U.S. patent application number 14/399153 was filed with the patent office on 2015-05-21 for shoe sole having diagonal groove.
This patent application is currently assigned to ASICS CORPORATION. The applicant listed for this patent is Yoshiyasu Ando, Masahiro Fujiwara, Takashi Inomata, Tsuyoshi Nishiwaki. Invention is credited to Yoshiyasu Ando, Masahiro Fujiwara, Takashi Inomata, Tsuyoshi Nishiwaki.
Application Number | 20150135558 14/399153 |
Document ID | / |
Family ID | 48481492 |
Filed Date | 2015-05-21 |
United States Patent
Application |
20150135558 |
Kind Code |
A1 |
Inomata; Takashi ; et
al. |
May 21, 2015 |
Shoe Sole Having Diagonal Groove
Abstract
A shoe sole including: an outsole having a tread surface to be
in contact with a road surface; and a midsole arranged on the
outsole, wherein: the midsole is exposed in a central section of a
rear foot section and an arch section; in the central section and a
lateral side section of the rear foot section of the shoe sole, a
diagonal groove is formed extending in a diagonal front-rear
direction in the rear foot section to an outer edge of a lateral
side of the rear foot section; an angle .beta., formed between a
virtual center line of the diagonal groove and a longitudinal axis
connecting between a center of a heel and a middle point between a
big-toe ball and a little-toe ball, is set in a range of 12.degree.
to 35.degree.; and a virtual intersection point between the
longitudinal axis and the center line is set within a range of 21%
to 43% of a full length of the longitudinal axis of the shoe sole
from a posterior end of the shoe sole, the diagonal groove
extending to a point anterior and medial to the intersection
point.
Inventors: |
Inomata; Takashi; (Kobe-shi,
JP) ; Nishiwaki; Tsuyoshi; (Kobe-shi, JP) ;
Fujiwara; Masahiro; (Kobe-shi, JP) ; Ando;
Yoshiyasu; (Kobe-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Inomata; Takashi
Nishiwaki; Tsuyoshi
Fujiwara; Masahiro
Ando; Yoshiyasu |
Kobe-shi
Kobe-shi
Kobe-shi
Kobe-shi |
|
JP
JP
JP
JP |
|
|
Assignee: |
ASICS CORPORATION
Kobe-shi
JP
|
Family ID: |
48481492 |
Appl. No.: |
14/399153 |
Filed: |
May 10, 2012 |
PCT Filed: |
May 10, 2012 |
PCT NO: |
PCT/JP2012/062010 |
371 Date: |
November 5, 2014 |
Current U.S.
Class: |
36/25R |
Current CPC
Class: |
A43B 13/14 20130101;
A43B 13/141 20130101; A43B 13/223 20130101 |
Class at
Publication: |
36/25.R |
International
Class: |
A43B 13/22 20060101
A43B013/22 |
Claims
1. A shoe sole comprising: an outsole having a tread surface to be
in contact with a road surface; and a midsole arranged on the
outsole, wherein: in a central section and a lateral side section
of a rear foot section of the shoe sole, a diagonal groove is
formed extending in a diagonal front-rear direction in the rear
foot section to an outer edge of a lateral side of the rear foot
section; an angle, formed by a virtual center line of the diagonal
groove and a longitudinal axis connecting between a center of a
heel and a middle point between a big-toe ball and a little-toe
ball, is set in a range of 12.degree. to 35.degree.; and a virtual
intersection point O between the longitudinal axis and the center
line is set within a range of 21% to 43% of a full length of the
longitudinal axis of the shoe sole from a posterior end of the shoe
sole, the diagonal groove extending to a point anterior and medial
to the intersection point.
2. The shoe sole according to claim 1, wherein: the diagonal groove
includes a front section located anterior to the intersection
point, and a rear section located posterior to the intersection
point; and a volume of the diagonal groove in the rear section is
larger than a volume of the diagonal groove in the front
section.
3. The shoe sole according to claim 1, wherein the diagonal groove
is unextended to a medial edge of the shoe sole.
4. The shoe sole according to claim 1, wherein the diagonal groove
of the outsole flares toward a diagonally posterior direction.
5. The shoe sole according to claim 1, further comprising a
transversal groove extending in a direction perpendicular to the
diagonal groove.
6. The shoe sole according to claim 1, wherein: the outsole is
divided into pieces arranged in a front foot section and in the
rear foot section, thereby leaving uncovered an arch section
between the front foot section and the rear foot section; a
reinforcement member formed by a non-foamed body of a resin is
attached on a lower surface of the midsole in the arch section; and
the reinforcement member has a diagonal section extending generally
parallel to the diagonal groove, and the diagonal section is
arranged in a vicinity of the diagonal groove and anterior to the
diagonal groove.
