SPORT SHOE MIDSOLE, SPORT SHOE, METHOD FOR ADAPTING A SPORT SHOE AND METHOD FOR PRODUCING A SPORT SHOE

Abstract

A sports shoe midsole includes a body and a cushioning element. The body, made of polymeric material, has an upper face and a lower face. The body defines at least one through-hole with a side wall connecting the upper face and the lower face. The cross section of the through-hole in the lower face is larger than the cross section of the through-hole in the upper face. The cushioning element is detachably mounted with respect to the body. The cushioning element fills the through-hole and bears continuously on the side wall. The cushioning element is arranged in a heel region or a metatarsal region.

Claims

1-15. (canceled)

16. A midsole of a sport shoe comprising a body defining at least one through hole and at least one cushioning part fitted in the at least one through hole; wherein the body is made from polymer material with a top face designed to contact an insole and a bottom face designed to be fixed to an outsole, the at least one through hole having a side wall connecting the top face to the bottom face, the at least one through hole presenting a variable cross-section between the bottom face and top face, the cross-section being measured in a cutting plane parallel to the top face, the at least one through hole presenting a reduction of the value of the cross-section, over at least a first part of the body, in a first direction perpendicular to the cutting plane and directed from the bottom face to the top face, the at least one through hole being arranged in a heel area or in a metatarsal area of the body; wherein the at least one cushioning part fills the at least one through hole from the top face to the bottom face, the at least one cushioning part having a top face flush with a top face of the body to absorb shocks caused by walking or running in the direction of the metatarsals or the heel; wherein the at least one cushioning part is removable with respect to the body, the at least one cushioning part pressing continuously on the side wall of the at least one through hole at least over the first part of the body.

17. The midsole of a sport shoe according to claim 16 wherein the at least one through hole presents an increase of the value of the cross-section, over at least a second part of the body, the increase being measured in the first direction perpendicular to the cutting plane and directed from the bottom face to the top face, the body successively comprising at least the bottom face, the first part, the second part and the top face.

18. The midsole of a sport shoe according to claim 17 wherein the second part extends from the top face.

19. The midsole of a sport shoe according to claim 18 wherein the cushioning part forms two opposite trapeziums joined by smaller bases.

20. The midsole of a sport shoe according to claim 18, wherein the at least one cushioning part has a complementary shape to the at least one through hole between the top face and the bottom face.

21. The midsole of a sport shoe according to claim 16, wherein the at least one cushioning part has a different stiffness from a stiffness of the body, the stiffness being measured in the first direction.

22. The midsole of a sport shoe according to claim 16 wherein the side wall defines a tilt angle in a second direction larger than a tilt angle in a longitudinal direction, the second direction being perpendicular to the first direction and perpendicular to the longitudinal axis of the body.

23. The midsole of a sport shoe according to claim 22, wherein the at least one cushioning part has a complementary shape to the at least one through hole between the top face and the bottom face.

24. The midsole of a sport shoe according to claim 16, wherein the at least one through hole and the at least one cushioning part together form an anti-rotation device, and wherein the at least one cushioning part has a different stiffness between a first lateral portion and a second lateral portion, the stiffness being measured in the first direction, a second direction connecting the first lateral portion and the second lateral portion, the second direction being perpendicular to the first direction and perpendicular to a longitudinal axis of the body.

25. The midsole of a sport shoe according to claim 24, wherein the at least one cushioning part can be arranged in the at least one through hole in a first position so that the first lateral portion is located in an inner portion of the body and the second lateral portion is located in an outer portion of the body, or in a second position so that the second lateral portion is located in an inner portion of the body and the first lateral portion is located in an outer portion of the body.

26. The midsole of a sport shoe according to claim 16, wherein the at least one cushioning part is formed by a deformable mesh having a first stiffness in the first direction different from a second stiffness in a second direction, the second direction being perpendicular to the first direction and perpendicular to a longitudinal axis of the body.

27. The midsole of a sport shoe according to claim 16, wherein the at least one cushioning part is formed by at least a first part and a second part, the first part being indissociable from the body when the first part and the second part are installed in the at least one through hole.

28. The midsole of a sport shoe according to claim 16 comprising an additional cushioning part fitted removable with respect to the body; wherein the body defines at least one additional through hole with a side wall connecting the top face and the bottom face, the cross-section of the additional through hole in the bottom face being larger than the cross-section of the additional through hole in the top face; wherein the additional cushioning part fills the additional through hole and presses continuously on the side wall of the additional through hole, the additional cushioning part being arranged in the metatarsal area and the cushioning part being arranged in the heel area.

29. A sport shoe comprising a midsole according to claim 16 and an outsole, the outsole being fixed in irremovable manner to the midsole and the outsole closing the through hole to prevent the at least one cushioning part from being removed via the bottom face of the body, the at least one cushioning part being removable via the top face of the body.

