U.S. patent application number 11/976186 was filed with the patent office on 2008-02-21 for sand walking sandal.
Invention is credited to Marshall G. Moseley.
Application Number | 20080040949 11/976186 |
Document ID | / |
Family ID | 36992178 |
Filed Date | 2008-02-21 |
United States Patent
Application |
20080040949 |
Kind Code |
A1 |
Moseley; Marshall G. |
February 21, 2008 |
Sand walking sandal
Abstract
The sand walking sandal is a hinged sandal for walking on sand
having a forward sole section with a foot receiving portion located
thereon and an extended forward sole width portion extending
outward and laterally from the foot receiving portion. A rearward
sole section has a foot receiving portion located thereon, an
extended rearward sole width portion extending outward and
laterally from the foot receiving portion, and a rearward sole
section length extension projecting rearward from the foot
receiving portion. A flexible hinge joins the forward and rearward
sole sections together, allowing each of the sole sections to
angularly rotate about the flexible hinge independent of each
other. A foot retaining thong or footwear retaining straps are
mounted on the foot receiving portion for securing a user's foot to
the hinged sandal.
Inventors: |
Moseley; Marshall G.;
(Destin, FL) |
Correspondence
Address: |
LITMAN LAW OFFICES, LTD.
P.O. BOX 15035
CRYSTAL CITY STATION
ARLINGTON
VA
22215
US
|
Family ID: |
36992178 |
Appl. No.: |
11/976186 |
Filed: |
October 22, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11259153 |
Oct 27, 2005 |
7284341 |
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11976186 |
Oct 22, 2007 |
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60622420 |
Oct 27, 2004 |
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60660079 |
Mar 9, 2005 |
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Current U.S.
Class: |
36/103 ;
36/11.5 |
Current CPC
Class: |
A43B 3/0026 20130101;
A43B 3/126 20130101; A43B 13/141 20130101; A43B 3/122 20130101;
A43B 3/108 20130101; A43B 3/26 20130101; A43B 13/16 20130101; A43B
3/103 20130101; A43B 3/20 20130101; A43B 3/128 20130101 |
Class at
Publication: |
036/103 ;
036/011.5 |
International
Class: |
A43B 13/00 20060101
A43B013/00; A43B 3/12 20060101 A43B003/12 |
Claims
1-10. (canceled)
11. A sandal sole system for walking on sand, said system
comprising: a rigid forward sole section having a footwear
receiving portion disposed thereon; a forward footwear retaining
strap assembly disposed on said forward sole section; a rigid
rearward sole section having a footwear receiving portion disposed
thereon, a rearward sole section length extension projecting
rearward from the footwear receiving portion, the rearward sole
section length extension being integral with the rearward sole
section; a rearward footwear retaining strap assembly disposed on
the rearward sole section; a middle sole section joining said
forward sole section and said rearward sole section; and a flexible
hinge joining the forward and middle sole sections, and said middle
and rearward sole sections together, the hinge allowing each of the
sole sections to angularly rotate about the flexible hinge
independent of each other.
12. The sandal sole system of claim 11, further comprising a
forward stationary foot-strap anchor and a forward adjustable
foot-strap anchor disposed in said forward sole section, the
anchors securing said forward footwear retaining strap assembly to
said forward sole section.
13. The sandal sole system of claim 11, further comprising a
rearward stationary foot-strap anchor and a rearward adjustable
foot-strap anchor disposed in said rearward sole section, the
anchors securing said rearward footwear retaining strap assembly to
said rearward sole section.
14. The sandal sole system of claim 11, wherein: said forward sole
section further comprises an extended forward sole width portion
extending outward and laterally from the foot receiving portion,
the extended forward sole width portion being integral with the
forward sole section; and said rearward sole section further
comprises an extended rearward sole width portion extending outward
and laterally from said foot receiving portion, the extended
rearward sole width portion being integral with the rearward sole
section; said extended forward and rearward sole width portions are
about 0.75 to 1.5 inches in extended width.
15. The sandal sole system of claim 11, wherein said forward,
middle and, rearward sole sections each have internal cavities
formed therein for reducing the weight of said forward and rearward
sole sections.
