Sole Structure for a Sports Shoe
A sole structure for a sports shoe that controls bendability of a forefoot region of the sole structure. The sole structure includes an upper midsole disposed on an upper side of the forefoot region of the sports shoe and formed of a soft elastic material, a lower midsole disposed under the upper midsole and formed of a soft elastic material, and an outsole that is disposed on a lower surface of the lower midsole and that has sole bent grooves extending substantially in a sole width direction. Both the lower surface of the upper midsole and the upper surface of the lower midsole have corrugated mating surfaces that are formed of wavy shapes extending substantially in a sole longitudinal direction. Ridge lines and trough lines of the wavy shapes of the upper midsole extend substantially in the sole width direction. The ridge lines of the wavy shapes of the upper midsole of a relatively higher hardness are overlapped with the sole bent grooves of the outsole in a vertical direction.
The present invention relates generally to a sole structure for a sports shoe, and more particularly, to the sole structure that can control bendability of a forefoot region by preventing an excessive bending of the forefoot region.
EP3146862A2 discloses an article of footwear that includes a midsole having an undulating (i.e. zigzag) shape with alternating peaks and troughs in a sole longitudinal direction (see para. [0018] and FIGS. 1 and 2). The midsole has a gap formed between the adjacent peaks (i.e. above the trough between the adjacent peaks) and between the adjacent troughs (i.e. below the peak between the adjacent troughs). The gap between the adjacent peaks and the gap between the adjacent troughs extend across the entire width of the midsole (see para. [0018] and FIGS. 1 and 2).
In the sole structure described in EP3146862A2, when the troughs of the undulating (or zigzag-shaped) midsole contact the ground surface a compressive force is exerted on the troughs to distort the gaps above the troughs thus securing cushioning properties (see paras. [0019] to[0020]).
Japanese Patent No. 3403952 discloses a sole structure where a sole bent groove is formed in a forefoot region of an outsole and an upper midsole formed of a soft EVA sponge material is disposed on an upper surface of the outsole (see FIG. 1). The sole bent groove of the outsole penetrates the outsole in an outsole thickness direction and the upper midsole is exposed at a bottom portion of the sole bent groove.
In the sole structure described in JP Pat. No. 3403952, at the time of bending of the outsole, the forefoot region of the outsole bends along the sole bent groove thus securing sole bendability.
However, in the structure of EP3146862A2, at the time of bending of the midsole, an excessive bending is likely to occur locally at the troughs of the zigzag-shaped midsole. An occurrence of such a locally excessive bending causes an energy loss.
In the structure of JP Pat. No. 3403952, since the soft upper midsole is exposed at the bottom portion of the sole bent groove, an excessive bending is similarly likely to occur to cause an energy loss at the time of bending along the sole bent groove.
The present invention has been made in view of these circumstances and its object is to provide a sole structure for a sports shoe that can control bendability of a forefoot region by preventing an excessive bending of the forefoot region.
Other objects and advantages of the present invention will be obvious and appear hereinafter.
SUMMARY OF THE INVENTIONA sole structure for a sports shoe according to first aspect of the present invention includes an upper midsole that is disposed on an upper side of a forefoot region of the sports shoe and that is formed of a soft elastic material, a lower midsole that is disposed on a lower side of the forefoot region, that has an upper surface adapted to contact a lower surface of the upper midsole, and that is formed of a soft elastic material, and an outsole that is disposed on a lower surface of the lower midsole, that has a ground contact surface adapted to contact a ground surface, and that has a sole bent groove extending substantially in a sole width direction. Both the lower surface of the upper midsole and the upper surface of the lower midsole have a corrugated surface that is formed of wavy shapes extending substantially in a sole longitudinal direction, ridge lines and trough lines of the wavy shapes extend substantially in the sole width direction, and the upper midsole and the lower midsole have a hardness difference. At least a portion of the ridge lines of the wavy shapes of the upper midsole or the lower midsole that has a relatively higher hardness is overlapped with the sole bent groove of the outsole in a vertical direction.
