U.S. patent application number 15/735914 was filed with the patent office on 2019-01-03 for shoe having shoe sole with divided rear foot portion.
The applicant listed for this patent is ASICS Corporation. Invention is credited to Seiya Hayashi, Masaru Ichikawa, Daisuke Kokubu, Kenta Moriyasu, Ken Sakamoto.
Application Number | 20190000180 15/735914 |
Document ID | / |
Family ID | 57586583 |
Filed Date | 2019-01-03 |
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United States Patent
Application |
20190000180 |
Kind Code |
A1 |
Moriyasu; Kenta ; et
al. |
January 3, 2019 |
SHOE HAVING SHOE SOLE WITH DIVIDED REAR FOOT PORTION
Abstract
A sole includes a rear end portion on a rear end side, and a
rear portion arranged anterior to the rear end portion; a rear
surface of the rear portion includes one inclined surface extending
in an upper-rear diagonal direction; a front surface of the rear
end portion includes another inclined surface extending in an
upper-rear diagonal direction; the inclined surface of the rear
portion and the inclined surface of the rear end portion together
define a first divide portion at which the surfaces are in contact
with each other or are capable of contacting each other; and the
inclined surface of the rear end portion is set so that the
inclined surface is rotatable relative to the inclined surface of
the rear portion in such a manner that a lower portion of the
divide portion opens.
Inventors: |
Moriyasu; Kenta; (Kobe-Shi,
JP) ; Ichikawa; Masaru; (Kobe-shi, JP) ;
Kokubu; Daisuke; (Kobe-shi, JP) ; Sakamoto; Ken;
(Kobe-shi, JP) ; Hayashi; Seiya; (Kobe-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ASICS Corporation |
Kobe-shi |
|
JP |
|
|
Family ID: |
57586583 |
Appl. No.: |
15/735914 |
Filed: |
June 26, 2015 |
PCT Filed: |
June 26, 2015 |
PCT NO: |
PCT/JP2015/068510 |
371 Date: |
December 12, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A43B 13/16 20130101;
A43B 13/383 20130101; A43B 5/06 20130101; A43B 23/027 20130101;
A43B 23/0275 20130101 |
International
Class: |
A43B 13/16 20060101
A43B013/16; A43B 13/38 20060101 A43B013/38; A43B 23/02 20060101
A43B023/02; A43B 5/06 20060101 A43B005/06 |
Claims
1. A shoe comprising: an upper configured to wrap around an instep
of a foot; and a main sole configured to support a sole of the
foot, wherein: the main sole includes a rear end portion on a rear
end side, and a rear portion arranged anterior to the rear end
portion; a rear surface of the rear portion includes one inclined
surface extending in an upper-rear diagonal direction; a front
surface of the rear end portion includes another inclined surface
extending in the upper-rear diagonal direction; the one inclined
surface of the rear portion and the other inclined surface of the
rear end portion together define a divide portion at which the one
and other surfaces are in contact with each other or are capable of
contacting each other; and the other inclined surface of the rear
end portion is set so that the other inclined surface is rotatable
relative to the one inclined surface of the rear portion in such a
manner that a lower portion of the divide portion opens.
2. The shoe according to claim 1, wherein the divide portion
includes a diagonal portion extending, from a central portion in a
medial-lateral direction, in an anterior lateral diagonal
direction.
3. The shoe according to claim 2, wherein an angle formed between
(i) a virtual transverse line perpendicular to a central axis,
which extends in a front-rear direction of the main sole, and (ii)
the diagonal portion of the divide portion is set in a range of
10.degree. to 40.degree..
4. The shoe according to claim 1, wherein a medial edge of the
divide portion is arranged rearward of a lateral edge of the divide
portion.
5. The shoe according to claim 1, further comprising: an insole
being continuous with the upper and configured to cover the sole of
the foot, the main sole covering the insole from below; and a
bridging portion provided on the rear portion and the rear end
portion so as to bridge the divide portion, wherein the bridging
portion connects between the rear portion and the rear end portion
so that the one inclined surface of the rear portion is rotatable
relative to the other inclined surface of the rear end portion,
wherein: a part of the bridging portion is arranged between the
insole and the rear portion; and another part of the bridging
portion is arranged between the insole and the rear end
portion.
6. The shoe according to claim 5, wherein the bridging portion is
formed from a plate-shaped member that is different from the main
sole.
7. The shoe according to claim 6, further comprising one engagement
portion and another engagement portion for positioning the bridging
portion, wherein the one engagement portion is formed on an upper
surface of the rear portion, and the other engagement portion is
formed on an upper surface of the rear end portion.
8. The shoe according to claim 7, wherein the rear portion and the
rear end portion define respective depressions into which the
bridging portion fits, the depression of the rear portion forms the
one engagement portion and the depression of the rear end portion
forms the other engagement portion.
9. The shoe according to claim 6, wherein an elastic modulus of the
bridging portion is equal to or greater than an elastic modulus of
the insole.
10. The shoe according to claim 6, wherein the bridging portion
defines a through hole, the through hole being arranged so as to
extend from the rear portion to the rear end portion.
11. The shoe according to claim 6, wherein a width of the bridging
portion in the divide portion is set to be 25% to 100% of a width
of the main sole.
12. The shoe according to claim 6, wherein a thickness of the
bridging portion is set to be 0.1 mm to 5.0 mm.
13. The shoe according to claim 1, wherein the rear portion extends
toward a front direction from the rear surface, the rear portion
defines a groove anterior to the rear surface, and the groove is
shallower than a depth of the divide portion and extends in a width
direction of the main sole.
