U.S. patent application number 13/728814 was filed with the patent office on 2014-07-03 for articles of footwear having lines of flexion.
The applicant listed for this patent is Michael MACK. Invention is credited to Michael MACK.
Application Number | 20140182169 13/728814 |
Document ID | / |
Family ID | 51015561 |
Filed Date | 2014-07-03 |
United States Patent
Application |
20140182169 |
Kind Code |
A1 |
MACK; Michael |
July 3, 2014 |
ARTICLES OF FOOTWEAR HAVING LINES OF FLEXION
Abstract
The invention herein is directed toward footwear containing a
central flex zone comprised of a novel combination of a central
flex channel with a central flex element that imparts either
bidirectional or multi-directional flexion to the shoe, according
to various embodiments, thereby allowing more natural flexibility
and allowing all surface contacting members to independently engage
and disengage from the contact surface of the user as the wearer's
weight shifts. The flex zones also naturally adapt to the amount of
stress put on the sole from ground elements, such as rocks or
branches that the sole encounters during wear and to adjust to
different terrain due thereby being particularly useful in
applications such as construction boots and athletic footwear.
Inventors: |
MACK; Michael; (Lexington,
NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MACK; Michael |
Lexington |
NC |
US |
|
|
Family ID: |
51015561 |
Appl. No.: |
13/728814 |
Filed: |
December 27, 2012 |
Current U.S.
Class: |
36/102 |
Current CPC
Class: |
A43B 13/125 20130101;
A43B 13/141 20130101; A43B 9/04 20130101 |
Class at
Publication: |
36/102 |
International
Class: |
A43B 7/32 20060101
A43B007/32 |
Claims
1. An article of footwear having a forefoot region, a midfoot
region, a heel region, a lateral region, a medial region, an upper
structure and a sole structure, the sole structure comprising: a
midsole positioned along the longitudinal length of the
downward-facing surface of the upper structure and connected
thereto; and a shock absorbing cushion integrally connected to the
downward-facing surface of the midsole; and an outsole integrally
connected to the downward-facing surface of the shock absorbing
cushion, said outsole comprising at least one flex channel in the
form of an aperture in the outsole; and wherein the shock absorbing
cushion extends downward and protrudes through and along said flex
channel of the outsole forming a corresponding flex element.
2. The article of footwear of claim 1, wherein the flex channel is
oriented in a longitudinal direction of the footwear from the
forefoot region to the heel region.
3. The article of footwear of claim 2, wherein the flex channel
extends substantially centrally in the longitudinally direction of
the footwear.
4. The article of footwear of claim 1, wherein the flex channel is
oriented in a substantially lateral direction of the footwear from
the medial region to the lateral region of the footwear.
5. The article of footwear of claim 1, wherein the footwear
comprises a plurality of flex channels in the outsole with
corresponding flex elements.
6. The article of footwear of claim 3, wherein the medial region
and the lateral region are partially connected to one another.
7. The article of footwear of claim 6, wherein medial region and
the lateral region are connected to one another at the heel or at
the toe or both.
8. The article of footwear of claim 1, wherein the outsole extends
partially upward from the sole structure to the upper structure to
form the welt of the footwear.
9. The article of footwear of claim 1, wherein the thickness of the
shock absorbing cushion varies along the forefoot region, the
midfoot region, the heel region, the medial region and/or the
lateral region.
10. The article of footwear of claim 1, wherein the width of the
flex element is approximately equal to the width of the flex
channel.
11. The article of footwear of claim 1, wherein the thickness of
the flex element is approximately equal to the thickness of the
flex channel.
12. The article of footwear of claim 1, wherein the thickness of
the shock absorbing cushion is from about 4 to about 15 mm.
13. The article of footwear of claim 1, wherein the thickness of
the flex element is from about 8 to about 10 mm.
14. The article of footwear of claim 1, wherein the shock absorbing
cushion comprises polyurethane or ethylvinylacetate.
15. The article of footwear of claim 1, wherein the outsole further
comprises traction lugs.
Description
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0001] The present invention was not developed with the use of any
Federal Funds, but was developed independently by the listed
inventor.
BACKGROUND
[0002] 1. Field
[0003] The present invention relates to the field of footwear. More
particularly, the invention is directed to a new shoe sole
construction wherein the shoe includes a midsole welted between an
upper structure and the bottom outsole and wherein the outsole
comprises an extruded channel spanning preferably centrally from
forefoot to heel area and comprising a shock absorbing cushion that
extends and protrudes through the channel within the outsole.
[0004] 2. Background
[0005] Industry reports indicate that as of 2010, the apparel
footwear and accessory industry had a market capitalization of
approximately fifty-seven billion US dollars. The shoe market
evolves continuously to meet the varied needs of the consumers.
Conventional articles of footwear traditionally include two primary
elements, an upper structure and a sole structure. The upper
structure provides a covering for the foot that securely receives
and positions the foot with respect to the sole structure. The sole
structure is secured to a lower surface of the upper structure and
is generally positioned between the foot and the ground in order to
cushion and protect the foot while walking. The sole structure may
in addition provide traction and control of foot motion.
