U.S. patent application number 14/787594 was filed with the patent office on 2016-03-24 for sole structure for a shoe.
The applicant listed for this patent is MIZUNO CORPORATION. Invention is credited to Kazunori IUCHI, Takaya KIMURA, Natsuki SATO.
Application Number | 20160081427 14/787594 |
Document ID | / |
Family ID | 52008038 |
Filed Date | 2016-03-24 |
United States Patent
Application |
20160081427 |
Kind Code |
A1 |
IUCHI; Kazunori ; et
al. |
March 24, 2016 |
Sole Structure for a Shoe
Abstract
The invention provides a sole structure that can not only
prevent deterioration of cushioning performance and improve
cushioning properties but also enhance flexibility. The sole
structure 1 includes a rear foot sole 2 disposed at a rear foot
region of the sole structure 1, a forefoot sole 3 disposed at a
forefoot part F of the sole structure 1, and a plate 4 disposed at
the rear foot region of the sole structure 1 and having an upwardly
convexly curved shape along a heel part H to a midfoot part M of
the sole structure 1. A front end portion 4f of the plate 4 is
disposed at a front end portion 2Af, 2Bf of the rear foot sole 2
(i.e. upper and lower soles 2A, 2B). There is formed a gap S in
front of the front end portion 4f of the plate 4 between the front
end portion 2Af, 2Bf of the rear foot sole 2 and a rear end portion
3r of the forefoot sole 3.
Inventors: |
IUCHI; Kazunori; (Suita-shi,
JP) ; SATO; Natsuki; (Portland, OR) ; KIMURA;
Takaya; (Nishinomiya-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MIZUNO CORPORATION |
Osaka |
|
JP |
|
|
Family ID: |
52008038 |
Appl. No.: |
14/787594 |
Filed: |
May 20, 2014 |
PCT Filed: |
May 20, 2014 |
PCT NO: |
PCT/JP2014/063763 |
371 Date: |
October 28, 2015 |
Current U.S.
Class: |
36/28 |
Current CPC
Class: |
A43B 13/16 20130101;
A43B 13/026 20130101; A43B 13/02 20130101; A43B 13/141 20130101;
A43B 13/122 20130101; A43B 13/145 20130101 |
International
Class: |
A43B 13/14 20060101
A43B013/14; A43B 13/02 20060101 A43B013/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 8, 2013 |
JP |
2013-121354 |
Claims
1. A sole structure for a shoe comprising: a rear foot sole
disposed at a rear foot region of the sole structure; a forefoot
sole disposed at a forefoot region of the sole structure; and a
plate disposed at the rear foot region of the sole structure and
having an upwardly convexly curved shape along a heel part to a
midfoot part of the sole structure; wherein a front end portion of
the plate is disposed at a front end portion of the rear foot sole,
and there is formed a gap in front of the front end portion of the
plate between the front end portion of the rear foot sole and a
rear end portion of the forefoot sole.
2. The sole structure according to claim 1, wherein the rear foot
sole and the forefoot sole are respectively formed of a midsole of
a soft elastic material, and wherein the rear end portion of the
forefoot sole is provided separately from the front end portion of
the rear foot sole through the gap.
3. The sole structure according to claim 2, wherein the rear foot
sole and the forefoot sole have a first ground-contact outsole and
a second ground-contact outsole respectively attached on a bottom
surface of each of the rear foot sole and the forefoot sole, and
wherein the first outsole and the second outsole are interconnected
with each other via a connection in the gap between the front end
portion of the rear foot sole and the rear end portion of the
forefoot sole.
4. The sole structure according to claim 3, wherein the connection
has a path length that is longer than a longitudinal length of the
gap between the front end portion of the rear foot sole and the
rear end portion of the forefoot sole.
5. The sole structure according to claim 4, wherein the connection
has a bending portion of an inverted V-shape or an inverted U-shape
as viewed from a side face of the connection in the gap.
6. The sole structure according to claim 1, wherein the rear foot
sole includes a heel sole that protrudes downwardly at the heel
part of the sole structure and a midfoot sole that that protrudes
downwardly at the midfoot part of the sole structure, and wherein
there is provided a region in which the rear foot sole is not
provided or the rear foot sole recedes upwardly between the heel
sole and the midfoot sole.
7. The sole structure according to claim 2, wherein the rear foot
sole is formed of an upper midsole disposed on an upper side of the
rear foot sole and a lower midsole disposed on a lower side of the
rear foot sole, and the plate is interposed between the upper
midsole and the lower midsole.
8. The sole structure according to claim 1, wherein the plate is
formed of a hard elastic material.
9. The sole structure according to claim 1, wherein the rear foot
sole and the forefoot sole are respectively formed of a midsole of
a soft elastic material, and wherein the rear foot sole and the
forefoot sole are connected to each other through a connection that
extends from the midsole and that is disposed in the gap between
the front end of the rear foot sole and the rear end of the
forefoot sole.
10. The sole structure according to claim 9, wherein the connection
is formed of a thin part of the midsole.
11. The sole structure according to claim 9, wherein the connection
has a path length that is longer than a longitudinal length of the
gap between the front end portion of the rear foot sole and the
rear end portion of the forefoot sole.