14. The shoe according to claim 1, wherein: a medial surface of the
upper includes a medial high-rigidity portion and a medial flexible
portion that bends more easily than the medial high-rigidity
portion, wherein the medial high-rigidity portion and the medial
flexible portion are separated from each other in a front-rear
direction; a lateral surface of the upper includes a lateral
high-rigidity portion and a lateral flexible portion that bends
more easily than the lateral high-rigidity portion, wherein the
lateral high-rigidity portion and the lateral flexible portion 32S
are separated from each other in the front-rear direction; at least
one of (i) a front edge portion of the medial high-rigidity portion
and (ii) the medial flexible portion extend in an upper-rear
diagonal direction from an upper end portion of a medial edge of
the divide portion; and at least one of (i) a front edge portion of
the lateral high-rigidity portion and (ii) the lateral flexible
portion extend in the upper-rear diagonal direction from an upper
end portion of a lateral edge of the divide portion.
15. The shoe according to claim 14, wherein: a strip-shaped
restraining member is arranged on the medial-side flexible portion
for restraining stretch of the medial-side flexible portion in the
front-rear direction; and another strip-shaped restraining member
is arranged on the lateral-side flexible portion for restraining
stretch of the lateral-side flexible portion in a front-rear
direction.
Description
TECHNICAL FIELD
[0001] The present invention relates to a shoe having a shoe sole
with a divided rear foot portion.
BACKGROUND ART
[0002] Shoes allowing users to run with a barefoot feel have
recently been gaining popularity among some fans. These shoes are
made to pursue a barefoot feel.
[0003] Barefoot-feel shoe soles are thin, and such thin shoe soles
will lower the shock-absorbing property.
CITATION LIST
Patent Literature
[0004] First Patent Document: JP3,119,977U (front page)
[0005] Second Patent Document: JP2007-89734A (front page)
[0006] Third Patent Document: JP2000-197503A (front page)
[0007] Fourth Patent Document: JP11-123101A (front page)
[0008] Fifth Patent Document: JP2001-70004A (front page)
[0009] Sixth Patent Document: JP2010-504839W (front page)
[0010] Seventh Patent Document: WO2013/168259A1 (front page)
[0011] WO2013/168259A1 proposes a shoe allowing the user to run
without stress while maintaining its shock-absorbing property. This
shoe is expected to suppress pronation of the heel portion
(eversion) occurring during the landing period while running, while
maintaining its shock-absorbing property.
SUMMARY OF INVENTION
[0012] However, this prior technique is not a proposal that pursues
a barefoot feel. Therefore, it is not possible to realize
barefoot-running joint movements.
[0013] Therefore, it is an object of the present invention to
provide a shoe that realizes foot joint movements close to
barefoot-running joint movements while realizing a better
shock-absorbing property than when running barefoot.
[0014] The present invention is directed to a shoe including an
upper 8 wrapping around an instep of a foot, and a main sole MS
supporting a sole of the foot, wherein:
[0015] the main sole MS includes a rear end portion 13 on a rear
end side, and a rear portion 12 arranged anterior DF to the rear
end portion 13;
[0016] a rear surface of the rear portion 12 includes one inclined
surface 12B extending in an upper-rear diagonal direction;
[0017] a front surface of the rear end portion 13 includes another
inclined surface 13B extending in an upper-rear diagonal
direction;
[0018] the inclined surface 12B of the rear portion 12 and the
inclined surface 13B of the rear end portion 13 together define a
divide portion D2 at which the inclined surface 12B of the rear
portion 12 and the inclined surface 13B of the rear end portion 13
are in contact with each other or are capable of contacting each
other; and
[0019] the inclined surface 13B of the rear end portion 13 is set
so that the inclined surface 13B is rotatable relative to the
inclined surface 12B of the rear portion 12 in such a manner that a
lower portion of the divide portion D2 opens (widens).
[0020] As used in the present specification, inclined surfaces
being in contact with each other means that at least a portion of
one inclined surface is in contact with at least a portion of the
other inclined surface when not worn. In this case, the load of the
forefoot section when worn can easily be supported by the main sole
MS.
[0021] On the other hand, inclined surfaces being capable of
contacting each other means that during the transition from
heel-contact to heel-rise when worn, preferably at least at the
stationary standing position ((load/shoe size)=1 kgf/cm), at least
a portion of one inclined surface is in contact with at least a
portion of the other inclined surface. In this case, the minimum
value of the distance between these surfaces when not worn is
preferably greater than 0.0 mm and less than 2.0 mm, and more
preferably less than 1.0 mm, and most preferably less than 0.5
mm.
[0022] In the present invention, during the period of transitioning
from heel-contact, where only the heel contacts the ground, to
foot-flat, where the sole of the foot entirely contacts the ground,
the rear portion 12 and the rear end portion 13 can rotate relative
to each other with the divide portion D2 therebetween. This
rotation will likely allow rotation of the subtalar joint STJ and
the midtarsal joint MTJ of the foot.
[0023] Thus, the divided main sole MS allows flexion and rotation
of various joints. As a result, one is likely to enjoy a running
feel that is close to a barefoot feel.
[0024] Note that the third and fourth inclined surfaces 12B, 13B of
the divide portion D2 extend in an upper-rear diagonal direction,
and the third portion 13, which receives the load immediately after
landing, therefore has a shape that flares downward. Therefore, the
load will be easily supported by the third portion 13.
BRIEF DESCRIPTION OF DRAWINGS
[0025] FIG. 1 is a medial side view showing a shoe according to one
embodiment of the present invention.
[0026] FIG. 2 is a lateral side view showing the same. Note that in
FIG. 1 and FIG. 2, areas where mesh fabric is exposed is
dotted.
[0027] FIG. 3 is a perspective view showing a shoe sole as seen
from the bottom surface side.
[0028] FIG. 4 shows a bottom surface of the shoe sole.
[0029] FIG. 5 is a plan view showing a midsole.
[0030] FIG. 6A, FIG. 6B, FIG. 6C, FIG. 6D, FIG. 6E, FIG. 6F and
FIG. 6G are cross-sectional views taken along respective lines
shown in FIG. 4.
[0031] FIG. 7 is an exploded perspective view of a midsole showing
a first portion to a third portion separated from each other.