[0006] The upper structure (the "upper") forms a void on the
interior of the footwear for receiving the foot. The void has the
general shape of the foot, and access to the void is provided by an
ankle opening. Accordingly, the upper extends over the instep and
toe areas of the foot, along the medial and lateral sides of the
foot, and around the heel area of the foot. A lacing system may be
incorporated into the upper to selectively increase the size of the
ankle opening and permit the wearer to modify certain dimensions of
the upper, particularly girth, to accommodate feet with varying
proportions. In addition, the upper may include a tongue that
extends under the lacing system to enhance the comfort of the
footwear, and the upper may include a heel counter to limit
movement of the heel.
[0007] The sole structure (the "sole") is designed to address the
particular functionality and use of a shoe. It became one of the
objects of the footwear industry to create a sole structure to
reduce and control ground reaction forces to the wearer. Lug soles
were created as a type of outer sole found on heavy-duty and
utility shoes such as hiking boots or work boots. Lug soles are
typically thick and designed with deep indentations to improve
stability and traction. The pattern of lug soles varies to include
indentations such as V-shaped and diamond shaped indentations. Lug
soles are most frequently found on construction, fishing, hunting,
logging, hiking, and other utility boots. Lug soles are typically
made of rubber and some may be injected molded from thermoplastic
polymers such as polyvinyl chloride (PVC) or polyurethane (PU). Lug
soles are generally slightly wider than the perimeter of the shoe.
Though lug soles offer improved traction and stability, they are
limited in flexibility and control. Lug soles also have a tendency
to accumulate mud in the deep indentations and they can be messy
and difficult to clean.
[0008] Athletic shoes are a generic name for footwear that is
primarily designed for sports or other forms of physical exercise
and have come to be used for casual everyday activities. They are
also known as sneakers, sneaks, sports shoes, trainers,
cross-trainers, jogging shoes, daps, gym shoes, running shoes,
runners, tennis shoes, rubber shoes, canvers and other names
commonly adapted to particular localities. Attributes of an
athletic shoe include a flexible sole with appropriate tread for
the function ability to absorb impact. As the industry and design
have expanded, the term "athletic shoes" is based as much on the
design of the bottom or sole of the shoe as the aesthetics of the
top or upper of the shoe. Today's designs include sandal, elevated,
and Mary Jane styles suitable for running, dancing and jumping. The
shoes themselves are made of flexible compounds, typically
featuring a sole made of dense rubber. While the original design
was basic, manufacturers have since tailored athletic shoes for the
differing purposes for which the shoe can be used. A specific
example of a particular design is the spiked shoe developed for
track running. Hiking, climbing and mountaineering shoes have
become a niche in the athletic shoe industry. Such shoes combine
elements of traditional athletic shoes together with elements
requiring a more rugged traction and stability.
[0009] In addition to functionality, shoes are also designed in
different shapes suited to different foot types and gait.
Generally, such shoes, especially running shoes, are divided into
neutral, over-pronation and under-pronation (supination) shoes to
fit the respective foot strike of the wearer. As athletic shoes
become more advanced, amateur joggers, as well as marathon runners,
are beginning to purchase shoes based on their running or walking
style and foot arch. This is often important for injury prevention,
as well as to increase athletic efficiency and comfort.
[0010] A common form of footwear construction, referred to as welt
construction, incorporates a "welt", which is a strip of leather,
rubber, or plastic that is stitched to the upper and the insole of
a shoe as an attach-point for the sole. The space enclosed by the
welt is then filled with cork or some other filler material (often
either porous or perforated, for breathability), and the outsole is
both cemented and stitched to the welt. Shoes with other types of
construction may also have welts for finished appearance, but they
generally serve little or no structural purpose.
[0011] Other sole designs have been introduced in order to reduce
the welt while rendering flexibility to the wearer. For example,
U.S. Pat. No. 6,163,982 discloses a the structure of a conventional
shoe sole that has been modified by having its sides bent up so
that their inner surface conforms to a shape nearly identical but
slightly smaller than the shape of the outer surface of the sides
of the foot sole of the wearer, instead of the shoe sole sides
conforming to the ground by paralleling it, as is conventional. The
shoe sole sides are sufficiently flexible to bend out easily when
the shoes are put on the wearer's feet and therefore the shoe soles
gently hold the sides of the wearer's foot sole when worn,
providing the equivalent of custom fit in a mass-produced shoe
sole.
[0012] In subsequent construction of footwear, a midsole was
introduced that is positioned between the upper and the sole of the
shoe in order to render greater comfort to the wearer along with
other desirable advantages. For example, U.S. Pat. No. 6,763,609 to
Robert Su disclosed a midsole that permits molten outer sole
material to flow through the midsole during the molding process and
fill the space between the insole and the midsole and thus sandwich
the midsole. This technique forms outer soles to be durably and
flexibly attached to the upper structure without use of traditional
adhesives. The term "outsole" was coined to differentiate the
midsole structure from the bottom-most sole structure that comes
into contact with the ground.
[0013] Numerous designs of footwear have been created that attempt
to incorporate a variety of elements into the design and
functionality of the shoe to improve flexibility and comfort. U.S.
Pat. No. 6,854,198 to Jeffrey Brooks discloses a design having
medial, lateral and arch regions that is based on the shape of the
toes of the foot in attempting to mimic a foot's natural outline
and mobility. U.S. Pat. No. 5,012,597 to Robert Thomasson discloses
an athletic shoe sole with a twist flex region positioned below the
ball portion of the foot that attempts to construct a flex function
which allows the wearer to twist the foot for athletic activities.