According to the first aspect of the present invention, as above-mentioned, both the lower surface of the upper midsole and the upper surface of the lower midsole have a corrugated surface, the upper midsole and the lower midsole have a hardness difference, at least a portion of the ridge lines of the wavy shapes of the upper midsole or the lower midsole that has a relatively higher hardness is overlapped with the sole bent groove of the outsole in the vertical direction, and the ridge lines of the wavy shapes of the lower surface of the upper midsole or the upper surface of the lower midsole that has a relatively higher hardness are disposed at the position of the sole bent groove of the outsole. That is, at the position of the sole bent groove of the outsole, a thick part (i.e. a high-rigidity part) of the upper midsole of a greater hardness that has a corrugated surface on a lower surface thereof, or a thick part (i.e. a high-rigidity part) of the lower midsole of a greater hardness that has a corrugated surface on an upper surface thereof is disposed.
When the forefoot region of the sole structure is going to bend along the sole bent groove of the outsole at the time of bending of the sole structure, the thick part of the upper midsole or the lower midsole of a relatively greater hardness disposed at the sole bent groove is also going to bend at the same time. However, since such a thick part is a high-rigidity part, it has a greater bending resistance and it thus prevents an excessive bending locally along the sole bent groove of the sole structure. Thereby, bendability of the forefoot region can be controlled and an occurrence of an energy loss resulted from a locally excessive bending can be prevented.
A sole structure for a sports shoe according to second aspect of the present invention includes an upper midsole that is disposed on an upper side of a forefoot region of the sports shoe and that is formed of a soft elastic material, a lower midsole that is disposed on a lower side of the forefoot region, that has an upper surface adapted to contact a lower surface of the upper midsole, and that is formed of a soft elastic material, and an outsole that is disposed on a lower surface of the lower midsole, that has a ground contact surface adapted to contact a ground surface, and that has a sole bent groove extending substantially in a sole width direction. Either one of the lower surface of the upper midsole or the upper surface of the lower midsole has a corrugated surface that is formed of wavy shapes extending substantially in a sole longitudinal direction, ridge lines and trough lines of the wavy shapes extend substantially in the sole width direction. At least a portion of the ridge lines of the wavy shapes is overlapped with the sole bent groove of the outsole in a vertical direction.
According to second aspect of the present invention, as above-mentioned, at least a portion of the ridge lines of the wavy shapes provided either at the lower surface of the upper midsole or the upper surface of the lower midsole is overlapped with the sole bent groove of the outsole in the vertical direction, and the ridge lines of the wavy shapes of the lower surface of the upper midsole or the ridge lines of the wavy shapes of the upper surface of the lower midsole are disposed at the position of the sole bent groove of the outsole. That is, at the position of the sole bent groove of the outsole, a thick part (i.e. a high-rigidity part) of the upper midsole that has a corrugated surface on the lower surface thereof, or a thick part (i.e. a high-rigidity part) of the lower midsole that has a corrugated surface on the upper surface thereof is disposed.
When the forefoot region of the sole structure is going to bend along the sole bent groove of the outsole at the time of bending of the sole structure, the thick part of the upper midsole or the lower midsole disposed at the position on of the sole bent groove is also going to bend at the same time. However, since such a thick part is a high-rigidity part, it has a greater bending resistance and it thus prevents an excessive bending locally along the sole bent groove of the sole structure. Thereby, bendability of the forefoot region can be controlled and an occurrence of an energy loss resulted from the locally excessive bending can be prevented.
The ridge lines of the wavy shapes may be overlapped with the sole bent groove in the vertical direction either at a medial side part, a lateral side part, or a sole laterally central part of the forefoot region.
The bent groove may comprise a first sole bent groove and a second sole bent groove that are spaced apart on opposite sides of a metatarsophalangeal joint of a foot of a shoe wearer in the sole longitudinal direction.
A third sole bent groove may be provided between the first sole bent groove and the second sole bent groove and the third sole bent groove may be spaced apart from the first sole bent groove and the second sole bent groove in the sole longitudinal direction.
The sole bent groove may open at least at either one of a medial side end portion or a lateral side end portion of the forefoot region.
The sole bent groove may close at both a medial side end portion and a lateral side end portion of the forefoot region.
The sole bent groove may include a slit extending through a thickness of the outsole.
The sole bent groove may further include a recessed groove formed at a position corresponding to the slit on the lower surface of the lower midsole.
The ridge lines and trough lines of the wavy shapes may extend across an entire width of the forefoot region.
The ridge lines and trough lines of the wavy shapes may be disposed only at a sole laterally central side portion of the forefoot region.