[0032] FIG. 8 is an exploded perspective view showing an insole
separated from a main sole. Note that in FIG. 8, the surface of the
paddle is dotted.
[0033] FIG. 9 is a lateral side view showing the shoe at
heel-rise.
[0034] FIG. 10 is a lateral side view showing the shoe at
heel-contact.
[0035] FIG. 11A, FIG. 11B and FIG. 11C are a medial side view, a
plan view and a lateral side view, respectively, showing the foot
bone structure.
[0036] FIG. 12A and FIG. 12B are a back view and a perspective view
of a worn shoe showing pronation and internal (medial) rotation of
the foot, respectively.
[0037] FIG. 13A, FIG. 13B, FIG. 13C, FIG. 13D and FIG. 13E are
schematic lateral side views showing respective test samples. Note
that in these figures, flexible portions are dotted.
[0038] FIG. 14A, FIG. 14B and FIG. 14C are graphs showing test
results.
[0039] FIG. 15A, FIG. 15B and FIG. 15C are graphs showing test
results.
[0040] FIG. 16 is a lateral side view showing a shoe according to
an alternative embodiment.
[0041] FIG. 17A, FIG. 17B, FIG. 17C, FIG. 17D, FIG. 17E, FIG. 17F
and FIG. 17G are cross-sectional views showing other alternative
embodiments.
DESCRIPTION OF EMBODIMENTS
[0042] Preferably, the divide portion D2 includes a diagonal
portion 181 extending, from a central portion 13C in a
medial-lateral direction, in an anterior DF-lateral diagonal
direction.
[0043] In this case, the diagonal portion 131 of the divide portion
D2 is likely to extend along a plane that intersects the axis of
the subtalar joint STJ or the midtarsal joint MTJ. Therefore, at
the divide portion D2, the inclined surfaces 12B, 13B rotate about
the axis relative to each other, which will more likely allow
rotation of the joints.
[0044] More preferably, an angle .alpha. formed between a virtual
transverse line VL perpendicular to a central axis S, which extends
in a front-rear direction FB of the main sole MS, and the diagonal
portion 131 of the divide portion D2 is set in a range of
10.degree. to 40.degree..
[0045] The diagonal portion 131, which is set in such an angle
range, is likely to extend along planes that intersect the axes of
the joints, which will more likely allow relative rotation about
the axes of the joints.
[0046] Preferably, a medial edge 1M of the divide portion D2 is
arranged rearward of a lateral edge 1L of the divide portion
D2.
[0047] With such an arrangement, the inclined surfaces 12B, 13B,
which form the divide portion D2, will likely extend along the
intersecting planes. This will more likely allow relative rotation
about the axes of the joints.
[0048] Preferably, the shoe further includes:
[0049] an insole 4 being continuous with the upper 3 and covering
the sole of the foot, the main sole MS covering the insole 4 from
below; and
[0050] a bridging portion 5B provided so as to bridge between the
rear portion 12 and the rear end portion 13 across the divide
portion D2, wherein the bridging portion 5B connects between the
rear portion 12 and the rear end portion 18 so that the inclined
surface 12B of the rear portion 12 is rotatable relative to the
inclined surface 13B of the rear end portion 13, wherein:
[0051] a part of the bridging portion 5B is arranged between the
insole 4 and the rear portion 12; and
[0052] another part of the bridging portion 5B is arranged between
the insole 4 and the rear end portion 13.
[0053] In this case, the bridging portion 5B that connects together
the rear portion 12 and the rear end portion 13 is arranged between
the insole 4 and the rear portion 12 and arranged between the
insole 4 and the rear end portion 13. Therefore, the rear portion
12 and the rear end portion 18, which are connected together via
the bridging portion 5B, can easily be positioned with respect to
each other. This as a result improves the positioning precision
between the main sole MS and the upper 3, and the performance will
be unlikely to vary from one product to another.
[0054] Preferably, the bridging portion 5B is formed from a
plate-shaped member that is different (separate) from the main sole
MS.
[0055] In this case, it will be easier to manufacture the shoe
sole, as compared with a case in which the bridging portion 5B is
formed from the main sole MS.
[0056] More preferably, the shoe further includes one engagement
portion 12E and another engagement portion 13E for positioning the
bridging portion 5B, wherein the one engagement portion 12E is
formed on an upper surface of the rear portion 12, and the other
engagement portion 13E is formed on an upper surface of the rear
end portion 13.
[0057] In this case, the bridging portion 5B is easily positioned
with respect to the rear portion 12 and the rear end portion 13.
This as a result will further improve the positioning precision
between the rear portion 12 and the rear end portion 13.
[0058] More preferably, the rear portion 12 and the rear end
portion 13 define respective depressions into which the bridging
portion 5B fits, the depression of the rear portion and the
depression of the rear end portion form the one engagement portion
12E and the other engagement portion 1E, respectively.
[0059] In this case, the bridging portion 5B fits in the
depressions of the rear portion 12 and the rear end portion 13, and
can therefore be easily positioned. This as a result will further
improve the positioning precision between the rear portion 12 and
the rear end portion 18.
[0060] Preferably, an elastic modulus of the bridging portion 5B is
equal to or greater than an elastic modulus of the insole 4.
[0061] In this case, the bridging portion 5F having a large elastic
modulus (Young's modulus) will suppress the inadvertent upward
relative warping of the rear end portion 13 with respect to the
rear portion 12.
[0062] Preferably, the bridging portion 5B defines a through hole
5H, the through hole 5H being arranged so as to extend from the
rear portion 12 to the rear end portion 13.
[0063] In such a case, the main sole MS can easily flex at the
bridging portion 5B.
[0064] Preferably, a width Wb of the bridging portion 5B in the
divide portion D2 is set to be 25% to 100% of a width W of the main
sole MS.
[0065] The bridging portion 5B having a large width Wb improves the
positioning precision.
[0066] Preferably, a thickness of the bridging portion 5B is set to
be 0.1 mm to 5.0 mm.