12. The sole structure according to claim 11, wherein the
connection has a bending portion of an inverted V-shape or an
inverted U-shape viewed from a side face of the connection in the
gap.
13. The sole structure according to claim 9, wherein the rear foot
sole and the forefoot sole have a first ground-contact outsole and
a second ground-contact outsole respectively attached on a bottom
surface of each of the rear foot sole and the forefoot sole, and
wherein the first outsole and the second outsole are separated
through the gap between the front end portion of the rear foot sole
and the rear end portion of the forefoot sole.
14. A sole structure for a shoe comprising: a forefoot sole
disposed at a forefoot region of the sole structure; a rear foot
sole disposed on a rear side of the forefoot region of the sole
structure; and a plate disposed along the rear foot sole; wherein
there is formed a gap without the rear foot sole in front of the
front end of the plate.
15. The sole structure according to claim 14, wherein the plate is
provided at a heel part or a midfoot part of the sole
structure.
16. The sole structure according to claim 14, wherein the plate has
an upwardly convexly curved shape.
Description
TECHNICAL FIELD
[0001] The present invention relates generally to a sole structure
for a shoe, and more particularly, to an improved sole structure
that can prevent deterioration of cushioning performance to improve
cushioning properties and that can enhance flexibility.
BACKGROUND ART
[0002] As a sole structure for a shoe that can prevent
deterioration of athletic ability while securing cushioning
properties at the time of striking the ground, the applicant of the
present invention has proposed such a sole structure as shown in
Japanese Patent No. 3308482. Japanese Patent No. 3308482 describes
a sole structure in which the wavy corrugated sheet is interposed
between the soft elastic upper midsole and the soft elastic lower
midsole at least at the heel region of the shoe (see FIG. 1 of JP
Pat. No. 3308482).
[0003] On the other hand, Japanese Patent No. 4656543 describes a
sole structure in which a number of deep indentations are formed on
the bottom surface of the midsole at the region extending from the
heel region to the forefoot region of the sole structure of the
shoe (see FIG. 1 of JP Pat. No. 4656543).
[0004] In the above-mentioned structure described in JP Pat. No.
3308482, the wavy corrugated sheet is interposed between the upper
and lower midsoles and the amplitude and/or wavelength of the wave
shape of the wavy corrugated sheet are changed appropriately
according to a part where the wavy corrugated sheet is disposed,
thereby adjusting the cushioning properties and preventing a foot
from leaning sideways to restrain deterioration of athletic
ability. Also, in the above-mentioned structure described in JP
Pat. No. 4656543, a number of deep indentations facilitates bending
deformation of the midsole, thus improving sole flexibility during
running (see FIG. 7 of JP Pat. No. 4656543).
[0005] However, in the structure of JP Pat. No. 3308482,
interposition of the wavy corrugated sheet between the upper and
lower midsoles can prevent deterioration of the cushioning
properties of the sole structure compared with a sole structure
without a wavy corrugated sheet, while longitudinal deformation of
the wavy corrugated sheet is restrained by the upper and lower
midsoles having the wavy corrugated sheet embedded therein thus
cushioning properties based on a vertical deformation of the wavy
corrugated sheet is restrained. Also, in the structure of JP Pat.
No. 4656543, a number of midsole elements, which are separated by a
number of deep indentations formed on the bottom surface of the
midsole along the approximately entire length of the midsole from
the heel part to the forefoot part of the midsole, are easy to
deform excessively and each of the midsole elements is easy to be
exposed to external environment. As a result, there is a risk that
cushioning properties of the midsole easily become
deteriorated.
[0006] The present invention has been made in view of these
circumstances and its object is to provide a sole structure for a
shoe that can not only prevent deterioration of cushioning
performance and improve cushioning properties but also enhance
flexibility.
DISCLOSURE OF INVENTION
[0007] A sole structure for a shoe according to a first aspect of
the present invention includes a rear foot sole disposed at a rear
foot region of the sole structure, a forefoot sole disposed at a
forefoot region of the sole structure, and a plate disposed at the
rear foot region of the sole structure and having an upwardly
convexly curved shape along a heel part to a midfoot part of the
sole structure. A front end portion of the plate is disposed at a
front end portion of the rear foot sole and there is formed a gap
in front of the front end port ion of the plate between the front
end portion of the rear foot sole and a rear end portion of the
forefoot sole.
[0008] According to the first aspect of the present invention,
since the plate having the upwardly convexly curved shape is
provided at the rear foot region of the sole structure,
deterioration of cushioning performance of the rear foot region of
the sole structure can be prevented. Also, since the front end of
the plate is disposed at the front end of the rear foot sole and
the gap is formed in front of the front end of the plate between
the front end of the rear foot sole and the rear end of the
forefoot sole, a forward movement of the front end of the plate at
the time of deformation of the plate is not hindered by the sole
thereby allowing for a smooth deformation of the plate to improve
cushioning properties. Moreover, the gap formed in front of the
front end of the plate facilitates bending deformation of the rear
foot sole relative to the forefoot sole thus enhancing
flexibility.
[0009] The rear foot sole and the forefoot sole may be respectively
formed of a midsole of a soft elastic material, and the rear end
portion of the forefoot sole may be provided separately from the
front end portion of the rear foot sole through the gap.