The upper surface of the lower midsole or the lower surface of the upper midsole without the corrugated surfaces may have a planar surface, and there may be formed a gap between the planar surface and the lower surface of the upper midsole or the upper surface of the lower midsole. Thus, when a load is transferred to the forefoot region of the sole structure, cushioning properties is improved.
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.
Referring now to the drawings,
As shown in
An upper or top surface 2a of the upper midsole 2 constitutes a foot-sole contact surface that directly contacts a foot sole of a shoe wearer or that indirectly contacts the foot sole of the wearer via an insole and the like disposed on the upper surface 2a. As shown in
As shown in
Ridge (or crest) lines and trough (or ravine) lines of the wavy shapes on the lower surface 2b of the upper midsole 2 are shown in dotted lines in the forefoot region F of
These ridge lines 2b1 and the trough lines 2b2 extend substantially in the sole width direction and both are gently curved lines that extends along the entire width of the sole. Here, the term, “substantially” means the following two cases:
i) The ridge lines 2b1 and the trough lines 2b2 are width lines that are exactly perpendicular to a longitudinal centerline of the sole (see line IV-IV of
ii) The ridge lines 2b1 and the trough lines 2b2 are lines that angle to the width lines to extend obliquely across the longitudinal centerline.
Also, each of the ridge lines 2b1 and the trough lines 2b2 angles gradually to a medial side toward the forward direction so as to follow the direction of a load transfer during running and the wavy shapes of the lower surface 2b of the upper midsole 2 progresses substantially in the sole longitudinal direction. Similarly, the term, “substantially” means the following two cases:
i) The wavy shapes progress exactly along the longitudinal centerline of the sole (see line IV-IV of
ii) The wavy shapes progress obliquely relative to the longitudinal centerline.
As shown in
As shown in
The first and second sole bent grooves G1, G2 open at both the medial side end and the lateral side end of the forefoot region F (see
As shown in
Here, the opening width and the depth of each of the sole bent grooves G1, G2, G3, G3′ are defined as follows using
As shown in
W=3-18 mm (preferably 7 mm)
d=0.5-10 mm (preferably 2 mm)
In this example, the opening width w of the concave groove 32 formed on the lower surface 3b of the lower midsole 3 is smaller than the opening width W of the slit 42 of the outsole 4. At an opening edge portion of the concave groove 32, there is formed a rim 32r that protrudes downwardly (or to the right in
The upper and lower midsoles 2, 3 are formed of soft elastic materials, more specifically, thermoplastic resin such as ethylene-vinyl acetate copolymer (EVA) and the like, foamed thermoplastic resin, thermosetting resin such as polyurethane (PU) and the like, foamed thermosetting resin, elastomers of these resin, rubber materials such as butadiene rubber, chloroprene rubber and the like, or foamed rubber materials.
A hardness of the upper midsole 2 is greater than a hardness of the lower midsole 3. Specifically, the hardness of the upper midsole 2 is set to, for example 60±4 C in the Asker C scale and the hardness of the lower midsole 3 is set to, for example 50±4 C in the Asker C scale. A difference between the hardness of the upper midsole 2 and the hardness of the lower midsole 3 is preferably approximately 5 C.
The outsole 4 is formed of a hard elastic member. specifically, the outsole 4 is formed of thermoplastic resin such as thermo plastic polyurethane (TPU), polyamide elastomer (PAE) and the like, thermosetting resin such as epoxy and the like, or solid rubber and the like. A hardness of the outsole 4 is set to, for example 60A in the Asker A scale.
According to this embodiment, when the forefoot region F of the sole structure 1 bends during running, the forefoot region F bends along the sole bent groove G2 on the rear side of the forefoot region F, the sole bent groove G3, G3′ at the longitudinally intermediate position of the forefoot region F, and the sole bent groove G2 on the front side of the forefoot region F, in order.