U.S. Pat. No. 7,124,519 to James Issler discloses a shoe sole
having a plurality of adjacent sections made of different materials
in order to improve flexibility. U.S. patent application Ser. No.
11/338,601 of Hazenberg et. al. discloses a shoe having a number of
fluid-filled chambers in one or more flexion zones of the sole.
U.S. Pat. No. 7,650,707 to Campbell et. al. discloses an outsole
with flex lines that improve the flexibility functionality of the
shoe. U.S. Pat. No. 7,350,320 to Chandler et. al. discloses a shoe
with a central flexing point that is focused on a suspension system
which allows the heel portion to act as a shock absorber cushioning
element. Conversely, U.S. Pat. No. 7,707,748 also to Derek Campbell
discloses a shoe with a design that enables the flexing of the
forefoot portion of the foot while inhibiting heel movement for
improved twisting or swinging action in golf shoes.
[0014] The previous examples demonstrate the great focus that has
been placed in the shoe industry on either the flexibility of the
footwear or the durability of the footwear in its construction.
Despite the tremendous size of the shoe industry, it continues to
be desirable to create a shoe structure wherein the upper, midsole
and the outsole structure operate cooperatively to provide
comfortable footwear that is suited for a wide variety of
ambulatory activities, such as walking, running, and jumping, as
well as being rigid enough for other activities such as hiking,
mountaineering and/or utility work among others and wherein the
shoe is particularly suited to the specific gait and pressure
points of each person. The present invention addresses a number of
issues in the shoe industry. The invention features a novel
structural configuration of the upper, midsole and outsole
structures that allow greater mobility to the foot of the wearer
based on the particular movement of the foot of each individual
while at the same time allowing traction, control and rigidity for
more rugged functionality and use as discussed in greater detail
below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The foregoing summary and the following detailed description
of the invention will be better understood when read in conjunction
with the appended drawings. For the purpose of illustrating the
invention, there are shown in the drawings embodiments which are
presently preferred. It should be understood, however, that the
invention is not limited to the precise arrangements and
instrumentalities shown.
[0016] FIG. 1 is an illustration of an article of footwear of the
invention.
[0017] FIG. 2 is a bottom view of the outsole of an article of
footwear of the invention.
[0018] FIG. 3 is side view of the sole elements of an article of
footwear of the invention.
[0019] FIG. 4 is a rear view of the sole of an article of footwear
of the invention and a rear view of the sole showing the lateral
directional flexion of the sole.
[0020] FIG. 5 is an alternative illustration of the sole of an
article of footwear of the invention.
DETAILED DESCRIPTION
[0021] The following detailed description of the invention is made
in reference to the accompanying drawings, which form a part
hereof, and which show by way of illustration various example
structures of the invention. It is to be understood that other
specific arrangements of parts, example structures, and embodiments
may be utilized and structural and functional modifications may be
made without departing from the scope of the present invention.
Also, while certain terms may be used in this specification to
describe various example features and elements of structures the
invention, for example, "heel", "forefoot", "midfoot", these terms
are used herein as a matter of convenience, e.g., based on the
example orientations shown in the figures and/or a typical
orientation during use. The terms "zones" and "regions" are used
interchangeably herein. The term downward-facing surface refers to
a surface area that is directed and oriented toward the ground.
[0022] "Footwear" is used interchangeably herein with "shoe" and
means any type of product worn on the feet, and this term includes,
but is not limited to all types of shoes, boots, sneakers, sandals,
flip-flops, mules, scuffs, slippers, sport-specific shoes (such as
golf shoes, tennis shoes, baseball cleats, soccer or football
cleats, ski boots, etc.), and the like. Footwear may protect the
feet from the environment such as rocks and the weather, and/or
enhance a wearer's performance, whether physically,
physiologically, medically, or otherwise.
[0023] Footwear (10) is depicted in FIG. 1 and includes an upper
element (20) and a sole structure (30). Upper (20) is formed from
various material elements that are stitched or adhesively bonded
together to form an interior void that comfortably receives a foot
and secures the position of the foot relative to sole structure
(30). Sole structure (30) is secured to the downward-facing surface
or lower portion of upper (20) and provides a durable,
wear-resistant component for attenuating ground reaction forces as
footwear (10) impacts the ground.
[0024] For purposes of reference, footwear (10) is divided into two
general regions: the exterior lateral zone (80) and an interior or
medial region (90), as defined in FIG. 2. Further depicted on FIG.
2, footwear (10) comprises a toe or forefoot region (12), a midfoot
region (14) and a heel or rearfoot region (16). Aforesaid regions
(80), (90), (12), (14) and (16) are not intended to demarcate
precise areas of footwear, but rather are intended to represent
general areas of footwear (10) that provide a frame of reference
during the following discussion.
[0025] Various materials may be utilized in manufacturing the upper
element (20). Flexibility, durability and/or temperature regulation
of the upper element of a shoe may be regulated by incorporating
multiple material layers that include an exterior layer, a middle
layer, and an interior layer. A variety of materials are suitable
for the upper, including the materials that are conventionally
utilized in footwear uppers. Accordingly, the upper may be formed
from combinations of leather, synthetic leather, natural or
synthetic textiles, polymer sheets, polymer foams, mesh textiles,
felts, non-woven polymers, or rubber materials, for example.
