Sole Structure for a Shoe

Abstract

The sole structure includes a sole body comprising a wavy structure and a midsole, and an outsole disposed below the sole body and having a ground contact surface. The wavy structure comprises a plurality of wavy extending parts that respectively extend in a wavy shape in the foot-length direction and that are disposed side by side in the foot-width direction, and a connecting portion that connects the wavy extending parts respectively in the foot-width direction. A thickness center plane of the wavy structure extends curvedly in the vertically direction toward the foot-length direction. The midsole is formed of a soft elastic member and includes a lower surface and an upper surface. The lower surface has a contact surface that the wavy structure is in contact with. The upper surface is fitted to an upper of a shoe.

Claims

1. A sole structure fora heel region, midfoot region, or a forefoot region of a shoe, said sole structure comprising: a sole body having a first shock absorbing component and a second shock absorbing component that are adapted to cooperate with each other; and an outsole provided below said sole body and having a ground contact surface, wherein said first shock absorbing component is formed of a wavy structure that comprises a plurality of wavy extending parts respectively extending in a wavy shape in a foot-length direction and disposed side by side in a foot-width direction and a connecting portion connecting the wavy extending parts respectively in said foot-width direction, and a thickness center plane of said wavy structure extends curvedly in a vertical direction toward said foot-length direction, wherein said second shock absorbing component is formed of a soft elastic member and includes a contact surface that said wavy structure is in contact with and a fitted surface that an upper of said shoe is fitted to.

2. The sole structure according to claim 1, wherein at least a portion of said wavy structure is fixedly attached to said second shock absorbing component, and wherein said first shock absorbing component formed of said wavy structure and said second shock absorbing component adapted to cooperate with said first shock absorbing component are integrated to constitute said sole body.

3. The sole structure according to claim 2, wherein at least a portion of said wavy structure is bonded to a lower surface of said second shock absorbing component.

4. The sole structure according to claim 2, wherein at least a portion of said wavy structure is embedded in an interior of said second shock absorbing component.

5. The sole structure according to claim 2, wherein said second shock absorbing component is formed of a soft foamed member in a foamed bead shape and said wavy structure is embedded in an interior of said second shock absorbing component.

6. The sole structure according to claim 1, wherein said wavy structure further comprises an upraised part that extends upwardly, and said upraised part is provided at said wavy extending parts of said wavy structure disposed on an outermost side in said foot-width direction.

7. The sole structure according to claim 1, wherein said wavy structure extends from said heel region through said midfoot region to said forefoot region of said shoe, and wherein said thickness center plane of said wavy structure is disposed below a thickness center plane of said sole body at said forefoot region, disposed above said thickness center plane of said sole body at an anterior end portion of said heel region, and disposed below said thickness center plane of said sole body at a posterior end portion of said heel region.

8. The sole structure according to claim 2, wherein said wavy structure extends from said heel region through said midfoot region to said forefoot region of said shoe, and wherein said thickness center plane of said wavy structure is disposed below a thickness center plane of said sole body at said forefoot region, disposed above said thickness center plane of said sole body at an anterior end portion of said heel region, and disposed below said thickness center plane of said sole body at a posterior end portion of said heel region.

9. The sole structure according to claim 3, wherein said wavy structure extends from said heel region through said midfoot region to said forefoot region of said shoe, and wherein said thickness center plane of said wavy structure is disposed below a thickness center plane of said sole body at said forefoot region, disposed above said thickness center plane of said sole body at an anterior end portion of said heel region, and disposed below said thickness center plane of said sole body at a posterior end portion of said heel region.

10. The sole structure according to claim 4, wherein said wavy structure extends from said heel region through said midfoot region to said forefoot region of said shoe, and wherein said thickness center plane of said wavy structure is disposed below a thickness center plane of said sole body at said forefoot region, disposed above said thickness center plane of said sole body at an anterior end portion of said heel region, and disposed below said thickness center plane of said sole body at a posterior end portion of said heel region.

11. The sole structure according to claim 5, wherein said wavy structure extends from said heel region through said midfoot region to said forefoot region of said shoe, and wherein said thickness center plane of said wavy structure is disposed below a thickness center plane of said sole body at said forefoot region, disposed above said thickness center plane of said sole body at an anterior end portion of said heel region, and disposed below said thickness center plane of said sole body at a posterior end portion of said heel region.

12. The sole structure according to claim 1, wherein at least two of said wavy extending parts of said wavy structure disposed adjacent to each other in said foot-width direction are integrated to each other to constitute an unitary wavy extending part at either of positions in said foot-length direction.

13. The sole structure according to claim 2, wherein at least two of said wavy extending parts of said wavy structure disposed adjacent to each other in said foot-width direction are integrated to each other to constitute an unitary wavy extending part at either of positions in said foot-length direction.

14. The sole structure according to claim 3, wherein at least two of said wavy extending parts of said wavy structure disposed adjacent to each other in said foot-width direction are integrated to each other to constitute an unitary wavy extending part at either of positions in said foot-length direction.

15. The sole structure according to claim 4, wherein at least two of said wavy extending parts of said wavy structure disposed adjacent to each other in said foot-width direction are integrated to each other to constitute an unitary wavy extending part at either of positions in said foot-length direction.

16. The sole structure according to claim 5, wherein at least two of said wavy extending parts of said wavy structure disposed adjacent to each other in said foot-width direction are integrated to each other to constitute an unitary wavy extending part at either of positions in said foot-length direction.

17. The sole structure according to claim 1, wherein said wavy structure is provided plurally in said foot-width direction or said foot-length direction.

18. The sole structure according to claim 1, wherein said wavy extending parts and said connecting portion of said wavy structure are formed integrally of the same material.

19. The sole structure according to claim 1, wherein said wavy structure is formed of a material of a higher rigidity than a material of said second shock absorbing component.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] For a more complete understanding of the invention, reference should be made to the embodiments illustrated in greater detail in the accompanying drawings and described below by way of examples of the invention.

[0025] FIG. 1 is a general lateral side schematic view of a shoe (fora left foot) employing a sole structure according to a first embodiment of the present invention.

[0026] FIG. 2 is a partial enlarged view (or an enlarged view of a heel region of the shoe) of FIG. 1.

[0027] FIG. 3 is a general bottom schematic view of the shoe of FIG. 1.

[0028] FIG. 4 is a partial enlarged view (or an enlarged view of a heel region of the shoe) of FIG. 3.

[0029] FIG. 5 is a general perspective view of a wavy structure constituting the sole structure of FIG. 1.

[0030] FIG. 6 is a lateral side view of the wavy structure of FIG. 5.

[0031] FIG. 7 is a blown-up perspective view of the shoe of FIG. 1.

[0032] FIG. 8 is a bottom-side general perspective view of a midsole constituting the sole structure of FIG. 1.

[0033] FIG. 9 is a cross sectional view of FIG. 1 taken along line IX-IX.

[0034] FIG. 10 is a general lateral side schematic view of a shoe (for a left foot) employing a sole structure according to a second embodiment of the present invention.

[0035] FIG. 11 is a bottom-side general perspective view of a midsole constituting the sole structure of FIG. 10.

[0036] FIG. 12 is a cross sectional view of FIG. 10 taken along line XII-XII.

[0037] FIG. 13 is a general lateral side schematic view of a shoe (for a left foot) employing a sole structure according to a third embodiment of the present invention.