[0010] Since the forefoot sole is separated from the rear foot sole
through the gap, the rear foot sole is easier to bending-deform
relative to the forefoot sole, thus further improving flexibility.
Also, cushioning properties can be further improved by employing
the midsole of soft elastic material.
[0011] The rear foot sole and the forefoot sole may have a first
ground-contact outsole and a second ground-contact outsole
respectively attached on a bottom surface of each of the rear foot
sole and the forefoot sole. The first outsole and the second
outsole may be interconnected with each other via a connection in
the gap between the front end portion of the rear foot sole and the
rear end portion of the forefoot sole.
[0012] The connection can prevent pebbles, sand and the like from
entering the gap from outside. Also, since the first outsole and
the second outsole are connected through the connection, the rear
foot sole and the forefoot sole are connected to each other through
the first and second outsoles and the connection and the entire
sole structure is thus integrated.
[0013] The connection may have a path length that is longer than a
longitudinal length of the gap between the front end portion of the
rear foot sole and the rear end portion of the forefoot sole.
[0014] Since the connection has an elongation allowance as the rear
foot sole bending-deforms relative to the forefoot sole, the
connection does not hinder bending-deformation of the rear foot
sole thus allowing for a smooth bending-deformation of the rear
foot sole to improve flexibility of the sole structure.
[0015] The connection may have a bending portion of an inverted
V-shape or an inverted U-shape viewed from a side face of the
connection in the gap. Such a bending portion of an inverted
V-shape or U-shape of the connection can secure adequate amount of
elongation allowance.
[0016] The rear foot sole may include a heel sole that protrudes
downwardly at the heel region of the sole structure and a midfoot
sole that that protrudes downwardly at the midfoot region of the
sole structure. There may be provided a region in which the rear
foot sole is not provided or the rear foot sole recedes upwardly
between the heel sole and the midfoot sole.
[0017] Since the rear end portion of the plate is supported by the
heel sole and the front end portion of the plate is supported by
the midfoot sole at the time of impacting the ground, thus allowing
for a stable support of the entire plate. Also, since there is
provided the region where the rear foot sole is not provided or the
rear foot sole recedes upwardly between the heel sole and the
midfoot sole and a thickness of the sole structure at the region is
thus made relatively small, thereby improving flexibility and
cushioning properties of the sole structure at the region.
[0018] The rear foot sole may be formed of an upper midsole
disposed on an upper side of the rear foot sole and a lower midsole
disposed on a lower side of the rear foot sole. The plate may be
interposed between the upper midsole and the lower midsole.
[0019] The upper midsole of a soft elastic material provided above
the plate can improve wearer's touch on the foot and the lower
midsole of a soft elastic material provided under the plate can
attenuate shock transmitted from the ground at the time of
impacting the ground thus further improving cushioning
properties.
[0020] The plate may be formed of a hard elastic material. Since
the plate is relatively hard to lose elasticity compared to the
case in which the plate is formed of a soft elastic material,
deterioration of cushioning performance of the sole structure can
be more securely prevented.
[0021] The rear foot sole and the forefoot sole may be respectively
formed of a midsole of soft elastic material. The rear foot sole
and the forefoot sole may be connected to each other through a
connection that extends from the midsole and that is disposed in
the gap between the front end of the rear foot sole and the rear
end of the forefoot sole.
[0022] The connection can prevent pebbles, sand and the like from
entering the gap from outside. Also, since the rear foot sole and
the forefoot sole are connected to each other through the
connection and the entire sole structure is thus integrated.
[0023] The connection may be formed of a thin part of the midsole.
Since the connection is easy to deform elastically, the connection
does not hinder bending-deformation of the rear foot sole relative
to the forefoot sole, thereby allowing for a smooth
bending-deformation of the rear foot sole to improve flexibility of
the sole structure.
[0024] The connection may have a path length that is longer than a
longitudinal length of the gap between the front end portion of the
rear foot sole and the rear end portion of the forefoot sole.
[0025] Since the connection has an elongation allowance as the rear
foot sole bending-deforms relative to the forefoot sole, the
connection does not hinder bending-deformation of the rear foot
sole thus allowing for a smooth bending-deformation of the rear
foot sole to improve flexibility of the sole structure.
[0026] The connection may have a bending portion of an inverted
V-shape or U-shape viewed from a side face of the connection in the
gap. Such a bending portion of an inverted V-shape or U-shape of
the connection can secure adequate amount of elongation
allowance.
[0027] The rear foot sole and the forefoot sole may have a first
ground-contact outsole and a second ground-contact outsole
respectively attached on a bottom surface of each of the rear foot
sole and the forefoot sole. The first outsole and the second
outsole may be separated through the gap between the front end
portion of the rear foot sole and the rear end portion of the
forefoot sole.
[0028] Since the first outsole and the second outsole are separated
through the gap, as the rear foot sole bending-deforms relative to
the forefoot sole the outsole does not hinder bending-deformation
of the rear foot sole, thereby allowing for ease of smooth
bending-deformation of the rear foot sole and thus improving
flexibility of the sole structure.