At this time, both the lower surface 2b of the upper midsole 2 and the upper surface 3a of the lower midsole 3 have corrugated surfaces, the ridge lines 2b1 of the wavy shapes of the upper midsole 2 of a relatively higher hardness are overlapped with the sole bent grooves G1, G2, G3, G3′ of the outsole 4 in a vertical direction, and at the positions of the sole bent grooves G1, G2, G3, G3′ of the outsole 4, the ridge lines 2b1 of the wavy shapes of the upper midsole 2 of a relatively higher hardness are located (see
Therefore, when the forefoot region F is going to bend along the sole bent grooves G1, G2, G3, G3′ of the outsole 4 during bending of the sole structure 1, the thick parts of the relatively harder upper midsole 2 disposed at the positions of the sole bent grooves G1, G2, G3, G3′ are going to bend at the same time. At this moment, since these thick parts are high-rigidity parts, an excessive bending locally along the sole bent grooves G1, G2, G3, G3′ of the sole structure 1 can be restricted. Thereby, the sole structure 1 can equally bend in the sole longitudinally direction, and bendability of the forefoot region F can thus be controlled. As a result, an occurrence of an energy loss resulted from locally excessive bending can be prevented.
First Alternative EmbodimentIn the above-mentioned embodiment, an example was shown in which the sole bent grooves G1, G2, G3, G3′ provided at the forefoot region F of the sole structure 1 comprise the slits (or through grooves) 40, 41, 42, 42′ passing through the outsole 4 and the concave grooves (or blind grooves) 30, 31, 32, 32′ formed on the lower midsole 3, respectively but application of the present invention is not limited to such an example.
Also, similar to the above-mentioned embodiment, the ridge lines 2b1 of the wavy surfaces of the lower surface 2b of the upper midsole 2 are vertically overlapped with the sole bent grooves G1, G2, G3 of the outsole 4, that is, each of the ridge lines 2b1 is disposed upwardly opposite the corresponding sole bent grooves G1, G2, G3, and the upper midsole 2 is harder than the lower midsole 3.
The opening width and the depth of each of the sole bent grooves G1, G2, G3 are defined as follows using
As shown in
W=1-15 mm (preferably 4 mm)
d=1-2 mm (preferably 1 mm)
When the forefoot region F of the sole structure 1 bends during exercise, the forefoot region F bends along the sole bent grooves G1, G2, G3. At this time, as above-mentioned, both the lower surface 2b of the upper midsole 2 and the upper surface 3a of the lower midsole 3 have corrugated surfaces, the ridge lines 2b1 of the wavy shapes of the upper midsole 2 of a relatively higher hardness are overlapped with the sole bent grooves G1, G2, G3 of the outsole 4 in a vertical direction, and at the positions of the sole bent grooves G1, G2, G3 of the outsole 4, the ridge lines 2b1 of the wavy shapes of the upper midsole 2 of a relatively higher hardness are located (see
Therefore, when the forefoot region F is going to bend along the sole bent grooves G1, G2, G3 of the outsole 4 during bending of the sole structure 1, the thick parts of the relatively harder upper midsole 2 disposed at the positions of the sole bent grooves G1, G2, G3 are going to bend at the same time. At this moment, since these thick parts are high-rigidity parts and thus have a greater bending resistance, an excessive bending locally along the sole bent grooves G1, G2, G3 of the sole structure 1 can be restricted. Thereby, the sole structure 1 can equally bend in the longitudinally direction, and bendability of the forefoot region F can thus be controlled. As a result, an occurrence of an energy loss resulted from locally excessive bending can be prevented.
Second Alternative EmbodimentIn the above-mentioned embodiment and the first alternative embodiment, an example was shown in which the ridge lines 2b1 of the wavy shapes of the lower surface 2b of the upper midsole 2 extend across the entire width of the sole (that is, from the medial side end to the lateral side end), but application of the present invention is not limited to such an example.
As shown in
Each of the ridge lines 2b1 and the trough lines 2b2 extends gently curvedly and substantially in the sole width direction. Here, the term, “substantially” means the following two cases similar to the above-mentioned embodiment:
i) The ridge lines 2b1 and the trough lines 2b2 are width lines that are exactly perpendicular to a longitudinal centerline of the sole; and
ii) The ridge lines 2b1 and the trough lines 2b2 are lines that angle to the width lines to extend obliquely across the longitudinal centerline.
Also, each of the ridge lines 2b1 and the trough lines 2b2 angles gradually to a medial side toward the forward direction so as to follow the direction of a load transfer during running and the wavy shapes of the bottom surface of the concavity 28 progress substantially in the sole longitudinal direction. Here, the term, “substantially” means the following two cases:
i) The wavy shapes progress exactly along the longitudinal centerline of the sole; and
ii) The wavy shapes progress obliquely relative to the longitudinal centerline.