[0038] FIG. 14 is a bottom-side general perspective view of a midsole constituting the sole structure of FIG. 13.

[0039] FIG. 15 is a general lateral side schematic view of a shoe (for a left foot) employing a sole structure according to a fourth embodiment of the present invention.

[0040] FIG. 16 is a bottom schematic view of the shoe of FIG. 15.

[0041] FIG. 17 is a blown-up perspective view of the shoe of FIG. 15.

[0042] FIG. 18 is a general perspective view of a wavy structure constituting the sole structure of FIG. 15.

[0043] FIG. 19 is a bottom view of the wavy structure of FIG. 18.

[0044] FIG. 20 is a lateral side view of the wavy structure of FIG. 18.

[0045] FIG. 21 is a longitudinal sectional schematic view of the shoe of FIG. 15.

[0046] FIG. 22 is a cross sectional view of FIG. 15 taken along line XXII-XXII.

[0047] FIG. 23 is a general lateral side schematic view of a shoe (for a left foot) employing a sole structure according to a fifth embodiment of the present invention.

[0048] FIG. 24 is a bottom schematic view of the shoe of FIG. 23.

[0049] FIG. 25 is a longitudinal sectional schematic view of the shoe of FIG. 23.

[0050] FIG. 26 is a cross sectional view of FIG. 23 taken along line XXVI-XXVI.

[0051] FIG. 27 is a general lateral side schematic view of a shoe (for a left foot) employing a sole structure according to a sixth embodiment of the present invention.

[0052] FIG. 28 is a bottom schematic view of the shoe of FIG. 27.

[0053] FIG. 29 is a longitudinal sectional schematic view of the shoe of FIG. 27.

[0054] FIG. 30 is a cross sectional view of FIG. 27 taken along line XXX-XXX.

[0055] FIG. 31 is a lateral side view of a wavy structure constituting a sole structure according to a seventh embodiment of the present invention.

[0056] FIG. 32 is a lateral side schematic view of a wavy structure constituting a sole structure according to an eighth embodiment of the present invention, illustrating the wavy structure along with a midsole constituting the sole structure.

[0057] FIG. 33 is a general lateral side schematic view of a shoe (for a left foot) employing a sole structure according to a ninth embodiment of the present invention.

[0058] FIG. 34 is a bottom schematic view of the shoe of FIG. 33.

[0059] FIG. 35 is a blown-up perspective view of the shoe of FIG. 33.

[0060] FIG. 36 is a general perspective view of a wavy structure constituting the sole structure of FIG. 33.

[0061] FIG. 37 is a bottom view of the wavy structure of FIG. 36.

[0062] FIG. 38 is a lateral side view of the wavy structure of FIG. 36.

[0063] FIG. 39 is a blown-up perspective view of a sole structure according to a tenth embodiment of the present invention.

[0064] FIG. 40 is a general lateral side schematic view of a shoe (for a left foot) employing a sole structure according to an eleventh embodiment of the present invention.

[0065] FIG. 41 is a bottom schematic view of the shoe of FIG. 40.

[0066] FIG. 42 is a blown-up perspective view of the shoe of FIG. 40.

[0067] FIG. 43 is a bottom-side general perspective view of a wavy structure and a midsole constituting the sole structure of FIG. 40.

[0068] FIG. 44 is a top-side general perspective view of the wavy structure of FIG. 43.

[0069] FIG. 45 is a bottom view of the wavy structure of FIG. 43.

[0070] FIG. 46 is a lateral side view of the wavy structure of FIG. 43.

[0071] FIG. 47 is a longitudinal sectional schematic view of the shoe of FIG. 40.

[0072] FIG. 48 is a cross sectional view of FIG. 40 taken along line XLVIII-XLVIII.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0073] The present invention will now be described in detail with reference to embodiments thereof as illustrated in the accompanying drawings.

First Embodiment

[0074] FIGS. 1 to 9 show a sole structure of a shoe according to a first embodiment of the present invention. Here, a running shoe is taken for an example, but the present invention can be also applied to a walking shoe or other sports shoe.

[0075] In the following explanation, “upward (upper side/upper)” and “downward (lower side/lower)” designate an upward direction and a downward direction, respectively, or vertical direction of the shoe, “forward (front side/front)” and “rearward (rear side/rear)” designate a forward direction and a rearward direction, respectively, or longitudinal direction (i.e. foot-length direction) of the shoe, and “a width or lateral direction” designates a crosswise direction (i.e. foot-width direction) of the shoe.

[0076] For example, in FIG. 1, a general lateral side schematic view of the shoe, “upward” and “downward” designate “upward” and “downward” in FIG. 1 respectively, or a vertical direction; “forward” and “rearward” designate “left to right direction” in FIG. 1, or a longitudinal direction; and “a width direction” designates “out of the page” and “into the page” of FIG. 1, or a lateral direction. Also, in the drawings, reference characters H, M, F designate a heel region, a midfoot region, and a forefoot region of the shoe, respectively. These regions correspond to and are adapted to cover a heel portion, a midfoot portion, and a forefoot portion of a foot of a shoe wearer.

[0077] As shown in FIGS. 1 to 4, Shoe Sp comprises a sole structure Sk and an upper U disposed above the sole structure Sk. The sole structure Sk includes a midsole (as a sole body; or a second shock absorbing component) S.sub.2 extending from the heel region H through the midfoot region M to the forefoot region F of the shoe Sp, a wavy structure (as a sole body; or a first shock absorbing component) S.sub.1 disposed below the midsole S.sub.2 and primarily at the heel region H of the shoe Sp (specifically, at the heel region H and a portion of the midfoot region M), and outsoles Os, Os' disposed below the midsole S.sub.2 and the wavy structure S.sub.1 and having ground-contact surfaces that come into contact with the ground.

[0078] The wavy structure S.sub.1, as shown in FIGS. 5 and 6, includes a plurality of (e.g. three) wavy extending parts 10, 11, 12 that respectively extend in a longitudinal direction (or in a left to right direction of FIG. 6) in a wavy shape and that are disposed side by side in a lateral direction (or into the page of FIG. 6), and a plurality of connecting portions 15 that connect the laterally adjacent wavy extending parts 10, 11, 12 in the lateral direction.

[0079] Each of the wavy extending parts 10, 11, 12 is a wavy corrugated thin sheet that extends in a belt-shape. In this exemplification, the wavy extending parts 10, 12 on the laterally opposite sides have the same wavy shape. That is, the wavy extending parts 10, 12 have the same wavelength and amplitude and thus they are overlapped with each other viewed from the side. The wavy extending part 11 on the laterally central side has a wavy shape different from the wavy shape of the wavy extending parts 10, 12 on the laterally opposite sides. The wavy shape of the wavy extending part 11 has an amplitude and a phase different from an amplitude and a phase of the wavy shapes of the wavy extending parts 10, 12, but the wavy shape of the wavy extending part 11 has the same wavelength as a wavelength of each of the wavy shapes of the wavy extending parts 10, 12. The phase of the wavy shape of the wavy extending part 11 is shifted by 7C (i.e.) 180° relative to the phase of the wavy shape of each of the wavy extending parts 10, 12. In FIG. 6, reference character 11A designates a crest or ridge portion (i.e. upwardly convex portion) of the wavy shape of the wavy extending part 11 and reference character 11B designates a trough or ravine portion (i.e. downwardly convex portion) of the wavy shape of the wavy extending part 11. Similarly, reference characters 12A, 10A designate a crest or ridge portion (i.e. upwardly convex portion) of the wavy shape of the wavy extending part 12, 10 and reference characters 12B, 10B designate a trough or ravine portion (i.e. downwardly convex portion) of the wavy shape of the wavy extending part 12, 10.