7. A shoe sole comprising: an outsole having a tread surface to be
in contact with a road surface; and a midsole arranged on the
outsole, the shoe sole supporting a foot in a front foot section,
an arch section, and a rear foot section, wherein: the outsole is
divided into pieces arranged in the front foot section and in the
rear foot section, thereby leaving uncovered the arch section, and
is formed in the rear foot section in a U shape, with a central
section cut out between a medial side and a lateral side of the
foot; the midsole is exposed in the arch section and the central
section of the rear foot section; a diagonal groove is formed in
the midsole in the central section of the rear foot section and in
the outsole in a lateral side section of the rear foot section, the
diagonal groove extending in a diagonal front-rear direction in the
rear foot section to an outer edge of the lateral side of the rear
foot section; an angle, formed by a virtual center line of the
diagonal groove and a longitudinal axis connecting between a center
of a heel and a middle point between a big-toe ball and a
little-toe ball, is set in a range of 12.degree. to 35.degree.; and
a virtual intersection point between the longitudinal axis and the
center line is arranged within a region from a rear half section of
the arch section to a front half section of the rear foot
section.
8. The shoe sole according to claim 7, wherein a position of the
virtual intersection point is arranged anterior to a centroid of
the central section.
9. The shoe sole according to claim 8, wherein: the diagonal groove
formed in the midsole in the central section of the rear foot
section is defined by one pair of first and second edge lines and
which face each other; the diagonal groove formed in the outsole is
defined by one pair of third and fourth edge lines and which face
each other; and the third and fourth edge lines and are generally
parallel to the first and second edge lines and, respectively, or
flare to form an angle therebetween larger than an angle formed by
the first and second edge lines and.
10. The shoe sole according to claim 7, wherein: the diagonal
groove extends to a medial side section of the midsole in the arch
section; and an average value of a cross-sectional area
perpendicular to the center line of the diagonal groove in the arch
section is smaller than an average value of a cross-sectional area
perpendicular to the center line of the diagonal groove in the
central section of the rear foot section in the midsole.
11. The shoe sole according to claim 7, wherein: the diagonal
groove is unextended to an edge of the medial side section of the
midsole in the arch section; and a tip of the diagonal groove is
arranged posterior to an anterior end of the arch section.
12. The shoe sole according to claim 7, wherein the diagonal groove
of the outsole flares toward a diagonally posterior direction.
13. The shoe sole according to claim 7, further comprising a
transversal groove perpendicular to the diagonal groove.
14. The shoe sole according to claim 7, wherein: a reinforcement
member formed by a non-foamed body of a resin is attached to a
lower surface of the midsole in the arch section; and the
reinforcement member has a diagonal section extending generally
parallel to the diagonal groove, and the diagonal section is
arranged in a vicinity of the diagonal groove and anterior to the
diagonal groove.
15. The shoe sole according to claim 14, wherein: the diagonal
section extends to the front foot section.
16. The shoe sole according to claim 15, wherein: the reinforcement
member further includes a lateral side section extending along a
lateral edge of the midsole in the arch section; and the lower
surface of the midsole is exposed between the lateral side section
and the diagonal section.
17. A shoe sole comprising: an outsole having a tread surface to be
in contact with a road surface; and a midsole arranged on the
outsole, the shoe sole supporting a foot in a front foot section,
an arch section, and a rear foot section, wherein: the outsole is
divided into pieces arranged in the front foot section and in the
rear foot section, thereby leaving uncovered the arch section; a
diagonal groove is formed in the midsole and the outsole, the
diagonal groove extending in a diagonal front-rear direction in the
rear foot section to an outer edge of a lateral side of the rear
foot section; an angle, formed by a virtual center line of the
diagonal groove and a longitudinal axis connecting between a center
of a heel and a middle point between a big-toe ball and a
little-toe ball, is set in a range of 12.degree. to 35.degree.; a
virtual intersection point between the longitudinal axis and the
center line is arranged within a region from a rear half section of
the arch section to a front half section of the rear foot section;
a reinforcement member formed by a non-foamed body of a resin is
attached on a lower surface of the midsole in the arch section; and
the reinforcement member has a diagonal section extending generally
parallel to the diagonal groove, and the diagonal section is
arranged in a vicinity of the diagonal groove and anterior to the
diagonal groove.
18. The shoe sole according to claim 17, wherein the diagonal
section extends to the front foot section.