30. A method for adapting a sport shoe comprising the following steps: providing a sport shoe according to claim 29; acquiring data relating to a step/stride of a user; removing the at least one cushioning part of the sport shoe; inserting at least one new cushioning part in the at least one through hole, the at least one new cushioning part having a stiffness different from a stiffness of the at least one cushioning part, the stiffness of the at least one cushioning part being defined from the acquired data so as to better suit to the user's step/stride.

31. The method for adapting a sport shoe according to claim 30 wherein the data relating to the step/stride of the user comprises at least one of the following data items: the user's weight, and determination of a pronated, supinated or neutral stride.

32. The method for adapting a sport shoe according to claim 30 wherein the at least one new cushioning part is formed by 3D printing in the form of a deformable mesh and wherein characteristics of the deformable mesh are defined by means of the acquired data.

33. A method for manufacturing a shoe comprising the following steps: providing at least one cushioning part or at least one pad representative of the at least one cushioning part; installing the at least one cushioning part or pad in a mould designed to form a body of a midsole; forming the body of the midsole from polymer material around the at least one cushioning part or pad, the body having a top face and a bottom face, the at least one cushioning part or pad passing through the body and extending from the top face to the bottom face, the at least one cushioning part or pad presenting a variable cross-section between the bottom face and the top face, the cross-section being measured in a cutting plane parallel to the top face, the at least one cushioning part or pad presenting an increase of the value of the cross-section, over at least a first part of the body, in a first direction perpendicular to the cutting plane and directed from the bottom face to the top face, the at least one cushioning part or pad having a top face flush with a top face of the body; fixing an outsole in irremovable manner on the bottom face of the midsole and fixing an upper on the top face of the midsole.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Other advantages and features will become more clearly apparent from the following description of particular embodiments and implementation modes of the invention given for non-restrictive example purposes only and represented in the appended drawings, in which:

[0037] FIG. 1 schematically illustrates a longitudinal cross-sectional view of a first embodiment of a midsole according to the invention;

[0038] FIG. 2 schematically illustrates a longitudinal cross-sectional view of a second embodiment of a midsole according to the invention;

[0039] FIG. 3 schematically illustrates a top view of a first embodiment of a midsole without a cushioning part according to the invention;

[0040] FIG. 4 schematically illustrates a top view of a first embodiment of a midsole with two cushioning parts according to the invention;

[0041] FIG. 5 schematically illustrates a cross-sectional view of a cushioning part in the form of a spring;

[0042] FIG. 6 schematically illustrates a cross-sectional view of a cushioning part made in two pieces;

[0043] FIG. 7 schematically illustrates a cross-sectional view of another embodiment of a cushioning part.

DESCRIPTION OF THE EMBODIMENTS

[0044] As illustrated in FIGS. 1 and 2, the midsole 1 of a sport shoe has a body 2 and at least one cushioning part 3. In conventional manner, the body 2 is made from a flexible material with a stiffness that is adapted to suit the activity required from the sport shoe. The body 2 of the sole is preferentially made from a polymer material and even more preferentially in the form of a foam. It is possible to use a thermoplastic polyurethane (TPU) foam or expanded thermoplastic polyurethane, an EVA foam, an association of the latter or another material suitable for forming a midsole of a sport shoe.

[0045] The midsole has a top face that is designed to be in contact with the insole of the shoe. The insole is designed to be in direct contact with the user's foot. The insole preferentially performs insulation and comfort functions. The midsole has a bottom face that is designed to be fixed to the outsole that is also called wear sole or tread sole. The outsole is the sole that is in contact with the ground and is made from a material that can withstand the aggressions of the ground. The outsole is fixed in irremovable manner to the midsole 1 and provides a strength in the directions perpendicular to the thickness direction, i.e. in the lengthwise and widthwise directions. For example, the outsole is made from rubber, polyurethane, or polyvinyl chloride (PVC). The outsole is made from a different material from the material forming the midsole, preferably from a material that is less compressible than the material forming the midsole, preferably from a solid material i.e. that is not a foam. The outsole presents a higher abrasion resistance, for example by means of a greater hardness than that of the material forming the midsole. The outsole can present a larger stiffness than the midsole in the first direction. In a particular embodiment, the midsole 1 and the outsole are formed monolithically. The same part forms the outsole and the midsole, for example the sole is made in a single moulding step. The outer part of the sole possesses mechanical properties of the upper part so as to dissociate the parts forming the outsole and the midsole 1.