[0080] In such a way, a phase shift of it (i.e. 180°) between the laterally adjacent wavy extending parts 10, 12 and the wavy extending part 11 can distribute the upwardly convex portions and the downwardly convex portions of the wavy shapes of the wavy extending parts 10, 11, 12 equally in the heel region H of the shoe Sp. Thereby, landing stability can be improved and a load locally exerted to a foot sole of a wearer can be lessened thus decreasing a push-up feeling at the time of impacting the ground. Also, in this case, the connecting portions 15 disposed between the laterally adjacent wavy extending parts 10, 11 and 12 can perform a torsional rigidity effectively thus improving a shock absorbance.

[0081] Each of the connecting portions 15, as shown in FIG. 6, is a bar that may have but not limited to a circular cross-sectional shape. Any suitable cross-sectional shape can be adopted as a bar. The connecting portions 15 interconnect the laterally adjacent wavy extending parts 10, 11 and 12 at positions where the wavy shapes of the wavy extending parts 10, 11, 12 intersect with each other viewed from the side. In this exemplification, as shown in FIG. 5, the connecting portions 15 extend across the entire width in the foot-width direction not only between the laterally adjacent wavy extending parts 10, 11 and 12 but also along the surfaces of the wavy extending parts 10, 11 and 12. Also, on a front end side of the wavy structure S.sub.1, the wavy extending parts 10, 11 and 12 are interconnected with each other through the connecting portion 15. On a rear end side of the wavy structure S.sub.1, the wavy extending parts 10, 11 and 12 are interconnected with each other through a connecting plate 16.

[0082] As shown by a dash-and-dot line of FIG. 6, a thickness center plane Oc (i.e. a plane passing through the center in the thickness direction) of the wavy structure S.sub.1 extends in a curved shape toward the foot-length direction. On the front end side, the thickness center plane Oc has an upwardly convexly curved shape and in a region extending from the central side to the rear side in the foot-length direction, the thickness center plane Oc has a downwardly convexly curved shape.

[0083] The wavy structure S.sub.1 may be formed of thermoplastic resin such as thermoplastic polyurethane (TPU), polyamide elastomer (PAE), Pebax®, BS (butadiene styrene) resin and the like, or thermosetting resin such as epoxy resin, unsaturated polyester resin and the like. Also, fiber reinforced plastics (CFRP/AFRP/GFRP) may be adopted in which carbon fibers, aramid fibers, glass fibers, respectively, or the like are incorporated as a strengthened fiber and thermosetting resin or thermoplastic resin is incorporated as matrix resin. The wavy structure S.sub.1 is formed by injection molding, press forming, 3D printing and the like. The wavy structure S.sub.1 may be preferably formed of a material of a higher rigidity than the midsole S.sub.2. The wavy extending parts 10, 11, 12, the connecting portion 15, and the connecting plate 16 of the wavy structure S.sub.1 may be preferably integrated with each other to facilitate forming.

[0084] The midsole S.sub.2, as shown in FIGS. 7 and 9, includes an upper surface (or installed surface) S.sub.2a that a bottom portion Ua of the upper U is pulled over and fixedly attached to by adhesives or the like and a lower surface S.sub.2b that the wavy structure S.sub.1 is in contact with. As shown in FIG. 8, on the lower surface S.sub.2b of the midsole S.sub.2, there are formed a plurality of laterally extending concavely curved surfaces S.sub.2b.sub.1, which have a complementary shape with the upwardly convex portions 10A, 11A, 12A of the wavy shapes of the wavy extending parts 10, 11, 12 of the wavy structure S.sub.1. The upwardly convex portions 10A, 11A, 12A of the wavy shapes of the wavy extending parts 10, 11, 12 of the wavy structure S.sub.1 are in contact with and fitted and fixedly attached (e.g. by bonding) to the corresponding concavely curved surfaces (or contact surface) S.sub.2b.sub.1 of the lower surface S.sub.2b of the midsole S.sub.2. At this juncture, the connecting plate 16 is also fixedly attached (e.g. by bonding) to the lower surface S.sub.2b of the midsole S.sub.2. As a result, the wavy structure S.sub.1 and the midsole S.sub.2 are integrated with each other to constitute the sole body S.sub.1, S.sub.2, such that thereby the wavy structure S.sub.1 and the midsole S.sub.2 cooperate with each other at the time of acting of the load.

[0085] In this exemplification, only the upper portions of the wavy structure S.sub.1 are fixedly attached to the midsole S.sub.2 and the lower portions of the wavy structure S.sub.1 are exposed below the midsole S.sub.2 as shown in FIGS. 1 and 2.

[0086] The midsole S.sub.2 may be formed of a soft elastic material, more specifically, thermoplastic synthetic resin and its foamed resin such as ethylene-vinyl acetate copolymer (EVA) or the like, thermosetting synthetic resin and its foamed resin such as polyurethane (PU) or the like, alternatively, rubber material and foamed rubber such as butadiene rubber, chloroprene rubber or the like.

[0087] As shown in FIGS. 3, 4 and 7, the outsoles Os are formed of a plurality of vertically curved plates of a rectangular shape or a belt-shape. As shown in FIG. 2, the outsole Os is disposed along and fixedly attached (e.g. by bonding) to the lower surfaces of the downwardly convex portions 10B, 11B, 12B of the wavy extending parts 10, 11, 12 of the wavy structure S.sub.1 and the connecting portion 16. As shown FIG. 1, an outsole Os' is fixedly attached (e.g. by bonding) to the lower surface of the midsole S.sub.2 at the forefoot region F of the shoe Sp.

[0088] The outsoles Os, Os' are formed of elastic materials harder than the midsole S.sub.2, more specifically, solid rubber, thermosetting polyurethane and the like.

[0089] According to the above-mentioned embodiment, when the shoe Sp impacts the ground, an impact force on landing can be absorbed by an elastic deformation of the midsole S.sub.2 formed of a soft elastic member, a shock absorbance can be improved and a higher resilience can be achieved by a compressive deformation of the respective wavy shapes of the wavy extending parts 10, 11, 12 of the wavy structure S.sub.1 and a subsequent torsional deformation and a restoration of the connecting portion 15. At this time, since the wavy extending parts 10, 11, 12 of the wavy structure S.sub.1 are interconnected to the connecting portion 15 on the front end side and to the connecting plate 16 on the rear end side, at the time of action of the load, an elongation of the wavy extending parts 10, 11, 12 is restrained by the connecting portion 15 on the front end side and by the connecting plate 16 on the rear end side, thus further enhancing a shock absorbance and resiliency.