19. The shoe sole according to claim 18, wherein: the reinforcement
member further includes a lateral side section extending along a
lateral side of the midsole in the arch section; and the lower
surface of the midsole is exposed between the lateral side section
and the diagonal section.
Description
TECHNICAL FIELD
[0001] The present invention relates to a shoe sole having a
diagonal groove.
BACKGROUND ART
[0002] Shoe soles having a diagonal groove are known in the art.
(the first patent document)
CITATION LIST
Patent Literature
[0003] First Patent Document: JP 2008-620 A (FIG. 4, FIG.
10(b))
[0004] Second Patent Document: JP H07-236503 A
SUMMARY OF INVENTION
[0005] As is well known in the art, a shoe sole is required to be
light in weight, be capable of suppressing eversion of the heel
area, and serve to absorb the impact on the heel area.
[0006] However, these functions cannot be realized sufficiently
only by forming a diagonal groove in a shoe sole.
[0007] It is therefore an object of the present invention to form
an appropriate diagonal groove so as to realize these
functions.
[0008] The present invention in one aspect is a shoe sole
including:
[0009] an outsole 1 having a tread surface to be in contact with a
road surface; and a midsole 2 arranged on the outsole 1,
wherein:
[0010] in a central section and a lateral side section of a rear
foot section R of the shoe sole, a diagonal groove 4 is formed
extending in a diagonal front-rear direction in the rear foot
section R to an outer edge of a lateral side of the rear foot
section R;
[0011] an angle .beta., formed by a virtual center line Lc of the
diagonal groove 4 and a longitudinal axis A2 connecting between a
center O4 of a heel and a middle point O3 between a big-toe ball O1
and a little-toe ball O5, is set in a range of 12.degree. to 35';
and
[0012] a virtual intersection point O between the longitudinal axis
A2 and the center line Lc is set within a range of 21% to 43% of a
full length of the longitudinal axis A2 of the shoe sole from a
posterior end of the shoe sole, the diagonal groove 4 extending to
a point anterior and medial to the intersection point O.
[0013] The present invention in another aspect is a shoe sole
including: an outsole 1 having a tread surface to be in contact
with a road surface; and a midsole 2 arranged on the outsole 1, the
shoe sole supporting a foot in a front foot section F, an arch
section M, and a rear foot section R, wherein:
[0014] the outsole 1 is divided into pieces arranged in the front
foot section F and in the rear foot section R, thereby leaving
uncovered the arch section M, and is formed in the rear foot
section R in a U shape, with a central section Rc cut out between a
medial side IN and a lateral side OUT of the foot;
[0015] the midsole 2 is exposed in the arch section M and the
central section Rc of the rear foot section R;
[0016] a diagonal groove 4 is formed in the midsole 2 in the
central section Rc of the rear foot section R and in the outsole 1
in a lateral side section 11 of the rear foot section R, the
diagonal groove 4 extending in a diagonal front-rear direction in
the rear foot section R to an outer edge of the lateral side OUT of
the rear foot section R;
[0017] an angle .beta., formed by a virtual center line Lc of the
diagonal groove 4 and a longitudinal axis A2 connecting between a
center O5 of a heel and a middle point O3 between a big-toe ball O1
and a little-toe ball O2, is set in a range of 12.degree. to
35.degree.; and
[0018] a virtual intersection point O between the longitudinal axis
A2 and the center line Lc is arranged within a region from a rear
half section Mb of the arch section M to a front half section Rf of
the rear foot section R.
[0019] Eversion of the heel area occurs as the foot is rotated
(twisted) about the subtalar joint axis A1. The subtalar joint axis
A1 is diagonally inclined, in the horizontal plane, with respect to
the anatomical longitudinal axis A2 of the foot section. According
to V. T Inman (1969), the inclination angle is 23.degree. on
average, and varies over a range of about .+-.11.degree. due to
individual differences. Therefore, for suppressing eversion of the
heel area, it is important to keep the torsional rigidity of the
sole so as to reduce the rotation about the subtalar joint axis A1,
which is inclined by 23.degree..+-.11.degree..
[0020] Typically, even if a groove is present along the torsional
axis, it does not substantially change the torsional rigidity about
the axis from that when such a groove is absent. Thus, in the
present invention, the presence of the diagonal groove 4 does not
substantially lower the rigidity about the subtalar joint axis A1,
and maintains stability against twisting.
[0021] However, it is very difficult to identify the position of
the subtalar joint axis A1 from the shape of the sole. Therefore,
according to the present invention, the invention is not defined by
the subtalar joint axis A1, but is defined by the position of the
diagonal groove 4 with respect to the sole, i.e., the position of
the intersection point O.
