SOLE STRUCTURE OF SPORT SHOE WITH SHOE STUDS AND MANUFACTURING METHOD THEREOF

Abstract

A sole structure of a sport shoe with shoe studs includes: inner cleat elements separated from each other and made of a first elastic material; an outsole layer including outsole holes through which the inner cleat elements pass, and hole surfaces of the outsole holes connecting with top portions of the inner cleat elements; and outer cleat elements, formed on and surrounding or being surrounded by the inner cleat elements, separated from each other and from the outsole layer, made of a second elastic material. Each of the inner cleat elements and the outer cleat element formed thereon together form the shoe stud. In the shoe stud, the inner cleat element is visible from a gap between the outer cleat element and the outsole layer. Elasticity of the first elastic material is higher than elasticity of the second elastic material.

Claims

1. A sole structure of a sport shoe with shoe studs, comprising: inner cleat elements, separated from each other and made of a first elastic material; an outsole layer, comprising outsole holes through which the inner cleat elements pass, and hole surfaces of the outsole holes connecting with top portions of the inner cleat elements; and outer cleat elements, formed on and surrounding or being surrounded by the inner cleat elements, separated from each other and from the outsole layer, and made of a second elastic material; wherein: each of the inner cleat elements and the outer cleat element formed thereon together form the shoe stud; in the shoe stud, the inner cleat element is visible from a gap between the outer cleat element and the outsole layer; and elasticity of the first elastic material is higher than elasticity of the second elastic material.

2. The sole structure of the sport shoe with the shoe studs according to claim 1, wherein at least one of the outer cleat elements comprises a cleat opening from which the inner cleat element of the shoe stud is visible and is contactable to the ground.

3. The sole structure of the sport shoe with the shoe studs according to claim 1, wherein the inner cleat element in the shoe stud comprises a side surface with a step-shaped structure.

4. The sole structure of the sport shoe with the shoe studs according to claim 3, wherein the step-shaped structure of the inner cleat element comprises a top step far from the ground, and at least one lower step connected to the top step and being close to the ground; and the top step is visible from the gap between the outsole layer and the outer cleat element in the shoe stud.

5. The sole structure of the sport shoe with the shoe studs according to claim 1, wherein the inner cleat element tapers from a top end of the inner cleat element far from the ground, to a bottom end of the inner cleat element close to the ground, and the outer cleat element tapers from a top end of the outer cleat element far from the ground, to a bottom end of the outer cleat element close to the ground.

6. The sole structure of the sport shoe with the shoe studs according to claim 1, wherein the outer cleat element fits in the inner cleat element, a step-shaped structure is formed in a connection interface between the inner cleat element and the outer cleat element, and the outer cleat element formed on and surrounded by the inner cleat element tapers from a bottom end of the outer cleat element close to the ground, to a top end of the outer cleat element far from the ground.

7. The sole structure of the sport shoe with the shoe studs according to claim 1, wherein the inner cleat element in the shoe stud comprises a side surface comprising a ring supporting surface visible from the gap between the outer cleat element and the outsole layer, the outer cleat element in the shoe stud comprises a contacting surface for contacting the ground, and an outer side surface connected to and not parallel to the contacting surface, and a lower edge of the ring supporting surface of the inner cleat element close to the ground is aligned with an upper edge of the outer side surface of the outer cleat element far from the ground.

8. The sole structure of the sport shoe with the shoe studs according to claim 1, wherein a top end of the outer cleat element far from the ground protrudes from a top portion of the inner cleat element in an axis vertical to a central axis of the shoe stud.

9. The sole structure of the sport shoe with the shoe studs according to claim 1, wherein the outer cleat element comprises a contacting surface for contacting the ground, and an outer side surface connected to and not parallel to the contacting surface, an intermediate portion of the outer side surface of the outer cleat element protrudes from two opposite ends of the outer side surface of the outer cleat element in an axis vertical to a central axis of the shoe stud, and the intermediate portion of the outer side surface of the outer cleat element is located between the two opposite ends of the outer side surface of the outer cleat element.

10. The sole structure of the sport shoe with the shoe studs according to claim 8, wherein the outer side surface of the outer cleat element has a regular concave-convex pattern.