[0090] Moreover, according to the present embodiment, the thickness center plane Oc of the wavy structure S.sub.1 extends curvedly in the vertical direction toward the foot-length direction, and more specifically, the thickness center plane Oc of the wavy structure S.sub.1 has a downwardly convexly curved shape on the central side to the rear side of the heel region H and has an upwardly convexly curved shape on the front end side of the heel region H. When a shock load is applied to a midportion of the heel region H at the time of impacting the ground, since the thickness center plane Oc of the wavy structure S.sub.1 has the downwardly convexly curved shape on the heel central side to the heel rear side as mentioned above, the entire wavy structure S.sub.1 curves and deforms downwardly, thereby contributing to the improvement of shock absorbance and improving cushioning property. Also, when the load is transferred from the heel region H to the midfoot region M, since the thickness center plane Oc of the wavy structure S.sub.1 has the upwardly convexly curved shape on the heel front end side as mentioned above, a shank effect to restrain an excessive downward deformation at the midfoot region M can be displayed, thus smoothly transferring the load from the midfoot region M to the forefoot region F. In such a manner, a running feeling during running can be improved.

[0091] Also, in this case, a portion of the wavy structure S.sub.1 is fixedly attached to the midsole S.sub.2, and the wavy structure S.sub.1 and the midsole S.sub.2 are integrated with each other to constitute the sole body S.sub.1, S.sub.2. As a result of this, at the time of a load transfer during landing and running, the wavy structure S.sub.1 and the midsole S.sub.2 cooperate with each other, such that thereby a load transfer between the wavy structure S.sub.1 and the midsole S.sub.2 can be performed in a smooth manner.

[0092] Furthermore, in this case, since the wavy structure S.sub.1 is formed of a material of a higher rigidity than the midsole S.sub.2, cushioning property on landing can be secured by the midsole S.sub.2 of a relatively lower rigidity and a shock absorbance and resilience during landing can be improved by the wavy structure S.sub.1 of a relatively higher rigidity.

[0093] In addition, for a midfoot runner who strikes onto the ground from the midfoot region M of the shoe Sp, the wavy structure S.sub.1 may be disposed at the midfoot region M, and for a forefoot runner who strikes onto the ground from the forefoot region F of the shoe Sp, the wavy structure S.sub.1 may be disposed at the forefoot region F. In such a manner, a shock absorbance and a running feeling can be effectively enhanced according to the characteristics of runners' running styles. Also, according to the characteristics of athletic events and running habits of shoe wearers, the wavy structure S.sub.1 may be disposed at the heel region H and the midfoot region M, alternatively at the forefoot region F and the midfoot region M of the shoe Sp.

[0094] In the present embodiment, an example was shown in which the lower surface S.sub.2b of the midsole S.sub.2 has concavely curved surfaces S.sub.2b.sub.1 formed thereon to be in surface-contact and engaged with the upper surface of the upwardly convex portions 10A, 11A, 12A of the wavy shapes of the wavy extending parts 10, 11, 12 of the wavy structure S.sub.1. However, concavely curved surfaces may be formed on the lower surface S.sub.2b of the midsole S.sub.2 that are to be in surface-contact and engaged with the upwardly convex portions 10A, 11A, 12A as well as the downwardly convex portions 10B, 11B, 12B. In this case, the entire upper surface of the wavy structure S.sub.1 is in surface contact with and bonded to the midsole S.sub.2.

Second Embodiment

[0095] FIGS. 10 to 12 show a sole structure of a shoe (or a running shoe) according to a second embodiment of the present invention. In these drawings, like reference characters indicate identical or functionally similar elements to those in the first embodiment.

[0096] As shown in FIGS. 10 to 12, this second embodiment differs from the first embodiment in that the midsole S.sub.2 has a pair of extensions S.sub.2h extending downwardly from the medial and lateral side edge portions. The extensions S.sub.2h, as shown in FIGS. 10 and 11, are provided principally at the midportion of the heel region H in this exemplification.

[0097] Provision of such extensions S.sub.2h facilitates a lateral positioning of the wavy structure S.sub.1 in installing the wavy structure S.sub.1 into the midsole S.sub.2. Also, after installation, a longitudinal central portion of the wavy structure S.sub.1 can be covered from the side, and after loading, a lateral movement of the wavy structure S.sub.1 can be restricted, thus improving landing stability.

Third Embodiment

[0098] FIGS. 13 and 14 show a sole structure of a shoe (or a running shoe) according to a third embodiment of the present invention. In these drawings, like reference characters indicate identical or functionally similar elements to those in the first and second embodiments.

[0099] In this third embodiment, an extension S.sub.2h′ extending downwardly from the midsole S.sub.2 is provided along the entire medial and lateral side edge portions of the midsole S.sub.2 at the heel region H to the midfoot region M and provided also at the heel side edge portions. That is, according to the third embodiment, the extension S.sub.2h′ circumscribes the entire heel region H and a portion of the midfoot region M along the outer circumferential edge portions of the midsole S.sub.2 at the heel region H to the midfoot region M. The midsole S.sub.2 has a concavity formed therein to accommodate the wavy structure S.sub.1.

[0100] Provision of such an extension S.sub.2h′ causes a lateral and longitudinal positioning of the wavy structure S.sub.1 to be conducted more easily in installing the wavy structure S.sub.1 into the midsole S.sub.2. Also, after installation, the wavy structure S.sub.1 can be covered from the side in the entire longitudinal direction, and after loading, a lateral movement of the wavy structure S.sub.1 can be more securely restricted, thus further improving landing stability.

Fourth Embodiment

[0101] FIGS. 15 and 22 show a sole structure of a shoe (or a running shoe) according to a fourth embodiment of the present invention. In these drawings, like reference characters indicate identical or functionally similar elements to those in the first to third embodiments.

[0102] This fourth embodiment differs from the first embodiment in that the midsole comprises an upper midsole S.sub.2 disposed on an upper side of the sole structure Sk and a lower midsole S.sub.2′ disposed on a lower side of the sole structure Sk, the wavy structure S.sub.1 extends from the heel region H through the midfoot region M to the forefoot region F of the shoe Sp, a portion of the wavy structure S.sub.1 is embedded into the upper and lower midsoles S.sub.2, S.sub.2′, and the outsoles Os, Os' are provided at the lower surface of the lower midsole S.sub.2′.

[0103] As shown in FIGS. 15 to 17 and 21, both of the upper and lower midsoles S.sub.2, S.sub.2′ extend from the heel region H through the midfoot region M to the forefoot region F of the shoe Sp. Between the lower surface S.sub.2b of the upper midsole S.sub.2 and the upper surface S.sub.2′a of the lower midsole S.sub.2′, there are formed a plurality of cushioning holes Ch extending in the lateral direction. The wavy structure S.sub.1 is sandwiched in the vertical direction between the upper and lower midsoles S.sub.2, S.sub.2′. As shown in FIGS. 17 and 22, the lower surface S.sub.2b of the upper midsole S.sub.2 has a recessed groove formed thereon, which has a contact surface S.sub.2b.sub.1 that is in contact with the wavy structure S.sub.1. Similarly, the upper surface S.sub.2′a of the lower midsole S.sub.2′ has a recessed groove formed thereon, which has a contact surface S.sub.2′a.sub.1 that is in contact with the wavy structure S.sub.1. That is, in this case, a portion of the wavy structure S.sub.1 is embedded into the upper and lower midsoles S.sub.2, S.sub.2′. The wavy structure S.sub.1 is fixedly attached by bonding or the like to the contact surface S.sub.2b.sub.1 of the upper midsole S.sub.2 and the contact surface S.sub.2′a.sub.1 of the lower midsole S.sub.2′.