[0022] That is, in one aspect, the position of the intersection
point O is defined by the dimension from the posterior end of the
shoe sole, and in another aspect, the position of the intersection
point O is defined by the position in the arch section M and the
rear foot section R of the shoe sole.
[0023] In the present specification, the arch section M refers to a
middle foot area where the outsole 1 is absent, and the rear foot
section R refers to an area posterior to the arch section M.
[0024] In the present invention, the diagonal groove 4 reaches the
outer periphery of the sole on the lateral posterior side.
Therefore, it is believed that the compressive rigidity of the sole
on the lateral posterior side lowers. While the heel contacts the
ground from the lateral posterior side, it is expected that the
lateral posterior side largely deforms in compressive deformation,
thereby inclining the sole upper surface immediately after the heel
contacts the ground, as compared with a case where the diagonal
groove 4 is absent. This inclination is an inclination opposite to
eversion, and therefore the angle of eversion of the heel area will
be smaller as compared with a case where the diagonal groove 4 is
absent.
[0025] The substantial deformation of the lateral posterior side
also improves the impact-absorbing property.
[0026] The weight of the sole is reduced through the provision of
the diagonal groove 4 extending along the subtalar joint axis A1,
in addition to the outsole 1 being cut out in the central section
Rc and absent in the arch section M.
[0027] Therefore, it is possible to suppress eversion of the heel
area and improve the impact absorption for the heel area, while
realizing a light weight.
[0028] Now, with the claimed arrangement of the diagonal groove 4,
the diagonal groove 4 extends diagonally across the lateral side of
the rear foot section of the outsole 1 having a U shape (horseshoe
shape) at an angle .beta. of 12.degree. to 35.degree.. Therefore,
the length of the diagonal groove 4 is large on the lateral side of
the outsole 1, which has a U shape and has a small area. That is, a
long diagonal groove 4 is formed in the outsole 1, which has a U
shape and has a small area. Therefore, it has a light weight, and
provides the highly advantageous effect of suppressing eversion and
absorbing impact.
[0029] The angle .beta. should in principle be set to 23.degree.,
but with 23.degree., the anterior end of the diagonal groove 4
would extend toward the vicinity of the big-toe ball O1, thereby
forming the diagonal groove 4 on the medial side of the front foot
section F. In order to avoid this, the angle .beta. may be
preferably about 20.degree. to 35.degree.. Note that the angle
.beta. is defined to be less than or equal to 35.degree., which is
1.degree. greater than 23.degree.+11.degree.=34.degree., taking
measurement errors into consideration.
[0030] Since the outsole 1 has a U shape in which the central
section Rc of the rear foot section R is cut out, the weight is
reduced also because of the cutting out of the central section Rc.
Now, the diagonal groove 4 is formed in the midsole 2 in the
central section Rc. This also reduces the weight of the midsole 2
while the midsole 2 still contributes to the torsional
rigidity.
BRIEF DESCRIPTION OF DRAWINGS
[0031] FIG. 1 is a perspective view showing a shoe according to one
embodiment of the present invention as seen from the bottom rear
side.
[0032] FIG. 2 is a perspective view showing the shoe as seen from
the bottom lateral side.
[0033] FIG. 3 is a bottom view showing a shoe sole.
[0034] FIG. 4 is a bottom view showing the shoe sole.
[0035] FIG. 5 is an enlarged bottom view showing an arch section
and a rear foot section of the shoe sole.
[0036] FIG. 6 is a plan view showing the foot bone structure.
[0037] FIG. 7A is a cross-sectional view taken along line VIIA-VIIA
of FIG. 3, and FIG. 7B is a cross-sectional view taken along line
VIIB-VIIB of FIG. 3.
[0038] FIGS. 8A to 8C show another embodiment, wherein FIG. 8A is a
cross-sectional view showing a shoe sole in the arch section, FIG.
8B is a cross-sectional view of the shoe sole in the front half
section of the rear foot section, and FIG. 8C is a cross-sectional
view of the shoe sole at the posterior end of the rear foot
section.
[0039] FIG. 9 is a bottom view of a shoe sole illustrating still
another embodiment.
DESCRIPTION OF EMBODIMENTS
[0040] Preferably, the diagonal groove 4 includes a front section
4F located anterior to the intersection point O, and a rear section
4B located posterior to the intersection point O; and a volume of
the diagonal groove 4 in the rear section 4B is larger than a
volume of the diagonal groove 4 in the front section 4F.
[0041] Then, in the rear section 4B where the volume of the
diagonal groove 4 is large, deformation is relatively substantial,
and the upper surface of the midsole 2 easily sinks, thereby making
it possible to easily absorb the impact of the first strike upon
landing. On the other hand, in the front section 4F where the
volume of the diagonal groove 4 is small, the upper surface of the
midsole 2 less easily sinks, and the center of gravity is unlikely
to remain stagnant on the medial side of the arch of the foot.