[0029] A sole structure for a shoe according to a second aspect of
the present invention includes a forefoot sole disposed at a
forefoot region of the sole structure, a rear foot sole disposed on
a rear side of the forefoot region of the sole structure, and a
plate disposed along the rear foot sole. There is formed a gap
without the rear foot sole in front of the front end of the
plate.
[0030] According to the second aspect of the present invention, the
plate provided at the rear foot sole of the sole structure can
prevent deterioration of cushioning performance of the rear foot
sole. Also, since there is formed a gap without the rear foot sole
in front of the front end of the plate, a forward movement of the
front end of the plate at the time of deformation of the plate is
not hindered by the sole thereby allowing for a smooth deformation
of the plate to improve cushioning properties. Moreover, the gap
formed in front of the front end of the plate facilitates bending
deformation of the rear foot sole relative to the forefoot sole
thus enhancing flexibility.
[0031] The plate may be provided at a heel part or a midfoot part
of the sole structure.
[0032] The plate may have an upwardly convexly curved shape.
BRIEF DESCRIPTION OF DRAWINGS
[0033] FIG. 1 is a bottom view of a sole structure for a shoe
according to an embodiment of the present invention;
[0034] FIG. 2 is a medial side view of the sole structure of FIG.
1;
[0035] FIG. 3 is a lateral side view of the sole structure of FIG.
1;
[0036] FIG. 4 is a top plan view of the sole structure of FIG.
1;
[0037] FIG. 5 is a longitudinal sectional view of FIGS. 1 and 4
taken along line V-V;
[0038] FIG. 6 is a cross sectional view of FIGS. 1 to 5 taken along
line VI-VI;
[0039] FIG. 7 is a cross sectional view of FIGS. 1 to 5 taken along
line VII-VII;
[0040] FIG. 8 is a cross sectional view of FIGS. 1 to 5 taken along
line VIII-VIII;
[0041] FIG. 9 is a cross sectional view of FIGS. 1 to 5 taken along
line IX-IX;
[0042] FIG. 10 illustrates a position of a gap between a rear foot
sole and a forefoot sole in the sole structure of FIG. 1 along with
a bone structure of a foot;
[0043] FIG. 11 is a perspective view of an entire plate composing
the sole structure of FIG. 1;
[0044] FIG. 12 is a bottom view of the plate of FIG. 11;
[0045] FIG. 13 is a medial side view of the plate of FIG. 11;
[0046] FIG. 14 is a lateral side view of the plate of FIG. 11;
[0047] FIG. 15 is a longitudinal sectional view of the plate of
FIG. 11;
[0048] FIG. 16 illustrates a longitudinal position and a vertical
protrusion height of a maximum protruding part of the plate of FIG.
11 along with a bone structure of a foot;
[0049] FIG. 17A corresponds to FIG. 5, illustrating a state of the
sole structure of FIG. 1 before impacting the ground;
[0050] FIG. 17B illustrates a foot-flat state of the sole structure
of FIG. 1 after impacting the ground;
[0051] FIG. 18 is a longitudinal sectional view of a sole structure
for a shoe according to another embodiment of the present
invention, corresponding to FIG. 5; and
[0052] FIG. 19 is a longitudinal sectional view of a sole structure
for a shoe according to a still another embodiment of the present
invention, corresponding to FIG. 5.
BEST MODE FOR CARRYING OUT THE INVENTION
[0053] Embodiments of the present invention will be hereinafter
described in accordance with the appended drawings.
[0054] FIGS. 1 to 17B show a sole structure for a shoe according to
an embodiment of the present invention. In the illustrated example,
a running shoe is taken as an example.
[0055] In the following explanations, upward direction (upper
side), downward direction (lower side), forward direction (front
side), and rearward direction (rear side) of the sole structure
designate upward direction (upper side), downward direction (lower
side), forward direction (front side), and rearward direction (rear
side) of the shoe, respectively. That is, taking FIG. 2 as an
example, an upward direction and a downward direction of the sole
structure indicate a left side and a right side of FIG. 2
respectively, and a forward direction and a rearward direction of
the sole structure indicate an upward direction and a downward
direction of FIG. 2 respectively. Also, in FIGS. 1 to 5, H
designates a heel part of the sole structure, M for a midfoot part,
and F for a forefoot part respectively.
[0056] As shown in FIGS. 1 to 5, Sole structure 1 for a shoe
includes a rear foot sole 2 (2A, 2B) disposed at a rear foot region
that extends from the heel part H to the midfoot part M of the sole
structure 1, a forefoot sole 3 disposed at the forefoot part F of
the sole structure 1, and a plate 4 disposed at the rear foot
region of the sole structure 1. The rear foot sole 2 is formed of
an upper sole 2A disposed on an upper side of the sole structure 1
and a lower sole 2B disposed below the upper sole 2A. The plate 4
is interposed between the upper sole 2A and the lower sole 2B.