Portions of the upper can form coextensive layers of material that
are stitched or adhesively bonded together. Various layers within
the upper element may be joined with adhesives, and stitching may
be utilized to join elements within a single layer or to reinforce
specific areas of the upper element.
[0026] In athletic footwear, materials forming the exterior layer
of the upper element may be selected based upon the properties of
wear-resistance, flexibility, and air-permeability, for example.
The exterior layer of the upper may be formed, therefore, from
numerous material elements that each imparts different properties
to specific areas of the upper. For example, certain embodiments
directed more toward athletic use may have an upper element having
a configuration that provides ventilation, thereby cooling the foot
and removing perspiration. In footwear intended for rugged
activities such as construction or trekking, materials such as
leather or canvas elements may be added to the design of the upper.
Further, the toe area and the heel area of the shoe may be formed
of materials such as leather, synthetic leather, or a rubber
material to impart a relatively high degree of wear-resistance.
Leather, synthetic leather, and rubber materials may not exhibit
the desired degree of flexibility and air-permeability.
Accordingly, areas of the exterior of the upper may be formed from
synthetic textiles imparting such characteristics if desired in the
particular design.
[0027] The mechanism for adjusting the fit of upper (20) and
accommodating various foot dimensions can be accomplished either by
incorporation of a tongue, with separate lacing or by other
mechanisms known in the art.
[0028] In some embodiments of the invention, the portion of upper
(20) in the heel region (12) may incorporate a conventional heel
counter formed of a semi-rigid polymer material, for example, to
ensure that the heel remains properly positioned with respect to
the upper. The heel counter may be located on an exterior of the
upper or within the various material elements forming the upper.
However, the configuration of the upper and the sole structure (30)
does not necessitate the presence of a heel counter. The shoe of
the invention may include additional structures or elements,
including conventional structures and/or elements known and used in
the art, such as securing systems (e.g., laces, buckles,
hook-and-loop fasteners, zippers, etc.); heel counters; insole
members; interior booties; sock liners; additional
impact-attenuating elements; impact-attenuating foam columns;
gas-filled bladders, and various others.
[0029] The sole structure (30) of the footwear of the invention
comprises a layered configuration demonstrated by FIG. 3 that
includes an insole (40), a midsole (50), and a shock absorbing
cushion structure (60) that is integrally connected to a
surface-contacting outsole (70) that together provide both
flexibility and abrasion-resistance and traction.
[0030] The insole of the invention (40) is a structure that is
conventionally a thin, comfort-enhancing member located within the
upper and adjacent the plantar (lower) surface of the foot usually
added to footwear in order to enhance footwear comfort. Often the
insole is formed of a moisture-wicking textile that removes
perspiration from the area immediately supporting the bottom of the
foot.
[0031] A middle layer of the sole of the footwear of the invention,
the midsole (50) structure is generally integrally connected to
insole (40) illustrated in FIG. 3. A conventional footwear midsole
is a unitary, polymer foam structure that extends throughout the
length of the foot and may have stiffness or inflexibility that
inhibits the natural motion of the foot. The midsole herein has a
conventional articulated structure that imparts relatively high
flexibility and articulation. The flexible structure of the midsole
(in combination with the structure of upper 20) is configured to
complement the natural motion of the foot during various
activities.
[0032] Midsole (50) includes an upper midsole surface (52) and an
opposite bottom midsole surface (54). Upper surface (52) is
positioned adjacent to the upper (20) and may be secured directly
to it, thereby providing support for the foot. Upper midsole
surface (52) may, therefore, be contoured to conform to the
natural, anatomical shape of the foot. Accordingly, the area of
upper midsole surface (52) that is positioned in the heel region
(12) may have a greater elevation than the area of upper midsole
surface (52) in the forefoot region (14). In addition, the midsole
may form an arch support area in midfoot region (16), and
peripheral areas of the midsole may be generally raised to provide
a depression for receiving and seating the foot. In other
embodiments, the midsole may have a non-contoured
configuration.
[0033] Midsole (50) may be formed from resilient materials such as
a lightweight polymer foam material that helps to absorb ground
reaction forces and protects the foot from objects that may contact
the upper element while simultaneously supporting the outsole.
Stability devices can be incorporated into the polymer foam
material of the midsole to control the degree of rotational
movement of the foot. Examples of stability devices are found in
U.S. Pat. No. 4,255,877 to Bowerman; U.S. Pat. No. 4,287,675 to
Norton et al; U.S. Pat. No. 4,288,929 to Norton et al; U.S. Pat.
No. 4,354,318 to Frederick et al.; U.S. Pat. No. 4,364,188 to
Turner et al; U.S. Pat. No. 4,364,189 to Bates; and U.S. Pat. No.
5,247,742 to Kilgore et al. In addition to stability devices,
conventional midsoles may include fluid-filled bladders, as
disclosed in U.S. Pat. Nos. 4,183,156 and 4,219,945 to Rudy, for
example.
The Shock Absorbing Cushion
[0034] The footwear of the invention comprises a shock absorbing
cushion element (60) that according to the invention functions
together with outsole (70) in a novel configuration and design in
order to render superior foot motion control while rendering shock
absorption, durability and traction. The shock absorbing cushion
(60) is recessed between the midsole (50) and the outsole (70). As
illustrated in FIG. 2 and FIG. 4, in the preferred embodiment of
the invention, the shock absorbing cushion element (60) comprises
one central protruding flex zone segment, the central flex element
(62) that extends longitudinally from the forefoot portion or toes
(14) (e.g., at or near the toe area of the sole (30)) to the
rearfoot portion or heel (12) (e.g., at or near the rear heel area
of the sole (30)). Central flex element (62) is integrally recessed
within the central flex channel (72) forming two halves or regions
of outsole structure (70).