Inside the concavity 28 of the upper midsole 2, a midsole insert 38 is housed. The midsole insert 38 is generally rectangular shaped and sized to correspond to the concavity 28. A top surface 38a of the midsole insert 38 has no wavy shapes, and it is a planar or gently curved surface and contacts the corrugated bottom surface of the concavity 28 of the upper midsole 2. That is, the top surface 38a of the midsole insert 38 contacts the ridge lines 2b1 of the corrugated surface of the concavity 28 of the upper midsole 2. There are formed a gap S between the upper surface 38a of the midsole insert 38 and the trough lines 2b2 of the corrugated surface of the concavity 28 of the upper midsole 2.
As shown in
As shown in
The outsole 4 is divided into two outsole parts 4A and 4B in the forefoot region F by the sole bent grooves G1, G2, G3, G3′ provided on the bottom side of the forefoot region F of the sole structure 1. In an area extending from the midfoot region M to the heel region H, the outsole 4 is divided into two outsole parts 4C1, 4C1′, 4D on the medial side and four outsole parts 4C2, 4C3, 4C4, 4D on the lateral side (see
As shown in
The opening width and the depth of each of the sole bent grooves G1, G2, G3, G3′ are defined in the same manner as the above-mentioned embodiment. That is, as the opening width of each of the sole bent grooves, the opening width of each of the slits of the outsole 4 is employed, and as the depth of each of the sole bent grooves, the depth measured from the lower surface 2b of the upper midsole 2 (i.e. the outsole-bonding surface of the upper midsole 2) is employed. Specific values are similar to those shown in the above-mentioned embodiment.
The upper midsole 2 and the midsole insert 38 are formed of a soft elastic material as with the above-mentioned embodiment, but unlike the above-mentioned embodiment, a hardness of the upper midsole 2 is not necessarily greater than a hardness of the midsole insert 38. A hardness difference between the upper midsole 2 and the midsole insert 38 may be null.
The reason is as follows:
Since the corrugated bottom surface of the concavity 28 of the upper midsole 2 contacts the planar upper surface 38a of the midsole insert 38, only the ridge lines 2b1 of the corrugated bottom surface is in contact with the upper surface 38a and a gap S is formed between the trough lines 2b2 and the upper surface 38a. Therefore, even if the upper midsole 2 and the midsole insert 38 have the same hardness, a portion including the ridge lines 2b1 of the upper midsole 2 is thick and thus its rigidity becomes greater than other portions of the upper midsole 2.
When the forefoot region F of the sole structure 1 bends during running, the forefoot region F is going to bend along the sole bent groove G2 at the rear of the forefoot region F, the sole bent grooves G3, G3′ at the longitudinally intermediate position of the forefoot region F, and the sole bent groove G1 in front of the forefoot region F, in order.
At this time, the bottom surface of the concavity 28 of the upper midsole 2 has a corrugated surface and portions including the ridge lines 2b1 (i.e. thick parts of higher rigidity) are vertically overlapped with and disposed opposite the sole bent grooves G3′ (see
Therefore, when the forefoot region F is going to bend along the sole bent grooves G3′ of the outsole 4 during bending of the sole structure 1, the portions including the ridge lines 2b of the upper midsole 2 disposed at the position of the sole bent groove G3′ are going to bend at the same time. At this moment, since these portions are high-rigidity parts and thus have a greater bending resistance, an excessive bending locally along the sole bent grooves G3′ of the sole structure 1 can be restricted. Thereby, the sole structure 1 can equally bend in the longitudinally direction, and bendability of the forefoot region F can thus be controlled. As a result, an occurrence of an energy loss resulted from locally excessive bending can be prevented. In addition, the midsole insert 38 may extend to either one of the medial side end or the lateral side end of the forefoot region F.
Third Alternative EmbodimentSpecifically, the hardness of the lower midsole 3 is set to, for example 60±4 C in the Asker C scale and the hardness of the upper midsole 2 is set to, for example 50±4 C in the Asker C scale. A difference between the hardness of the upper midsole 2 and the hardness of the lower midsole 3 is preferably approximately 5 C.
Also, in this third alternative embodiment, a phase of the wavy shapes of the upper and lower midsoles 2, 3 relative to each of the sole bent grooves G1, G2, G3 differs from that in the above-mentioned embodiment. In the above-mentioned embodiment, the ridge lines 2b1 of the wavy shapes of the upper midsole 2 are disposed opposite the sole bent grooves G1, G2, G3, but in this third alternative embodiment, the ridge lines 3a1 of the wavy shapes of the lower midsole 3 are disposed opposite the sole bent grooves G1, G2, G3.
