U.S. patent application number 11/257830 was filed with the patent office on 2006-02-16 for shoe sole with rounded inner and outer surfaces.
Invention is credited to Frampton E. III Ellis.
Application Number | 20060032086 11/257830 |
Document ID | / |
Family ID | 22903192 |
Filed Date | 2006-02-16 |
United States Patent
Application |
20060032086 |
Kind Code |
A1 |
Ellis; Frampton E. III |
February 16, 2006 |
Shoe sole with rounded inner and outer surfaces
Abstract
An athletic shoe sole for a shoe has side portions with
concavely rounded inner and outer surfaces, as viewed in at least a
heel area and a midtarsal area of the sole. The concavely rounded
portion of the sole outer surface located at the heel area extends
substantially continuously through a sidemost part of the sole
side. The rounded portion of the sole outer surface located at the
midtarsal area extends up the sole side to at least a level
corresponding to a lowest point of the sole inner surface. A
midsole component of the shoe sole extends into the sidemost
section of the sole side and also extends up the sole side to above
a level corresponding to a lowest point of the sole inner surface.
The concavely rounded portions of the sole midtarsal area are
located at least at the sole lateral side. The sole outer surface
of at least part of the midtarsal area is substantially convexly
rounded, as viewed in a shoe sole sagittal plane.
Inventors: |
Ellis; Frampton E. III;
(Arlington, VA) |
Correspondence
Address: |
KNOBLE, YOSHIDA & DUNLEAVY
EIGHT PENN CENTER
SUITE 1350, 1628 JOHN F KENNEDY BLVD
PHILADELPHIA
PA
19103
US
|
Family ID: |
22903192 |
Appl. No.: |
11/257830 |
Filed: |
October 25, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10291319 |
Nov 8, 2002 |
|
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11257830 |
Oct 25, 2005 |
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08477640 |
Jun 7, 1995 |
6629376 |
|
|
10291319 |
Nov 8, 2002 |
|
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|
08162962 |
Dec 8, 1993 |
5544429 |
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08477640 |
Jun 7, 1995 |
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07930469 |
Aug 20, 1992 |
5317819 |
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08162962 |
Dec 8, 1993 |
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07239667 |
Sep 2, 1988 |
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07930469 |
Aug 20, 1992 |
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Current U.S.
Class: |
36/25R |
Current CPC
Class: |
A43B 13/146 20130101;
A43B 13/141 20130101; A43B 13/148 20130101; A43B 13/145 20130101;
A43B 13/125 20130101; A43B 13/143 20130101; A43B 13/14 20130101;
A43B 5/06 20130101; A43B 5/00 20130101 |
Class at
Publication: |
036/025.00R |
International
Class: |
A43B 13/14 20060101
A43B013/14 |
Claims
1. A shoe sole construction for a shoe, such as a running shoe,
comprising: a sole having a sole portion, a uniform frontal plane
thickness, and a naturally-contoured side portion merging with at
least a portion of said sole portion and conforming substantially
to the shape of the associated edges of the foot; said sole portion
including a foot support surface; said naturally-contoured side
portion being defined at least in part by a curved surface defined
by a locus of points determined by the uniform frontal plane
thickness of said sole portion and extending vertically beyond an
upper plane of a foot supporting surface of said sole portion.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This invention is a continuation of U.S. patent application
Ser. No. 10/291,319; filed Nov. 8, 2002, currently pending; which
is a continuation of U.S. patent application Ser. No. 08/477,640,
filed Jun. 7, 1995, now U.S. Pat. No. 6,629,376, which is a
continuation of U.S. patent application Ser. No. 08/162,962, filed
Dec. 8, 1993, now U.S. Pat. No. 5,544,429, which is a continuation
of U.S. patent application Ser. No. 07/930,469, filed Aug. 20,
1992, now U.S. Pat. No. 5,317,819, which is a continuation of U.S.
patent application Ser. No. 07/239,667, filed Sep. 2, 1988, now
abandoned.
BACKGROUND OF THE INVENTION
[0002] This invention relates to a shoe, such as a street shoe,
athletic shoe, and especially a running shoe with a contoured sole.