[0042] Preferably, the diagonal groove 4 does not extend to a
medial edge of the shoe sole.
[0043] Then, the upper surface of the midsole 2 less easily sinks
in the arch section M or the middle foot section.
[0044] Preferably, the diagonal groove 4 of the outsole 1 flares
toward a diagonally posterior direction (widens in its width as it
extends in a diagonally posterior direction).
[0045] Then, it is possible to easily absorb the impact of the
first strike as described above, and the center of gravity is
unlikely to remain stagnant on the medial side of the arch of the
foot.
[0046] Preferably, the shoe sole further includes a transversal
groove 5 extending in a direction perpendicular to the diagonal
groove 4.
[0047] Such a transversal groove 5 will divide the outsole 1 into
pieces on the lateral side of the foot, and will facilitate the
deformation of the outsole 1 and the midsole 2 on the lateral side
of the foot.
[0048] Preferably, the outsole 1 is divided into pieces arranged in
a front foot section F and in the rear foot section R, thereby
leaving uncovered an arch section M between the front foot section
F and the rear foot section R;
[0049] a reinforcement member 3 formed by a non-foamed body of a
resin is attached on a lower surface of the midsole 2 in the arch
section M; and
[0050] the reinforcement member 3 has a diagonal section 31
extending generally parallel to the diagonal groove 4, and the
diagonal section 31 is arranged in a vicinity of the diagonal
groove 4 and anterior to the diagonal groove 4.
[0051] In this case, the lowering of the arch section M due to the
diagonal groove 4 in the arch section M or in the vicinity of the
arch section M will be prevented by the diagonal section 31 of the
reinforcement member 3.
[0052] Preferably, a position of the virtual intersection point O
is arranged anterior to a centroid G of the central section Rc.
[0053] With such an arrangement, the diagonal groove 4 is arranged
over, or in the vicinity of, the subtalar joint axis A1.
[0054] Preferably, the diagonal groove 4 formed in the midsole 2 in
the central section Rc of the rear foot section R is defined by one
pair of first and second edge lines L1 and L2 which face each
other;
[0055] the diagonal groove 4 formed in the outsole 1 is defined by
one pair of third and fourth edge lines L3 and L4 which face each
other; and
[0056] the third and fourth edge lines L3 and L4 are generally
parallel to the first and second edge lines L1 and L2,
respectively, or flare (gradually widen therebetween) to form an
angle therebetween larger than an angle formed by the first and
second edge lines L1 and L2.
[0057] In this case, the diagonal groove 4 of the midsole 2 and
that of the outsole 1 cooperate with each other, thereby enhancing
the advantageous effect of the present invention.
[0058] Preferably, the diagonal groove 4 extends to a medial side
section 20 of the midsole 2 in the arch section M; and an average
value of a cross-sectional area perpendicular to the center line Lc
of the diagonal groove 4 in the arch section M is smaller than an
average value of a cross-sectional area perpendicular to the center
line Lc of the diagonal groove 4 in the central section Rc of the
rear foot section R in the midsole 2.
[0059] Preferably, the diagonal groove 4 does not extend to an edge
of the medial side section 20 of the midsole 2 in the arch section
M; and a tip of the diagonal groove 4 is arranged posterior to an
anterior end of the arch section M.
[0060] In these cases, the cross-sectional area of the diagonal
groove 4 is small on the medial side of the arch section M, or the
diagonal groove 4 does not extend to the medial edge of the arch
section M, so that the sinking of the upper surface of the midsole
is small on the medial side of the arch section M. Therefore, it is
possible to suppress pronation of the foot, and to prevent the
center of gravity from remaining stagnant on the medial side of the
arch section M.
[0061] Preferably, the diagonal groove 4 of the outsole 1 flares
toward a posterior direction (widens in its width as it extends in
a posterior direction).
[0062] Preferably, the shoe sole further includes a transversal
groove perpendicular to the diagonal groove 4.
[0063] Preferably, a reinforcement member 3 formed by a non-foamed
body of a resin is attached to a lower surface of the midsole 2 in
the arch section M; and
[0064] the reinforcement member 3 has a diagonal section 31
extending generally parallel to the diagonal groove 4, and the
diagonal section 31 is arranged in a vicinity of the diagonal
groove 4 and anterior to the diagonal groove 4.
[0065] In this case, the lowering of the arch section M due to the
diagonal groove 4 in the arch section M or in the vicinity of the
arch section M will be prevented by the diagonal section 31 of the
reinforcement member 3.