11. The sole structure of the sport shoe with the shoe studs according to claim 1, wherein the inner cleat element in the shoe stud comprises a first taper portion far from the ground, a second taper portion for contacting the ground, and a third taper portion located between the first taper portion and the second taper portion, the first taper portion is tapered from a top end far from the ground, to a bottom end close to the ground, the second taper portion is tapered from a top end far from the ground, to a bottom end close to the ground, the third taper portion is tapered from a bottom end close to the ground, to a top end far from the ground, the top and bottom ends of the third taper portion are respectively connected to the bottom end of the first taper portion and the top end of the second taper portion, and a part of the first taper portion is visible from the gap between the outer cleat element and the outsole layer in the shoe stud.

12. The sole structure of the sport shoe with the shoe studs according to claim 1, wherein the outer cleat element in the shoe stud comprises a taper portion far from the ground, and a contacting portion connected to the taper portion and configured to contact the ground, and the taper portion is tapered from a top end far from the ground, to a bottom end close to the ground.

13. The sole structure of the sport shoe with the shoe studs according to claim 1, wherein the outer cleat element in the shoe stud comprises a contacting surface for contacting the ground, a recess is formed on the contacting surface, and a cleat opening of the outer cleat element is formed at the recess; and the inner cleat element comprises a contacting surface for contacting the ground, and a side surface connected to and not parallel to the contacting surface, and a ring side surface of the recess faces and surrounds the side surface of the inner cleat element.

14. The sole structure of the sport shoe with the shoe studs according to claim 1, wherein the inner cleat element in the shoe stud comprises a first contacting surface for contacting the ground, the outer cleat element in the shoe stud comprises a second contacting surface for contacting the ground, and the first contacting surface of the inner cleat element is aligned with or protrudes from and is surrounded by the second contacting surface of the outer cleat element in the shoe stud.

15. The sole structure of the sport shoe with the shoe studs according to claim 1, wherein the inner cleat element comprises a side surface, the outer cleat element comprises an inner side surface for facing and connecting to the side surface of the inner cleat element, and no gap exists between the side surface of the inner cleat element and the inner side surface of the outer cleat element in the shoe stud.

16. The sole structure of the sport shoe with the shoe studs according to claim 1, wherein a bottom end of the inner cleat element close to the ground has a smaller projection in a central axis of the shoe stud than a top end of the inner cleat element far from the ground, and a bottom end of the outer cleat element close to the ground has a smaller projection in the central axis of the shoe stud than a top end of the outer cleat element far from the ground.

17. The sole structure of the sport shoe with the shoe studs according to claim 1, wherein outline or shape of the inner or outer cleat element of at least one of the shoe studs on the sole structure is asymmetrical.

18. The sole structure of the sport shoe with the shoe studs according to claim 1, wherein outline or shape of the inner or outer cleat element of at least one of the shoe studs on the sole structure is symmetrical.

19. A sport shoe having the sole structure according to claim 1.

20. A manufacturing method of the sole structure of the sport shoe with the shoe studs according to claim 1, comprising the following steps: (A) forming the inner cleat elements on a bottom portion of the sport shoe; and (B) forming the outer cleat elements on the inner cleat elements while simultaneously forming the outsole layer on the bottom portion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] After studying the detailed description in conjunction with the following drawings, other aspects and advantages of the present invention will be discovered:

[0025] FIG. 1 is an exploded view of a sole structure of a sport shoe according to an embodiment of the present invention;

[0026] FIG. 2 is a perspective view of a sport shoe with a sole structure according to an embodiment of the present invention;

[0027] FIG. 3 is a cross-sectional view of the sport shoe along a section line 3-3 in FIG. 2 to show the sole structure disposed on a bottom portion of the sport shoe;

[0028] FIGS. 4A to 4L are structural schematic diagrams of different examples of shoe studs in the present invention;

[0029] FIG. 5 is a flow chart of a manufacturing method according to an embodiment of the present invention; and

[0030] FIG. 6 is a schematic diagram of steps of producing a shoe stud on a lasting board of a lasted upper in the manufacturing method of FIG. 5.

DETAILED DESCRIPTION

[0031] Sole structures according to various embodiments of the present invention are applicable to sport shoes needing shoe studs for providing greater traction on the field and gripping the ground in order to avoid slipping and sliding.

[0032] Types of such sport shoes include spiked shoes, antiskid shoes, and other sport shoes with buffer protrusions at the sole, for example, but not limited to, football boots (or called soccer shoes), golf shoes, baseball shoes, rugby boots (or called American football boots), cricket shoes, etc. Of course, the design of sole structure in the present invention can also be appliable to all other types of footwear after suitable modification, such as basketball shoes, running shoes, outdoor shoes, etc. To clarify the present invention, a particular example is focused on football boots/soccer shoes.

