions of deformability of the sole based upon the propeller effect that is present.

Preferably, the two elongated extensions have a substantially symmetrical shape in relation to the longitudinal axis. In this manner, it is possible that the contribution of the elongated extensions is symmetrical and uniform in relation to the sole.

According to one embodiment, the recess passes through the sole and the insert has a thickness that is equal to that of the recess in such a way as to create thickness continuity on the tread surfaces and on a surface opposite to that of the tread surfaces of the sole.

In this manner, the effect of the insert is optimised, acting as an element of continuous interaction of the forces applied between the surfaces of the tread and the surface facing the foot of the user.

Alternatively, the thickness of the insert is less than that of the recess by between 1 mm and 5 mm, hereby establishing an indent when compared to the tread surfaces.

In this manner, the integrity of the insert that only carries out the function of response element in function of the propeller effect is further protected.

Preferably, the aforementioned support end of the elongated extension comprises at least one part that extends to parts of the inner and/or outer flank. Preferably, when said internal and/or external flank present a development, including in a plane that is transverse to the plane formed by the longitudinal axis and the first extension axis, the aforementioned support ends of the elongated extension extend to also affect portions of this transverse plane.

Preferably, each of the four elongated extensions comprise respectively one support end perpendicular to the longitudinal axis.

According to one embodiment, each of the four support ends is respectively formed in line with a metatarsal plantar sector.

In this context, four plantar metatarsal sectors are found, two of which are placed in the vicinity of the right flank and distanced along the longitudinal axis, while the remaining two are positioned substantially parallel to the axis that is perpendicular to the longitudinal axis, and placed in the vicinity of the external flank. The Applicant has verified that these plantar metatarsal sectors are most significant for the application of loads when walking.

Thanks to the fact that the support ends of the insert are oriented perpendicular to the longitudinal axis, this furthermore allows for the concentration, limitation and optimisation of the propeller effect and the elastic response of the first material during the gait, thus increasing the comfort of the footwear.

According to one embodiment, the insert comprises a bead, found in the vicinity of the tread surfaces and projecting from a base of the insert found in the vicinity of the opposite surface. Advantageously, the bead projects in a direction that is perpendicular to the plane of the longitudinal axis and of the first extension axis.

In this manner, it is possible to optimise the behaviour of the portion of the insert that is facing and/or in contact with the tread, and thus with the ground, which thereby is less prone to incisions, cuts and damage by the ground.

Preferably, the base of the insert comprises a central body and protrusions projecting from the central body. Advantageously, the projecting protrusions are coplanar to the longitudinal axis and to the first extension axis.

According to an implementation, the operating modalities of the aforementioned shoe sole, which define the production process of this invention, comprise the steps described below: providing a first mould for an insert formed from a first material, forming the insert comprising at least one elongated extension and having a main development along a first extension axis, countersinking the insert in a second plastic material having the shape of a shoe sole in such a manner that the first extension axis is transverse to a longitudinal axis of the shoe sole.

In this manner, one obtains the advantage of forming a stable bond between the insert and the recess of the sole in which it is housed and it is possible to have an efficient response of the insert to the torsional and bending forces that occur during the gait.

Preferably, the first material has hardness and/or modulus of elasticity values that are 20-30% greater than those of the second material. According to an implementation, the method comprises the extraction of the insert from the first mould, providing a second mould for the shoe sole formed in a second plastic material, the insertion and the bonding of the insert in the second mould, proceeding with the forming of the sole in a second plastic material countersinking the insert in the shoe sole in such a manner that the first extension axis is transverse to a longitudinal axis of the shoe sole and comprising a support end having a development perpendicular to the longitudinal axis.

Brief description of the drawings

The features and the advantages of the finding will be described in greater detail in the description of an illustrated production sample, which includes but is not limited to the drawings wherein:

Fig. 1 is a plan view from below of a shoe sole,

Fig. 2 is a plan view from below of an insert included in the sole of Fig. 1 ,

Figs. 3a and 3b are perspective views of a variant of soles for footwear,

Fig. 4a is a plan view from below of an insert of the sole of Fig. 1 ,

Fig. 4b is a cross-sectional view of the cross-section of the insert of Fig. 4a in the IVb plane,

Fig. 5 is a perspective view of a preferred embodiment of the insert,

Fig. 6 is a cross-sectional view of the sole of Fig. 3b in the VI plane,

Fig. 7 is a perspective view of a variant of a shoe sole,

Fig. 8 is a plan side view of a variant of a shoe sole,

Fig. 9 is a plan view from below of a detail of the insert of Fig. 5.