[0066] Preferably, the diagonal section 31 extends to the front
foot section F.
[0067] In this case, excessive bending of the sole is prevented,
thereby enabling efficient running.
[0068] Preferably, the reinforcement member 3 further includes a
lateral side section 32 extending along a lateral edge of the
midsole 2 in the arch section M; and
[0069] the lower surface of the midsole 2 is exposed between the
lateral side section 32 and the diagonal section 31.
[0070] In this case, it is possible to reduce the weight of the
reinforcement member 3.
[0071] The present invention in one aspect is a shoe sole
including: an outsole 1 having a tread surface to be in contact
with a road surface; and a midsole 2 arranged on the outsole 1, the
shoe sole supporting a foot in a front foot section F, an arch
section M, and a rear foot section R, wherein:
[0072] the outsole 1 is divided into pieces arranged in the front
foot section F and in the rear foot section R, thereby leaving
uncovered the arch section M;
[0073] a diagonal groove 4 is formed in the midsole 2 and the
outsole 1, the diagonal groove 4 extending in a diagonal front-rear
direction in the rear foot section R to an outer edge of a lateral
side of the rear foot section R;
[0074] an angle .beta., formed by a virtual center line Lc of the
diagonal groove 4 and a longitudinal axis A2 connecting between a
center of a heel and a middle point O3 between a big-toe ball O1
and a little-toe ball O5, is set in a range of 12.degree. to
35.degree.;
[0075] a virtual intersection point O between the longitudinal axis
A2 and the center line Lc is arranged within a region from a rear
half section Mb of the arch section M to a front half section Rf of
the rear foot section R;
[0076] a reinforcement member 3 formed by a non-foamed body of a
resin is attached on a lower surface of the midsole 2 in the arch
section M; and
[0077] the reinforcement member 3 has a diagonal section 31
extending generally parallel to the diagonal groove 4, and the
diagonal section 31 is arranged in a vicinity of the diagonal
groove 4 and anterior to the diagonal groove 4.
[0078] In this aspect, the lowering of the arch section M due to
the diagonal groove 4 in the arch section M or in the vicinity of
the arch section M will be prevented by the diagonal section 31 of
the reinforcement member 3.
[0079] Preferably, the diagonal section 31 extends to the front
foot section F.
[0080] In this case, excessive bending of the sole is prevented,
thereby enabling efficient running.
[0081] Preferably, the reinforcement member 3 further includes a
lateral side section 32 extending along a lateral side of the
midsole 2 in the arch section M; and
[0082] the lower surface of the midsole 2 is exposed between the
lateral side section 32 and the diagonal section 31.
[0083] In this case, it is possible to reduce the weight of the
reinforcement member 3.
EMBODIMENT
[0084] 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 relied upon in defining 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.
[0085] One embodiment of the present invention will now be
described with reference to the drawings.
[0086] As shown in FIGS. 1 and 2, the shoe sole includes the
outsole 1 and the midsole 2. Note that FIGS. 1 to 5 do not show
small grooves (so called "design") formed in the tread surface of
the outsole 1.
[0087] As indicated by the regular dots in FIG. 3, the outsole 1 is
arranged over the front foot section F and the rear foot section R.
The outsole 1 is formed by a foamed body or a non-foamed body of a
rubber, for example, and has a tread surface is (FIG. 7A) to be in
contact with the road surface. Note that in FIG. 3, the outsole 1
is shaded with regular large dots.
[0088] The midsole 2 is formed by a foamed body of a resin such as
EVA, for example, and is arranged on the outsole 1, as shown in
FIG. 2, for absorbing the impact upon landing. Therefore, the
midsole 2 is formed to be thicker than the outsole 1.
[0089] As shown in FIGS. 1 to 3, a lower surface 2u (FIG. 7A) of
the midsole 2 is provided with the diagonal groove 4 and the
transversal groove 5 to be described later, and with the outsole 1
divided into a plurality of parts. As shown in these figures, the
midsole 2 may be exposed in the central section Rc of the rear foot
section R and/or the arch section M.
[0090] As clearly shown in FIG. 3, the outsole 1 is divided into
pieces arranged in the front foot section F and in the rear foot
section R, thereby leaving uncovered the arch section M, and is
formed in the rear foot section R in a U shape in which the central
section Rc is cut out. That is, in the central section Rc of the
rear foot section R, the outsole 1 is not provided on the surface
of the midsole 2.