[0057] The plate 4 extends from a heel rear end of the sole
structure 1 to a border or in the vicinity of the border between
the midfoot part M and the forefoot pat F. A front end 4f of the
plate 4 is located at a front end portion of the rear foot sole 2,
that is, a front end portion 2Af of an upper sole 2A and a front
end portion 2Bf of a lower sole 2B. There is formed a gap S in
front of the front end 4f of the plate 4 between the front end
portion of the rear foot sole 2 and a rear end portion 3r of the
forefoot sole 3. In other words, in front of the front end portion
4f of the plate 4 is formed a space area in which the rear foot
sole 2 as well as the forefoot sole 3 does not exist. A
longitudinal clearance of the gap S depends on the size of the shoe
but is set to 1-10 mm. Because the gap S of at least 1 mm enables a
forward movement of the plate 4 (the details of the grounds are
described hereinafter) and when the gap S exceeds 10 mm a sensory
evaluation test by a wearer who actually wore the shoe proved that
wearer's touch on the foot worsened due to an excessive clearance
under a foot sole of the wearer. The rear end portion 3r of the
forefoot sole 3 is separated from the front end portion of the rear
foot sole 2 through the gap S.
[0058] In this embodiment, the rear foot sole 2 (i.e. the upper and
lower soles 2A, 2B) and the forefoot sole 3 are preferably formed
of a midsole of a soft elastic material, 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,
rubber materials such as butadiene rubber, chloroprene rubber and
the like, or foamed rubber materials.
[0059] The plate 4 is preferably formed of a hard elastic material,
more specifically, thermoplastic resin such as thermo plastic
polyurethane (TPU), polyamide elastomer (PAE),
acrylonitrile-butadiene-styrene (ABS) resin and the like, or
thermosetting resin such as epoxy resin, unsaturated polyester
resin and the like. In addition, the plate 4 may be formed of fiber
reinforcedprastics (FRP) formed of reinforcing fibers such as
carbon fibers, aramid fibers, glass fibers or the like and matrix
resin such as thermosetting resin or thermoplastic resin.
[0060] On bottom surfaces of the lower sole 2B and the forefoot
sole 3, outsoles 5A, 5B and 5C each having ground contact surface
that contacts the ground are attached. The outsole 5A is disposed
at a heel rear end portion of the lower sole 2B, the outsole 5B at
a midfoot portion of the lower sole 2B, and the outsole 5C at the
forefoot sole 3.
[0061] The outsoles 5B and 5C are connected to each other through a
connection 50 that extends from the outsoles 5B, 5C in the gap S
between the front end portion of the rear foot sole 2 and the rear
end portion 3r of the forefoot sole 3. The connection 50 extends
not only in a longitudinal direction but also in a sole width
direction in the gap S. Also, the connection 50 has a bending
portion of an inverted V-shape or an inverted U-shape viewed from a
side face of the connection 50 in the gap S. The connection 50 thus
has a path length that is longer than a longitudinal length of the
gap S between the front end portion of the rear foot sole 2 and the
rear end portion 3r of the forefoot sole 3.
[0062] In this embodiment, the outsole 5C has a groove 51 extending
substantially in the longitudinal direction. The outsole 5C is
separated in the longitudinal direction by a clearance 52 extending
in the width direction and also separated in the width direction by
a clearance 53 extending in the longitudinal direction. The
clearances 52, 53 may be a groove, and the outsole 5C is not
necessarily separated in the longitudinal/width direction. On the
other hand, the outsole 5B is separated in the width direction by a
clearance 54 that extends in the longitudinal direction along the
clearance 53. The clearance 54 may be a groove, and the outsole 5B
is not necessarily separated in the width direction. In either
case, in the event that the outsole is separated by the clearance,
respective parts separated by the clearance are easier to deform
independently from other parts, which contributes to improvement of
sole flexibility (in the longitudinal direction as well as the
width direction) at the time of impacting the ground.
[0063] As shown in cross sectional views of FIGS. 7-9, the upper
sole 2A of the rear foot sole 2 has a foot sole contact portion
2A.sub.0 that a wearer's foot sole contacts via an upper bottom
portion, insole board, insole or the like (not shown). On opposite
sides of the foot sole contact portion 2A.sub.0, an upraised
portion 2A.sub.1 extending upwardly is provided. Similarly, as
shown in a cross sectional view of FIG. 6, the forefoot sole 3 has
a foot sole contact portion 30 that the wearer's foot sole contacts
via the upper bottom portion, insole board, insole or the like (not
shown). On opposite sides of the foot sole contact portion 30, an
upraised portion 31 extending upwardly is provided. A thickness of
the foot sole contact portion 30 is determined such that an
unnatural difference in surface level is not generated at the front
and the rear of the gap S between a surface of the foot sole
contact portion 30 and a surface of the foot sole contact portion
2A.sub.0 of the upper sole 2A (see FIG. 5). In addition, at the
time of assembly of the shoe, the upper bottom portion or the
insole board is fixedly attached through bonding and the like to
the foot sole contact portion 2A.sub.0 of the upper sole 2A and the
upraised portion 2A.sub.1, and the foot sole contact portion 30 of
the forefoot sole 3 and the upraised portion 31 (not shown).
[0064] Turning back to FIGS. 1-5, the lower sole 2B of the rear
foot sole 2 has a vertically extending through hole 21 formed at a
heel central portion thereof (see FIG. 9). A bottom surface of the
lower sole 2B is located above the ground contact surfaces of the
outsoles 5A, 5B at a region extending from the heel central portion
to a midfoot central portion and the lower sole 2B thus has a
concave portion 20 at the region. A heel rear end portion and the
heel central portion of the lower sole 2B protrude downwardly at
the rear of the concave portion 20. The midfoot central portion of
the lower sole 2B protrudes downwardly in front of the concave
portion 20.