[0067] In this case, the bridging portion 5B being thin contributes
to maintaining a light weight, and awkwardness is unlikely to be
felt on the sole of the foot.
[0068] Preferably, the rear portion 12 extends toward a front
direction DF from the rear surface, the rear portion 12 defines a
groove 12G anterior DF to the rear surface, and the groove 12G is
shallower than a depth of the divide portion D2 and extends in a
width direction W of the main sole MS.
[0069] In this case, the main sole MS can easily twist in the rear
portion 12, which will more likely allow relative rotation about
the axes of the joints.
[0070] Preferably, a medial surface 31 of the upper 3 includes a
medial high-rigidity portion 31H and a medial flexible portion 31S
that bends more easily than the medial high-rigidity portion 31H,
wherein the medial high-rigidity portion 31H and the medial
flexible portion 318S are separated from each other in a front-rear
direction;
[0071] a lateral surface 32 of the upper 8 includes a lateral
high-rigidity portion 32H and a lateral flexible portion 32S that
bends more easily than the lateral high-rigidity portion 32H,
wherein the lateral high-rigidity portion 32H and the lateral
flexible portion 32S are separated from each other in a front-rear
direction;
[0072] a front edge portion of the medial high-rigidity portion 31H
and/or the medial flexible portion 31S extend in an upper-rear
diagonal direction from an upper end portion of a medial edge 1M of
the divide portion D2; and
[0073] a front edge portion of the lateral high-rigidity portion
32H and/or the lateral flexible portion 32S extend in an upper-rear
diagonal direction from an upper end portion of a lateral edge 1L
of the divide portion D2.
[0074] At heel-contact immediately after landing, an area of the
upper 3 that is in an upper-rear diagonal direction of the divide
portion D2 is compressed as the rear end portion 13 rotates
relative to the rear portion 12 of the main sole MS. Since the
upper 3 of this example includes the flexible portions 328, 31S,
the flexible portions 328, 318 will easily contract (creating
creases) at heel-contact. Thus, the rotation at the divide portion
D2 is unlikely to be inhibited.
[0075] Preferably, a strip-shaped restraining member 34M is
arranged on the medial-side flexible portion 31S for restraining
stretch of the medial-side flexible portion 31S in a front-rear
direction FB; and
[0076] another strip-shaped restraining member 84L is arranged on
the lateral-side flexible portion 32S for restraining stretch of
the medial-side flexible portion 31S in a front-rear direction
FD.
[0077] At heel-rise, the heel of the foot is likely to rise inside
the upper 3. While the flexible portions 328, 31S (FIG. 1) are
present, the restraining members 34L, 34M are provided on the
flexible portions 328, 31S. Therefore, it is possible to restrain
the stretch of the flexible portion of the upper 3 at heel-rise,
and it is therefore possible to prevent the heel from rising inside
the upper 3.
[0078] Any feature illustrated and/or depicted in conjunction with
one of the aforementioned aspects or the following embodiments may
be used in the same or similar form in one or more of the other
aspects or other embodiments, and/or may be used in combination
with, or in place of, any feature of the other aspects or
embodiments.
EMBODIMENTS
[0079] The present invention will be understood more clearly from
the following description of preferred embodiments taken in
conjunction with the accompanying drawings. Note however that the
embodiments and the drawings are merely illustrative and should not
be taken to define the scope of the present invention. The scope of
the present invention shall be defined only by the appended claims.
In the accompanying drawings, like reference numerals denote like
components throughout the plurality of figures.
[0080] Embodiment 1 of the present invention will now be described
with reference to FIG. 1 to FIG. 10.
[0081] The present embodiment is directed to a shoe sole of a shoe
for running or walking, for example.
[0082] A main sole MS shown in FIG. 1 includes a rubber-made
outsole 2 and a resin-made midsole 1. An upper 3 wrapping around
the instep of the foot is provided over the main sole MS.
[0083] The midsole 1 includes a midsole body made of a resin-made
foamed material such as EVA, for example, and may further include a
reinforcement device. The term "made of resin" means that a resin
component such as a thermoplastic component is contained, and may
include any other suitable component. A paddle 5 of FIG. 8 made of
a high-resilience material, for example, is provided on the upper
surface of the midsole 1.
[0084] The outsole 2 of FIG. 1 is a tread sole having a higher
abrasion resistance than the foamed material of the midsole body,
and typically has a higher hardness than the foamed material of the
midsole body. Note that the term "made of rubber" means that it
contains a natural rubber component or a synthetic rubber
component, and it may contain any other component.
[0085] As shown in FIG. 3 to FIG. 5, the midsole 1 of the present
embodiment and the insole 4 of FIG. 8 generally cover the entire
surface of the sole of the foot. On the other hand, as shown in
FIG. 1 and FIG. 2, the outsole 2 is attached to the lower surface
of the midsole 1 and partially covers the sole of the foot. That
is, the main sole MS of FIG. 8 including the midsole 1 and the
outsole 2 covers the insole 4 from below and supports the sole of
the foot.
[0086] The insole 4 of FIG. 8 and FIG. 6B to FIG. 6G is continuous
with the upper 3 of FIG. 2. The upper 3 is shaped so as to wrap
around the instep of the foot. Note that the shoe may include a
shoelace for fitting the upper 3 to the foot.
[0087] The main sole MS is divided into a toe-side first portion
11, a second portion (rear portion) 12 arranged posterior DB to the
first portion, and a third portion 13 (rear end portion) on the
rear end side.
[0088] The rear surface of the first portion 11 includes a first
inclined surface 11F extending in an upper-front diagonal
direction. The front surface of the second portion 12 includes a
second inclined surface 12F extending in an upper-front diagonal
direction. The first inclined surface 11F and the second inclined
surface 12F together define a first divide portion D1 at which the
surfaces 11F, 12F are in contact with each other or are capable of
contacting each other.
[0089] The rear surface of the second portion 12 includes a third
inclined surface 12B extending in an upper-rear diagonal direction.