[0046] The body of the midsole 1 defines at least one hole 4 that is designed to receive a cushioning part 3. The body 2 of the midsole 1 defines a hole 4 that can be a blind hole but that is preferentially a through hole. The hole 4 extends in a first direction that corresponds to the thickness of the midsole 1, i.e. in a direction that passes through a top face and a bottom face of the sole. The hole 4 preferentially extends over at least 50% of the thickness of the midsole 1, preferably over at least 75% of the thickness of the midsole 1 and even more preferentially over the whole thickness of the midsole 1, and the hole 4 is then a through hole. The larger the thickness of the midsole 1, the greater the modulation of the mechanical characteristics of the midsole 1 will be, in particular modulation of the stiffness in a first direction that connects the top face and the bottom face. The body 2 defines a ring that is continuous around the hole 4, when observed in the thickness direction. The ring formed by the body 2 enables a mechanical continuity to be maintained thereby providing the midsole 1 with a certain rigidity. The body 2 can define one or more holes 4, for example under the heel and/or under the metatarsal area. It is also possible to provide for the midsole 1 to define two holes or more than two holes in order to provide a greater adaptability of the mechanical performances of the midsole 1. In advantageous manner, the hole 4 located under the user's heel is a through hole. However, it is also possible for the hole 4 located under the metatarsal area to also be a through hole so as to be able to install a cushioning part 3 proposing a cushioning that is better suited to the user. In preferential manner, the cushioning part or parts 3 provide a cushioning that is better suited to the user's needs under the calcaneum and the metatarsals performing absorption of shocks. The tapered shape of the cushioning parts 3 facilitates a maximum spread of the shock wave and transmission of the latter to the body 2. The body 2 is preferentially configured to provide dynamic and support properties of the foot arch. For example purposes, the body 2 can comprise strengtheners, preferentially thermoplastic plates. As illustrated in FIGS. 1 and 2, it is preferable for the cushioning part 3 to extend over the whole of the bearing surface of the metatarsal area or of the heel area. As illustrated in FIGS. 1 and 2, it is particularly advantageous for the top face of the cushioning part 3 to be flush with the top face of the body 2 to absorb shocks during walking and running phases.

[0047] The body 2 of the midsole 1 defines a hole 4 that is bounded by a side wall extending from the top face to the opposite end, preferentially up to the bottom face. To increase the efficiency of modulation of the cushioning, it is advantageous to have a cushioning part 3 with a large surface under the area or areas transmitting stresses from the foot. It is therefore advantageous to have a hole 4 that extends as far as possible in the widthwise direction of the midsole 1. The width is measured in a direction that connects the inner face and the outer face of the midsole 1.

[0048] By providing a sole that comprises a body 2 and a cushioning part 3 that are made from different materials, the body 2 and the cushioning part 3 deform differently in the walking phases and especially when running. The difference of behaviour can give rise to an unpleasant sensation. It is therefore advantageous to master the differential deformation between the body 2 and the cushioning part 3. Formation of a side wall that extends substantially perpendicularly to the top face of the midsole is to be prevented as this gives rise to creation of a step between the body 2 and the cushioning part 3, which is unpleasant especially during running phases.

[0049] To achieve a good mechanical securing between the body 2 and the cushioning part 3, it is advantageous for the through hole 4 to present a variable cross-section between the bottom face and the top face. The cross-section is measured in a cutting plane parallel to the top face. More preferentially, the through hole 4 presents a reduction of the value of the cross-section, over at least a first part of the thickness of the body 2, in a direction perpendicular to the cutting plane and directed from the bottom face to the top face. The thickness is measured in the direction perpendicular to the cutting plane. In this way, when moving away from the bottom face, the cross-section of the hole 4 decreases continuously, in the first part, i.e. a tapering is observed. In the embodiment illustrated in FIG. 1, the first part extends over the whole thickness of the body 2.

[0050] The cushioning part 3 fills the through hole 4 and presses continuously on the side wall of the hole 4 at least over the first part of the thickness of the body 2. This continuous pressing between the side wall of the body 2 and the side wall of the cushioning part 3 enables a good transfer of the lateral stresses to be had between the cushioning part 3 and the body 2.

[0051] In advantageous manner, the hole 4 has a cross-section in the top face that is smaller than the cross-section in the thickness of the body 2 and smaller than the cross-section of the hole 4 at the opposite end, preferably when the latter opens into the bottom face. The reduced cross-section in the top face means that the mechanical properties are not impaired near the attachment between the upper and the midsole 1. The large cross-section in the bottom face enables a good transfer of energy to be had with the outsole that is more rigid.

[0052] Preferentially, the cushioning part 3 has a complementary or substantially complementary shape to that of the hole 4 so as to perform an efficient transfer of stresses between the body 2 and the cushioning part 3 during running phases, when jumping and more generally when shocks occur between the foot and the ground. The use of a cushioning part 3 that has an inclined side wall with respect to the top face of the body 2 of the midsole 1 enables the cushioning part 3 to be kept firmly in the hole 4 when shocks occur without forming a hampering area at the interface between the cushioning part 3 and the body 2. The use of inclined side walls also enables the stiffness to be modulated in the first direction when moving progressively away from the cushioning part 3. Such a configuration makes it possible to avoid a hard spot sensation under the foot. The overlap between the body 2 and the cushioning part 3 with preferentially complementary lateral faces enables the stiffness to be modulated, thereby enhancing the mechanical interaction between the body 2 and the cushioning part 3.