In this way, at the positions of the sole bent grooves G1, G2, G3, the ridge lines 3a1 of the wavy shapes of the upper surface of the lower midsole 3 having a relatively greater hardness are disposed, that is, thick parts (or high-rigidity parts) of the lower midsole 3 of a greater hardness are disposed. When the forefoot region F of the sole structure 1 is going to bend along the sole bent grooves G1, G2, G3 during exercise such as running, the thick parts (or high-rigidity parts) of the lower midsole 3 of a relatively greater hardness disposed at the positions of the sole bent grooves G1, G2, G3 are going to bend at the same time, which generates a greater bending resistance. Thereby, a locally excessive bending along the sole bent grooves G1, G2, G3 of the sole structure 1 can be restricted. In such a manner, the sole structure 1 is able to bend equally in the longitudinally direction to control bendability of the forefoot region F. As a result, an occurrence of an energy loss resulted from locally excessive bending can be prevented.
Fourth Alternative EmbodimentThe ridge lines 2b1 of the corrugated lower surface 2b of the upper midsole 2 contact the planar upper surface 3a of the lower midsole 3, the trough lines 2b2 do not contact the planar upper surface 3a of the lower midsole 3, and there is formed a gap S between the trough lines 2b2 and the planar upper surface 3a of the lower midsole 3. Also, the ridge lines 2b1 of the upper midsole 2 and thus thick parts or high-rigidity parts of the upper midsole 2 are vertically overlapped with or disposed opposite the positions of the sole bent grooves G1, G2 of the outsole 4.
In such a manner, since the thick parts or high-rigidity parts of the upper midsole 2 are disposed at the positions of the sole bent grooves G1, G2, when the forefoot region F of the sole structure 1 is going to bend along the sole bent grooves G1, G2 during exercise such as running, the thick parts or high-rigidity parts of the upper midsole 2 disposed at the positions of the sole bent grooves G1, G2 are going to bend at the same time, which generates a greater bending resistance, thus restricting an excessive bending locally along the sole bent grooves G1, G2 of the sole structure 1. Thereby, the sole structure 1 can bend equally in the longitudinally direction to control bendability of the forefoot region F. As a result, an occurrence of an energy loss resulted from locally excessive bending can be prevented.
Additionally, in this fourth alternative embodiment, as with the second alternative embodiment, the hardness of the upper midsole 2 is not necessarily higher than the hardness of the lower midsole 3 and a hardness difference does not necessarily exist between the upper and lower midsoles 2, 3. That is because a rigidity of an area including the ridge lines 2b1 of the upper midsole 2 is higher than rigidities of other areas even if the upper and lower midsoles 2, 3 have the same hardness.
Fifth Alternative EmbodimentThe ridge lines 3a1 of the corrugated upper surface 3a of the lower midsole 3 contact the planar lower surface 2b of the upper midsole 2, the trough lines 3a2 do not contact the lower planar lower surface 2b of the upper midsole 2, and there is formed a gap S between the trough lines 3a2 and the planar lower surface 2b of the upper midsole 2. Also, the ridge lines 3a1 of the lower midsole 3 and thus thick parts or high-rigidity parts of the lower midsole 3 are vertically overlapped with or disposed opposite the positions of the sole bent grooves G1, G2 of the outsole 4.
In such a manner, since the thick parts or high-rigidity parts of the lower midsole 3 are disposed at the positions of the sole bent grooves G1, G2, when the forefoot region F of the sole structure 1 is going to bend along the sole bent grooves G1, G2 during exercise such as running, the thick parts or high-rigidity parts of the lower midsole 3 disposed at the positions of the sole bent grooves G1, G2 are going to bend at the same time, which generates a greater bending resistance, thus restricting an excessive bending locally along the sole bent grooves G1, G2 of the sole structure 1. Thereby, the sole structure 1 can bend equally in the longitudinally direction to control bendability of the forefoot region F. As a result, an occurrence of an energy loss resulted from locally excessive bending can be prevented.