More particularly, this invention relates to a novel contoured sole
design for a running shoe which improves the inherent stability and
efficient motion of the shod foot in extreme exercise. Still more
particularly, this invention relates to a running shoe wherein the
shoe sole conf6rms to the natural shape of the foot, particularly
the sides, and has a constant thickness in frontal plane cross
sections, permitting the foot to react naturally with the ground as
it would if the foot were bare, while continuing to protect and
cushion the foot.
[0003] By way of introduction, barefoot populations universally
have a very low incidence of running "overuse" injuries, despite
very high activity levels. In contrast, such injuries are very
common in shoe shod populations, even for activity levels well
below "overuse". Thus, it is a continuing problem with a shod
population to reduce or eliminate such injuries and to improve the
cushioning and protection for the foot. It is an understanding of
the reasons for such problems, and proposing a novel solution to
the problems, to which this improved shoe is directed.
[0004] A wide variety of designs are available for running shoes
which are intended to provide stability, but which lead to a
constraint in the natural efficient motion of the foot and ankle.
However, such designs which can accommodate free, flexible motion
in contrast create a lack of control or stability. A popular
existing shoe design incorporates an inverted, outwardly-flared
shoe sole wherein the ground engaging surface is wider than the
heel engaging portion. However, such shoes are unstable in extreme
situations because the shoe sole, when inverted or on edge,
immediately becomes supported only by the sharp bottom sole edge.
The entire weight of the body, multiplied by a factor of
approximately three at running peak, is concentrated at the sole
edge. Since an unnatural lever arm and a force moment are created
under such conditions, the foot and ankle are destabilized. When
the destabilization is extreme, beyond a certain point of rotation
about the pivot point of the shoe sole edge, ankle strain occurs.
In contrast, the unshod foot is always in stable equilibrium
without a comparable lever arm or force moment. At its maximum
range of inversion motion, about 20.degree., the base of support on
the barefoot heel actually broadens substantially as the calcaneal
tuberosity contacts the ground. This is in contrast to the
conventionally available shoe sole bottom which maintains a sharp,
unstable edge.
[0005] It is thus an overall objective of this invention to provide
a novel shoe design which approximates the barefoot. It has been
discovered, by investigating the most extreme range of ankle motion
to near the point of ankle sprain, that the abnormal motion of an
inversion ankle sprain, which is a tilting to the outside or an
outward rotation of the foot, is accurately simulated while
stationary. With this observation, it can be seen that the extreme
range stability of the conventionally shod foot is distinctly
inferior to the barefoot and that the shoe itself creates a gross
instability which would otherwise not exist.
[0006] Even more important, a normal barefoot running motion, which
approximately includes a 7.degree. inversion and a
7.degree.eversion motion, does not occur with shod feet, where a
30.degree. inversion and eversion is common. Such a normal barefoot
motion is geometrically unattainable because the average running
shoe heel is approximately 60% larger than the width of the human
heel. As a result, the shoe heel and the human heel cannot pivot
together in a natural manner; rather, the human heel has to pivot
within the shoe but is resisted from doing so by the shoe heel
counter, motion control devices, and the lacing and binding of the
shoe upper, as well as various types of anatomical supports
interior to the shoe.
[0007] Thus, it is an overall objective to provide an improved shoe
design which is not based on the inherent contradiction present in
current shoe designs which make the goals of stability and
efficient natural motion incompatible and even mutually exclusive.
It is another overall object of the invention to provide a new
contour design which simulates the natural barefoot motion in
running and thus avoids the inherent contradictions in current shoe
designs.
[0008] It is another objective of this invention to provide a
running shoe which overcomes the problems of the prior art.
[0009] It is another objective of this invention to provide a shoe
wherein the outer extent of the flat portion of the sole of the
shoe includes all of the support structures of the foot but which
extends no further than the outer edge of the flat portion of the
foot sole so that the transverse or horizontal plane outline of the
top of the flat portion of the shoe sole coincides as nearly as
possible with the load-bearing portion of the foot sole.
[0010] It is another objective of the invention to provide a shoe
having a sole which includes a side contoured like the natural form
of the side or edge of the human foot and conforming to it.
[0011] It is another objective of this invention to provide a novel
shoe structure in which the contoured sole includes a shoe sole
thickness that is precisely constant in frontal plane cross
sections, and therefore biomechanically neutral, even if the shoe
sole is tilted to either side, or forward or backward.
[0012] It is another objective of this invention to provide a shoe
having a sole fully contoured like and conforming to the natural
form of the non-load-bearing human foot and deforming under load by
flattening just as the foot does.