16. The sandal sole system of claim 11, wherein said rearward sole
length extension is about 1.125 to 1.5 inches in length, said
extension extending behind the footwear receiving portion of said
rearward sole section.
17. The sandal sole system of claim 11, wherein an inverted,
downwardly opening, transversely extending V-shaped notch is
defined between said forward and middle soles sections, and said
middle and rearward sole sections.
18. The sandal sole system of claim 11, wherein said forward and
rearward footwear retaining strap assemblies each further comprise:
adjustable foot-strap anchors mounted on said forward and rearward
sole sections; retaining straps secured to said forward and
rearward sole sections; and corresponding stud-mate attachments
attached to the retaining straps for releaseable attachment to said
adjustable foot-strap anchors to allow a user to easily attach and
detach footwear from said sandal sole system.
19. The sandal sole system of claim 11, further including a
footwear heel backstop disposed on the rearward sole section.
20. The sandal sole system of claim 11, wherein said middle sole
section includes a plurality of sole sections joining said forward
and rearward sole sections.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional
Patent Application Ser. No. 60/622,420, filed Oct. 27, 2004 and
U.S. Provisional Patent Application Ser. No. 60/660,079, filed Mar.
9, 2005.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The present invention relates to footwear, specifically an
improved sandal with a flexibly-hinged, three-part, extended, rigid
sole system that is designed to enable normal, full-stride walking
on very soft sand.
[0004] The present invention additionally relates to footwear,
specifically a sandal designed for use with feet that are also clad
in conventional walking shoes or jogging sneakers. The invention's
objective of eliminating deep foot sinking is achieved by employing
a flexibly-hinged, three-part, rigid sole system comprised of
three, rigid sole sections: a forward sole section, a middle sole
section, and a rear sole section.
[0005] 2. Description of the Prior Art
[0006] Rigid sole sandals and clogs have long been the footwear of
choice for walking on very soft sand, like that typically found at
beach and desert locations. The reason for this preference is that
conventional, rigid sole sandals and clogs, as opposed to
conventional, flexible sole sandals, function significantly better
in preventing foot sinking. But, this superior performance occurs
only when the sandal-wearer is engaged in short-stride walking, not
full-stride walking. Prior to the present invention there has never
been a sandal, flexible sole or rigid sole, that could eliminate,
or even significantly reduce, deep foot sinking during full-stride
walking without also being accompanied by very serious, negative
side effects such as having to walk with one's feet positioned
further apart than normal. During past history some inventors must
surely have attempted to solve the foot-sinking problem in the most
obvious way, by designing sandals with over-sized soles, not too
unlike old-fashioned snow shoes that look like tennis rackets, that
indeed would eliminate deep foot sinking in soft sand during
full-stride walking. Most such solutions, however, would also have
been accompanied by very serious side effects such as awkwardness
and discomfort when walking, which would explain why we do not see
any such products on the market today. Beach goers who prefer
full-stride walking to short-stride walking, have traditionally had
to restrict their walking to the water's edge where the sand is
firmer and where there is little foot sinking.
[0007] The conventional, rigid sole sandal or clog that is most
commonly used for walking on very soft sand is comprised of a
one-part, rigid sole and a thong for securing that sole to a
person's foot. The size of the sole universally conforms, more or
less, to the size and shape of the sandal-wearer's foot; and the
foot's heel is always positioned very close to the back edge of the
sole.
[0008] The foot-sinking problem can be better understood by
analyzing the performance of a conventional, one-part, rigid sole
sandal or clog during the various stages of a full-stride walking
cycle, as explained below.
[0009] When wearing conventional, one-part, rigid sole sandals or
clogs and engaged in full-stride walking, vs. short-stride walking,
the sandal-wearer's upper body begins the cycle by leaning forward
as a foot is thrust forward in the air, above the soft sand, toward
a first step. At the same moment, the trailing foot responds to the
body's forward motion by instinctively arcing its heel and instep
upward, away from the back portion of the sandal sole as half of
the sandal-wearer's body's weight, which had been supported by the
heel, shifts forward to the ball joints of the toes, and with a
small amount to the toes themselves.