[0053] In advantageous manner, the through hole 4 presents an increase of the value of the cross-section, over at least a second part of the thickness of the body 2, in the direction perpendicular to the cutting plane and directed from the bottom face to the top face, i.e. a broadening. The body 2 successively comprises at least the bottom face, the first part, the second part and the top face. In other words, the cross-section of the through hole increases when approaching the top face. As it approaches the top face, the cushioning part 3 takes up more room thus enabling the interface between the cushioning part 3 and the body 2 to be moved to the lateral edges of the sole, i.e. in less sensitive places. The side wall of the body 2 can define a convex surface whereas the side wall of the cushioning part 3 can define a concave surface. Preferentially, the two surfaces are complementary. In an embodiment illustrated in FIG. 7, in cross-section in the transverse direction, the cushioning part 3 is in the form of an hourglass, i.e. with two substantially opposite trapeziums joined by their smaller bases. This embodiment is more advantageous than the configuration illustrated in FIG. 1 as it enables the differences of stiffness between the cushioning part 3 and the body 2 to be better managed, particularly when the body 2 is made from a more rigid material than the cushioning part 3. The cushioning part 3 has a restriction area where its cross-section is reduced enabling a complementary area to be formed where the body 2 presents a larger cross-section enhancing the mechanical strength.

[0054] The side wall can be flat or substantially flat. The incline of the side wall results in the cross-section of the hole 4 increasing continuously from the top face to the opposite end. In another embodiment, the lateral faces are textured and can define hollows and bumps. It is preferable for the side walls of the hole 4 and of the cushioning part 3 to be complementary to secure the cushioning part 3 in the body 2 in the lengthwise direction, in the widthwise direction and also in the thickness direction, and to better spread the stresses between the cushioning part 3 and the body 2.

[0055] It is advantageous to have a continuous contact between the side wall of the cushioning part 3 and the side wall of the body 2 over the whole height of the hole 4 and over the whole perimeter of the hole 4 so as to have a cushioning part 3 that is held securely in the body 2 and that transfers the stresses with the body 2 efficiently.

[0056] The body 2 and the cushioning part 3 are formed by elastically deformable materials that present different stiffnesses in the thickness direction. When walking or running, the body 2 and the cushioning part 3 deform differently. The body 2 and the cushioning part 3 are made from compressible materials, for example foams. The cushioning part 3 can be formed from a single material, but it is also possible to use a composite material, an association of several foams and possibly an association of foam and gel.

[0057] Fitting a cushioning part 3 that is better suited to the biomechanical specificities of the user enables the performances of the midsole 1 of a shoe to be adapted to meet its user's requirements. It is of interest to adapt a running shoe, but it is also possible to adapt the mechanical performances of a walking shoe, a racket sport shoe or an indoor sport shoe. In all these configurations, it is of interest to adapt the mechanical performances of the midsole 1 to better match the specificities of the user. It is advantageous to use a cushioning part 3 that has a more viscoelastic nature than that of the material forming the body 2.

[0058] It is preferable for the hole 4 to extend as far as possible in the widthwise direction so as to receive the stresses originating from the foot and mainly from the heel or from the metatarsal area without disturbing the attachment area between the body 2 and the upper. To enhance dissipation of energy, it is preferable for the cushioning part 3 to extend as far as possible in the widthwise direction inside the body 2, and it is advantageous for the cushioning part 3 to extend underneath the attachment areas between the body 2 and the upper, for example under the seams (in the first direction).

[0059] In a preferential embodiment, the ratio between the width of the hole 4 in the top face and the width of the hole 4 at the opposite end is more than 0.5, preferentially more than 0.7 and advantageously less than 0.9. The width is measured in a second direction that is perpendicular to the first direction and that is also perpendicular to the longitudinal direction of the midsole 1. The longitudinal direction of the midsole corresponds to the direction of the largest dimension of the sole which corresponds to the direction connecting the heel to the toes. The ratio of the dimension between the top of the hole (the top face) and the bottom of the hole (the opposite end) can present another value along the longitudinal axis. The cushioning part 3 has a ratio between the dimension of the top of the hole and the dimension of the bottom of the hole along the longitudinal axis that is different from the ratio along the transverse axis.

[0060] In a particular embodiment illustrated in FIGS. 1 and 2, the hole 4 is in the form of a truncated cone, i.e. it defines an axis of symmetry that is parallel to the first direction. In cross-sectional view in the thickness direction of the midsole 1, the hole 4 is in the form of a trapezium. The tilt angle of the side wall with respect to the first direction is constant. As an alternative, the side wall can define a curve or steps or other shapes.

[0061] It is possible to have side walls having more complex shapes, for example with slots to better secure the cushioning part 3 in the hole 4.

[0062] In a preferred embodiment, the tilt angle of the side wall with respect to the first direction is different depending on whether a cross-section is observed in the longitudinal direction or in the second direction. It is preferable for the tilt angle in the cross-section in the second direction to be larger than in the longitudinal direction.