[0035] Midsole (50) and the shock absorbing cushion of the
invention (60) are preferably joined through a mechanical interface
rather than an adhesive or chemical interface. The primary element
of a conventional midsole is a resilient, polymer foam material,
such as polyurethane or ethylvinylacetate, which extends throughout
the length of the footwear. The properties of the polymer foam
material in the midsole are primarily dependent upon factors that
include the dimensional configuration of the midsole and the
specific characteristics of the material selected for the polymer
foam, including the density of the polymer foam material.
Similarly, suitable polymer foam materials for the shock absorbing
cushion element (60) of the invention include ethylvinylacetate
("EVA") or polyurethane ("PU") that compress resiliently under an
applied load to attenuate contact surface reaction forces.
Conventional polymer foam materials are resiliently compressible,
in part, due to the inclusion of a plurality of open or closed
cells that define an inner volume substantially displaced by gas.
By varying these factors throughout the midsole, the relative
stiffness, degree of ground reaction force attenuation, and energy
absorption properties may be altered to meet the specific demands
of the activity for which the footwear is intended to be used.
[0036] Depending on a desired design aesthetic, the shock absorbing
cushion (60) of the invention may be either open and exposed to the
external environment, such that it is distinctly visible and
identifiable from the side view of the shoe; or it may be hidden
within another material (such as in impact-attenuating material) or
partially hidden in such a material, without departing from this
invention. The thicknesses of the midsole and of the shock
absorbing cushion are depicted graphically in FIG. 3 as thickness
dimension (55) and (65), respectively.
The Outsole
[0037] The outsole of a shoe is generally the sole layer that is in
direct contact with the ground. The outsole (70) of the invention
is secured to a lower surface of the shock absorbing cushion (72)
to provide wear-resistance. As in conventional outsoles, the
outsole of the invention (70) is fashioned from a durable,
wear-resistant material. Suitable materials for outsole (70)
include abrasion-resistant materials such as any of the
conventional rubber materials that are utilized in footwear
outsoles, such as carbon black rubber compound, blown rubber, or a
combination of blown and carbon rubbers.
[0038] The outsole (70) sometimes includes texturing in order to
improve traction of the footwear, illustrated in FIG. 5. Likewise,
the outsole (70) of the invention forms the ground-contacting
element of the footwear of the invention. In the preferred
embodiment of the invention, the outsole (70) is divided
longitudinally into two regions or halves extending from the
forefoot (12) to the heel (16). As illustrated in FIGS. 2 and 5,
the region of the shoe closest to the exterior of the foot shall be
termed the lateral region (80) and the region of the shoe closer to
the interior of the foot shall be termed the medial region (90).
The line or area of division between the two halves or regions of
the outsole (70) forms the central flex channel (72) of the
invention through which protrudes the central flex element (62) of
the invention and extends from the forefoot (12) to the heel (16)
and illustrated in FIGS. 2 and 5 or as will be discussed
hereinbelow.
[0039] The thickness of the outsole is defined as the dimension
that extends between the shock absorbing cushion (60) and the outer
bottom surface of the outsole (70) that is in contact with the
ground. The thickness of the outsole may vary along the
longitudinal length of the midsole. The thickness is depicted
graphically in FIG. 3 as thickness dimension (75). One skilled in
the relevant art will recognize that a variety of thickness
dimensions and variations will be suitable for the outsole
depending on the use for which the footwear is contemplated and
designed.
The Central Flex Zone
[0040] The shock absorbing cushion element of the invention (60) is
designed such that it protrudes between the two longitudinal
regions of the outsole, the lateral region (80) and the medial
region (90) through the central flex channel (72) thereby creating
the central flex element (62). The central flex element is visible
from the bottom view of the shoe as illustrated in FIG. 5.
Together, the central flex channel (72) and the central flex
element (62) form the central flex zone which provides a line of
flex in the sole (30) and divide outsole (60) into the lateral
region (80) and the medial region (90). The central flex zone acts
as the center flexing point for the sole. Whereas the conventional
footwear outsole is usually a unitary element of polymer foam, the
central flex channel (72) of the invention forms a flexion line in
the outsole and, therefore, imparts a direction of longitudinal
flex in the sole. The manner in which the sole structure (30) is
consequently able to flex or articulate as a result of the novel
central flex zone disclosed herein, is graphically depicted in FIG.
4. The central flex zone acts as a live hinge for the sole allowing
the sole to move in a birdlike flapping motion of its wings.
[0041] In general, during the time that the foot is in contact with
the ground, the motion of the foot during walking is such that the
foot typically rolls from the outside or lateral side to the inside
or medial side, a process called pronation. That is, normally, the
outside of the heel strikes first and the toes on the inside of the
foot leave the ground last. The separation of footwear (10) into
the lateral (80) and medial (90) regions creates a structure that
allows the lateral and medial zones to move independently of each
other allowing each of the regions of the outsole to bend in
response to elements on the ground and thereby imparting
bidirectional flexibility and flexion.