Additionally, in this fifth alternative embodiment, the hardness of the lower midsole 3 is not necessarily higher than the hardness of the upper midsole 2 and a hardness difference does not necessarily exist between the upper and lower midsoles 2, 3. That is because a rigidity of an area including the ridge lines 3a1 of the lower midsole 3 is higher than rigidities of other areas even if the upper and lower midsoles 2, 3 have the same hardness.
Sixth Alternative EmbodimentIn the above-mentioned embodiment and the first, third to fifth alternative embodiments, an example was shown in which the ridge lines 2b1 of the wavy shapes of the upper midsole 2 or the ridge lines 3a1 of the wavy shapes of the lower midsole 3 are vertically overlapped with the sole bent grooves G1, G2, G3, G3′ along the entire width of the sole (i.e. from the medial side end to the lateral side end of the forefoot region F) or the entire length of the sole bent grooves (see
A portion of each of the ridge lines 2b1, 3a1 may be vertically overlapped with the sole bent grooves G1, G2, G3, G3′. An overlapped area may be, for example, either one or two of a medial side part, a lateral side part, or a sole laterally central part of the forefoot region F. For example, the ridge lines 2b1 may be vertically overlapped with the sole bent groove G2 at the medial side part of the forefoot region F (that is, the ridge lines 2b1 may be disposed opposite the sole bent groove G2 in the vertical direction at the medial side part) and are not vertically overlapped with the sole bent groove G2 at the lateral side part and the sole laterally central part of the forefoot region F (that is, the ridge lines 2b1 are not disposed opposite the sole bent groove G2 in the vertical direction at the lateral side part and the sole laterally central part). In this case, providing an additional explanation by referring to
In the above-mentioned embodiment and the first and second alternative embodiments, an example was shown in which the sole bent grooves G1, G2 open both at the medial side end and at the lateral side end of the forefoot region F, but the sole bent grooves G1, G2 may open either at the medial side end or at the lateral side end of the forefoot region F, that is, the sole bent grooves G1, G2 close either at the lateral side end or at the medial side end of the forefoot region F. Alternatively, the sole bent grooves G1, G2 may close both at the medial side end and at the lateral side end of the forefoot region F. Similarly, the sole bent grooves G3 may close at the medial side end and the sole bent grooves G3′ may close at the lateral side end of the forefoot region F. Each of the sole bent grooves is not necessarily a continuous groove extending along the length of the groove and it may be a discontinuous groove along the length of the groove. Additionally, the ridge lines 2b1 of the wavy shapes of the upper midsole 2 may have a length that corresponds to a length of each of the sole bent grooves. For example, in the event that a sole bent groove closes both at the medial side end and at the lateral side end of the forefoot region F, the ridge lines 2b1 of the wavy shapes of the upper midsole 2 do not extend to the medial side end and the lateral side end of the forefoot region F. At the medial and lateral side ends, the wavy shapes of the upper midsole 2 may not appear.
OTHER APPLICATIONIn the above-mentioned embodiments and each of the alternative embodiments, an example was shown in which the sole structure of the present invention was applied to the running shoe or indoor shoe, but the application of the present invention was not limited to such an example. The present invention also has application to other sports shoes.
As above-mentioned, the present invention is useful for a sole structure for a sports shoe that requires control of bendability of the forefoot region.
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.
Claims
1. A sole structure for a sports shoe disposed in a forefoot region of said sports shoe comprising:
- an upper midsole that is disposed on an upper side of said forefoot region of said sports shoe and that is formed of a soft elastic material;
- a lower midsole that is disposed on a lower side of said forefoot region, that has an upper surface adapted to contact a lower surface of said upper midsole, and that is formed of a soft elastic material; and
- an outsole that is disposed on a lower surface of said lower midsole, that has a ground contact surface adapted to contact a ground surface, and that has a sole bent groove extending substantially in a sole width direction,
- wherein both said lower surface of said upper midsole and said upper surface of said lower midsole have a corrugated surface that is formed of wavy shapes extending substantially in a sole longitudinal direction, ridge lines and trough lines of said wavy shapes extend substantially in the sole width direction, and said upper midsole and said lower midsole have a hardness difference,
- wherein at least a portion of said ridge lines of said wavy shapes of said upper midsole or said lower midsole that has a relatively higher hardness is overlapped with said sole bent groove of said outsole in a vertical direction.
2. The sole structure according to claim 1, wherein said ridge line of said wavy shapes are overlapped with said sole bent groove in the vertical direction either at a medial side part, a lateral side part, or a sole laterally central part of said forefoot region.