[0065] The midfoot central portion of the lower sole 2B has a
laterally extending groove 20. The outsole 5B attached on a bottom
surface of the midfoot portion of the lower sole 2B has a thin part
that extends in a groove 22 of the midfoot portion in a bent shape
like a flat inverted V-shape or U-shape and a front portion and a
rear portion of the outsole 5B are connected through the thin
part.
[0066] The outsole 5B has respective contact surfaces 5B.sub.1
across the groove 22, which are attached to the respective lower
surfaces of the midfoot portion of the lower sole 2B and have
arc-shaped surfaces or curved surfaces that extend upwardly in a
curved shape. At the rear of the groove 22, the contact surface
5B.sub.1 is located at an uppermost position immediately adjacent
the groove 22, and in front of the groove 22, the contact surface
5B.sub.1 is located at an uppermost position farthest from the
groove 22. That is, the outsole 5B has a thickness that gradually
becomes thin toward the groove 22 at the rear of the groove 22 and
that gradually becomes thin away from the groove 22 in front of the
groove 22. The respective contact surfaces 5B.sub.1 act in such a
way as to conduct a smooth forward load transfer at the time of
impacting the ground and to promote deformation of the lower sole
2B and the plate 4 along with the lower sole 2B. Also, the midfoot
portion of the lower sole 2B is separated in the width direction by
a longitudinally extending clearance 23 (see FIG. 7). Respective
separated regions improve sole flexibility in the width
direction.
[0067] Then, we will explain the longitudinal position of the gap S
formed between the front end portion of the rear foot sole 2 and
the rear end portion 3r of the forefoot sole 3, using the schematic
of the bone structure of a wearer's foot shown in FIG. 10.
[0068] The position of the gap S is shown by a double dotted line
in FIG. 10. As shown in FIG. 10, the gap S preferably extends from
a generally central portion of the first metatarsus MB.sub.1 of the
foot to a generally central portion of the fifth metatarsus
MB.sub.5. In other words, the gap S is disposed at the rear of
distal end portions of the first to fifth metatarsi MB.sub.1 to
MB.sub.5. This is intended so that the gap S does not exist at the
ball of the foot for avoiding the stat that the wearer feels
uncomfortable around the foot sole when wearing the shoe. In FIG.
10, the solid line MJ designates the position of the
metatarsophalangeal joints.
[0069] Next, the shape of the plate 4 will be explained using FIGS.
11 to 16.
[0070] As shown in FIG. 11, the plate 4 has a body portion 40
extending in the longitudinal direction (i.e. up-and-down direction
of FIG. 11) as well as in the width direction and an upraised
portion 41 provided at an outer circumferential edge portion of the
body portion 40 and extending upwardly. On the bottom surface of
the plate 4, as shown in FIG. 12, a plurality of longitudinally
extending ribs 4r are provided (see FIGS. 1, 7-9). The body portion
40 of the plate 4, as shown in FIGS. 13-15, has an upwardly
convexly curved shape at a rear portion (corresponding to the heel
part H) to a longitudinally central portion (corresponding to the
midfoot part M). The body portion 40 is disposed below the foot
sole of the wearer (see FIGS. 5, 7-9). The upraised portion 41 of
the plate 4 is disposed at the heel rear end of the foot to the
medial and lateral sides of the heel part.
[0071] With regard to the upwardly convexly curved shape of the
body portion 40 of the plate 4, in this embodiment, the position of
the highest point of a medial longitudinal arch in the body portion
40 of the plate 4 is set at a higher position than the position of
the highest point of a lateral longitudinal arch. In this case,
since respective arch shapes on the medial and lateral sides of the
plate 4 correspond to the shape of a human's foot, wearer's touch
on the foot is made favorable, whereas a pronation angle is made
greater. To the contrary, the position of the highest point of the
medial longitudinal arch in the body portion 40 of the plate 4 may
be set at a lower position than the position of the highest point
of the lateral longitudinal arch. In this case, since the arch
drops lower on the lateral side than on the medial side, supination
is thus easy to occur and also arch shapes do not correspond to the
shape of the human's foot and wearer's touch on the foot is thus
made worse, whereas a pronation angle is made smaller.
[0072] The position of the highest point disposed at the uppermost
position in the upwardly convexly curved shape of the body portion
40 of the plate 4 is designated by the mark in FIG. 13 and the mark
.gradient. in FIG. 14. The positions of these marks do not coincide
with each other and are spaced apart at a small distance in the
longitudinal direction on the lateral side and the medial side of
the foot. The position of the highest point on the media side is
shown in the bone structure schematic of FIG. 16. As shown by the
mark of FIG. 16, the longitudinal position of the highest point of
the upwardly convexly curved shape of the plate 4 is located at the
position corresponding to the longitudinal arch of the foot and
corresponds to the position directly under the navicular bone NA
and the cuneiform bone CN of the foot. This is for making the plate
4 follow the shape of the foot and for securing a movable range of
the plate 4. In FIG. 16, reference character CA shows calcaneus of
the foot.