Preferred embodiment of the invention

In Figure 1 , 1 indicates a shoe sole as a whole. The finding made according to this invention comprises a main part 4 developed along a longitudinal axis X, which is to be found in a toe-to- heel direction, comprising respective forefoot 2, midfoot 3 and hindfoot 3b regions which are contiguous along the longitudinal axis X.

Preferably, the forefoot 2, midfoot 3 and hindfoot 3b regions bear respective tread surfaces 5, 6, 6b, each delimited perimetrically by a respective inner and outer flank 7, 8 of sole 1 . In this context, the midfoot 3 region is the region relating to the metatarsal support M region of the foot.

With reference to Figures 1 and 2, the sole 1 is, preferably, affected in at least one of the forefoot 2 and/or midfoot 3 regions by at least one recess 9 extending transverse to the longitudinal axis X, the at least one insert 10 is at least partially housed in the at least one recess 9 and the insert 10 comprises at least elongated extension 1 1 having a main development along a first extension axis E1 transverse to the longitudinal axis X.

Preferably, the insert 10 is formed from a first material P1 , and said forefoot 2 and/or midfoot 3 region of the main part 4 are formed from a second material P2, with the first material P1 having a higher modulus of elasticity and/or a greater hardness than the second material P2.

According to one embodiment, the first material P1 has a hardness value that exceeds the hardness value of the second material P2 by between 10 and 50 Shore A.

Preferably, an optimum range of difference between the first material P1 and the second material P2 falls between 15 and 30 Shore A.

According to one embodiment, the first material is formed from thermoplastic urethane expanded elastomer (TPU) or nylon or similar whereas the sole is formed of thermoplastic elastomer material (TR or TPE), EVA, polyurethane, TPU, expanded foams or similar.

As an example and not exhaustively, in the case of use of TPU thermoplastic materials, the first material P1 has a hardness equal to 85 Shore A and the second material P2 has a hardness equal to 70 Shore A. Another example is represented by the use of polyurethane polymeric materials wherein the first material P1 has a hardness equal to 70 Shore A, whereas the second material P2 has a hardness equal to 50 Shore A. A further example is represented by the use of EVA expanded polymeric materials wherein the first material P1 has a hardness equal to 80 Shore A, whereas the second material P2 has a hardness equal to 45 Shore A.

According to one embodiment and with reference to Figure 1 , the at least one elongated extension 1 1 comprises a support end 1 1 a1 that is perpendicular to the longitudinal axis X. With reference to Figures 1 , 2, 3b the elongated extension 1 1 of the insert 10 preferably has a substantially constant section perpendicular to said first extension axis E1 . Alternatively, the aforementioned section perpendicular to the first or to the second extension axis E1 , E2 is tapered as it moves away from or gets close to the support end 1 1 a1 .

With reference to Figure 4b, the section of the elongated extension 1 1 is preferably of a square, circular or polygonal shape.

According to one embodiment, the insert 10 has the first extension axis E1 that is substantially coincident with a first torsion axis T1 or with a second torsion axis T2 of sole 1 , this in compliance with the definitions used in this document.

As shown in Figure 1 , the first torsion axis T1 and/or the second torsion axis T2 are preferably inclined at an angle of between 10° and 60° in relation to the longitudinal axis X.

Preferably, the first torsion axis T1 and/or second torsion axis T2 are inclined at an angle of approximately 45° in relation to the longitudinal axis X.

Preferably, with reference to Figures 1 , 3b and 7, the insert 10 extends to affect substantially the entirety of the transverse extension of the tread surfaces 5, 6 of the sole 1 and advantageously also a lateral portion of the sole 1 .

According to one embodiment, the at least one elongated extension 1 1 consists of two elongated extensions 1 1 a, 1 1 b, one having a main development along the first extension axis E1 and the other along a second extension axis E2, with the first and second extension axes E1 , E2 being transverse to the longitudinal axis X.

According to a further embodiment and with reference to Figures 1 , 2 and 4a, the insert 10 comprises four elongated extensions 1 1 a, 1 1 b, 1 1 c, 1 1 d, a first and a third elongated extension 1 1 a, 1 1 c, of the four elongated extensions 1 1 a, 1 1 b, 1 1 c, 1 1 d having a main development along the first extension axis E1 that coincides with the first torsion axis T1 , a second and a fourth elongated extensions 1 1 b, 1 1 d of the four elongated extensions 1 1 a, 1 1 b, 1 1 c, 1 1 d having a main development along the second extension axis E2 that coincides with the second torsion axis T2. With reference to the Figures 1 , 2, 3b and 4a, the four elongated extensions 1 1 a, 1 1 b, 1 1 c, 1 1 d intersect with one another in at least un intersection point I belonging to the longitudinal axis X.