The front surface of the third portion 13 includes a fourth
inclined surface 13B extending in an upper-rear diagonal direction.
The third inclined surface 12B and the fourth inclined surface 13B
together define a second divide portion D2 at which the surfaces
12B, 13B are in contact with each other or are capable of
contacting each other.
[0090] The midsole 1 and the outsole 2 are each divided into parts
in a front-rear direction at the first and second divide portions
D1, D2 (see FIG. 7).
[0091] As shown in FIG. 9, the second inclined surface 12F of the
second portion 12 is configured so that it can rotate relative to
the first inclined surface 11F of the first portion 11 in such a
manner that the lower portion of the first divide portion D1 opens.
As shown in FIG. 10, the fourth inclined surface 13B of the third
portion 13 is configured so that it can rotate relative to the
third inclined surface 12B of the second portion 12 in such a
manner that the lower portion of the second divide portion D2
opens.
[0092] In FIG. 5, the position of the medial edge 1M of the upper
end of the first divide portion D1 is set in the range of 65% to
75%, from the rear end 1B of the main sole MS, of the maximum
length Lm from the front end 1F to the rear end 1B of the main sole
MS, along the center axis S (FIG. 4) extending in the front-rear
direction FB of the main sole MS.
[0093] The position of the lateral edge 1L of the upper end of the
first divide portion D1 is set in the range of 60% to 70%, from the
rear end 1B of the main sole MS, of the maximum length Lm of the
main sole MS, along the center axis S of the main sole MS.
[0094] With the first divide portion D1 set in such a range, the
line obtained by aligning the upper end of the first divide portion
D1 with the width direction DW of the main sole MS is arranged
posterior DB to the metatarsal phalangeal joints MP of the first
toe B1 to the fifth toe B5 and is arranged anterior DF to the bases
B11, B51 of the first to fifth metatarsal bones B1, B5. More
preferably, the line is arranged posterior DB to the heads B12, B52
of the metatarsal bones. Note that the base refers to a portion of
each bone that is close to a joint posterior thereto and that is
slightly expanding to a greater thickness, and it is referred to
also as the proximal head. On the other hand, the head refers to a
portion of each bone that is close to a joint anterior thereto and
that is slightly expanding to a greater thickness, and it is
referred to also as the distal head.
[0095] In FIG. 4, the first divide portion D1 has a shape that is
protruding toward the front direction DF as seen in a plan view. On
the other hand, the second divide portion D2 has a shape that is
protruding toward the rear direction DB as seen in a plan view.
[0096] In the present embodiment, the first portion 11 is
continuous without being divided from the first divide portion D1
to the tip of the main sole MS. The first portion 11 defines a
groove 11G, the groove 11G of FIG. 1 being shallower than the depth
of the first divide portion D1 and extending in the width direction
DW of the main sole MS of FIG. 4.
[0097] The second portion (rear portion) 12 extends toward the
front direction DF from the rear surface. The second portion 12
defines a groove 12G anterior DF to the rear surface. The groove
12G is shallower than the depth of the second divide portion D2
(FIG. 1) and extends in the width direction W of the main sole
MS.
[0098] Next, the paddle 5 of FIG. 8 will be described.
[0099] The paddle 5 is formed from a member different from the main
sole MS. The elastic modulus of the paddle 5 is greater than or
equal to the elastic modulus of the insole 4 and, more preferably,
greater than the elastic modulus of the insole 4. The paddle 5 is
formed from a resin-made flat plate having a thickness of 0.1 mm to
5.0 mm, more preferably 0.5 mm to 1.5 mm.
[0100] The paddle 5 is arranged so as to extend across the first to
third portions 11 to 13. The paddle 5 is sandwiched between the
upper surface of the midsole 1 and the lower surface of the insole
4. The paddle 5 includes a bridging portion 5F on the forefoot
side, and a bridging portion 5B on the rear foot side.
[0101] A portion of the bridging portion 5F on the forefoot side of
FIG. 8 is arranged between the insole 4 and the first portion 11.
On the other hand, another portion of the bridging portion 5F is
arranged between the insole 4 and the second portion 12.
[0102] A portion of the bridging portion 5B on the rear foot side
is arranged between the insole 4 and the second portion 12. On the
other hand, another portion of the bridging portion 5B is arranged
between the insole 4 and the third portion 13.
[0103] In order for the bridging portion 5F on the forefoot side of
FIG. 8 to be positioned with respect to the main sole MS, the first
engagement portion 11E is formed on the upper surface of the first
portion 11 and the second engagement portion 12E is formed on the
upper surface of the second portion 12. The first portion 11 and
the second portion 12 of FIG. 7 define the first depression and the
second depression, respectively, into which the bridging portion 5F
(FIG. 8) fits, wherein the first depression and the second
depression form the first and second engagement portions 11E and
12E, respectively.
[0104] In order for the bridging portion 5B on the rear foot side
of FIG. 8 to be positioned with respect to the main sole MS, the
second engagement portion 12E is formed on the upper surface of the
second portion 12 and the third engagement portion 18E is formed on
the upper surface of the third portion 13. The second portion 12
and the third portion 13 of FIG. 7 each define a depression into
which the bridging portion 5B (FIG. 8) fits, wherein the
depressions form the respective engagement portions 11E, 12E.
[0105] In FIG. 5, the widths 5Wf, Wb of the bridging portions 5F,
5B of the first and second divide portions D1, D2 are each set to
be 25% to 100% of the width W of the main sole MS.
[0106] In FIG. 8, the bridging portions 5F, 5B define a plurality
of through holes 5H. The through holes 5H on the forefoot side are
arranged so as to extend from the first portion 11 to the second
portion 12. The through holes 5H on the rear foot side are arranged
so as to extend from the second portion 12 to the third portion
13.
[0107] Note that it is preferred that the through holes 5H on the
rear foot side are so structured that the third portion 13 can
easily be displaced in the width direction DW.