[0033] As shown in FIGS. 1 to 3, a sole structure includes a bottom portion of the sport shoe, shoe studs 2, and an outsole layer 31.

[0034] In this embodiment, the bottom portion of the sport shoe is a lasting board 11 of a lasted upper 1; and however, a midsole layer (not shown in the figures) can also be contemplated to serve as the bottom portion of the sport shoe in other embodiments.

[0035] Every shoe stud 2 includes (or is composed of) an inner cleat element 21 and an outer cleat element 22.

[0036] The inner cleat elements 21 are formed at designated positions on the lasting board 11, are separated from each other, and are made of a first elastic material. The inner cleat element 21 is a solid element and includes a connecting surface 211 contacting the lasting board 11, a side surface 212 connected to and not parallel to the connecting surface 211, and a contacting surface 213 (or referred to as first contacting surface) connected to the side surface 212 and opposite to the connecting surface 211.

[0037] The outer cleat elements 22 are formed on and surround the upper part to the bottom end of the side surface 212 of the inner cleat elements 21, are separated from each other, and are made of a second elastic material. The elasticity of the first elastic material is higher than the elasticity of the second elastic material (i.e., the second elastic material is harder than the first elastic material), so the outer cleat elements 22 are harder than the inner cleat elements 21.

[0038] The outer cleat element 22 includes an inner side surface 221 contacting (i.e., connected with) the side surface 212 of the inner cleat element 21, an outer side surface 222 opposite to the inner side surface 221 and visible to human eyes, a ring connecting surface 223 contacting (i.e., connected with) the side surface 212 of the inner cleat element 21 and connecting the top of the inner side surface 221 to the top of the outer side surface 222, and a contacting surface 224 (or referred to as second contacting surface) opposite to the ring connecting surface 223 and connecting the bottom of the inner side surface 221 to the bottom of the outer side surface 222. The contacting surface 224 will contact the ground if the shoe stud 2 is pressed towards the ground.

[0039] The outsole layer 31 is also formed on the lasting board 11, surrounding the top portion of the side surface 212 of the inner cleat elements 21, which creates outsole holes 32 for the inner cleat elements 21 to pass through, and is separated from the outer cleat elements 22. The outsole layer 31 is also made of a second elastic material. The outsole layer 31 includes a hole surface 33 of the outsole hole 32 contacting (i.e., connected with) the side surface 212 of the inner cleat element 21, particularly to the side surface of the top portion of the inner cleat element 21. Moreover, a gap exists between the outer cleat element 22 and the outsole layer 31, so from this gap, the top portion of the inner cleat elements 21 is visible to human eyes.

[0040] Furthermore, other optional details of the shoe stud 2 are exemplarily described as follows.

[0041] In this embodiment shown in FIGS. 1 to 3, a cleat opening 225 is further formed on the contacting surface 224 of the outer cleat elements 22, so the contacting surface 224 as a ring contacting surface surrounds the contacting surface 213 of the inner cleat element 21. From the cleat opening 225, the contacting surface 213 of the inner cleat element 21 is visible to human eyes. Therefore, the contacting surface 213 of the inner cleat element 21 will contact the ground if the shoe stud 2 is pressed towards the ground.

[0042] In this embodiment shown in FIGS. 1 to 3, the outer cleat element 22 further includes a recess 226 serving as a part of the cleat opening 225 and formed on the contacting surface 224. Specifically, the recess 226 includes a bottom surface 2261 and a ring side surface 2262 connected to and surrounding the bottom surface 2261. The ring side surface 2262 is outwardly inclined with respect to the bottom surface 2261 of the recess 226 and the central axis C of the shoe stud 2, and has a gap with the side surface 212 of the inner cleat element 21 that is exposed by the cleat opening 225 of the outer cleat element 22 and located at a bottom end of the inner cleat element 21 far from the lasting board 11 but close to the ground.

[0043] In this embodiment shown in FIGS. 1 to 3, the bottom end of the inner cleat element 21 far from the lasting board 11 but close to the ground has a smaller projection in the central axis C of the shoe stud 2 than a top end of the inner cleat element 21 close to the lasting board 11 but far from the ground. Specifically, the inner cleat element 21 is a tapered element.