[0073] Also, the position of the highest point of the upwardly
convexly curved shape of the plate 4 on the medial side is
preferably located at the position of the line L.sub.1 that is
spaced upwardly away from the line L.sub.0 by at least height h
((foot length).times.2%) as shown in FIG. 16, wherein the line
L.sub.0 is drawn to connect a skin surface directly under the
distal end portion of the first metatarsus MB.sub.1 to a skin
surface directly under the calcaneus CA. The height h is
approximately 5 mm in the case of the foot length of 26 cm. This is
for preventing the plate 4 from bottoming. In this case, the amount
(calculated value) of forward movement of the front end portion 4f
of the plate 4 is 1 mm.
[0074] Then, the action and effect of the present invention will be
explained using FIGS. 17A and 17B.
[0075] Here, FIG. 17A shows the state before the shoe impacts the
ground and FIG. 17B shows the state at the time of foot flat (i.e.
the entire sole surface is in contact with the ground) after the
shoe has impacted the ground.
[0076] When impacting the ground, the sole structure 1 deforms from
the state of FIG. 17A to the state of FIG. 17B. At this juncture,
the upwardly convexly curved shape elastically compression-deforms
downwardly, so that the body portion 40 of the plate 4 changes into
a flat shape. Accordingly, the foot sole contact portion 2A.sub.0
of the rear foot sole 2 also changes into a flat shape. Also, the
midfoot portion of the lower sole 2B of the rear foot sole 2
deforms so as to be fallen forwardly. Further, the gap S between
the forefoot sole 3 and the upper and lower soles 2A, 2B of the
rear foot sole 2 is narrowed, and the connection 50 between the
outsoles 5B and 5C compression-deforms longitudinally.
[0077] In this case, the upwardly convexly curved shape of the body
portion 40 of the plate 4 elastically deforms downwardly, such that
thereby the cushioning properties can be maintained and
deterioration of the cushioning performance can be prevented.
Moreover, in this case, the gap S is formed in front of the front
end portion 4f of the plate 4, such that thereby at the time of
elastic deformation of the plate 4 the forward movement of the
front end portion 4f of the plate 4 can be conducted smoothly
without being obstructed by the rear foot sole 2 (the upper and
lower soles 2A, 2B) and the forefoot sole 3. Thereby, the plate 4
can deform smoothly thus improving the cushioning properties.
Furthermore, in this case, since the gap S formed in front of the
front end portion 4f of the plate 4 facilitates bending-deformation
of the rear foot sole 2 relative to the forefoot sole 3,
flexibility of the rear foot sole 2 relative to the forefoot sole 3
can be enhanced especially after transition from the foot-flat
moment to the heel-off moment. Also, since the plate 4 can be
smoothly deformed forwardly, shock in the longitudinal direction as
well can be mitigated at the time of impacting the ground.
[0078] In addition, the front end portion 4f of the plate 4 faces
the connection 50 disposed in front of the front end portion 4f
(see FIGS. 3, 5). However, since the connection 50 is a thin member
and is extensible and contractable in the forward direction in the
gap S, the forward movement of the front end portion 4f of the
plate 4 is not hindered by the connection 50.
Alternative Embodiment 1
[0079] In the above-mentioned embodiment, an example was explained
in which the heel part of the plate 4 is formed in a heel-cup shape
by providing the upraised portion 41 at the region extending from
the heel rear end of the body portion 40 of the plate 4 to the heel
medial and lateral sides, but the application of the present
invention is not limited to such an embodiment. Of the entire
upraised portion 41 of the body portion 40, the upraised portion 41
provided at the heel rear end may be omitted.
[0080] In the event that the upraised portion 41 is provided at the
heel rear end of the plate 4, when impact load in the forward
direction is applied to the plate 4 at the time of impacting the
ground the upraised portion 41 at the heel rear end may interfere
with the heel rear end surface of the upper sole 2A and the forward
movement of the plate 4 may be restricted. However, by removing the
upraised portion at the heel rear end of the plate 4, the forward
movement of the plate 4 is conducted in a smooth manner without
being restricted by the upraised portion at the heel rear end.
Thereby, the impact load to the plate 4 in the forward direction
can be effectively decreased.
Alternative Embodiment 2
[0081] In the above-mentioned embodiment, as a preferred
embodiment, an example was shown where the plate 4 extends along
the rear foot region from the heel part H to the midfoot part M of
the sole structure 1. However, at the heel part H, the plate 4 has
only to be placed to cover the position directly under at least the
calcaneus CA, and at the midfoot part M, the plate 4 has only to be
placed at the position to cover at least the proximal portions of
the first to fifth metatarsus MB.sub.1 to MB.sub.5. This is for
receiving the shock load securely at the time of heel contact and
midfoot contact during running. The present invention also has
application to the structure where the plate 4 is provided either
at the heel part H only or at the midfoot part M only.