[0013] It is still another objective of this invention to provide a
new stable shoe design wherein the heel lift or wedge increases in
the sagittal plane the thickness of the shoe sole or toe taper
decrease therewith so that the sides of the shoe sole which
naturally conform to the sides of the foot also increase or
decrease by exactly the same amount, so that the thickness of the
shoe sole in a frontal planar cross section is always constant.
[0014] These and other objectives of the invention will become
apparent from a detailed description of the invention which follows
taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In the drawings:
[0016] FIG. 1 is a perspective view of a typical prior art running
shoe to which the improvement of the present invention is
applicable;
[0017] FIG. 2 is a frontal plane cross section showing a shoe sole
of uniform thickness that conforms to the natural shape of the
human foot, the novel shoe design according to the invention;
[0018] FIGS. 3A-3D show a load-bearing flat component of a shoe
sole and naturally contoured stability side component, as well as a
preferred horizontal periphery of the flat load-bearing portion of
the shoe sole when using the sole of the invention;
[0019] FIGS. 4A and 4B are diagrammatic sketches showing the novel
contoured side sole design according to the invention with variable
heel lift;
[0020] FIG. 5 is a side view of the novel stable contoured shoe
according to the invention showing the contoured side design;
[0021] FIG. 6D is a top view of the shoe sole shown in FIG. 5,
wherein FIG. 6A is a cross-sectional view of the forefoot portion
taken along lines 6A of FIG. 5 or 6D; FIG. 6B is a view taken along
lines 6B of FIGS. 5 and 6D; and FIG. 6C is a cross-sectional view
taken along the heel along lines 6C in FIGS. 5 and 6D;
[0022] FIGS. 7A-7E show a plurality of side sagittal plane
cross-sectional views showing examples of conventional sole
thickness variations to which the invention can be applied;
[0023] FIGS. 8A-8C show frontal plane cross-sectional views of the
shoe sole according to the invention showing a theoretically ideal
stability plane and truncations of the sole side contour to reduce
shoe bulk;
[0024] FIGS. 9A-9C show the contoured sole design according to the
invention when applied to various tread and cleat patterns;
[0025] FIG. 10 illustrates, in a rear view, an application of the
sole according to the invention to a shoe to provide an
aesthetically pleasing and functionally effective design;
[0026] FIG. 11 shows a fully contoured shoe sole design that
follows the natural contour of the bottom of the foot as well as
the sides.
[0027] FIGS. 12 and 13 show a rear diagrammatic view of a human
heel, as relating to a conventional shoe sole (FIG. 12) and to the
sole of the invention (FIG. 13);
[0028] FIGS. 14A-14F show the naturally contoured sides design
extended to the other natural contours underneath the load-bearing
foot such as the main longitudinal arch;
[0029] FIGS. 15A-15E illustrate the fully contoured shoe sole
design extended to the bottom of the entire non-load-bearing foot;
and
[0030] FIG. 16 shows the fully contoured shoe sole design
abbreviated along the sides to only essential structural support
and propulsion elements.
[0031] FIG. 17 shows a method of establishing the theoretically
ideal stability plane using a line perpendicular to a line tangent
to a sole surface; and
[0032] FIG. 18 shows an embodiment wherein the contour of the sole
according to the invention is approximated by a plurality of line
segments.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] A perspective view of an athletic shoe, such as a typical
running shoe, according to the prior art, is shown in FIG. 1
wherein a running shoe 20 includes an upper portion 21 and a sole
22. Typically, such a sole includes a truncated outwardly flared
construction, wherein the lower portion of the sole heel is
significantly wider than the upper portion where the sole 22 joins
the upper 21. A number of alternative sole designs are known to the
art, including the design shown in U.S. Pat. No. 4,449,306 to
Cavanagh wherein an outer portion of the sole of the running shoe
includes a rounded portion having a radius of curvature of about 20
mm. The rounded portion lies along approximately the rear-half of
the length of the outer side of the mid-sole and heel edge areas
wherein the remaining border area is provided with a conventional
flaring with the exception of a transition zone. The U.S. Pat. No.
4,557,059 to Misevich, also shows an athletic shoe having a
contoured sole bottom in the region of the first foot strike, in a
shoe which otherwise uses an inverted flared sole.