[0063] The cushioning part 3 is elastically deformable under the effect of a stress in the first direction. The cushioning part 3 can be in the form of a foam, for example an EVA foam or a thermoplastic polyurethane foam. The cushioning part 3 can also be a polymer spring obtained by 3D printing or a gel. It is also possible to combine these materials in order to adjust the characteristics of the cushioning part 3 as regards the cushioning and reactivity of the sole or the propulsion capacity of the sole. It is advantageous to form a cushioning part in the form of a mesh the side wall of which is continuous, i.e. with no holes. What is meant by 3D printing is an additive method wherein material is added in successive layers to form a predefined three-dimensional model and a subtractive method wherein a block of material is etched to define the predefined three-dimensional model.

[0064] The cushioning part 3 fills the hole 4 and presses continuously on the side wall. In preferential manner, the cushioning part 3 is fitted removable with respect to the body 2. The cushioning part 3 is fitted removable thereby enabling the latter to be replaced by another the cushioning part 3 that is better suited to the user's requirements in order to adjust the performances of the sole to match the specificities of the user. This also enables the cushioning part 3 to be replaced when the latter is worn, for example when the Young's modulus of the cushioning part 3 or the stiffness in the first direction has decreased by 10%.

[0065] The shoe progressively deteriorates with use. Deterioration of the multiple components of the shoe is not however uniform. The area of the midsole 1 situated under the heel supports a large majority of the impacts resulting in preferential wear of this part of the shoe compared with the other components. By making it possible to disassemble a cushioning part 3 that is situated in the midsole under the heel, it becomes easier to replace the cushioning part 3 when the latter is worn. The same can be the case under the metatarsal area.

[0066] The cushioning part 3 can then be replaced enabling the shoe to be used for a new cycle of use. Replacement of the cushioning part 3 enables a shoe to be formed that is suitable for its original use. Replacement of the cushioning part 3 reduces the ecological footprint of the shoe by only replacing the element that is considered to be worn.

[0067] The use of a midsole 1 provided with a cushioning part 3 that is removable with respect to the body 2 enables the cushioning part 3 to be replaced by another one having a stiffness that is better suited to the user's requirements. When it is manufactured, the midsole 1 is configured for a user of predefined weight (reference weight). The stiffness of the midsole 1 and more particularly the area under the heel is dimensioned to support the shocks that occur during running phases for a user having the predefined weight. However, when the user is heavier, the cushioning procured by the sole may be insufficient which may result in injuries. On the contrary, when the user is lighter, the sole does not respond as expected as it becomes too rigid. It is therefore advantageous to be able to adjust the mechanical performances of the sole quickly and easily, and preferentially the area under the heel or the metatarsal area.

[0068] In one embodiment, the cushioning part 3 has a difference of stiffness between a first lateral portion and a second lateral portion. The two lateral portions are adjacent in the widthwise direction. The use of a cushioning part 3 that has a difference of stiffness between a first lateral portion and a second lateral portion is particularly advantageous to be able to deal with pronated or supinated step/stride phenomena. By using the appropriate cushioning part 3, it is possible to increase the stiffness of the inner portion of the midsole with respect to the outer portion or to reduce the stiffness of the inner portion of the midsole with respect to the outer portion. The use of a midsole 1 having a hole 4 that allows the cushioning part 3 to be disassembled is particularly advantageous to better adapt the mechanical characteristics of the shoe to suit a pronated stride or a supinated stride. Furthermore, as each shoe is able to be modified independently from the other, it is possible to adapt a shoe to a type of stride chosen from a pronated, supinated or neutral stride and to adapt the other shoe independently to a type of stride chosen from a pronated, supinated or neutral stride.

[0069] In a particular embodiment, the hole 4 and the cushioning part 3 together form an anti-rotation device configured to prevent rotation of the cushioning part 3 in the hole 4 around an axis substantially parallel to the first direction. The use of an anti-rotation device is particularly advantageous when the cushioning part 3 has a difference of thickness between a first lateral portion and a second lateral portion. The difference of thickness is measured in the widthwise direction, i.e. in the second direction that is perpendicular to the direction connecting the bottom face and top face of sole 1. When repeated shocks occur in connection with the running phases or when walking, the cushioning part 3 deforms. The anti-rotation means prevent the forces applied on the cushioning part 3 from making the cushioning part 3 rotate in the hole 4.

[0070] In preferential manner, the cushioning part 3 that has a difference of stiffness between a first lateral portion and a second lateral portion can be installed in the hole 4 in a first position or in a second position. The first position can be suitable for a pronated step/stride whereas the second position can be suitable for a supinated step/stride. The anti-rotation means prevent rotation of the cushioning part 3 when the latter is in the hole 4.

[0071] In a particular embodiment, the cushioning part 3 is a foam. In another embodiment, the cushioning part 3 is a deformable mesh. It is advantageous to have a deformable mesh that defines a first thickness in the first direction that is different from a second thickness in the second direction. The first direction connects the bottom face and the top face, and the second direction is perpendicular to the first direction and perpendicular to the longitudinal axis of the body 2.