[0042] The welt has always given boots its tough and durable trait.
However the welt takes away from a boots overall flexibility and
ultimately adds to the overall weight of the boot. Cement
construction in is widely used by the athletics footwear market for
its flexibility and light weight. The problem with cement
construction is that it does not impart toughness and durability.
In order to address the limitations presented by the welt, the
outsole of the invention utilizes the strength and durability found
in the welt. Thereby, in contrast to conventional footwear of the
prior art, footwear of the invention directed to applications such
as construction boots and trekking boots can handle the toughness
and durability required on the construction site and yet imparts a
more natural flexibility and comfort to the footwear. The central
flex zones allow the shoe to feel more like an extension of the
foot, flexing in places at which the foot naturally wants to flex
rather than fighting the foot's natural motion which is the problem
with common construction and trekking boots. Further, the footwear
of the invention is able to adjust to different terrain due to its
ability to flex.
[0043] In one preferred embodiment of the invention, the weight of
the welt is countered by using a polyurethane injection molded
midsole. This design eliminates the weight that is traditionally
tacked on by the standard solid rubber lug outsole. Adding the
strength of the good year welt construction to the design combines
the best qualities of athletic and occupational footwear.
[0044] In the preferred embodiment, the lateral and medial regions
form two separate segments on the outsole of the footwear of the
invention. However, in yet another embodiment of the invention,
lateral region (80) and medial region (90) are connected at the
heel (16) of the footwear thereby forming one continuous segment.
In another embodiment, lateral region (80) and medial region (90)
are connected at the forefoot segment (12) of the footwear thereby
also forming one continuous segment. Also contemplated is an
embodiment where the lateral and medial regions are connected at
both the heel (16) and toe (12) regions.
[0045] Though preferably the individual central flex channel (72)
and the corresponding central flex element (62) creating the line
of flex extend completely from the forefoot (12) to the rearfoot
(16) regions, embodiments are contemplated where the central flex
element (72) extends and protrudes only partially through the
central flex channel (72) i.e., the length of the central flex
element (62) being less than the length of the central flex channel
(72) along the outsole of the shoe.
[0046] Optionally, central flex element (62) comprises a
longitudinal central flex groove which imparts yet additional
longitudinal bidirectional flexibility and flexion. The flexible
footwear of the types described above allow independent movement of
the lateral and/or medial segments of the outsole member (e.g.,
independent movement or rotation with respect to one another about
the lines of flex) to thereby allow more of the outsole to remain
in contact with the ground e.g., as compared to support structures
that do not include such flexibility and independently and
relatively movable regions, which may improve safety and
functionality during operation on a construction worksite and
advantages during certain sporting activities such as for example
during a golf or baseball swing (or other swinging activities) as
weight tends to shift, and the wearer's center of gravity moves
from the center or medial side to the lateral side and/or moves
from the lateral side to the medial side. Moreover, the increased
lateral stability and/or decreased lateral flexibility as compared
to the medial side's stability and/or flexibility characteristics
provide excellent support and/or comfort during various moving,
twisting or swinging actions.
[0047] According to some embodiments of the invention, central flex
element (62) (and central flex channel (72)) is positioned not
precisely within or toward the longitudinal center of the foot but
either more laterally toward the lateral region (80) or more
medially toward the medial region (90), respectively. A
configuration wherein central flex zone (62) is positioned medially
provides a shoe where the lateral side of the foot is made less
flexible and/or more stable than its medial side. Such a design may
be particularly useful for individuals having specific gait
characteristics, for example those individuals who tend to place
more weight toward the lateral part of the foot as they walk.
[0048] Embodiments of the invention are provided wherein the
thickness of the outsole (70) differs throughout the length of the
shoe particularly where the thickness of the lateral region (80)
differs from the thickness of the medial region (90). The variation
in the thicknesses between the lateral and medial regions of the
outsole with respect to one another allow for yet further control
and comfort to the wearer, such as, for example, for individuals
having specific preferences or medical requirements for the height
of their foot arches.
[0049] The central flex channel (72) may extend for any desired
length in the outsole without departing from the invention. The
channel may run along the entire length of the shoe or along only a
partial length of the shoe. The width of the central flex channel
is from about 2 to about 20 mm wide, illustrated as dimension (75)
in FIG. 4, preferably from 4 mm to about 14 mm wide. Though
preferred, not all of the central flex channel (72) and the
corresponding central flex element (62) in a given shoe need have
the same dimensional characteristics. The invention herein will be
operable as long as the dimensions of the central flex channel (72)
are greater than the dimensions of the central flex element (62)
such that the central flex element (62) is able to protrude through
the central flex channel (72). However, in the preferred
embodiment, the dimensions of the central flex channel and the
central flex element are approximately equal so as to prevent
rocks, soil or other ground materials to accumulate in the central
flex channel which may cause discomfort to the wearer and potential
puncture of the sole structure at the recessed central flex
channel.
[0050] The thickness of the central flex element (62) is preferably
approximately equal to or less than the thickness of the outsole of
the shoe. The thickness of the central flex zone may vary along its
longitudinal length. The thickness is depicted graphically in FIG.
4 as thickness dimension (63). For example, dimension (63) in the
forefoot region (12), may be, for example, approximately 4 mm to 15
mm. One skilled in the relevant art will recognize, however, that a
variety of thickness dimensions and variations will be suitable for
the central flex element.