[0034] FIG. 2 shows in a frontal plane cross section at the heel
(center of ankle joint) of the general concept of the applicant's
design: a shoe sole 28 that conforms to the natural shape of the
human foot 27 and that has a constant thickness (s) in frontal
plane cross sections. The surface 29 of the bottom and sides of the
foot 27 should correspond exactly to the upper surface 30 of the
shoe sole 28. The shoe sole thickness is defined as the shortest
distance (s) between any point on the upper surface 30 of the shoe
sole 28 and the lower surface 31 by definition, the surfaces 30 and
31 are consequently parallel. In effect, the applicant's general
concept is a shoe sole 28 that wraps around and conforms to the
natural contours of the foot 27 as if the shoe sole 28 were made of
a theoretical single flat sheet of shoe sole material of uniform
thickness, wrapped around the foot with no distortion or
deformation of that sheet as it is bent to the foot's contours. To
overcome real world deformation problems associated with such
bending or wrapping around contours, actual construction of the
shoe sole contours of uniform thickness will preferably involve the
use of multiple sheet lamination or injection molding
techniques.
[0035] FIGS. 3A, 3B, and 3C illustrate in frontal plane cross
section a significant element of the applicant's shoe design in its
use of naturally contoured stabilizing sides 28a at the outer edge
of a shoe sole 28b illustrated generally at the reference numeral
28. It is thus a main feature of the applicant's invention to
eliminate the unnatural sharp bottom edge, especially of flared
shoes, in favor of a naturally contoured shoe sole outside 31 as
shown in FIG. 2. The side or inner edge 30a of the shoe sole
stability side 28a is contoured like the natural form on the side
or edge of the human foot, as is the outside or outer edge 31a of
the shoe sole stability side 28a to follow a theoretically ideal
stability plane. According to the invention, the thickness (s) of
the shoe sole 28 is maintained exactly constant, even if the shoe
sole is tilted to either side, or forward or backward. Thus, the
naturally contoured stabilizing sides 28a, according to the
applicant's invention, are defined as the same as the thickness 33
of the shoe sole 28 so that, in cross section, the shoe sole
comprises a stable shoe sole 28 having at its outer edge naturally
contoured stabilizing sides 28a with a surface 31a representing a
portion of a theoretically ideal stability plane and described by
naturally contoured sides equal to the thickness (s) of the sole
28. The top of the shoe sole 30b coincides with the shoe wearer's
load-bearing footprint, since in the case shown the shape of the
foot is assumed to be load-bearing and therefore flat along the
bottom. A top edge 32 of the naturally contoured stability side 28a
can be located at any point along the contoured side 29 of the
foot, while the inner edge 33 of the naturally contoured side 28a
coincides with the perpendicular sides 34 of the load-bearing shoe
sole 28b. In practice, the shoe sole 28 is preferably integrally
formed from the portions 28b and 28a. Thus, the theoretically ideal
stability plane includes the contours 31a merging into the lower
surface 31b of the sole 28. Preferably, the peripheral extent 36 of
the load-bearing portion of the sole 28b of the shoe includes all
of the support structures of the foot but extends no further than
the outer edge of the foot sole 37 as defined by a load-bearing
footprint, as shown in FIG. 3D, which is a top view of the upper
shoe sole surface 30b. FIG. 3D thus illustrates a foot outline at
numeral 37 and a recommended sole outline 36 relative thereto.
Thus, a horizontal plane outline of the top of the load-bearing
portion of the shoe sole, therefore exclusive of contoured
stability sides, should, preferably, coincide as nearly as
practicable with the load-bearing portion of the foot sole with
which it comes into contact. Such a horizontal outline, as best
seen in FIGS. 3D and 6D, should remain uniform throughout the
entire thickness of the shoe sole eliminating negative or positive
sole flare so that the sides are exactly perpendicular to the
horizontal plane as shown in FIG. 3B. Preferably, the density of
the shoe sole material is uniform.
[0036] Another significant feature of the applicant's invention is
illustrated diagrammatically in FIGS. 4A and 4B. Preferably, as the
heel lift or wedge 38 of thickness (s1) increases the total
thickness (s+s1) of the combined midsole and outersole 39 of
thickness (s) in an aft direction of the shoe, the naturally
contoured sides 28a increase in thickness exactly the same amount
according to the principles discussed in connection with FIGS.