[0082] In the event that the plate 4 is provided only at the heel
part H, for example, the plate 4 is provided along the heel portion
of the rear foot sole 2B (to cover the position directly under at
least the calcaneus CA) and the front end portion 4f of the plate 4
faces outwardly from the front end surface of the heel portion of
the rear foot sole 2B, there is formed a gap without the rear foot
sole in front of the front end portion 4f of the plate 4 as with
the above-mentioned embodiment. Also, in the event that the plate 4
is provided only at the midfoot part M, for example, the plate 4 is
provided along the midfoot portion of the rear foot sole 2B and the
front end portion 4f of the plate 4 faces outwardly from the front
end surface of the midfoot portion of the rear foot sole 2B, there
is formed a gap without the rear foot sole in front of the front
end portion 4f of the plate 4 as with the above-mentioned
embodiment. In this case, the plate 4 preferably has an upwardly
convexly curved shape similar to the above-mentioned
embodiment.
Alternative Embodiment 3
[0083] In the above-mentioned embodiment, an example was shown
where the connection 50 has a single bent portion of an inverted
V-shape or U-shape (see FIGS. 2, 3, 5), but the present invention
also has application to the case in which the connection 50 has a
plurality of bent portions of inverted V-shapes or U-shapes. In
this case, the connection 50 is bent in a bellows-shape as viewed
from the side thereof.
Alternative Embodiment 4
[0084] In the above-mentioned embodiment, an example was shown
where the rear foot sole 2 and the forefoot sole 3 are
interconnected through the connection 50 in the gap S extending
from the outsoles 5B, 5C, but the application of the present
invention is not limited to such an example. FIGS. 18 and 19
illustrate a sole structure according to another embodiment of the
present invention. In these drawings, the same reference numbers as
those in the above-mentioned embodiment indicate identical or
functionally similar elements.
[0085] This embodiment differs from the above-mentioned embodiment
in that the upper midsole 2A of the rear foot sole 2 and the
forefoot sole 3 are interconnected through a connection 20 or 20'
in the gap S extending from the upper sole 2A and the forefoot sole
3. That is, in this embodiment, the rear foot sole 2 and the
forefoot sole 3 are interconnected through an extension of the
midsole of a soft elastic material. The outsoles 5B, 5C are
separated via the gap S. In this case as well, the gap S is
disposed in front of the front end portion of the plate 4.
[0086] In the structure shown in FIG. 18, the connection 20
includes a thin bending portion of a V-shape or a U-shape as viewed
from the side of the structure. The connection 20 has a path length
that is longer than a longitudinal length of the gap S between the
front end of the rear foot sole 2 and the rear end portion 3r of
the forefoot sole 3. Also, the connection 20 extends in the gap S
in the sole width direction as well as in the longitudinal
direction. The connection 20 is not limited to such one as includes
a single V-shaped or U-shaped bending portion. The connection 20
may include a plurality of V-shaped or U-shaped bending portions.
In this case, the connection 20 is bent in a bellows-shape as
viewed from the side of the structure.
[0087] In the structure shown in FIG. 19, the connection 20' is
formed of a thin extending portion that extends linearly in the
longitudinal direction. The connection 20' extends in the gap S in
the sole width direction as well as in the longitudinal direction.
The connection 20' has a path length that is substantially the same
as a longitudinal length of the gap S between the front end of the
rear foot sole 2 and the rear end portion 3r of the forefoot sole
3. The reason why the path length of the connection 20' is not made
longer than the longitudinal length of the gap S is as follows:
[0088] When the rear foot sole 2 bending-deforms relative to the
forefoot sole 3 at the gap S, the bending center is located at the
position immediately adjacent the connection 20'. Accordingly,
elongation of the connection 20' is small at the time of bending
deformation and the connection 20' can absorb such elongation
through its own elastic deformation. As a result, there is no need
to secure extension allowance in the connection 20' in advance.
[0089] In either of the sole structures shown in FIGS. 18 and 19,
when the shoe strikes onto the ground, the upwardly convexly curved
shape of the body portion 40 of the plate 4 elastically deforms
downwardly, such that thereby the cushioning properties can be
maintained and deterioration of the cushioning performance can be
prevented. At this juncture, since the gap S is formed in front of
the front end portion 4f of the plate 4, such that thereby at the
time of elastic deformation of the plate 4 the forward movement of
the front end portion 4f of the plate 4 can be performed smoothly
without being obstructed by the rear foot sole 2 (the upper and
lower soles 2A, 2B) and the forefoot sole 3. Thereby, the plate 4
can deform smoothly thus improving the cushioning properties.
Furthermore, in this case, since the gap S formed in front of the
front end portion 4f of the plate 4 facilitates bending-deformation
of the rear foot sole 2 relative to the forefoot sole 3,
flexibility of the rear foot sole 2 relative to the forefoot sole 3
can be enhanced.
[0090] Additionally, in the structure shown in FIG. 18, the
connection 20 disposed in front of the plate 4 faces the front end
portion 4f of the plate 4. Since this connection 20 is a thin soft
elastic member and extensible in the gap S in the longitudinal
direction, the forward movement of the front end portion 4f of the
plate 4 is not hindered by the connection 20.
Other Applicable Example
[0091] In the above examples, the sole structure of the present
invention was applied to a running shoe, but the application of the
present invention is not limited to such an example. The present
invention also has application to other various sports shoes
including walking shoes.
INDUSTRIAL APPLICABILITY
[0092] As mentioned above, the present invention is of use to a
sole structure for a shoe, and it is especially suitable for a sole
structure for a sports shoe that requires a superb sole
deformability.
* * * * *