[0091] Here, "a U shape in which the central section Rc of the
outsole 1 is cut out" includes arrangements where the outsole 1 is
divided into a plurality of parts in the rear foot section R by a
plurality of diagonal and transversal grooves 4 and 5, and further
means that the outsole 1 is absent in the central section Rc and
that the outsole 1 at the anterior end of the rear foot section R
is divided into medial and lateral pieces by the diagonal groove
4.
[0092] Note that in the elliptical area of the central section Rc,
the midsole 2 may be slightly dented.
[0093] In FIGS. 1 to 3, the bottom surfaces of the diagonal groove
4 and the transversal groove 5 are shaded with irregular, fine
dots.
[0094] In the medial side section 20 of the arch section M of the
midsole 2, the central section Rc of the rear foot section R of the
midsole 2, and the lateral side section 11 of the outsole 1, the
diagonal groove 4 extends in a diagonal front-rear direction from
the medial edge on the medial side IN of the arch section M to the
lateral edge on the lateral side OUT of the rear foot section
R.
[0095] The depth of the deepest portion of the diagonal groove 4 in
the central section Rc is preferably about 5 mm to about 10 mm, for
example, and the depth of the deepest portion of the diagonal
groove 4 in the lateral side section 11 is preferably about 5 mm to
about 15 mm, for example. This is because the advantageous effects
such as the light weight cannot be obtained sufficiently if the
depth is too small, whereas the stable foot support cannot be
obtained if the depth is too large.
[0096] The width of the diagonal groove 4 in the central section Rc
is preferably about 5 mm to about 15 mm, for example, except for
the area of the transversal groove 5. The torsional rigidity lowers
significantly if the width of the groove is too large, whereas the
advantageous effects such as the light weight cannot be obtained if
the width of the groove is small.
[0097] As shown in FIG. 9, the diagonal groove 4 does not need to
extend to the medial edge on the medial side IN in the arch section
M. Where the diagonal groove 4 does not extend to the medial side
section 20 of the midsole 2 in the arch section M, the anterior end
of the diagonal groove 4 may be arranged posterior to the arch
section M or the anterior end of the rear foot section R.
[0098] Referring to FIG. 6, the angle .alpha. formed between the
subtalar joint axis A1 and the longitudinal axis A2 is said to be
23.degree..+-.11.degree.. Now, the longitudinal axis A2 is
represented by a straight line connecting between the center O4 of
the heel and the middle point P3 between the center of the big-toe
ball O1 and the center of the little-toe ball O5.
[0099] On the other hand, the subtalar joint axis A1 is represented
by a straight line connecting between the head O6 of the talus and
the calcaneus lateral tubercle O7.
[0100] The diagonal groove 4 is formed along the subtalar joint
axis A1. That is, in FIG. 5, the angle .beta. formed by the
longitudinal axis A2 and the virtual center line Lc of the diagonal
groove 4 is set in the range of 12.degree. to 35.degree., and is
set to about 30.degree. in the present embodiment, for example.
[0101] The virtual intersection point O between the center line Lc
and the longitudinal axis A2 is set in a region from the rear half
section of the arch section M to the front half section Rf of the
rear foot section R. Represented by a dimensional proportion, the
virtual intersection point O of FIG. 5 is set in a range of 21% to
43% of the full length of the longitudinal axis A2 of the shoe sole
from the posterior end. The diagonal groove 4 extends anterior and
medial to the intersection point O and extends posterior and
lateral to the intersection point O.
[0102] In the present embodiment, the position of the virtual
intersection point O is provided in the central section Rc of the
rear foot section R, and is arranged anterior to the centroid G of
the central section Rc. With such an arrangement, the diagonal
groove 4 is arranged over the subtalar joint axis A1 (FIG. 6). Note
that the centroid G refers to the center of the planar shape of the
central section Rc.
[0103] The diagonal groove 4 includes the front section 4F anterior
to the intersection point O, and the rear section 4B posterior to
the intersection point O. The volume Vb of the diagonal groove 4 in
the rear section 4B is greater than the volume Vf of the diagonal
groove 4 in the front section 4F.
[0104] Now, the volume Vb, Vf of the diagonal groove 4 is the
cross-sectional area of the diagonal groove 4 multiplied by the
length of the diagonal groove 4 across the corresponding section.
Therefore, the diagonal groove 4 in the arch section M is shallow,
for example, and the average value of the cross-sectional area
perpendicular to the center line Lc is as shown in FIGS. 8A to 8C,
where the average value of the cross-sectional area of the diagonal
groove 4 in the arch section M is smaller than the average value of
the cross-sectional area of the diagonal groove 4 in the central
section Rc of the rear foot section R of the midsole 2.