[0108] The bridging portion 5F on the forefoot side of FIG. 8 is
provided so as to bridge between the first portion 11 and the
second portion 12 across the first divide portion D1, and the
bridging portion 5F connects between the first portion 11 and the
second portion 12 so that the inclined surface 12F of the second
portion 12 is rotatable relative to the inclined surface 11F of the
first portion 11, as shown in FIG. 9.
[0109] The bridging portion 5B on the rear foot side of FIG. 8 is
provided so as to bridge between the second portion 12 and the
third portion 13 across the second divide portion D2, and the
bridging portion 5B connects between the second portion 12 and the
third portion 13 so that the inclined surface 12B of the second
portion 12 is rotatable relative to the inclined surface 13B of the
third portion, as shown in FIG. 10.
[0110] In FIG. 4, the second divide portion D2 includes a diagonal
portion 131 that extends toward the medial side in a diagonal
forward direction DF from a central portion 13C between the medial
side and the lateral side. The angle .alpha. formed between a
virtual transverse (horizontal) line VL that is perpendicular to
the center axis S extending in the front-rear direction FD of the
main sole MS and the diagonal portion 131 of the second divide
portion D2 is set in a range of 10.degree. to 40.degree..
[0111] The medial edge 1M of the second divide portion D2 is
arranged posterior DB to the lateral edge 1L of the second divide
portion D2.
[0112] In the rear foot portion, a medial side surface 31 of the
upper 3 of FIG. 1 includes a medial-side high rigidity portion 31H
and a medial-side flexible portion 31S that is more flexible than
the medial-side high rigidity portion 31H, which are separated from
each other in the front-rear direction. A lateral side surface 32
of the upper 3 of FIG. 2 includes a lateral-side high rigidity
portion 32H and a lateral-side flexible portion 32S that is more
flexible than the lateral-side high rigidity portion 32H.
[0113] The front edge portion of the medial-side high rigidity
portion 31H and/or the medial-side flexible portion 31S of FIG. 1
extend in an upper-rear diagonal direction from the upper end
portion of the medial edge 1M of the second divide portion D2. The
front edge portion of the lateral-side high rigidity portion 32H
and/or the lateral-side flexible portion 32S of FIG. 2 extend in an
upper-rear diagonal direction from the upper end portion of the
lateral edge 1L of the second divide portion D2. Note that the term
"from the upper end portion" means from the upper end or a vicinity
thereof.
[0114] The high rigidity portions may each be formed from a
synthetic-resin plate, for example. The low rigidity portions may
each be formed from a fabric (cloth) such as a mesh fabric, a knit
fabric, a woven fabric or a non-woven fabric, for example.
[0115] A plurality of strip-shaped restraining members 34M are
arranged on the medial-side flexible portion 31S of FIG. 1 for
restraining the stretch of the medial-side flexible portion 31S in
the front-rear direction FB. Another plurality of strip-shaped
restraining members 34L are arranged on the lateral-side flexible
portion 32S of FIG. 2 for restraining the stretch of the
lateral-side flexible portion 32S in the front-rear direction
FD.
[0116] The restraining members may be a comb-shaped thin film
bonded or welded (including transfer printing) on the surface of
the mesh fabric.
[0117] In the forefoot portion, including directly above the first
divide portion D1, the flexible portion 385 of the upper 3 is
formed from a low rigidity material, e.g., a cloth-like fabric such
as a mesh fabric, a knit fabric, a woven fabric or a non-woven
fabric, for example. The flexible portion 35 as described above
allows the inclined surface 12F of the second portion 12 to rotate
while moving in an upper-front diagonal direction as shown in FIG.
9.
[0118] Next, a part of a shoe manufacturing process will be
described.
[0119] As shown in FIG. 8, the paddle 5 is adapted to the
engagement portions 11E to 13E, which are depressions in the first,
second and third portions 11 to 13, thereby attaching (bonding) the
paddle 5 to the upper surface of the midsole 1. Thus, the first
portion 11 and the second portion 12 are positioned with respect to
each other, and the second portion 12 and the third portion 13 are
positioned with respect to each other.
[0120] The midsole 1, which is made integral by means of the paddle
5, is bonded to the reverse surface of the insole 4, which is
integral with the upper 3 (not shown; FIG. 1). At this point,
although the insole 4 and the upper 3 are surrounded by a last well
known in the art, the midsole 1 is not divided in the front-rear
direction as described above so that the midsole 1 can easily be
positioned with respect to the insole 4 at the time of bonding.
[0121] Next, the behavior of the forefoot portion of the shoe while
running will be described.
[0122] When not worn (FIG. 2), the first inclined surface 11F and
the second inclined surface 12F of the first divide portion D1 are
partly in contact with each other, and there may be a slight gap
between the first inclined surface 11F and the second inclined
surface 12F of the first divide portion D1 due to manufacturing
errors. However, at the standstill position with the shoe on or at
foot-flat while running, the first inclined surface 11F and the
second inclined surface 12F contact each other with a strong
pressure due to compressive deformation of the midsole 1, etc.
Therefore, it will be possible to stably support the foot.
[0123] At heel-rise, the upper 8 and the main sole MS flex as shown
in FIG. 9, and the second portion 12 is displaced so as to rotate
relative to the first portion 11. As described above, the midsole 1
is attached to the upper 3 via the paddle 5 (FIG. 8). Therefore,
the second portion 12 rotates, relative to the first portion 11,
about the vicinity of the upper end of the first divide portion
D1.
[0124] On the other hand, although the forefoot portion of the
upper 3 is compressed, the flexible portion 385 of the upper 3
directly above, and anterior/posterior to, the first divide portion
D1 of the present embodiment is formed from a flexible material
such as a mesh fabric described above, for example, and the
flexible portion 35 can easily be creased 35W, thereby making it
unlikely that the rotation is inhibited. For example, the flexible
portion 35 has no defined center of flexion, and therefore the
inclined surface 12F of the second portion 12 rotates while moving
in the upper-front diagonal direction in accordance with the
flexion of the foot.