[0051] The width of the central flex element (62) of the invention
is defined by dimension (65) demonstrated in FIG. 4 and is
preferably typically approximately equal to the width of the
central flex channel (72) in order for the central flex element
(62) to protrude through the central flex channel (72). The width
of the central flex element is preferably between 2 mm and 20 mm,
more preferably between 4 mm and 15 mm, and more preferably between
6 mm and 10 mm. A relatively thin thickness of the central flex
element will, in general, possess more flexibility than flex
element having a greater thickness. Variations in the thickness
may, therefore, be utilized to modify the flexibility of the sole
structure in specific areas of the foot. For example, the forefoot
region may be configured to have relatively high flexibility by
forming a central flex element with a lesser thickness while a
relatively low flexibility may be imparted to the midfoot region by
forming the central flex element with a greater thickness.
Similarly, an intermediate flexibility may be imparted to the heel
region by forming a central flex element with a thickness that is
between the thicknesses of the forefoot region and the midfoot
region.
[0052] In other embodiments of the invention, multiple central flex
elements may be introduced dividing the outsole of the shoe into
various regions, for example, further separating and subdividing
each of the lateral region (80) and the medial region (90). In an
example structure, provided is a shoe comprising three central flex
elements, as illustrated in FIG. 5, having subdivided forefoot
sub-lateral zones (82) and (84) and sub-medial zones (92) and (94),
wherein each of the zones provide discrete areas of the sole
structure such that they are each individually movable about the
lines of flex (64) and (66) with respect to one another to allow
the various regions to independently engage and disengage from a
contact with the ground elements. The dimensions of the central
flex channel (72) and corresponding central flex element (62) may
vary along the overall length, width, and/or depth of an individual
zone segment.
[0053] While referred to as extending in the "longitudinal
direction", the central flex zone need not extend exclusively in a
direction of a longitudinal center line of the sole structure.
Rather, as shown in FIG. 2, the term "longitudinal direction", as
used herein in this context, means that the central flex channel
(72) and the corresponding central flex element (62) creating the
line of flex defined thereby extend predominantly in the
longitudinal direction, e.g., generally from the shoe's front or
toe (12) toward its back or heel (16), and may optionally extend in
a curved manner in order to, for example, to correspond to the
location(s) of a typical foot's lines of flex and/or flexibility in
the longitudinal direction or simply for a desirable fashion
element. When such multiple longitudinally extending central flex
elements are present, the various segments need not be parallel to
one another and they need not extend in precisely the same
directions, in the same arch or curvature, or at the same
dimensions (e.g., to the same depth in the base level, at the same
width or length, etc.)
[0054] Similarly, while referred to as extending in the "lateral
direction", the central flex channel (72) and the corresponding
central flex element (62) creating the line of flex need not extend
exclusively in a direction laterally across the sole structure.
Rather, as shown in the figures, the term "lateral direction", as
used herein in this context, means that the central flex channel
(72) and the corresponding central flex element (62) creating the
line of flex defined thereby extend predominantly in the lateral
direction (e.g., generally from the shoe's lateral side toward its
medial side), optionally in a curved manner (e.g., to correspond to
a typical foot's lines of flex and/or flexibility in the lateral
direction), as illustrated in FIGS. 2 and 5. Additionally, if
desired, it is not necessary for an individual central flex channel
(72) and the corresponding central flex element (62) to extend
completely across the sole. They may extend any desired distances.
When multiple laterally extending central flex channels are present
(e.g., additional central flex channels in the heel and forefoot
portions, etc.), the various central flex channels need not be
parallel to one another and they need not extend in precisely the
same directions, in the same curvature, or at the same dimensions
(e.g., to the same depth in the base level, at the same width or
length, etc.). Optionally, if desired, the central flex elements
and lines of flex in the outsole structure may correspond to
typical areas of flex or joints in a wearer's foot. Also, if
desired, lines of flex may be provided in the heel area in at least
some example sole structures. Such designs allow the wearer to
adjust more naturally to a particular terrain, where for example
the lateral side may flex more than the medial side and vise versa.
Such footwear allows more of the sole to remain in contact with the
ground providing a solid base for support for movement and
activity.
Additional Elements
[0055] The footwear according to some examples of this invention
may include additional features or structures. If desired, some
portions of the shock absorbing cushion (60) and/or of the outsole
(70) may be at least partially filled with another material, e.g.,
a material softer than a material making up a major portion of the
shock absorbing cushion or the outsole, to further promote the
flexibility characteristics of the shoe's structure while
preventing wearer feel of ground elements.
[0056] The footwear further may include plural ground penetrating
traction elements, commonly referred to as "traction lugs" (78),
illustrated in FIG. 5. The shape of the traction lugs is determined
by the positions of the various treads, or spaces that extend
upward into the outsole material and extend between the sole
elements forming an articulated configuration of the bottom
ground-facing surface of outsole. For example, the outsole (70) may
include one or more traction lugs in its forefoot or heel portions,
extending in the lateral or longitudinal directions on the bottom
surface of the outsole. Preferably the traction lugs will be placed
at locations corresponding to natural foot flexibility, to provide
additional flexibility and lines of flex and to further improve
traction capability in desired applications. Typical embodiments of
the invention will comprise outsoles having a "breasted" heel with
lateral tread to render improved traction to the shoe, thus
allowing full range of motion such as walking, running or climbing.