According to one embodiment represented in Figures 1 , 2, 3b and 4a, the four elongated extensions 1 1 a, 1 1 c and 1 1 b, 1 1 d substantially lay two by two with the first torsion axis T1 and the second torsion axis T2 respectively. Such a shape, when seen from above or below, confers to insert 10 a shape similar to an "X".

Preferably, the two elongated extensions 1 1 a, 1 1 b or the four elongated extensions 1 1 a, 1 1 b, 1 1 c, 1 1 d have shapes that are substantially symmetrical in relation to the longitudinal axis X. This means that their shape is similar to a symmetrical "X" in relation to the intersection point I and that therefore the elongated extensions have portions that are substantially of the same length when measured starting from the point of intersection I.

According to one embodiment and as shown in Figure 7, the recess 9 passes through the sole 1 and the insert 10 has a thickness that is equal to that of the recess 9 to re-establish the continuity of the thickness on the tread surfaces 5, 6 and on a surface 5b opposite to the one of the tread surfaces 5, 6 of the sole 1 .

In such a manner, the effect of the insert is optimised, acting as an element of continuous interaction of the forces applied between the surfaces of the tread and the surface facing the foot of the user.

Preferably, the insert 10 produces precise surface continuity with the opposite surface 5b when properly and completely inserted in recess 9.

Alternatively and with reference to Figure 6, the insert 10 has a thickness that is less by between 1 mm and 5 mm than that of said recess 9, hereby establishing an indent when compared to said tread surfaces 5, 6.

Preferably, each of the four elongated extensions 1 1 a, 1 1 b, 1 1 c, 1 1 d comprises respectively a support end 1 1 a1 , 1 1 b1 , 1 1 c1 , 1 1 d1 perpendicular to the longitudinal axis X.

Advantageously, the junction between the elongated extensions 1 1 a, 1 1 b, 1 1 c, 1 1 d and said support ends 1 1 a1 , 1 1 b1 , 1 1 c1 , 1 1 d1 that are perpendicular to the longitudinal axis may be made while maintaining the section constant or modifying it in a tapered manner.

According to one embodiment, each of the four support ends 1 1 a1 , 1 1 b1 , 1 1 c1 , 1 1 d1 is respectively formed in line with a metatarsal plantar sector S1 , S2, S3, S4.

With reference to Figure 1 , the four plantar metatarsal sectors are identified as S1 , S2, S3 and S4. As one can see, the first and the fourth sectors S1 and S4 are found in the vicinity of the internal side 7 whereas the second and the fourth sectors S2 and S4 are found in the vicinity of the external side 8. Furthermore, preferably, the first and the fourth sectors S1 and S4 are positioned on the same right lines perpendicular to the longitudinal axis X and passing through the second and the third sectors S2 and S3 respectively.

Advantageously, the third plantar sector S3 represents the first point of support during the gait, the second plantar sector S2 serves as a guide and control for balance whereas the fourth plantar sector S4 and the first plantar sector S1 substantially serve as support in the phase in which one falls forward during the gait.

Preferably and with reference to Figure 9, the first and the third elongated extensions 1 1 a, 1 1 c are arranged in relation to the longitudinal axis at an angle alpha a that is greater than 45° and lesser than 60°, the second and fourth elongated extensions 1 1 b, 1 1 d are arranged in relation to the longitudinal axis at an angle beta β equal to 45°.

Once again with reference to Figure 9, the first and third elongated extensions 1 1 a, 1 1 c form a first segment P1 having a first length L1 that is lesser than a second length L2 in relation to a second segment P2 formed by the second and fourth elongated extensions 1 1 b, 1 1 d.

In this manner, one forms a slightly asymmetrical X shape which further optimally follows the shape of the foot and its behaviour during application of the loads during the gait.