[0125] Next, the structure of the rear foot section of a human will
be described briefly with reference to FIG. 11A to FIG. 12B.
[0126] As shown in FIG. 11A to FIG. 11C, the subtalar joint (STJ)
and the midtarsal joint (MTJ) exist below the ankle. These joints
STJ and MTJ can rotate about the axis Ss and the axis Sm,
respectively. These axes Ss and Sm are orthogonal to intersecting
planes Bs, Bm. The intersecting planes Bs, Bm are inclined planes
that are inclined by about 42.degree. and 15.degree. with respect
to the vertical plane in FIG. 11A and FIG. 11C. The intersecting
planes Bs, Bm are also inclined planes that are inclined by about
20.degree. and 9.degree. with respect to the longitudinal axis of
the foot in FIG. 11B.
[0127] Considering the angles of the intersecting planes, the angle
.alpha.2 formed between the inclined surfaces 12B, 13B of the
second divide portion D2 of FIG. 2 and the vertical plane is
preferably about 5.degree. to 45.degree. on the lateral side of the
foot, more preferably about 10.degree. to 40.degree., and most
preferably about 15.degree. to 35.degree..
[0128] On the other hand, the angle .alpha.1 between the inclined
surfaces 12F, 13F of the first divide portion D1 of FIG. 2 and the
vertical plane is preferably about 20.degree. to 70.degree. on the
lateral side of the foot, more preferably about 25.degree. to
65.degree., and most preferably about 30.degree. to 60.degree..
[0129] Next, the mechanism of the pronation occurring while running
will be described briefly.
[0130] After landing while running, first, the joint STJ of FIG.
11A to FIG. 11C rotates, and the heel thereby pronates as shown in
FIG. 12A. Then, the joint MTJ rotates in conjunction with the
rotation of the joint STJ of FIG. 11A to FIG. 11C, and the lower
leg thereby medially rotates as shown in FIG. 12B. Thus, pronation
occurs. In order to realize movements of joints that are close to
barefoot running, it is believed that there is a need for a shoe
structure that allows, without inhibiting, the action of the joints
STJ, MTJ, the pronation and the internal rotation.
[0131] Next, the behavior of the rear foot portion of the foot
while running will be described.
[0132] In the main sole MS of the embodiment of FIG. 1, the second
divide portion D2 of the rear foot section extends in an upper-rear
diagonal direction, the second divide portion D2 of FIG. 5 includes
the diagonal portion 131 on the lateral side. Therefore,
immediately after landing such as first strike of FIG. 10, the
lower portion of the second divide portion D2 is displaced so as to
open, and it is unlikely to inhibit the action of the joints STJ,
MTJ of FIG. 11A to FIG. 11C, the pronation of FIG. 12A and the
internal rotation of FIG. 12B. Therefore, it is likely to realize
an action of pronation that is proximate to that during barefoot
running.
[0133] On the other hand, immediately after landing, a large impact
load is applied to the third portion 13 of FIG. 10. However, at the
second divide portion D2, the third portion 13 and the second
portion 12 are in contact with each other and are separated from
each other. Therefore, the third portion 13, which is separated
from the second portion 12, will easily deform after landing.
Therefore, a good shock-absorbing property will be realized.
[0134] During the transition from heel-contact of FIG. 10 to
foot-flat of FIG. 2, the second portion 12 is in contact with the
third portion 13. Therefore, the transition will go smoothly. Thus,
it is likely that movements of joints during barefoot running will
be realized.
[0135] Immediately after landing as shown in FIG. 10, the main sole
MS flexes, and the third portion 13 is displaced so as to rotate
relative to the second portion 12. As described above, the midsole
1 is attached to the upper 3 via the paddle 5 (FIG. 8). Therefore,
the third portion 13 rotates, relative to the second portion 12,
about the vicinity of the upper end of the second divide portion
D2.
[0136] On the other hand, as can be seen from a comparison between
FIG. 2 and FIG. 10, at heel-contact immediately after landing, an
area of the upper 3 that is in an upper-rear diagonal direction of
the second divide portion D2 is compressed as the third portion 13
rotates relative to the second portion 12. Since the upper 3 of the
present embodiment includes the flexible portions 328, 31S (FIG.
1), the flexible portions 328, 31S (FIG. 1) of FIG. 2 will easily
contract (creating creases) as shown in FIG. 10. Thus, the rotation
at the second divide portion D2 is unlikely to be inhibited.
[0137] At heel-rise of FIG. 9, the heel of the foot is likely to
rise inside the upper 3. In the present embodiment, while the
flexible portions 328, 31S (FIG. 1) are present, the restraining
members 34L, 34M (FIG. 1) are provided on the flexible portions
328, 31S (FIG. 1). Therefore, it is possible to restrain the
stretch of the flexible portion of the upper 3 at heel-rise, and it
is as a result possible to prevent the heel from rising inside the
upper 3.
[0138] Next, a reference example and test examples will be
illustrated in order to elucidate the advantageous effects of the
present embodiment.
[0139] First, as a reference example, test sample T1 of FIG. 13A
was provided that did not have the divide portions D1, D2. On the
other hand, test samples T2 to T5 of FIG. 13B to FIG. 13E were
provided as test examples.
[0140] In sample T2, the main sole MS is divided along a plane that
is orthogonal to the axis Ss (FIG. 11A). In sample T3, the main
sole MS is divided at four divide portions D1, D2, D11, D21 along
planes that are orthogonal to the axis Ss (FIG. 11A) and the axis
Sm (FIG. 11A). In samples T4 and T5, diagonal flexible portions 33S
are provided on the medial side and the lateral side of the upper 3
so as to function in conjunction with the divide portions D1, D2 of
samples T2 and T3. Note that sample T1 is not provided with the
divide portions and the flexible portions.