3A-3D. Thus, according to the applicant's design, the thickness of
the inner edge 33 of the naturally contoured side is always equal
to the constant thickness (s) of the load-bearing shoe sole 28b in
the frontal cross-sectional plane.
[0037] As shown in FIG. 4B, for a shoe that follows a more
conventional horizontal plane outline, the sole can be improved
significantly according to the applicant's invention by the
addition of a naturally contoured side 28a which correspondingly
varies with the thickness of the shoe sole and changes in the
frontal plane according to the shoe heel lift 38. Thus, as
illustrated in FIG. 4B, the thickness of the naturally contoured
side 28a in the heel section is equal to the thickness (s+s1) of
the shoe sole 28 which is thicker than the shoe sole 39 thickness
(s) shown in FIG. 5A by an amount equivalent to the heel lift 38
thickness (s1). In the generalized case, the thickness (s) of the
contoured side is thus always equal to the thickness (s) of the
shoe sole.
[0038] FIG. 5 illustrates a side cross-sectional view of a shoe to
which the invention has been applied and is also shown in a top
plane view in FIG. 6. Thus, FIGS. 6A, 6B and 6C represent frontal
plane cross-sections taken along the forefoot, at the base of the
fifth metatarsal, and at the heel, thus illustrating that the shoe
sole thickness is constant at each frontal plane cross-section,
even though that thickness varies from front to back, due to the
heel lift 38 as shown in FIG. 5, and that the thickness of the
naturally contoured sides is equal to the shoe sole thickness in
each FIGS. 6A-6C cross section. Moreover, in FIG. 6D, a horizontal
plane overview of the left foot, it can be seen that the contour of
the sole follows the preferred principle in matching, as nearly as
practical, the load-bearing sole print shown in FIG. 3D.
[0039] FIGS. 7A-7E show typical conventional sagittal plane shoe
sole thickness variations, such as heel lifts or wedges 38, or toe
taper 38a, or full sole taper 38b, in FIGS. 7A-7E and how the
naturally contoured sides 28a equal and therefore vary with those
varying thicknesses as discussed in connection with FIGS. 4A and
4B.
[0040] FIGS. 8A-8D illustrate an embodiment of the invention which
utilizes varying portions of the theoretically ideal stability
plane 51 in the naturally contoured sides 28a in order to reduce
the weight and bulk of the sole, while accepting a sacrifice in
some stability of the shoe. Thus, FIG. 8A illustrates the preferred
embodiment as described above in connection with FIGS. 4A and 4B
wherein the outer edge 31a of the naturally contoured sides 28a
follows a theoretically ideal stability plane 51. As in FIGS. 2 and
3A-3D, the contoured surfaces 31a, and the lower surface of the
sole 31b lie along the theoretically ideal stability plane 51. The
theoretically ideal stability plane 51 is defined as the plane of
the surface of the bottom of the shoe sole 31, wherein the shoe
sole conforms to the shape of the wearer's foot sole, particularly
the sides, and has a constant thickness in frontal plane cross
sections. As shown in FIG. 8B, an engineering trade off results in
an abbreviation within the theoretically ideal stability plane 51
by forming a naturally contoured side surface 53a approximating the
natural contour of the foot (or more geometrically regular, which
is less preferred) at an angle relative to the upper plane of the
shoe sole 28 so that only a smaller portion of the contoured side
28a defined by the constant thickness lying along the surface 31a
is coplanar with the theoretically ideal stability plane 51. FIGS.
8C and 8D show similar embodiments wherein each engineering
trade-off shown results in progressively smaller portions of
contoured side 28a, which lies along the theoretically ideal
stability plane 51. The portion of the surface 31a merges into the
upper side surface 53a of the naturally contoured side.
[0041] The embodiment of FIGS. 8A-8D may be desirable for portions
of the shoe sole which are less frequently used so that the
additional part of the side is used less frequently. For example, a
shoe may typically roll out laterally, in an inversion mode, to
about 200.degree. on the order of 100 times for each single time it
rolls out to 40.degree.. For a basketball shoe, shown in FIG. 8B,
the extra stability is needed. Yet, the added shoe weight to cover
that infrequently experienced range of motion is about equivalent
to covering the frequently encountered range. Since, in a racing
shoe this weight might not be desirable, an engineering trade-off
of the type shown in FIG. 8D is possible. A typical running/jogging
shoe is shown in FIG. 8C. The range of possible variations is
limitless, but includes at least the maximum of 90 degrees in
inversion and eversion, as shown in FIG. 8A.