As shown in Figure 8, the aforementioned perpendicular support ends of the elongated extension comprise at least a portion that extends in portions from the internal and/or external flank. Preferably, when said internal and/or external flank also present a development in a plane that is transverse to the plane formed by the longitudinal axis and by the first extension axis, the aforementioned extremities of the elongated extension extend to also affect portions of this transverse plane. Preferably, the recess 9 also extends in portions included in said transverse plane. Advantageously, when the recess 9 extends in portions included in said transverse plane and the insert 10 is countersunk or engaged in said recess 9, the insert 10 also appears visible from a lateral plan view of the shoe sole 1 .

According to one embodiment and with reference to Figures 4a, 4b, 5, 6 and 7, the insert 10 comprises a bead 10a, found in the vicinity of the tread surfaces 5, 6 and projecting from a base 10b of the insert 10 found in the vicinity of the opposite surface 5b.

Preferably, the bead 10a has a bevelled and/or rounded shape so as to offer a smaller interaction surface with a support surface and further facilitate the torsional movements of the affected parts of the sole located in the vicinity of the elongated extensions 1 1 a, 1 1 b.

According to one embodiment shown in Figures 4a, 4b and 5, the base 10b of the insert 10 comprises a central body 10c and protrusions 10d projecting from the central body 10c.

Preferably, the central body 10c and the protrusions 10d present a section, when found perpendicular in relation to the first or second extension axis E1 , E2, of a substantially rectangular shape. Advantageously, the protrusions 10d project from the central body 10c by a measurement greater than 5 mm.

The operating procedures defining the production method of this invention include the following described phases.

According to one implementation, provision of a first mould 21 for an insert 10 formed from a first material P1 , formation of the insert 10 comprising at least one elongated extension 1 1 having a main development along a first extension axis E1 , countersinking of the insert 10 in a second plastic material P2 having the shape of a shoe sole 1 in such a manner that the first extension axis E1 is transverse to a longitudinal axis X of the shoe sole 1 and comprising a support end 1 1 a1 having a development perpendicular to said longitudinal axis X.

Advantageously, it is then possible to form a multi-injection (foreseeing co-injection, overmoulding, sequential injections, two-colour moulding, etc.) of the first material P1 and of the second material P2 inside the first mould 21 .

Preferably, the first material P1 is TPU expanded polymer material or nylon or the like, and the first mould 21 is formed from aluminium (or its alloys), steel, or similar materials.

According to an implementation of the method, forming of the insert 10 which comprises at least one elongated extension 1 1 and having a main development along a first extension axis E1 and comprising a support end 1 1 a1 having development perpendicular to the longitudinal axis X, by means of moulding or injection, casting, thermoforming or similar industrial production techniques.

Preferably, method 200 entails the subsequent removal of the insert 10 from the first mould 21 , providing a second mould 22 for the shoe sole 1 to be formed from the second plastic material P2.

Advantageously, the second plastic material is expanded EVA material of the like having Shore A hardness that is lesser by approximately 10-50 Shore A in relation to the hardness of the first material P1 .

Preferably, even the second mould 22 is formed from aluminium (or its alloys), steel, or similar materials.

According to an implementation, method 200 subsequently entails the insertion and bonding of the insert 10 in the second mould 22, then proceeding to the injection of the second plastic material P2 countersinking the insert 10 in the shoe sole 1 in such a manner that the first extension axis E1 is transverse to a longitudinal axis X of the shoe sole 1 .

According to this form of implementation of method 200, it is possible to then form a multi- injection (which foresees overmoulding, sequential injections, two-colour moulding, etc.) of the first material P1 and of the second material P2 on the inside of the second mould 22.

Claims

1 . Shoe sole (1 ) comprising

• a main part (4) developed along a longitudinal axis (X), which is to be found in a toe-to- heel direction, comprising respective forefoot (2), midfoot (3) and hindfoot (3b) regions which are contiguous along said longitudinal axis (X),

• said forefoot (2), midfoot (3) and hindfoot (3b) regions bearing respective tread surfaces (5, 6, 6b) each delimited perimetrically by a respective inner and outer flank (7, 8) of said sole

(1 ),

• said sole (1 ) being affected in at least one of said forefoot (2) and/or midfoot (3) regions by at least one recess (9) extending transverse to said longitudinal axis (X),

• at least one insert (10) being at least partially housed in said at least one recess (9),

• said insert (10) comprises at least elongated extension (1 1 ) having a main development along a first extension axis (E1 ), said first extension axis (E1 ) being transverse to said longitudinal axis (X),

• said insert (10) is formed from a first material (P1 ), and said forefoot (2) and/or midfoot (3) region of said main part (4) are formed from a second material (P2), said first material (P1 ) having a higher modulus of elasticity and/or greater hardness than said second material (P2),

• characterized by the fact that said at least one elongated extension (1 1 ) comprises a support end (1 1 a1 ) that is perpendicular to said longitudinal axis (X).