[0044] In this embodiment shown in FIGS. 1 to 3, the side surface 212 of the inner cleat element 21 has a step-shaped structure 214. Specifically, the step-shaped structure 214 includes, for example, but not limited to, a top step 215 contacting the lasting board 11 and the outsole layer 31 but far from the ground, and three lower steps 216 (i.e., lower steps 216A to 216C) far from the lasting board 11 but close to the ground.

[0045] The top step 215 is visible from the gap between the outer cleat element 22 and the outsole layer 31, and all of the lower steps 216 are covered by the outer cleat element 22. The lower step 216A, i.e., the lower step 216 farthest from the ground, is connected to the top step 215, the lower step 216B is located between and connected to the lower step 216A and the lower step 216C (i.e., the lower step 216 closest to the ground and serving as a bottom step for contacting the ground).

[0046] The top step 215 includes a ring supporting surface 2151 (i.e., first ring supporting surface) connected to and not parallel to the connecting surface 211, and a ring pressed surface 2152 (i.e., first ring pressed surface) connected to and not parallel to the ring supporting surface 2151.

[0047] The lower step 216 includes a ring supporting surface 2161 (i.e., second ring supporting surface) connected to and not parallel to the ring pressed surface 2152 of the top step 215, and a ring pressed surface 2162 (i.e., second ring pressed surface) connected to and not parallel to the ring supporting surface 2161.

[0048] The ring supporting surface 2151 is inwardly inclined with respect to the central axis C of the shoe stud 2, and the ring supporting surface 2161 of each of the lower steps 216 is also inwardly inclined with respect to the central axis C of the shoe stud 2.

[0049] The heights of the ring supporting surfaces of the steps of the inner cleat element 21 in the central axis C of the shoe stud 2 are different.

[0050] In this embodiment shown in FIGS. 1 to 3, a bottom end of the outer cleat element 22 far from the lasting board 11 but close to the ground has a smaller projection in the central axis C of the shoe stud 2 than a top end of the outer cleat element 22 close to the lasting board 11 but far from the ground. Specifically, the outer cleat element 22 is a tapered hollow element.

[0051] In this embodiment shown in FIGS. 1 to 3, a lower edge of the ring supporting surface 2151 of the top step 215 far from the lasting board 11 but close to the ground is aligned with an upper edge of the outer side surface 222 of the outer cleat element 22 close to the lasting board 11 but far from the ground.

[0052] In this embodiment shown in FIGS. 1 to 3, the contacting surface 213 of the inner cleat element 21 is aligned with the contacting surface 224 of the outer cleat element 22 in the shoe stud 2.

[0053] In this embodiment shown in FIGS. 1 to 3, no gap exists in a connection interface between the side surface 212 of the inner cleat element 21 and the inner side surface 221 of the outer cleat element 22 in the shoe stud 2.

[0054] In this embodiment shown in FIG. 3, the height of the outer side surface 222 of the outer cleat element 22 at a first side of the shoe stud 2 with respect to the central axis C is the same as or similar to the height of the outer side surface 222 of the outer cleat element 22 at a second side of the shoe stud 2 opposite to the first side with respect to the central axis C. Moreover, a maximum/average/minimum distance between the ring pressed surface 2152 of the top step 215 and the contacting surface 224 of the outer cleat element 22 at a first side of the shoe stud 2 with respect to the central axis C is the same as or similar to a maximum/average/minimum distance between the ring pressed surface 2152 of the top step 215 and the contacting surface 224 of the outer cleat element 22 at a second side of the shoe stud 2 with respect to the central axis C.

[0055] In this embodiment shown in FIGS. 1 to 3, the harder cleat element, i.e., the outer cleat element 22, of the shoe stud 2 is formed on and surrounds the softer cleat element, i.e., the inner cleat element 21, of the shoe stud 2.

[0056] In this embodiment shown in FIGS. 1 to 3, the outlines of some of the inner cleat elements 21 of the shoe studs 2 on the sole structure are symmetrical but the outlines of the others of the inner cleat elements 21 of the shoe studs 2 on the sole structure are asymmetrical. Specifically, the outlines of the inner cleat elements 21 of some of the shoe studs 2 in the region corresponding to the toes and ball of the foot, on the sole structure are symmetrical, and the outlines of the inner cleat elements 21 of the others of the shoe studs 2 on the sole structure are asymmetrical. This is conducive to being adaptive to football boots'needs.