[0072] The use of a deformable mesh is particularly advantageous as it is possible to form an anisotropic cushioning part 3 and preferably a highly anisotropic cushioning part 3. It is particularly advantageous to form a mesh with a Young's modulus in the second direction that is lower than the Young's modulus in the first direction. It is then easy to deform the cushioning part 3 in the second direction for ease of installing the latter in the hole 4. Once in place, the cushioning part 3 is mainly stressed in the first direction. For example, the Young's modulus or the stiffness in the second direction is lower than the Young's modulus or the stiffness in the first direction by at least 30%.

[0073] In particularly advantageous manner, the cushioning part 3 made from a mesh is formed by 3D printing, preferably by means of an additive method that enables the mechanical characteristics of the mesh to be adapted to suit the user's requirements, in particular its stiffness in the first direction. It is also possible to adjust the chemical composition of the material to the user's requirements, in particular to obtain the required thickness in the first direction. The mesh is custom-made to be able to adjust as faithfully as possible to the specific requirements of the user.

[0074] In another embodiment, the cushioning part 3 is formed by an isotropic element, for example in the form of a gel or a foam. The use of a deformable mesh and a foam or a gel can be combined in order to adjust the mechanical characteristics of the cushioning part 3 more finely.

[0075] In a preferential embodiment, the cushioning part 3 is formed by at least first and second parts, the first part 3a being indissociable from the body 2 when the second part 3b is installed in the hole 4. When the cushioning part 3 has a large stiffness and in particular a large stiffness in the second direction and/or the longitudinal direction, it is advantageous to divide the cushioning part 3 into several distinct parts 3a/3b. The first part 3a is installed in the hole 4 and the second part 3b is then installed in the hole 4 to block the first part 3a in the hole 4. It is also possible to provide for the cushioning part 3 to be formed by a plurality of foam and/or gel elements having different mechanical properties, certain of these elements being able to be disassembled from the others. Once the mechanical characteristics of the cushioning part 3 have been defined in the first direction, the right set of elements can be chosen to form the cushioning part 3.

[0076] In a particular embodiment illustrated in FIG. 5, the first part 3a and the second part 3b have different stiffnesses in the first direction thereby enabling a cushioning part 3 to be formed with different stiffnesses between the first lateral portion and the second lateral portion, for example to deal with pronated or supinated gaits.

[0077] It is particularly advantageous to form a sport shoe that has a midsole 1 according to one of the configurations presented above. In the case where the body 2 of the midsole 1 defines a through hole 4, the outsole closes the through hole 4 so that the association of the midsole 1 and outsole defines a blind hole. The cushioning part 3 presses on the outsole. It is particularly advantageous to have a through hole 4 as the stresses between the cushioning part 3 and the body 2 are then better managed.

[0078] To adapt the mechanical performances of the midsole 1 more precisely to the specificities of the user, it is advantageous to determine one or more characteristics relating to the use of the shoe.

[0079] To adapt the mechanical performances of the sole and therefore of the shoe to suit the user's requirements better, it is advantageous to determine the user's weight. Once the user's weight is known, the value obtained can be compared with a reference value, i.e. the current value of the midsole.

[0080] When the user's weight does not correspond to the reference weight or to the reference weight range, the cushioning part 3 has to be replaced by another cushioning part 3 with a more suitable stiffness, i.e. a cushioning part 3 the reference weight of which corresponds to or comprises the user's weight.

[0081] As an alternative or as a complement, it is advantageous to determine the user's experience which may condition his running technique and therefore the cushioning need. The mechanical characteristics of the cushioning part 3 depend on the user's experience. The less experience he has, the more advantageous it is to provide cushioning. The stiffness of the cushioning part is at least a function of a parameter representative of the user's experience.

[0082] As an alternative or as a complement, it is advantageous to determine whether the shoe is designed to be used over short distances, for example less than 10 km, or whether on the contrary the shoe is designed for longer distances, for example more than 20 km. It is also advantageous to know the weekly mileage involved. It is advantageous to provide greater cushioning for long distances in comparison with short distances. Once the mean running distance is known, the cushioning part 3 can be replaced by another cushioning part 3 with a more suitable stiffness. It is advantageous to combine this information with the user's weight so as to provide an even more suitable cushioning part 3. The mechanical characteristics of the cushioning part 3 depend on the mileage per run and on the weekly mileage. The greater the mileage, the more advantageous it is to have cushioning. The stiffness of the cushioning part 3 is at least a function of a parameter representative of the mean or weekly distance intended to be covered by the user.

[0083] As an alternative or as a complement, it is advantageous to determine whether the shoe is designed for training or for competition, i.e. whether the shoe has to have a strong reactivity or a weak reactivity. Once the use of the shoe has been determined, it is advantageous to determine the most suitable mechanical characteristics for the cushioning part 3. It is also possible to determine the type of terrain (flat or rugged) and the altitude differences.

[0084] According to the information provided by the user, the mechanical performances of the cushioning part can then be modified to adapt the latter more finely to the user's requirements.

[0085] As adjustment is performed independently for each shoe, it is possible to make different modifications between the two shoes.