2. Shoe sole (1 ) according to the previous Claim, in which said at least one elongated extension (1 1 ) of said insert (10) has a substantially constant section perpendicular to said first extension axis (E1 ).

3. Shoe sole (1 ) according to Claim 1 or 2, in which said insert (10) has said first extension axis (E1 ) substantially coincident with a first torsion axis (T1 ) or with a second torsion axis (T2) of said sole (1 ).

4. Shoe sole (1 ) according to the previous Claim, in which said first torsion axis (T1 ) and/or second torsion axis (T2) are inclined at an angle of between 10° and 60° to said longitudinal axis (X).

5. Shoe sole (1 ) according to the previous Claim, in which said first torsion axis (T1 ) and/or second torsion axis (T2) are inclined at an angle of 45° to said longitudinal axis (X).

6. Shoe sole (1 ) according to one of the preceding Claims, in which said insert (10) extends to affect substantially the entirety of the transverse extension of said tread surfaces (5, 6) of said sole (1) and advantageously also a lateral portion of said sole (1).

7. Shoe sole (1) according to one of the Claims 3 through 6, in which said insert (10) comprises four elongated extensions (11a, 11b, 11c, 11d), a first and a third elongated extension (11a, 11c) of said four elongated extensions (11a, 11b, 11c, 11 d) having a main development along said first extension axis (E1) that coincides with said first torsion axis (T1), a second and a fourth elongated extensions (11b, 11 d) of said four elongated extensions (11a, 11b, 11c, 11 d) having a main development along said second extension axis (E2) that coincides with said second torsion axis (T2).

8. Shoe sole (1) according to Claim 7, in which said four elongated extensions (11a, 11b, 11c, 11 d) intersect with one another in at least one intersection point (I) belonging to said longitudinal axis (X).

9. Shoe sole (1) according to any one of the preceding Claims, in which said recess (9) passes through said sole (1) and said insert (10) has a thickness that is less than that of said recess (9) of between 1 mm and 5 mm hereby establishing an indent with respect to said tread surfaces (5, 6).

10. Shoe sole (1) according to one of the Claims 7 through 9, in which each of said four elongated extensions (11a, 11b, 11c, 11 d) comprises respectively a support end (11a1, 11b1, 11c1, 11d1) perpendicular to said longitudinal axis (X).

11. Shoe sole (1) according to the previous Claim, in which each of said four support ends (11a1, 11b1, 11c1, 11d1) is respectively formed corresponding to a metatarsal plantar sector (S1, S2, S3, S4).

12. Shoe sole (1) according to the previous Claim, in which said first and third elongated extensions (11a, 11c) are arranged in relation to said longitudinal axis (X) at an angle alpha (a) that is greater than 45° and lesser than 60°, said second and fourth elongated extensions (11b, 11d) are arranged in relation to said longitudinal axis (X) at an angle beta (β) equal to 45°.

13. Shoe sole (1 ) according to the previous Claim, in which said first and third elongated extensions (1 1 a, 1 1 c) form a first segment (P1 ) having a first length (L1 ) that is lesser than a second length (L2) in relation to a second segment (P2) formed by said second and fourth elongated extensions (1 1 b, 1 1 d).

14. Shoe sole (1 ) according to any one of the preceding Claims, in which said insert (10) comprises a bead (10a), found in the vicinity of said tread surfaces (5, 6) and projecting from a base (10b) of said insert (10) found in the vicinity of said opposite surface (5b).

15. Shoe sole (1 ) according to Claim 14, in which said base (10b) of said insert (10) comprises a central body (10c) and protrusions (1 Od) protruding from said central body (10c).

16. Method (200) for production of a shoe sole (1 ) having the characteristics of any of the preceding Claims, comprising

• providing a first mould (21 ) for an insert (10) formed from a first material (P1 ),

• forming said insert (10) comprising at least one elongated extension (1 1 ) having a main development along a first extension axis (E1 ) transverse to a longitudinal axis (X) of said sole (1 ) and comprising a support end (1 1 a1 ) having a development perpendicular to said longitudinal axis (X),

• countersinking said insert (10) in a second plastics material (P2) having the shape of a shoe sole (1 ) in such a way that the first extension axis (E1 ) is transverse to a longitudinal axis (X) of said shoe sole (1 ).