[0104] As shown in FIGS. 18 to 20, the wavy structure S.sub.1 comprises a plurality of (e.g. five) wavy extending parts 10, 10′ that extend in a wavy-shape in the foot-length direction (i.e. to the left-to-right direction in FIGS. 19 to 20) respectively and are disposed side by side in the foot-width direction (i.e. in the upward/downward direction in FIG. 19, into/out of the page of FIG. 20) and a plurality of connecting portions 15 that interconnect the laterally adjacent wavy extending parts 10, 10′ in the foot-width direction.

[0105] The wavy extending parts 10, 10′ are thin corrugated sheets that respectively extend in a belt-shape. In this exemplification, the wavy extending parts 10 that are disposed on laterally opposite end sides and in the laterally central position have the same wavy shape, in which respective wave lengths and amplitudes are equal to each other, such that thereby respective wavy extending parts 10 are overlapped with each other viewed from the side. Likewise, the wavy extending parts 10′ that are disposed immediately inside the outermost wavy extending parts 10 on the laterally opposite end sides have the same wavy shape, in which respective wave lengths and amplitudes are equal to each other, such that thereby respective wavy extending parts 10′ are overlapped with each other viewed from the side. The respective wavy shapes of the wavy extending parts 10, 10′ are different, and thus the respective amplitudes and phases are different from each other but the respective wavelengths are equal to each other. The phase of the wavy shape of the wavy extending part 10′ is shifted by π (i.e. 180°) relative to the phase of the wavy shape of the wavy extending part 10. In FIG. 20, reference characters 10A, 10′A designate crest portions (i.e. upwardly convex portions) of the wavy shapes of the wavy extending parts 10, 10′, and reference characters 10B, 10′B designate trough portions (i.e. downwardly convex portions) of the wavy shapes of the wavy extending parts 10, 10′.

[0106] As shown in FIGS. 18 to 20, in this exemplification, each of the connecting portions 15 is formed of a thin plate-like portion that has the same thickness as that of the wavy extending portions 10, 10′. The connecting portions 15 interconnect the wavy extending parts 10, 10′ at positions that the respective wavy shapes of the respective wavy extending parts 10, 10′ intersect with each other viewed from the side.

[0107] As shown by a dash-and-dot line in FIG. 20, the thickness center plane Oc of the wavy structure S.sub.1 extends curvedly in the vertical direction toward the foot-length direction. The thickness center plane Oc has a downwardly convexly curved shape at the heel region H, an upwardly convexly curved shape at the midfoot region M, and a downwardly convexly curved shape at the forefoot region F.

[0108] According to the embodiment, when the shoe Sp impacts the ground, an impact force on landing can be absorbed by an elastic deformation of the midsoles S.sub.2, S.sub.2′ formed of a soft elastic member, a shock absorbance can be improved and a higher resilience can be achieved by a compressive deformation of the respective wavy shapes of the wavy extending parts 10, 10′ of the wavy structure S.sub.1 and a subsequent torsional deformation and a restoration of the connecting portion 15. At this time, since the wavy extending parts 10, 10′ of the wavy structure S.sub.1 are interconnected to the connecting portions 15 on the front and rear end sides, at the time of action of the load, an elongation of the wavy extending parts 10, 10′ is restrained by the connecting portions 15 on the front and rear end sides, thus further enhancing a shock absorbance and resiliency.

[0109] Moreover, according to the present embodiment, the thickness center plane Oc of the wavy structure S.sub.1 extends curvedly in the vertical direction toward the foot-length direction, and more specifically, the thickness center plane Oc of the wavy structure S.sub.1 has a downwardly convexly curved shape at the heel region H, an upwardly convexly curved shape at the midfoot region M, and a downwardly convexly curved shape at the forefoot region F. When a shock load is applied to a midportion of the heel region H at the time of impacting the ground, since the thickness center plane Oc of the wavy structure S.sub.1 has the downwardly convexly curved shape at the heel region H, as mentioned above, the entire wavy structure S.sub.1 curves and deforms downwardly, thereby contributing to the improvement of shock absorbance and improving cushioning property. Also, when the load is transferred from the heel region H to the midfoot region M, since the thickness center plane Oc of the wavy structure S.sub.1 has the upwardly convexly curved shape at the midfoot region M, as mentioned above, a shank effect to restrain an excessive downward deformation at the midfoot region M can be displayed, thus smoothly transferring the load from the midfoot region M to the forefoot region F. In such a manner, a running feeling during running can be improved. Moreover, when the load is transferred to the forefoot region F, since the thickness center plane Oc of the wavy structure S.sub.1 has the downwardly convexly curved shape at the forefoot region F, as mentioned above, a sole bendability at the forefoot region F can be improved thus enhancing a running feeling during running.

[0110] Also, in this case, a portion of the wavy structure S.sub.1 is fixedly attached to the midsoles S.sub.2, S.sub.2′ and the wavy structure S.sub.1 and the midsoles S.sub.2, S.sub.2′ are integrated to constitute the sole body S.sub.1, S.sub.2, S.sub.2′. As a result of this, at the time of a load transfer during landing and running, the wavy structure S.sub.1 and the midsoles S.sub.2, S.sub.2′ cooperate with each other, such that thereby the load transfer between the wavy structure S.sub.1 and the midsoles S.sub.2, S.sub.2′ can be performed in a smooth manner.

Fifth Embodiment

[0111] FIGS. 23 to 26 show a sole structure of a shoe (or a running shoe) according to a fifth embodiment of the present invention. In these drawings, like reference characters indicate identical or functionally similar elements to those in the first to fourth embodiments.

[0112] In this fifth embodiment, as shown in FIGS. 23, 25 and 26, a portion of the wavy structure S.sub.1 (specifically, the upwardly convex portions of the wavy shapes) is embedded in the midsole S.sub.2. For example, the wavy structure S.sub.1 may be formed by insert molding when forming the midsole S.sub.2.

[0113] In this case, when fixing the wavy structure S.sub.1 to the midsole S.sub.2, bonding work becomes unnecessary. Also, since a portion of the wavy structure S.sub.1 is embedded and fixed in the midsole S.sub.2, the wavy structure S.sub.1 can be more firmly fixed to the midsole S.sub.2 thus improving a strength of the entire sole structure Sk.

Sixth Embodiment

[0114] FIGS. 27 to 30 show a sole structure of a shoe (or a running shoe) according to a sixth embodiment of the present invention. In these drawings, like reference characters indicate identical or functionally similar elements to those in the first to fifth embodiments.

[0115] In this sixth embodiment, as shown in FIGS. 27, 29 and 30, the entire wavy structure S.sub.1 is embedded in the midsole S.sub.2. For example, the wavy structure S.sub.1 is formed by insert molding when forming the midsole S.sub.2. In this case, for example, the wavy structure S.sub.1 may be put into a forming die for the midsole S.sub.2 along with expandable beads (e.g. E-TPU (Expanded-Thermo Plastic Polyurethane)), and the expandable beads may be fusion-bonded by steam and the like. By so doing, the midsole S.sub.2 is formed of a soft foamed member of aggregate of beads, the surface of the wavy structure S.sub.1 is covered by the bead-like soft foamed member, and the bead-like soft foamed member enters into the wavy structure S.sub.1. In such a manner, the wavy structure S.sub.1 is embedded into the bead-like soft foamed member. Additionally, the bead-like soft foamed member may be bonded to the surface of the wavy structure S.sub.1 via a bonding layer.