[0086] Modification of the midsole 1 to better adapt its mechanical performances to the user's requirements is more advantageous than modification of the insole as the available thickness is greater. It is also apparent that modification of the midsole is compatible with the use of a made-to-measure insole to adapt to the morphology of the foot. Modification of the midsole avoids having to modify the inner volume of the shoe.

[0087] As an alternative or as a complement, to better adapt the technical characteristics of the sole, it is advantageous to define the characteristics of the stride. It is advantageous to determine the characteristics of the user's step/stride. If analysis of the step/stride determines that the step/stride is pronated or supinated, it is advantageous to modify the characteristics of the cushioning part 3 to adapt the mechanical characteristics in the second direction to the characteristics of the step/stride. Depending on whether the attack of the step/stride takes place via the heel or via the middle of the foot, the characteristics of the cushioning part 3 are modified so as to define the value of the stiffness and therefore the necessary cushioning. It is therefore of interest to take images of the step/stride to analyze the step/stride and determine the characteristics defining the cushioning part 3.

[0088] To perform adaptation of a sport shoe, it is advantageous to have an adaptation method that comprises the following steps: [0089] providing a shoe according to any one of the foregoing configurations; [0090] acquiring data relating to the step/stride of a user; [0091] determining the mechanical characteristics of a cushioning part 3 to adapt to the user's step/stride; [0092] removing the cushioning part 3 from the shoe; [0093] inserting a new cushioning part 3 according to the acquired data, the new cushioning part 3 being better suited to the user's step/stride.

[0094] In preferential manner, the data relating to the user's step/stride comprises at least one of the following data items: the user's weight, and determination of a pronated, supinated or neutral step/stride. It is also advantageous for the data to comprise determination of the expected distance to be covered (mean or weekly) and determination of the attack of the foot in the user's step/stride.

[0095] Once analysis of the step/stride has been performed, this data is transmitted to a processing circuit that proposes to install one or more cushioning parts 3 in the midsole. The processing circuit indicates which type of the cushioning part 3 is to be installed.

[0096] In preferential manner, a new cushioning part 3 is formed by 3D printing in the form of a deformable mesh. The characteristics of the deformable mesh are defined by means of the data relating to the user's step/stride. The processing circuit can provide the plans of the mesh to the 3D printing device that will form the cushioning part 3 according to the collected data.

[0097] As a multitude of shoe models exist, it is particularly advantageous to use 3D printing to form the cushioning part 3 so as to adapt the mechanical performances of the cushioning part 3 to the space available in the hole 4 of the body 2. The volume of the hole 4 can vary from one model to the other or from one shoe size to the other. It is therefore advantageous to identify the type of shoe in order to identify the dimensions of the hole and the mechanical characteristics of the body 2 of the sole. The mechanical characteristics of the cushioning part 3 will be defined in accordance with this data to integrate the cushioning part 3 optimally in the sole and to adapt the sole to the user's requirements.

[0098] In a particular case, the shape of the hole 4 is defined when manufacture of the midsole is performed, preferably before the latter is secured to the upper and/or fixed to the outsole. The hole 4 has a height (the dimension in the first direction) and transverse dimensions that are predefined and correspond to an imposed shape for this sole model. It is then possible to form one or more cushioning parts 3 with different stiffnesses to be able to adapt the performances of the sole quickly and choose the most suitable cushioning part 3 according to the information obtained from the user.

[0099] In a first embodiment, the cushioning part 3 or a pad representing the cushioning part 3 is installed in a mould. The polymer material or materials designed to form the body 2 are inserted in the mould and form the body 2 around the cushioning part 3. The cushioning part 3 opens at least onto the top face of the midsole 1. The cushioning part 3 or a pad representing the cushioning part 3 defines the hole 4. It is advantageous to manufacture the shoe with the cushioning part 3 rather than the pad so that the shoe can be used immediately. The midsole 1 is substantially identical to a sole of the prior art thereby avoiding having to extensively modify the manufacturing methods of the shoe.

[0100] The midsole is fixed to the bottom sole in conventional manner, for example by gluing. It is advantageous to add a separating layer between the cushioning part 3 and the layer of glue that is designed to secure the midsole 1 with the bottom sole. The separating layer makes removal of the cushioning part 3 easier by preventing the cushioning part 3 from adhering to the bottom sole. As an alternative, it is always possible to remove the cushioning part 3 by etching before installing a new cushioning part 3.

[0101] This embodiment is simple to implement and enables a manufacturing method of the midsole to be had that is close to those of the prior art.

[0102] The midsole is fixed to the upper and to the other elements of the sport shoe in the same way as in manufacturing methods of the prior art. To access the cushioning part 3, the insole simply has to be removed. The cushioning part 3 is removed and is replaced by a more suitable cushioning part 3. The insole can then be refitted.