[0057] In the present invention, the harder cleat element (i.e., the outer cleat element 22) can protect the softer cleat element (i.e., the inner cleat element 21) from wear and tear as the harder cleat element covers on the softer cleat element, whereby the shoe stud 2 in the present invention may ensure wear resistance and durability. Moreover, since the gap between the harder cleat element and the outsole layer 31 exposes the softer cleat element, it is possible for the shoe stud 2, particularly the softer cleat element, to: (1) provide lower impact, better compression and cushioning/buffering performance (i.e., force/shock absorption), whereby a wearer may feel more comfortable underfoot when wearing sport shoes with such a sole structure; (2) provide better rebound, whereby the wearer may achieve faster speed; and (3) provide directional bending of each individual stud to enable quicker stops, starts, and changes in direction, whereby the wearer may achieve faster acceleration. The combination of the above factors may lead to reduced stress on joints and ligaments, thereby preventing or reducing the risk of injuries to the wearer.

[0058] However, it should be noted that the present invention is not limited to such a structural design of the shoe stud 2 of FIG. 3, and the structural design of the shoe stud of the present invention could have various modifications. Some of the possible modifications of the shoe stud of the present invention are exemplarily described as follows.

[0059] In other embodiments, it could be contemplated that no cleat opening is formed on a contacting surface of an outer cleat element in a shoe stud. For example, no cleat opening is formed on a contacting surface 824/116 of an outer cleat element 82/112 in a shoe stud 8/110 as shown in FIG. 4G/4H/4L.

[0060] In other embodiments, it could be contemplated that the size of the recess of the outer cleat element and the area of the contacting surface of the inner cleat element can be varied. For example, contacting surfaces 413 of inner cleat elements 41 in shoe studs 4 as shown in FIGS. 4A to 4C are different in area from each other under the condition where the recesses 426 are the same; and therefore, the shoe studs in FIGS. 4A to 4C have a difference therebetween in the size of gap between the ring side surface 4262 and the side surfaces 412.

[0061] In other embodiments, it could be contemplated that the contacting surface of the inner cleat element is not aligned with the contacting surface of the outer cleat element in the shoe stud. For example, as shown in FIGS. 4D to 4F, the contacting surface 513/613/713 of the inner cleat element 51/61/71 protrudes with respect to the contacting surface 524/624/724 of the outer cleat element 52/62/72 in the shoe stud 5/6/7.

[0062] In other embodiments, it could be contemplated that the ring side surface of the recess formed on the contacting surface of the outer cleat element is vertical with respect to the bottom surface of the recess, meaning it is parallel to a central axis of the shoe stud.

[0063] In other embodiments, it could be contemplated that no recess is formed on a contacting surface of an outer cleat element in a shoe stud; and therefore, no gap exists between an inner cleat element and the outer cleat element at a cleat opening of the outer cleat element. For example, as shown in FIGS. 4E and 4F, the contacting surface 624/724 of the outer cleat element 62/72 in the shoe stud 6/7 has no recess formed thereon, so no gap exists between the inner cleat element 61/71 and the outer cleat element 62/72 at the cleat opening 621/721 of the outer cleat element 62/72.

[0064] In other embodiments, it could be contemplated that the number of lower steps in the inner cleat element can be one, two or more than three. For example, the inner cleat element 71/81 of the shoe stud 7/8 shown in FIGS. 4F, 4H and 4I has only one lower step 716/816, connected to the top step 715/815 and serving as a bottom step for contacting the ground.

[0065] In other embodiments, it could be contemplated that a part of the top step of the inner cleat element is covered by the outer cleat element. For example, as show in FIG. 4I, an upper part of the top step 815 is exposed by the gap between the outer cleat element 82 and the outsole layer, and the other part of the top step 815 is covered by the outer cleat element 82 in a condition that the outer cleat element 82 exposes the contacting surface 813 of the lower step 816.

[0066] In other embodiments, it could be contemplated that the side surface of the inner cleat element exposed by the gap between the outer cleat element and the outsole layer is not inclined. For example, as shown in FIGS. 4H and 4I, the ring supporting surface 8151 of the top step 815 of the inner cleat element 81 of the shoe stud 8 exposed by the gap between the outer cleat element 82 and the outsole layer is parallel to the central axis C of the shoe stud 8. For example, as shown in FIG. 4G, the side surface 812 of the inner cleat element 81 exposed by the gap between the outer cleat element 82 and the outsole layer is parallel to the central axis C of the shoe stud 8.