[0116] In this case, when fixing the wavy structure S.sub.1 to the midsole S.sub.2, bonding work becomes unnecessary. Also, since the entire wavy structure S.sub.1 is embedded and fixed in the midsole S.sub.2, the wavy structure S.sub.1 can be furthermore firmly fixed to the midsole S.sub.2 thus improving the strength of the entire sole structure Sk.

Seventh Embodiment

[0117] FIG. 31 shows a wavy structure constituting a sole structure according to a seventh embodiment of the present invention. In the drawing, like reference characters indicate identical or functionally similar elements to those in the first to sixth embodiments. FIG. 31 illustrates a variant of FIG. 20 in the fourth embodiment of the present invention.

[0118] According to this seventh embodiment, in the wavy structure S.sub.1 shown in FIG. 20, upraised portions 10Ah extending upwardly are provided at the wavy extending part 10 on the outermost side in the foot-width direction.

[0119] In this case, the upraised portions 10Ah can support the midsole S.sub.2 in the foot-width direction, thereby preventing the foot from leaning sideways to support the foot stably. Also, provision of the upraised portions 10AH can increase a fixing area (e.g. a bonding area) to improve the strength of the entire sole structure Sk.

Eighth Embodiment

[0120] FIG. 32 shows a wavy structure constituting a sole structure according to an eighth embodiment of the present invention. In the drawing, like reference characters indicate identical or functionally similar elements to those in the first to seventh embodiments. FIG. 32 illustrates another variant of FIG. 20 in the fourth embodiment of the present invention.

[0121] In this eighth embodiment, the wavy structure S.sub.1 extends from the heel region H through the midfoot region M to the forefoot region F of the shoe and the entire wavy structure S.sub.1 is embedded in the midsole S.sub.2. The thickness center plane Oc of the wavy structure S.sub.1 is disposed below the thickness center plane S.sub.2c of the sole body S.sub.1, S.sub.2 at the forefoot region F, disposed above the thickness center plane S.sub.2c of the sole body S.sub.1, S.sub.2 at an anterior end portion of the heel region H, and disposed below the thickness center plane S.sub.2c of the sole body S.sub.1, S.sub.2 at a posterior end portion of the heel region H.

[0122] In this case, since the thickness center plane Oc of the wavy structure S.sub.1 is disposed above the thickness center plane S.sub.2c of the sole body S.sub.1, S.sub.2 at the anterior end portion of the heel region H and below the thickness center plane S.sub.2c of the sole body S.sub.1, S.sub.2 at the posterior end portion of the heel region H, as mentioned above, the thickness center plane Oc of the wavy structure S.sub.1 is inclined diagonally upwardly toward the forward direction at the posterior end portion to the anterior end portion of the heel region H. Therefore, at the time of a heel-impact onto the ground, a shock load F imparted diagonally forwardly from the heel of the foot to the sole below acts onto a diagonally-upwardly inclined portion of the wavy structure S.sub.1 generally perpendicularly at the anterior end portion of the heel region H. Thereby, the shock load at the time of a heel-impact can be securely received by the wavy structure S.sub.1 at the anterior end portion of the heel region H. As a result of this, a shock absorbance can be improved.

[0123] Also, since the thickness center plane Oc of the wavy structure S.sub.1 is disposed below the thickness center plane Sec of the sole body S.sub.1, S.sub.2 at the forefoot region F and above the thickness center plane S.sub.2c of the sole body S.sub.1, S.sub.2 at the anterior end portion of the heel region H, as mentioned above, the thickness center plane Oc of the wavy structure S.sub.1 is inclined diagonally downwardly toward the forward direction at the forefoot region F. Thereby, bending rigidity of the wavy structure S.sub.1 can be enhanced at the forefoot region F, and as a result of this, an energy loss during running can be reduced.

Ninth Embodiment

[0124] FIGS. 33 to 38 show a sole structure of a shoe (or a running shoe) according to a ninth embodiment of the present invention. In these drawings, like reference characters indicate identical or functionally similar elements to those in the first to eighth embodiments.

[0125] In this ninth embodiment, as shown in FIGS. 33 to 35, the upper midsole S.sub.2 extends from the heel region H through the midfoot region M to the forefoot region F of the shoe Sp, whereas the lower midsole S.sub.2′ is disposed at the heel region H to the midfoot region M of the shoe Sp. The wavy structure S.sub.1 extends from the heel region H through the midfoot region M to the forefoot region F of the shoe Sp. The outsole Os is disposed on the lower surface of the lower midsole S.sub.2′ at the heel region H of the shoe Sp and the outsole Os' is disposed on the lower surface of the wavy structure S.sub.1 at the forefoot region F of the shoe Sp.

[0126] As shown in FIGS. 36 to 38, the wavy structure S.sub.1 comprises a plurality of (e.g. five) wavy extending parts 10.sub.1, 10.sub.2, 10.sub.3, 10′ that extend in a wavy-shape in the foot-length direction (i.e. to the left-to-right direction in FIGS. 37 and 38) and that are disposed side by side in the foot-width direction (i.e. in the upper/lower direction of FIG. 37; in the perpendicular direction to the page of FIG. 38), and a plurality of connecting portions 15 that interconnect the laterally adjacent wavy extending parts 10.sub.1, 10.sub.2, 10.sub.3, 10′ in the foot-width direction. The wavy extending part 10′ is disposed on laterally opposite outermost sides of the wavy structure S.sub.1 and the wavy extending parts 10.sub.1, 10.sub.2, 10.sub.3 are disposed between the oppositely disposed wavy extending parts 10′ and 10′ on the outermost sides.

[0127] Each of the wavy extending parts 10.sub.1, 10.sub.2, 10.sub.3, 10′ is a thin wavy corrugated sheet that extends in a belt-shape. The phase of the wavy shape of each of the wavy extending parts 10′, 10.sub.2, is shifted by π (i.e. 180°) relative to the phase of the wavy shape of each of the wavy extending parts 10.sub.1, 10.sub.3. In FIG. 38, reference characters 10A designate the crest portions (i.e. the upwardly convex portions) of the wavy shapes of the wavy extending parts 10.sub.1, 10.sub.3, and reference characters 10′A designate the crest portions (i.e. the upwardly convex portions) of the wavy shapes of the wavy extending parts 10.sub.2, 10′. Reference characters 10B designate the trough portions (i.e. the downwardly convex portions) of the wavy shapes of the wavy extending parts 10.sub.1, 10.sub.3, and reference characters 10′B designate the trough portions (i.e. the downwardly convex portions) of the wavy shapes of the wavy extending parts 10.sub.2, 10′.

[0128] In the wavy structure S.sub.1, the wavy extending parts 10′, 10′ on the laterally opposite outermost sides and the wavy expending parts 10.sub.1, 10.sub.3 disposed inside the wavy extending parts 10′, 10′ extend from the heel rear end of the heel region H through the midfoot region M to the forefoot region F of the shoe Sp, but the centrally-disposed wavy extending part 10.sub.2 is not disposed at the heel region H and extends from the front-end side portion of the midfoot region M to the forefoot region F.

[0129] The laterally adjacent wavy extending parts 10′, 10.sub.1 on the lateral side are provided separately from each other via a slit e from the forefoot region F to the front end portion of the heel region H, but are integrated with each other to form one unitary wavy extending part 10″ from the front end portion of the heel region H to the heel rear end. Likewise, the laterally adjacent wavy extending parts 10′, 10.sub.3 on the medial side are provided separately from each other via a slit e from the forefoot region F to the front end portion of the heel region H, but are integrated with each other to form one unitary wavy extending part 10″ from the front end portion of the heel region H to the heel rear end.