[0042] FIGS. 9A-9C show the theoretically ideal stability plane 51
in defining embodiments of the shoe sole having differing tread or
cleat patterns. Thus, FIGS. 9A-9C illustrate that the invention is
applicable to shoe soles having conventional bottom treads.
Accordingly, FIG. 9A is similar to FIG. 8B further including a
tread portion 60, while FIG. 9B is also similar to FIG. 8B wherein
the sole includes a cleated portion 61. The surface 63 to which the
cleat bases are affixed should preferably be on the same plane and
parallel the theoretically ideal stability plane 51, since in soft
ground that surface rather than the cleats become load-bearing. The
embodiment in FIG. 9C is similar to FIG. 8C showing still an
alternative tread construction 62. In each case, the load-bearing
outer surface of the tread or cleat pattern 60-62 lies along the
theoretically ideal stability plane 51.
[0043] FIG. 10 shows, in a rear cross sectional view, the
application of the invention to a shoe to produce an aesthetically
pleasing and functionally effective design. Thus, a practical
design of a shoe incorporating the invention is feasible, even when
applied to shoes incorporating heel lifts 38 and a combined midsole
and outersole 39. Thus, use of a sole surface and sole outer
contour which track the theoretically ideal stability plane does
not detract from the commercial appeal of shoes incorporating the
invention.
[0044] FIG. 11 shows a fully contoured shoe sole design that
follows the natural contour of all of the foot, the bottom as well
as the sides. The fully contoured shoe sole assumes that the
resulting slightly rounded bottom when unloaded will deform under
load and flatten just as the human foot bottom is slightly rounded
unloaded but flattens under load; therefore, shoe sole material
must be of such composition as to allow the natural deformation
following that of the foot. The design applies particularly to the
heel, but to the rest of the shoe sole as well. By providing the
closest match to the natural shape of the foot, the fully contoured
design allows the foot to function as naturally a possible. Under
load, FIG. 11 would deform by flattening to look essentially like
FIG. 10. Seen in this light, the naturally contoured side design in
FIG. 10 is a more conventional, conservative design that is a
special case of the more general fully contoured design in FIG. 11,
which is the closest to the natural form of the foot, but the least
conventional. The amount of deformation flattening used in the FIG.
10 design, which obviously varies under different loads, is not an
essential element of the applicant's invention.
[0045] FIGS. 10 and 11 both show in frontal plane cross section the
essential concept underlying this invention, the theoretically
ideal stability plane, which is also theoretically ideal for
efficient natural motion of all kinds, including running, jogging
or walking. FIG. 11 shows the most general case of the invention,
the fully contoured design, which conforms to the natural shape of
the unloaded foot. For any given individual, the theoretically
ideal stability plane 51 is determined, first, by the desired shoe
sole thickness (s) in a frontal plane cross section, and, second,
by the natural shape of the individual's foot surface 29, to which
the theoretically ideal stability plane 51 is by definition
parallel.
[0046] For the special case shown in FIG. 10, the theoretically
ideal stability plane for any particular individual (or size
average of individuals) is determined, first, by the given frontal
plane cross section shoe sole thickness (s); second, by the natural
shape of the individual's foot; and, third, by the frontal plane
cross section width of the individual's load-bearing footprint 30b,
which is defined as the upper surface of the shoe sole, that is in
physical contact with and supports the human foot sole, as shown in
FIGS. 3A-3D.
[0047] The theoretically ideal stability plane for the special case
is composed conceptually of two parts. Shown in FIGS. 10 and 3A-3D
the first part is a line segment 31b of equal length and parallel
to 30b at a constant distance (s) equal to shoe sole thickness.
This corresponds to a conventional shoe sole directly underneath
the human foot, and also corresponds to the flattened portion of
the bottom of the load-bearing foot sole 28b. The second part is
the naturally contoured stability side outer edge 31a located at
each side of the first part, line segment 31b. Each point on the
contoured side outer edge 31a is located at a distance which is
exactly shoe sole thickness (s) from the closest point on the
contoured side inner edge 30a; consequently, the inner and outer
contoured edges 31A and 30A are by definition parallel.