3. The sole structure according to claim 1, wherein said bent groove comprises a first sole bent groove and a second sole bent groove that are spaced apart on opposite sides of a metatarsophalangeal joint of a foot of a shoe wearer in the sole longitudinal direction.
4. The sole structure according to claim 3, wherein a third sole bent groove is further disposed between said first sole bent groove and said second sole bent groove and said third sole bent groove is spaced apart from said first sole bent groove and said second sole bent groove in the sole longitudinal direction.
5. The sole structure according to claim 1, wherein said sole bent groove opens at least at either one of a medial side end or a lateral side end of said forefoot region.
6. The sole structure according to claim 1, wherein said sole bent groove closes at both a medial side end and a lateral side end of said forefoot region.
7. The sole structure according to claim 1, wherein said sole bent groove includes a slit that extends through a thickness of said outsole.
8. The sole structure according to claim 1, wherein said sole bent groove includes a recessed groove that is formed on said lower surface of said lower midsole.
9. The sole structure according to claim 1, wherein said ridge lines and trough lines of said wavy shapes extend across an entire width of said forefoot region.
10. The sole structure according to claim 1, wherein said ridge lines and trough lines of said wavy shapes are disposed only at a laterally central side portion of said forefoot region.
11. A sole structure for a sports shoe disposed in a forefoot region of said sports shoe comprising:
- an upper midsole that is disposed on an upper side of said forefoot region of said sports shoe and that is formed of a soft elastic material;
- a lower midsole that is disposed on a lower side of said forefoot region, that has an upper surface adapted to contact a lower surface of said upper midsole, and that is formed of a soft elastic material; and
- an outsole that is disposed on a lower surface of said lower midsole, that has a ground contact surface adapted to contact a ground surface, and that has a sole bent groove extending substantially in a sole width direction,
- wherein either one of said lower surface of said upper midsole or said upper surface of said lower midsole has a corrugated surface that are formed of wavy shapes extending substantially in a sole longitudinal direction, ridge lines and trough lines of said wavy shapes extend substantially in the sole width direction, and at least a portion of said ridge lines of said wavy shapes is overlapped with said sole bent groove of said outsole in a vertical direction.
12. The sole structure according to claim 11, wherein said ridge line of said wavy shapes are overlapped with said sole bent groove in the vertical direction either at a medial side part, a lateral side part, or a sole laterally central part of said forefoot region.
13. The sole structure according to claim 11, wherein said bent groove comprises a first sole bent groove and a second sole bent groove that are spaced apart on opposite sides of a metatarsophalangeal joint of a foot of a shoe wearer in the sole longitudinal direction.
14. The sole structure according to claim 13, wherein a third sole bent groove is further disposed between said first sole bent groove and said second sole bent groove and said third sole bent groove is spaced apart from said first sole bent groove and said second sole bent groove in the sole longitudinal direction.
15. The sole structure according to claim 11, wherein said sole bent groove opens at least at either one of a medial side end or a lateral side end of said forefoot region.
16. The sole structure according to claim 11, wherein said sole bent groove closes at both a medial side end and a lateral side end of said forefoot region.
17. The sole structure according to claim 11, wherein said sole bent groove includes a slit that extends through a thickness of said outsole.
18. The sole structure according to claim 11, wherein said sole bent groove includes a recessed groove that is formed on said lower surface of said lower midsole.
19. The sole structure according to claim 11, wherein said ridge lines and trough lines of said wavy shapes extend across an entire width of said forefoot region.
20. The sole structure according to claim 11, wherein said ridge lines and trough lines of said wavy shapes are disposed only at a laterally central side portion of said forefoot region.
21. The sole structure according to claim 11, wherein said upper surface of said lower midsole or said lower surface of said upper midsole that does not have said corrugated surface has a planar surface, and wherein there is formed a gap between said planar surface and said lower surface of said upper midsole or said upper surface of said lower midsole.
Type: Application
Filed: Sep 18, 2018
Publication Date: Mar 21, 2019
Inventors: Kazunori IUCHI (Suita-shi), Takao ODA (Takarazuka-shi), Shin HIRAI (Himeji-shi), Masashi UDA (Yao-shi), Ayaka YAMADA (Osaka-shi)
Application Number: 16/133,981