Accordingly, tread marks are formed and distributed over the bottom
surface of the outsole to selectively vary the degree of stretch
and flexibility in specific portions of the outsole. In addition to
functionality, the traction lugs and tread marks are often applied
to vary the overall aesthetics (e.g., color) of the outsole of the
shoe as desirable to consumers.
[0057] Additional traction elements, such as golf spikes, may be
attached at various locations on the exterior surface of the
outsole. These traction elements may be mounted to the outsole
member in any desired manner, including via threads, other
retaining systems, etc., including through the use of conventional
mounting systems that are known and used in the art. Any type or
arrangement of traction elements may be used without departing from
the invention. Such traction elements may be included as part of
the sole structure in any desired manner without departing from the
invention, such as by integrally molding them into the sole
structure along with other portions of the sole or by attaching
them to the sole structure (e.g., by adhesives, cements, screws,
clasps, retaining elements, other mechanical connectors, etc.) If
desired, according to at least some examples of this invention,
traction elements of the types and/or in the arrangements shown in
U.S. Pat. Nos. 6,817,117 and/or 6,705,027 may be used without
departing from this invention, each of which is incorporated herein
by reference. Additionally or alternatively, if desired, any
indentations, weld areas, or other recessed structures on the
exterior surfaces of the outsole may include additional support
structures, such as plastic supports (e.g., PEBAX.RTM. (a
polyether-block co-polyamide polymer available from Atofina
Corporation of Puteaux, France), which can help make the lateral
side more stable and less flexible than the medial side. In
addition, other ways of providing lateral support and/or medial
flexibility may be used, in place of or in combination with the
various examples described above, without departing from the
invention. Also, if desired, various types of heel units, midsole
elements, or impact-attenuating elements or structures may be
provided without departing from the invention, such as conventional
foam or other impact-attenuating materials, columnar shock
absorbing type elements and the like.
[0058] It is one advantage of the invention that if components of
the sole (30) of the invention becomes worn or otherwise damaged,
the damaged component may be replaced without the necessity of
replacing the undamaged component, and the damaged component may be
more easily recycled. For example, since the outsole will be
generally formed from a polymer material, following significant
use, the polymer foam material may experience compression set or
otherwise degrade or become significantly worn. Rather than dispose
of the footwear (10), either the shock absorbing cushion (60) or
the outsole (70) may be properly recycled and replaced with an
alternate component, respectively, thus extending the lifespan of
the footwear. In the event that the lateral region (80) of the
outsole becomes punctured, only the lateral outsole component can
be replaced, without replacing the medial region (90) of the
outsole and in lieu of replacing the entire outsole. Furthermore,
the outsole may be interchanged with alternate components to suit a
particular activity or a preference of an individual.
Manufacturing
[0059] A number of manufacturing methods are suitable for forming
the sole elements of the invention. Conventional footwear
construction generally follows two methods, welted construction and
molded construction. In the invention herein, the outsole may be
formed as a unitary element with the central flex channel (72)
subsequently formed through an incision process, for example. The
outsole may also be molded such that the central flex channel is
formed during the molding process. Suitable molding methods for the
outsole, the shock absorbing cushion, and the midsole include
injection molding, pouring, or compression molding, for example. In
each of the molding methods, a blown polymer resin is placed within
a mold having the general shape and configuration of the desired
structural element. The mold includes thin blades that correspond
with the positions of the flex channels. The polymer resin is
placed within the mold and around each of the blades. Upon setting,
the structural element is removed from the mold, with the desired
dimensions being formed during the molding process.
[0060] The central flex channel (62) of the invention may be
provided in the outsole (60) structure during the manufacturing
process, such as during a sole member molding process, by a cutting
action (e.g., using knives, blades, lasers, etc.), and/or in any
other manner, including in conventional methods known and used in
the art for the manufacture of outsoles. Any desired types of
materials may be used for the structures of the shock absorbing
cushion (60) and central flex element (62) and the outsole (70)
structures, including rubber or polymeric materials (such as
thermoplastic polyurethanes), including materials that are known
and conventionally used in the art. As some more specific examples,
the outsole material may be constructed from a rubber material,
e.g., having a hardness of 60 to 90 Shore A (and in some examples,
64-70 Shore A), and the shock absorbing cushion (60) material may
have about the same level of hardness, or perhaps a bit softer
(optionally made from rubber or a thermoplastic polyurethane
material). The material of the shock absorbing cushion (60) and
central flex element (72) need not be the same material as the
outsole (70), and can be made of either a harder or a softer
material. Of course, a wide variety of materials, hardness,
combinations of materials, and/or combinations of hardness may be
used without departing from the invention.
[0061] As discussed above, the sole (30) is permanently secured to
the lower portion of the upper (20). A variety of attachment
techniques may be utilized for permanently securing the outsole to
the sides of the upper, including stitching, adhesive bonding,
thermobonding, or a combination thereof, for example.
[0062] The various structural features and the various aspects of
the invention described above may be used in any desired
combinations, permutations, and sub-combinations without departing
from the invention. It will be apparent to those skilled in the art
that various modifications may be made to the present invention
without departing from the intended scope of the invention since it
is not considered limited to the specific embodiments described in
the specification and drawings.
* * * * *