[0048] In summary, the theoretically ideal stability plane is the
essence of this invention because it is used to determine a
geometrically precise bottom contour of the shoe sole based on a
top contour that conforms to the contour of the foot. This
invention specifically claims the exactly determined geometric
relationship just described. It can be stated unequivocally that
any shoe sole contour, even of similar contour, that exceeds the
theoretically ideal stability plane will restrict natural foot
motion, while any less than that plane will degrade natural
stability, in direct proportion to the amount of the deviation.
[0049] FIG. 12 illustrates, in a pictorial fashion, a comparison of
a cross section at the ankle joint of a conventional shoe with a
cross section of a shoe according to the invention when engaging a
heel. As seen in FIG. 12, when the heel of the foot 27 of the
wearer engages an upper surface of the shoe sole 22, the shape of
the foot heel and the shoe sole is such that the conventional shoe
sole 22 conforms to the contour of the ground 43 and not to the
contour of the sides of the foot 27. As a result, the conventional
shoe sole 22 cannot follow the natural 7.degree. inversion/eversion
motion of the foot, and that normal motion is resisted by the shoe
upper 21, especially when strongly reinforced by firm heel counters
and motion control devices. This interference with natural motion
represents the fundamental misconception of the currently available
designs. That misconception on which existing shoe designs are
based is that, while shoe uppers are considered as a part of the
foot and conform to the shape of the foot, the shoe sole is
functionally conceived of as a part of the ground and is therefore
shaped flat like the ground, rather than contoured like the
foot.
[0050] In contrast, the new design, as illustrated in FIG. 13,
illustrates a correct conception of the shoe sole 28 as a part of
the foot and an extension of the foot, with shoe sole sides
contoured exactly like those of the foot, and with the frontal
plane thickness of the shoe sole between the foot and the ground
always the same and therefore completely neutral to the natural
motion of the foot. With the correct basic conception, as described
in connection with this invention, the shoe can move naturally with
the foot, instead of restraining it, so both natural stability and
natural efficient motion coexist in the same shoe, with no inherent
contradiction in design goals.
[0051] Thus, the contoured shoe design of the invention brings
together in one shoe design the cushioning and protection typical
of modem shoes, with the freedom from injury and functional
efficiency, meaning speed, and/or endurance, typical of barefoot
stability and natural freedom of motion. Significant speed and
endurance improvements are anticipated, based on both improved
efficiency and on the ability of a user to train harder without
injury.
[0052] FIGS. 14A-14D illustrate, in frontal plane cross sections,
the naturally contoured sides design extended to the other natural
contours underneath the load-bearing foot, such as the main
longitudinal arch, the metatarsal (or forefoot) arch, and the ridge
between the heads of the metatarsals (forefoot) and the heads of
the distal phalanges (toes). As shown, the shoe sole thickness
remains constant as the contour of the shoe sole follows that of
the sides and bottom of the load-bearing foot. FIG. 14E shows a
sagittal plane cross section of the shoe sole conforming to the
contour of the bottom of the load-bearing foot, with thickness
varying according to the heel lift 38. FIG. 14F shows a horizontal
plane top view of the left foot that shows the areas 85 of the shoe
sole that correspond to the flattened portions of the foot sole
that are in contact with the ground when load-bearing. Contour
lines 86 and 87 show approximately the relative height of the shoe
sole contours above the flattened load-bearing areas 85 but within
roughly the peripheral extent 35 of the upper surface of sole 30
shown in FIGS. 3A-3D. A horizontal plane bottom view (not shown) of
FIG. 14F would be the exact reciprocal or converse of FIG. 14F
(i.e. peaks and valleys contours would be exactly reversed).