[0141] A test experiment was conducted with one subject at a
running speed of 4 min/km. Comparisons were made between running
with shoes of FIG. 13A to FIG. 13E and running barefoot. The
flexion/extension angle of the foot joint was measured while
running, and the ground reaction force was measured in the
front-rear direction and in the vertical direction.
[0142] Then, the maximum propulsion force and the propulsion
impulse (impulse product) were calculated from the angle and the
ground reaction force in the front-rear direction. The values are
shown in FIG. 14A and FIG. 14B. These graphs indicated that samples
T2, T3, T4, T5 having the divide portions, as compared with
barefoot and sample T1, required a greater maximum propulsion force
and a greater propulsion impulse while running at the same
speed.
[0143] FIG. 14C shows a comparison result for the work of the foot
joint required for push-off. As can be seen from the figure, the
amount of work is greater for samples T2, T3, T4, T5 provided with
the divide portions than for barefoot and sample T1. It can be seen
that this resulted in a greater load on the lower leg.
[0144] The reason for such results is assumed to be because the
triceps of the lower leg, which are important for running, are used
more due to the significant decrease in the rigidity of the main
sole MS. Therefore, by running with these shoes on, one can expect
a high effectiveness in training.
[0145] Then, the heel portion pronation angle .beta. and the lower
leg internal rotation angle .gamma. of FIG. 12A and FIG. 12B were
calculated from the flexion/extension angle. The results are shown
in FIG. 15A and FIG. 15B. As a result of comparing the heel portion
pronation angle .beta., it can be seen that sample T1 has a greater
absolute value of the pronation angle .beta. than barefoot, whereas
samples T2, T3, T4, T5 have joint angles closer to barefoot
running. As for the lower leg internal rotation angle .gamma.,
sample T1 has a smaller absolute value of the internal rotation
angle .gamma. than barefoot, whereas samples T2, T3, T4, T5 have
joint angles closer to barefoot running.
[0146] Therefore, it can be seen that with the provision of the
second divide portion D2 of FIG. 10, more preferably with the
provision of the groove 12G and the flexible portions 32S, 31S
(FIG. 1), it is possible to realize a shoe with which joint
movements are closer to barefoot running.
[0147] Then, the value of the impact load was calculated by
dividing the ground reaction force in the vertical direction by the
unit time. The results are shown in FIG. 15C. It can be seen from
the figure that samples T2, T3, T4, T5 have an equivalent
shock-absorbing property to sample T1, and have a good
shock-absorbing property with a smaller impact value than
barefoot.
[0148] Samples T2 to T5 of FIG. 13B to FIG. 13E were produced by
modifying the main sole MS and the upper 3 of existing shoes.
Therefore, they do not have the paddle (FIG. 8).
[0149] A shoe of the present invention may have a structure like
those of samples T2 to T5, or may have a structure of samples T2 to
T5 with the paddle (FIG. 8) added thereto.
[0150] The bridging portions 5F, 5B of the paddle 5 of FIG. 8 may
be separated from each other. However, the paddle 5 being
continuous from the first portion 11 to the third portion 13 has a
greater Young's modulus than the midsole 1, and will be useful as a
reinforcement device of the second portion 12.
[0151] When the paddle 5 of FIG. 8 is provided, the through holes
5H do not need to be provided in the paddle 5. When the through
holes 5H are provided, protruding portions may be formed on the
upper surface of the midsole 1 so as to correspond to the through
holes 5H, so that the upper surface of the midsole 1 in the through
holes 5H is set to be at about the same level (height) as the upper
surface of the paddle 5.
[0152] As in the alternative example of FIG. 16, this shoe may be
provided with grooves Gm arranged in a staggered pattern on the
lower surface of the main sole MS and on the upper surface of the
main sole MS.
[0153] FIG. 17A to FIG. 17D show alternative examples.
[0154] As shown in the examples of these figures, at the divide
portions D1, D2, the sections 11, 12, 18 of the main sole may be in
contact with each other via bridging portions 5F, 5B that are
protruding downward. At the divide portions D1, D2, the bridging
portions 5F, 5B may be such that the midsoles are not in direct
contact with each other, but outsoles are in direct or indirect
contact with each other.
[0155] FIG. 17E to FIG. 17G show other alternative examples.
[0156] In these figures, the upper surface of the midsole 1 is
attached to the lower surface of the insole 4, and the paddle 5
(FIG. 8) is absent. In these cases, the midsoles 1 may be bound
together in areas other than the divide portions D1, D2 via a
bonded or welded attachment portion 19 that is dotted in the
figure. That is, the midsole 1 may form the bridging portions 5F,
5B.
[0157] While preferred embodiments have been described above with
reference to the drawings, various obvious changes and
modifications will readily occur to those skilled in the art upon
reading the present specification.
[0158] For example, the midsole may be provided with gel or
pod-like shock-absorbing parts. The main sole may be formed solely
from a flexible midsole-like material or solely from an
outsole.
[0159] Thus, such changes and modifications are deemed to fall
within the scope of the present invention.
INDUSTRIAL APPLICABILITY
[0160] The present invention is applicable to various shoes for
running, walking, training, etc.
REFERENCE SIGNS LIST
[0161] 1L: Lateral edge, 1M: Medial edge [0162] 12: Rear portion
(second portion), 12B: Inclined surface, 12E: Engagement portion
[0163] 13: Rear end portion (third portion), 13B: Inclined surface,
[0164] 13C: Central portion [0165] 13E: Engagement portion, 131:
Diagonal portion [0166] 3: Upper, 31H: Medial-side high rigidity
portion, 31S: Medial-side flexible portion, 32: Lateral side
surface [0167] 34L: Restraining member, 34M: Restraining member
[0168] 4: Insole, MS: Main sole [0169] 5H: Through hole [0170] D2:
Divide portion, DB: Posterior, DF: Anterior, FB: Front-rear
direction, S: Center axis [0171] VL: Transverse line [0172]
.alpha.: Angle
* * * * *