[0103] In another embodiment, the midsole was initially manufactured without defining a hole 4. It is then possible to define a hole 4 and preferably a through hole 4 by eliminating a part of the body 2 of the midsole 1. In one embodiment, the hole 4 is formed before the midsole 1 is secured with the outsole and/or the upper. In another embodiment, the shoe is finished or the shoe has even already been worn or even used, and it comprises the outsole and the upper.

[0104] The hole 4 in the midsole 1 is formed by any suitable means for etching the body 2, for example by means of a drill bit or a milling cutter. It is particularly advantageous to use a template that will enable the precise position of the hole 4 to be defined, as well as the depth and shape of the latter. Association of a predefined drill bit with a predefined template enables the depth of the hole 4 to be controlled in order not to weaken the outsole. This also makes it possible to form the hole 4 that best matches the configuration of the shoe, i.e. a hole 4 enabling a cushioning part 3 to be fitted, i.e. having dimensions in the first direction and perpendicularly to the first direction that ensure that a notable effect is had on modification of the stiffness in the first direction without impairing the mechanical performances of the midsole 1 in the second direction and in the longitudinal direction.

[0105] In a particular embodiment, the dimensions of the hole are unknown, for example the hole was etched in the midsole 1 from its top face. It is advantageous to make a three-dimensional optical impression of the hole to know its exact shape. Once the shape is known and the data relating to the user's stride are known, it is possible to define which type of cushioning part 3 is most suitable. Preferentially, determination of the thickness of the body of the sole is performed in order to form a cushioning part that takes account of the mechanical performances of the body surrounding the latter. When the sole is known, this information can be present in the memory of the processing device and taken into account in defining the technical characteristics of the cushioning part 3.

[0106] In one embodiment, the hole 4 is formed by etching after the data relating to the user (weight, stride, mileage, etc.) has been acquired. This data can be used to adapt the shape of the hole 4. It is then advantageous to use a cushioning part formed by 3D printing.

[0107] The cushioning part 3 is inserted in the hole 4 to modify the mechanical behaviour of the midsole 1. The cushioning part 3 has a different stiffness from the stiffness of the etched part of the midsole 1.

[0108] In conventional manner, the midsoles 1 of running shoes are made from EVA foam, EVA standing for ethylene vinyl acetate. This material procures a very good trade-off between weight and cushioning, i.e. a good shock absorption. However, the manufacturing process of an EVA sole is fairly difficult to master and generates a large environmental impact. It is therefore advantageous to limit the use of such a material as far as possible. Shoes also exist having a midsole 1 made from thermoplastic polyurethane, but the performances not as good.

[0109] The use of a midsole 1 such as the one presented in the above enables the mechanical performances of the sole to be differentiated in the first direction for different portions of the sole. It is possible to differentiate the mechanical performances of the midsole between the heel area and the foot arch area and/or between the metatarsal area and the foot arch area.

[0110] To provide a sport shoe sole that is pleasant to use, it is particularly advantageous to have an important cushioning under the heel and/or under the metatarsal area. On the other hand, the cushioning requirements are lesser under the foot arch, under the toes and over the whole periphery of the sole. It is therefore particularly advantageous to form a body 2 from a material other than an EVA foam and to add a cushioning part 3 made from an EVA foam to the latter. For example, the body 2 of the midsole 1 is made from a thermoplastic polyurethane foam or from another material that is different from EVA and the cushioning part 3 is made from an EVA foam. Such an association enables a sole of a running shoe to be formed mainly from polyurethane foam with the same level of cushioning as a foam sole formed exclusively or almost exclusively from EVA. In a particular embodiment, the body 2 is made from a different polymer material from EVA and from thermoplastic polyurethane foam. The cushioning part 3 is made from EVA and/or from thermoplastic polyurethane or from a deformable mesh. The body 2 is made from a material that presents less cushioning than the material forming the cushioning part 3. The body 2 is made from a material that procures a greater mechanical rigidity in order to withstand lateral stresses better. It is advantageous for the body 2 to be devoid of EVA and even more preferentially devoid of EVA and of expanded thermoplastic polyurethane.

[0111] In a particular embodiment, the cushioning part 3 made from EVA foam is not removable with respect to the body 2 of the midsole 1. The EVA foam element can be replaced by a cushioning part 3 made by three-dimensional printing with a mesh that defines a porous mesh. The mesh makes it possible to form a cushioning part 3 that has a higher Young's modulus or a larger stiffness in the thickness direction of the sole than the Young's moduli or a stiffness in the lengthwise and widthwise direction.

[0112] The cushioning part 3 made from EVA foam is installed in a mould and the body 2 is formed around the cushioning part 3 made from EVA foam. The cushioning part 3 extends from one end of the body 2 to the other in the thickness direction. The cushioning part 3 and the body 2 have complementary shapes facilitating transfer of stresses between the cushioning part 3 and the body 2. As indicated in the above, the side walls are inclined resulting in a better transfer of stresses between the cushioning part 3 and the body 2. If a pad representative of the cushioning part 3 is used, the pad is removed after the body has been formed to be replaced by the cushioning part made from EVA, from expanded thermoplastic polyurethane or in the form of a deformable mesh.