[0053] More particularly, FIGS. 14C and 14D disclose a shoe sole 28
having a sole inner surface 30 adjacent the location of an intended
wearer's foot 27 inside the shoe including at least a first
concavely rounded portion 43, as viewed in a frontal plane. The
concavity being determined relative to the location of an intended
wearer's foot 27 inside the shoe, during an upright, unloaded shoe
condition. The shoe sole 28 further includes a lateral or medial
sidemost section 45 defined by that part of the side of the shoe
sole 28 located outside of a straight line 55 extending vertically
from a sidemost extent 46 of the sole inner surface 30, as viewed
in the frontal plane during a shoe upright, unloaded condition. A
sole outer surface 31 extends from the sole inner surface 30 and
defines the outer boundary of the sidemost section 45 of the side
of the shoe sole 28, as viewed in the frontal plane. The shoe sole
28 further including a second concavely rounded portion 44 forming
at least the outer sole surface 31 of the sidemost section 45, the
concavity being determined relative to the location of an intended
wearer's foot 27 inside the shoe, as viewed in the frontal plane
during a shoe upright, unloaded condition. The second concavely
rounded portion 44 extending through a sidemost extent 47 of the
sole outer surface 31 of the sole sidemost section 45, as viewed in
the frontal plane during an upright, unloaded condition. Further,
the second concavely rounded portion 44 extends to a height above a
horizontal line 48 through the lowermost point of the sole inner
surface 30, as viewed in the frontal plane in the heel area 51
during an upright, unloaded shoe condition. FIG. 14C illustrates
the above aspects of the shoe sole 28 at the shoe midtarsal area 52
located between the forefoot area 50 and the heel area 49.
[0054] FIGS. 15A-15D show, in frontal plane cross sections, the
fully contoured shoe sole design extended to the bottom of the
entire non-load-bearing foot. FIG. 15E shows a sagittal plane cross
section. The shoe sole contours underneath the foot are the same as
FIGS. 14A-14E except that there are no flattened areas
corresponding to the flattened areas of the load-bearing foot. The
exclusively rounded contours of the shoe sole follow those of the
unloaded foot. A heel lift 38, the same as that of FIGS. 14A-14D,
is incorporated in this embodiment, but is not shown in FIGS.
15A-15D.
[0055] FIG. 16 shows the horizontal plane top view of the left foot
corresponding to the fully contoured design described in FIGS.
14A-14E, but abbreviated along the sides to only essential
structural support and propulsion elements. Shoe sole material
density can be increased in the unabbreviated essential elements to
compensate for increased pressure loading there. The essential
structural support elements are the base and lateral tuberosity of
the calcaneus 95, the heads of the metatarsals 96, and the base of
the fifth metatarsal 97. They must be supported both underneath and
to the outside for stability. The essential propulsion element is
the head of first distal phalange 98. The medial (inside) and
lateral (outside) sides supporting the base of the calcaneus are
shown in FIG. 15 oriented roughly along either side of the
horizontal plane subtalar ankle joint axis, but can be located also
more conventionally along the longitudinal axis of the shoe sole.
FIG. 15 shows that the naturally contoured stability sides need not
be used except in the identified essential areas. Weight savings
and flexibility improvements can be made by omitting the
non-essential stability sides. Contour lines 86 through 89 show
approximately the relative height of the shoe sole contours within
roughly the peripheral extent 35 of the undeformed upper surface of
shoe sole 30 shown in FIG. 3A-3D. A horizontal plane bottom view
(not shown) of FIG. 15 would be the exact reciprocal or converse of
FIG. 15 (i.e. peaks and valleys contours would be exactly
reversed).
[0056] FIG. 17 illustrates the method of measuring sole thickness
in accordance with the present invention. The sole thickness is
defined as the distance between a first point on the inner surface
30 of the sole 28 and a second point on the outer surface 31 of the
sole 28, the second point being located along a straight line
perpendicular to a straight line tangent to the inner surface 30 of
the sole 28 at the first point, as viewed in a shoe sole frontal
plane when the shoe sole is upright and in an unloaded
condition.
[0057] The theoretically ideal stability can also be approximated
by a plurality of line segments 110, such as tangents, chords, or
other lines, as shown in FIG. 18. Both the upper surface of the
shoe sole 28, which coincides with the side of the foot 30a, and
the bottom surface 31a of the naturally contoured side can be
approximated. While a single flat plane 110 approximation may
correct many of the biomechanical problems occurring with existing
designs, because it can provide a gross approximation of both the
natural contour of the foot and the theoretically ideal stability
plane 51, the single plane approximation is presently not
preferred, since it is the least optimal. By increasing the number
of flat planar surfaces formed, the curve more closely approximates
the ideal exact design contours, as previously described. Single
and double plane approximations are shown as line segments in the
cross section illustrated in FIG. 18.
[0058] Thus, it will clearly be understood by those skilled in the
art that the foregoing description has been made in terms of the
preferred embodiment and various changes and modifications may be
made without departing from the scope of the present invention
which is to be defined by the appended claims.
* * * * *