[0130] A pair of upwardly extending upraised portions 10′A are provided at the laterally opposite outermost wavy extending parts 10′, 10′. The connecting portions 15 interconnect the wavy extending parts 10.sub.1, 10.sub.2, 10.sub.3, 10′ at positions that the wavy shapes of the wavy extending parts 10.sub.1, 10.sub.3 intersect the wavy shapes of the wavy extending parts 10.sub.2, 10′ viewed from the side.

[0131] According to the present invention, since the laterally adjacent wavy extending parts 10′, 10.sub.1 (or 10′, 10.sub.3) are integrated to form a unitary wavy extending part 10″ at the front end portion of the heel region H to the heel rear end as mentioned above, bending rigidity can be enhanced in the foot-width direction of the wavy structure S.sub.1, thus strengthening the landing stability and the running stability. In addition, the wavy extending parts to be integrated with each other are not limited to those on the medial/lateral side but may be the one/ones on the laterally central side. Also, the number of the wavy extending parts to be integrated with each other may be three or more. Furthermore, the position of the two or more wavy extending parts to be integrated with each other may be any of the positions in the foot-length direction.

[0132] According to the present embodiment, since the upraised portions 10′Ah are provided at the wavy extending part 10′, the midsole S.sub.2 can be supported in the foot-width direction thus preventing the foot from leaning sideways to support the foot stably. Also, a provision of the upraised portions 10′Ah can increase a fixing area (e.g. bonding area) relative to the midsole S.sub.2 thus strengthening the sole structure Sk.

Tenth Embodiment

[0133] FIG. 39 shows a sole structure of a shoe (or a running shoe) according to a tenth embodiment of the present invention. In these drawings, like reference characters indicate identical or functionally similar elements to those in the first to ninth embodiments.

[0134] In this tenth embodiment, as shown in FIG. 39, the wavy structure comprises two wavy structures S.sub.1, S.sub.1′. The wavy structures S.sub.1, S.sub.1′ are separated from and adjacent to each other in the foot-width direction. The wavy structure S.sub.1 is formed of a plurality of (e.g. two) wavy extending parts 10, 10′ whose phases are shifted by π (i.e. 180°) and the wavy extending parts 10, 10′ are interconnected to each other by the connecting portions 15. In the same manner, the wavy structure S.sub.2 is formed of a plurality of (e.g. two) wavy extending parts 10, 10′ whose phases are shifted by it (i.e.) 180° and the wavy extending parts 10, 10′ are interconnected to each other by the connecting portions 15.

[0135] In this case, the wavy structures S.sub.1, S.sub.1′ disposed independently of each other on the medial and lateral sides of the foot can exhibit an independent function, thereby performing a more delicate control of shock absorbance and running feeling. In addition, the wavy structures of two or more may be separated from each other (e.g. at the midfoot region M) in the foot-length direction. In this case, the wavy structures S.sub.1, S.sub.1′ disposed independently of each other between the front side and the rear side of the foot can exhibit an independent function respectively, thereby performing a more delicate control of shock absorbance and running feeling. Additionally, the wavy structures to be separated from each other in the foot-width and/or foot-length direction may be composed of three wavy structures.

Eleventh Embodiment

[0136] FIGS. 40 to 48 show a sole structure of a shoe (or a running shoe) according to an eleventh embodiment of the present invention. In these drawings, like reference characters indicate identical or functionally similar elements to those in the first to tenth embodiments.

[0137] In the above-mentioned first to tenth embodiments, each of the wavy extending parts of the wavy structure S.sub.1 is formed of a belt-shaped wavy sheet, but in this eleventh embodiment, the wavy structure S.sub.1 comprises wavy-shaped wires.

[0138] As shown in FIGS. 40, 42, the midsole S.sub.2 extends from the heel region H through the midfoot region M to the forefoot region F of the shoe Sp. As shown in FIG. 43, there is formed a cavity S.sub.2B to accommodate the wavy structure S.sub.1 in the lower surface of the midsole S.sub.2. The cavity S.sub.2B is enclosed by peripheral wall portions S.sub.2h″ disposed along the outer circumferential edge portions of the midsole S.sub.2 at the entire heel region H and a portion of the midfoot region M. In the lower surface S.sub.2b of the midsole S.sub.2 in the cavity S.sub.2B, there are formed a plurality of engagement grooves S.sub.2b.sub.1′ to be engaged with a part of the crest portions (i.e. upwardly convex portions) of the wavy shapes of the wavy structure S.sub.1. As shown in FIGS. 47, 48, a part of the upper portions of the wavy structure S.sub.1 is embedded in the midsole S.sub.2 and fixedly attached to the engagement grooves S.sub.2b.sub.1′ by bonding and the like. As shown in FIG. 40, a part of the trough portions (i.e. downwardly convex portions) of the wavy shapes of the wavy structure S.sub.1 is exposed below the midsole S.sub.2.

[0139] As shown in FIGS. 44 to 46, the wavy structure S.sub.1 comprises a plurality of (e.g. nine) wavy extending parts 10.sub.1 to 10.sub.9 that respectively extend in a wavy-shape in the foot-length direction (i.e. to the left-to-right direction of FIGS. 45, 46) and that are disposed side by side in the foot-width direction (i.e. upward/downward direction of FIG. 45; direction perpendicular to the page of FIG. 46), and a plurality of connecting portions 15.sub.1 to 15.sub.8, 15′ that interconnect the laterally adjacent wavy extending parts 10.sub.1 to 10.sub.9.

[0140] Each of the wavy extending parts 10.sub.1 to 10.sub.9 is a wavy corrugated wire that is formed in a wavy-shape. In this exemplification, the wavy extending parts 10.sub.1, 10.sub.3, 10.sub.5, 10.sub.7, 10.sub.9 have the same wavy-shape and the respective wavelength and amplitude are equal to each other. As viewed from the side, the wavy extending parts 10.sub.1, 10.sub.3, 10.sub.5, 10.sub.7, 10.sub.9 are overlapped with each other (see FIG. 46). The wavy extending parts 10.sub.2, 10.sub.4, 10.sub.6, 10.sub.8 disposed respectively between the wavy extending parts 10.sub.1, 10.sub.3, 10.sub.5, 10.sub.7, 10.sub.9 have the same wavy-shape and the respective wavelengths and amplitudes are equal to each other. As viewed from the side, the wavy extending parts 10.sub.2, 10.sub.4, 10.sub.6, 10.sub.8 are overlapped with each other (see FIG. 46), but the respective phases of the wavy-shapes of the wavy extending parts 10.sub.2, 10.sub.4, 10.sub.6, 10.sub.8 are shifted or dephased by n (i.e. 180°) relative to the respective phases of the wavy-shapes of the wavy extending parts 10.sub.1, 10.sub.3, 10.sub.5, 10.sub.7, 10.sub.9. In FIG. 46, reference characters 10A indicate the crest portions (i.e. upwardly convex portions) of the respective wavy shapes of the wavy extending parts 10.sub.1 to 10.sub.9. Reference characters 10B indicate the trough portions (i.e. downwardly convex portions) of the respective wavy shapes of the wavy extending parts 10.sub.1 to 10.sub.9. The wavy structure S.sub.1 is preferably formed of a material of a higher rigidity than that of the midsole S.sub.2.