[0067] In other embodiments, it could be contemplated that the heights of the ring supporting surfaces of the steps of the inner cleat element in the central axis of the shoe stud are the same, or that the heights of some of the ring supporting surfaces of the steps of the inner cleat element in the central axis of the shoe stud are different while the heights of the others of the ring supporting surfaces of the steps of the inner cleat element in the central axis of the shoe stud are the same.

[0068] In other embodiments, it could be contemplated that the inner cleat element of the shoe stud has no step-shaped structure on the side surface thereof. For example, the inner cleat element 81/91 of the shoe stud 8/9 shown in FIGS. 4G and 4J has no steps on the side surface 812/911 thereof.

[0069] In other embodiments, it could be contemplated that at least one gap exists in the connection interface between the side surface of the inner cleat element and inner side surface of the outer cleat element in the shoe stud.

[0070] In other embodiments, an edge of the outer side surface of the outer cleat element far from the ground is not aligned with an edge of the side surface of the inner cleat element exposed at the gap between the outer cleat element and the outsole layer and close to the ground. For example, as shown in FIGS. 4G, 4I and 4J, an edge of the outer side surface 822/921 of the outer cleat element 82/92 far from the ground protrudes with respect to an edge of the side surface 812/911 of the inner cleat element 81/91 exposed at the gap between the outer cleat element 82 and the outsole layer and close to the ground, in the axis L vertical to the central axis C of the shoe stud 8/9.

[0071] In other embodiments, the inner cleat element of the shoe stud could have more modifications in shape.

[0072] For example, as shown in FIG. 4G, the inner cleat element 81 in the shoe stud 8 includes (is composed of) a pillar portion 817 far from the ground, and a contacting portion 818 connected to the pillar portion 817 and close to the ground, and an end surface 8181 of the contacting portion 818 far from the pillar portion 817 is an arc surface.

[0073] In another instance, the shape of the lower step 816 as shown in FIG. 4H is similar to or the same as the shape of the inner cleat element 81 as shown in FIG. 4G.

[0074] In yet another instance, the shape of the top step 815 as shown in FIG. 4I is similar to or the same as the shape of the inner cleat element 81 as shown in FIG. 4G.

[0075] In yet another instance, as shown in FIG. 4J, the inner cleat element 91 in the shoe stud 9 includes a first taper portion 912 far from the ground, a second taper portion 913 for contacting the ground, and a third taper portion 914 located between the first taper portion 912 and the second taper portion 913. The first taper portion 912 and the second taper portion 913 are tapered from a top end far from the ground, to a bottom end close to the ground. The third taper portion 914 is tapered from a bottom end close to the ground, to a top end far from the ground, the top and bottom ends of the third taper portion 914 are respectively connected to the bottom end of the first taper portion 912 and the top end of the second taper portion 913, and a ring recess 915 is formed at the connection between the first taper portion 912 and the third taper portion 914. A part of the first taper portion 912 is visible from the gap between the outer cleat element 92 and the outsole layer.

[0076] In other embodiments, the outer cleat element of the shoe stud could have more modifications in shape.

[0077] For example, as shown in FIGS. 4G to 4I, the intermediate portion 8223 of the outer ring side surface 822 of the outer cleat element 82 between the top end 8221 and bottom end 8222 of the outer ring side surface 822 protrudes with respect to the top end 8221 and bottom end 8222 in the axis L vertical to the central axis C of the shoe stud 8.

[0078] For example, the outer side surface of the outer cleat element has a pattern formed thereon, such as a regular concave-convex pattern RC formed on the outer side surface 822 as shown in FIGS. 4G to 4I.

[0079] For example, as shown in FIG. 4J, the outer cleat element 92 includes a taper portion 923 far from the ground, and a contacting portion 924 connected to the taper portion 923 and close to the ground for contacting the ground. The taper portion 923 is tapered from a top end far from ground to a bottom end close to the ground in a central axis C of the shoe stud 9. The contacting portion 924 is a tapered hollow shape.