[0105] In the present embodiment, the depth of the diagonal groove
4 in the arch section M of FIG. 2 gradually decreases as the groove
4 extends in the diagonally anterior direction. The cross-sectional
area of the diagonal groove 4 may be largest in the central section
Rc of the rear foot section R of FIG. 7A, and the cross-sectional
area of the diagonal groove 4 may be slightly smaller in a rear
portion of the rear foot section R of FIG. 7B.
[0106] In FIG. 5, the diagonal groove 4 formed in the central
section Rc of the rear foot section R of the midsole 2 is defined
by one pair of first and second edge lines L1 and L2 which are
parallel to and facing each other. On the other hand, the diagonal
groove 4 formed in the outsole 1 is defined by one pair of third
and fourth edge lines L3 and L4 which are parallel to and facing
each other.
[0107] While the third and fourth edge lines L3 and L4 are
generally parallel to the first and second edge lines L1 and L2,
respectively, in the present embodiment, the third and fourth edge
lines L3 and L4 may be formed to flare (gradually widen in width
therebetween) with an angle greater than the angle formed by the
first and second edge lines L1 and L2 as shown in FIG. 9. That is,
the diagonal groove 4 in the lateral side section 11 of the outsole
1 may be formed to flare toward the diagonally posterior
direction.
[0108] While the transversal groove 5 of FIG. 5 extends in a
direction perpendicular to the diagonal groove 4, and the
transversal groove 5 is arranged so as to be perpendicular to the
diagonal groove 4 in the present embodiment, the angle formed
between the transversal groove 5 and the diagonal groove 4 may be
set to about 70.degree. to about 90.degree..
[0109] The transversal groove 5 divides the outsole 1 into pieces
in the medial side section 10 and in the lateral side section 11 of
the U-shaped outsole 1. Note that as shown in FIG. 9, the
transversal groove 5 may be formed to flare (gradually widen) in
the direction from the medial side IN toward the lateral side
OUT.
[0110] As indicated by the dots in FIG. 4, the reinforcement member
3 formed by a non-foamed body of a resin is attached on the lower
surface of the midsole 2 in the arch section M. The reinforcement
member 3 has the diagonal section 31 extending generally parallel
to the diagonal groove 4, and the diagonal section 31 is arranged
in the vicinity of the diagonal groove 4 and anterior to the
diagonal groove 4. The diagonal section 31 may be extending from
the arch section M to at least the posterior end of the front foot
section F.
[0111] The reinforcement member 3 further includes the lateral side
section 32 extending along the lateral side of the midsole 2 in the
arch section M. An exposed section 22, which is the lower surface
of the midsole 2, is exposed between the lateral side section 32
and the diagonal section 31.
[0112] A connecting section 33 is provided to bridge between the
diagonal section 31 and the lateral side section 32 so as to
connect between these sections 31 and 32. That is, the exposed
section 22 of the midsole 2 is exposed in the area surrounded by
the diagonal section 31, the lateral side section 32 and the
connecting section 33.
[0113] The diagonal section 31 only needs to be arranged along the
diagonal groove 4 above the diagonal groove 4, and therefore even a
reinforcement member 3 that covers generally the entire area of the
arch section M, as shown in FIG. 9, has a diagonal section 31.
[0114] 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.
[0115] For example, the outsole 1 may be provided generally over
the entire length from the front foot section F to the rear foot
section R and across the entire area thereof. Moreover, in the arch
section M or the rear foot section R, the midsole 2 may not be
exposed. The reinforcement member 3 and the transversal groove 5
may be absent.
[0116] Thus, such changes and modifications are deemed to fall
within the scope of the present invention, which is defined by the
appended claims.
INDUSTRIAL APPLICABILITY
[0117] The present invention is applicable to various athletic
shoes such as for running.
REFERENCE SIGNS LIST
[0118] 1: Outsole 1s: Tread surface 10: Medial side section 11:
Lateral side section [0119] 2: Midsole 2u: Lower surface 20: Medial
side section 22: Exposed section [0120] 3: Reinforcement member 31:
Diagonal section 32: Lateral side section 33: Connecting section
[0121] 4: Diagonal groove 4F: Front section 4B: Rear section [0122]
5: Transversal groove [0123] A1: Subtalar joint axis A2:
Longitudinal axis [0124] Lc: Center line L1 to L4: First to fourth
lines [0125] F: Front foot section [0126] R: Rear foot section Rc:
Central section Rf Front half section [0127] M: Arch section Mb:
Rear half section [0128] O: Intersection point [0129] O1: Big-toe
ball O2: little-toe ball, [0130] IN: Medial side OUT: Lateral side
[0131] .alpha., .beta.: Angle
* * * * *