[0141] As shown FIG. 44, on the front-end side of the wavy structure S.sub.1, there are provided connecting portions 15.sub.1 to 15.sub.8 that interconnect the respective front ends of the wavy extending parts 10.sub.1 to 10.sub.9. The connecting portion 15.sub.1 interconnects the front ends of the wavy extending parts 10.sub.1, 10.sub.2, the connecting portion 15.sub.2 interconnects the front ends of the wavy extending parts 10.sub.2, 10.sub.3, the connecting portion 15.sub.3 interconnects the front ends of the wavy extending parts 10.sub.3, 10.sub.4, the connecting portion 15.sub.4 interconnects the front ends of the wavy extending parts 10.sub.4, 10.sub.5, the connecting portion 15.sub.5 interconnects the front ends of the wavy extending parts 10.sub.5, 10.sub.6, the connecting portion 156 interconnects the front ends of the wavy extending parts 10.sub.6, 10.sub.7, the connecting portion 157 interconnects the front ends of the wavy extending parts 10.sub.7, 10.sub.8, and the connecting portion 15.sub.8 interconnects the front ends of the wavy extending parts 10.sub.8, 10.sub.9, respectively. The connecting portions 15.sub.1 to 15.sub.8 extend diagonally relative to the foot-width direction. On the rear end side of the wavy structure S.sub.1, there are provided connecting portions 15′ that interconnect the respective rear ends of the wavy extending parts 10.sub.1 to 10.sub.9. Between the front end side and the rear end side of the wavy structure S.sub.1, no connecting portion is provided that interconnects the wavy extending parts 10.sub.1 to 10.sub.9. The connecting portions 15.sub.1 to 15.sub.8 and 15′ are formed of wires similar to the wavy extending parts 10.sub.1 to 10.sub.9. In this exemplification, each of the wavy extending parts 10.sub.1 to 10.sub.9 and the connecting portions 15.sub.1 to 15.sub.8, 15′ has a circular cross-sectional shape, but the respective cross-sectional shapes may be rectangular or other shapes.

[0142] As shown by a dash-and-dot-line of FIG. 46, the thickness center plane Oc of the wavy structure S.sub.1, that is, the plane passing through the center of the thickness of the wavy structure S.sub.1, extends curvedly in the vertical direction toward the foot-length direction. The thickness center plane Oc has an upwardly convexly curved shape on the front-end side and a downwardly convexly curved shape on the central side to the rear end side in the foot-length direction.

[0143] As shown FIG. 41, on lower surfaces of the trough portions 10B (i.e. downwardly convex portions) of the wavy shapes of the wavy extending parts 10.sub.1 to 10.sub.9 of the wavy structure S.sub.1, outsoles Os are fixedly attached by bonding and the like. Each of the outsoles Os is a half-cut semi-cylindrical member that is wrapped around and fixedly attached to an outer circumferential lower portion of the downwardly convex portion 10B.

[0144] When the shoe Sp strikes onto the ground, an impact force can be absorbed by an elastic deformation of the midsole S.sub.2 of a soft elastic member, a shock absorbance can be improved and a high resilience can be achieved by a compressive deformation of the wavy shapes of the wavy extending parts 10.sub.1 to 10.sub.9 of the wavy structure S.sub.1 and subsequent deformation of the connecting portions 15.sub.1 to 15.sub.8 and its restoration. At this juncture, since the front and rear end sides of the wavy extending parts 10.sub.1 to 10.sub.9 of the wavy structure S.sub.1 are respectively interconnected to each other through the connecting portions 15.sub.1 to 15.sub.8, 15′ and at the time of action of the load an elongation of each of the wavy extending parts 10.sub.1 to 10.sub.9 is restricted by the connecting portions 15.sub.1 to 15.sub.8, 15′ on the front and rear end sides, a shock absorbance and resilience can be further improved.

[0145] Moreover, in this case, the thickness center plane Oc of the wavy structure S.sub.1 extends curvedly in the vertical direction toward the foot-length direction, and more specifically, the thickness center plane Oc has a downwardly convexly curved shape at the central side to the rear end side of the heel region H and an upwardly convexly curved shape at the front end side of the heel region H. When a shock load is imparted to the central portion of the heel region H at the time of impacting the ground, since the region from the heel central side to the heel rear end side has a downwardly convex shape, the entire wavy structure S.sub.1 deforms to bend downwardly, which contributes to improve shock absorbance to enhance cushioning property. Also, when a load is transferred from the heel region H to the midfoot region M, since the heel front end side region has an upwardly convex shape, which exhibits a shank effect to restrain an excessive downward bending at the midfoot region M, thus transferring the load smoothly from the midfoot region M to the forefoot region F to improve a running feeling during running.

[0146] Moreover, in this case, since a portion of the wavy structure S.sub.1 is fixedly attached to the midsole S.sub.2, such that thereby the wavy structure S.sub.1 and the midsole S.sub.2 are integrated with each other to constitute the sole body S.sub.1, S.sub.2. As a result, at the time of a load transfer during landing and running, the wavy structure S.sub.1 and the midsole S.sub.2 cooperate together, thus performing a load transmission between the wavy structure S.sub.1 and the midsole S.sub.2 in a smooth manner.

[0147] Furthermore, in this case, since the wavy structure S.sub.1 is formed of a material of a higher rigidity than a material of the midsole S.sub.2, the midsole S.sub.2 of a relatively lower rigidity can secure cushioning property on lading and the wavy structure S.sub.1 of a relatively higher rigidity can improve shock absorbance on landing and enhance running stability.

[0148] Additionally, in the present embodiment, an example was shown in which the cavity S.sub.2B is formed in the lower surface of the midsole S.sub.2 to accommodate the wavy structure S.sub.1, but an application of the present invention not limited to such an example. A portion of or the entire wavy structure S.sub.1 may be embedded in the midsole S.sub.2 by a foam molding using an insert molding or foamed beads.

[0149] <First Variant>

[0150] The wavy shape of each of wavy extending parts of the wavy structure S.sub.1 is not limited to such wavy shapes as shown in the respective above-mentioned embodiments. A sinusoidal wavy shape, trapezoidal wavy shape, triangular wavy shape or any other suitable shapes can be adopted and a combination of different wavy shapes can be also employed. Amplitudes, wavelengths and phases of the wavy shapes of the wavy extending parts may be equal to each other or different from each other. Furthermore, widths, thicknesses and diameters of the wavy extending parts may be equal to each other or different from each other. The thicknesses and diameters may be altered at the same wavy extending parts, for example, thicker in thickness and greater in diameter at the heel region.

[0151] <Second Variant>

[0152] The respective connecting portions of the wavy structure S.sub.1 do not need to have the same diameter and size. Also, the distance of the respective connecting portions in the foot-length direction may be equal or different.

[0153] As mentioned above, the present invention is useful for a sole for a shoe that can absorb the impact force at the time of impacting the ground and that can improve running feeling during running.

[0154] Those skilled in the art to which the invention pertains may make modifications and other embodiments employing the principles of this invention without departing from its spirit or essential characteristics particularly upon considering the foregoing teachings. The described embodiments and examples are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. Consequently, while the invention has been described with reference to particular embodiments and examples, modifications of structure, sequence, materials and the like would be apparent to those skilled in the art, yet fall within the scope of the invention.