[0080] In other embodiments, it could be contemplated that the outlines of the inner cleat elements of all the shoe studs on the sole structure are symmetrical, or that the outlines of the inner cleat elements of all the shoe studs on the sole structure are asymmetrical

[0081] In other embodiment, it can be contemplated that the heights of first-side and second-side portions of an outer side surface of an outer cleat element with respect to a central axis of a shoe stud are visibly different; and a maximum/average/minimum distance between a ring pressed surface of a top step of an inner cleat element and a contacting surface of an outer cleat element at a first side of the shoe stud with respect to the central axis is visibly different from a maximum/average/minimum distance between a ring pressed surface of the top step of an inner cleat element and a contacting surface of the outer cleat element at a second side of the shoe stud with respect to the central axis.

[0082] For example, as shown in FIG. 4K, the ring pressed surface 104 of the top step 103 of the inner cleat element 101 at a first side of the shoe stud 100 (e.g., at the left side of the drawing) with respect to a central axis C of the shoe stud 100 is closer to the ground than the ring pressed surface 104 at a second side of the shoe stud 100 (e.g., at the right side of the drawing) with respect to the central axis C while the ring connecting surface 105 of the outer cleat element 102 at a first side of the shoe stud 100 (e.g., at the left side of the drawing) with respect to the central axis C is also closer to the ground than the ring connecting surface 105 at a second side of the shoe stud 100 (e.g., at the right side of the drawing) with respect to the central axis C. In other words, the height of the first-side portion of the outer side surface 106 of the outer cleat element 102 with respect to the central axis C is visibly shorter than the height of the second-side portion of the outer side surface 106 with respect to the central axis C; and a maximum/average/minimum distance between the first-side portion of the ring pressed surface 104 of the top step 103 of the inner cleat element 101 and the contacting surface 107 of the outer cleat element 102 with respect to the central axis C is visibly shorter than a maximum/average/minimum distance between the second-side portion of the ring pressed surface 104 of the top step 103 and the second-side portion of the contacting surface 107 of the outer cleat element 102 with respect to the central axis C.

[0083] In other embodiments, it can also be contemplated that the softer cleat element of the shoe stud surrounds the harder cleat element of the shoe stud. For example, in the shoe stud 110 as shown in FIG. 4L, the inner cleat element 111 surrounds the outer cleat element 112; and specifically, the bottom portion 113 of the inner cleat element 111 closer to the ground provides a concave 114 into which the top portion 115 of the outer cleat element 112 far from the ground can fit, a bottom portion 117 of the outer cleat element 112 is for contacting the ground, a step-shaped structure 118 is formed in a connection interface between the inner cleat element 111 and the outer cleat element 112, and the outer cleat element 112 in the inner cleat element 111 tapers from a bottom end of a top portion 115 of the outer cleat element 112 close to the ground, to a top end of the top portion 115 of the outer cleat element 112 far from the ground.

[0084] Hereinafter, a manufacturing method of the aforementioned sole structures according to an embodiment of the present invention is exemplarily illustrated in conjunction with FIGS. 5 and 6. The manufacturing method includes the following steps.

[0085] Step S1: forming the inner cleat elements 21 on the bottom portion of a sport shoe (e.g., the lasting board 11).

[0086] Step S2: forming the outer cleat elements 22 on the inner cleat elements 21 while simultaneously forming the outsole layer 31 on the bottom portion of the sport shoe. The inner cleat elements 21 and the outer cleat elements 22 covered thereon together form the shoe studs 2.

[0087] Optionally, a direct injection process (DIP) can be performed in the manufacturing method of the present invention, thereby increasing the efficiency of the manufacturing method and making it more environmentally friendly. Alternatively, a high-pressure injection molding, vulcanization process, compression molding process, pouring molding process, steam molding process, low-pressure molding process, flow molding process, micro molding process or other possible process is used in the manufacturing of the inner cleat elements and the outer cleat elements separately, followed by standard assembling methods (e.g., cementing or glueing) to achieve the structural design of the shoe stud of the present invention.

[0088] In the present invention, the inner cleat elements made of a relatively-softer elastic material is compressible and a bit bendable when contacting the ground so it is possible to provide better cushioning/shock-absorption, under-foot comfort, and rebound, to provide directional bending of each individual stud, enabling quicker stops, starts, and changes in direction, ultimately increasing acceleration and to provide a better and longer ground-contact which may help with directional movements of the wearers and thereby increase speed. The combination of the above factors may lead to reduced stress on joints and ligaments, thereby preventing or reducing the risk of injuries to the wearer. Moreover, the outer cleat elements made of a relatively-harder elastic material can enhance the structural strength and abrasion resistance.

[0089] While we have shown and described various embodiments in accordance with the present invention, it is clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.