[0010] As the sandal-wearer's body and outstretched leading leg
continue their forward movement, the heel and instep of the
trailing foot continue their arcing motion upward as the instep
begins pressing firmly against the thong straps that wrap across
and around it. But, because the body's full weight is pressing
heavily down upon the forward portion of the sandal's one-part,
rigid sole, the entire sole is held down flatly and firmly upon the
soft sand, causing the tension upon the thong straps to become
greater and greater. After causing considerable foot discomfort the
ever-increasing tautness of the thong straps eventually overcomes
the pressure of the sandal-wearer's heavy body weight pressing the
forward portion of the one-part, rigid sole firmly upon the
sand.
[0011] As the back portion of the sandal sole is forced up above
the soft sand by the pulling thong straps, at an angle of roughly
15 to 25 degrees, the entire sole (which is constructed of one
rigid piece) is forced up at that angle. When the tilting occurs,
the front end of the sole immediately punches deeply down into the
soft sand (approximately 1.25 to 2 inches, or more) as a result of:
(1) the heavy, body weight pressure that continues to be
concentrated at the forward end of the sandal sole; and (2) the 15-
to 25-degree angle of the sandal sole.
[0012] When the rear portion of the sandal sole is forced up above
the soft sand at an angle, it leaves the forward portion of the
sandal with an insufficient number of square inches of sole surface
area in contact with the soft sand to fully support the body's
weight. Consequently, the forward end of the sole immediately
punches down into the soft sand until enough square inches of sole
surface area are once again in contact with the soft sand to
support the sandal-wearer's heavy body weight.
[0013] It should be noted that when any flat plane comes in contact
with soft sand while positioned at an angle, its weight-supporting
capability per-square-inch of surface contact is diminished; and
when the angle of the plane increases, its weight-supporting
capability decreases--an inverse proportion. To be precise, the 15-
to 25-degree angle of the sole reduces the sole's weight-supporting
capability by 16.7% to 27.8%, respectively. Immediately after that
abrupt foot sinking of the trailing foot, the sandal-wearer's
full-body weight is instinctively shifted from the trailing foot,
forward to the heel of the leading foot as it strikes the soft sand
ahead at a 15- to 25-degree angle at the completion of its airborne
stepping action forward. And, for basically the same reasons listed
for the trailing foot above, the leading foot sinks down deeply
(approximately 1.25 to 2 inches, or more) into the soft sand ahead
because: (1) the heavy, body weight pressure is concentrated
totally upon the foot's heel which is positioned at, or very near,
the back edge of the sandal sole; and (2) the sandal sole is
positioned at a 15- to 25-degree angle, in its relationship to the
surface of the sand.
[0014] When the rear portion of the sandal sole strikes the soft
sand at an angle, it has an insufficient number of square inches of
sole surface area in contact with the soft sand to fully support
the body's weight because the forward portion of the sandal is
still positioned above the soft sand. Consequently, the back end
portion of the sole punches down deeply into the soft sand until
enough square inches of sole surface area come in contact with the
soft sand to support the sandal-wearer's heavy body weight. Had the
stepping action been a short-stride step, vs. a full-stride step,
the leading leg and foot, as well as the trailing leg and foot,
would have been positioned at a much lesser angle, and consequently
the sandal-wearer would have experienced very little foot sinking,
and very little, or no, foot discomfort due to thong pressures.
[0015] The degree of foot sinking that occurs on very soft sand is
directly proportional to the angle of the sandal sole, and
indirectly proportional to the square-inch area of sandal sole that
is in contact with the soft sand. In further explanation, it should
be noted that during full-stride walking, when the leading leg is
thrust forward at a 15- to 25-degree angle, in its relationship to
the vertical, the sandal-wearer's foot and sandal sole both strike
the soft sand at approximately that same 15- to 25-degree angle,
but in relationship to the soft sand, not the vertical, maintaining
the anatomically natural and instinctive 90-degree angle
relationship between the leg and the foot. In further explanation
still, when a leg is thrust forward in the air toward a new step, a
person's body instinctively locks the foot of that leg at an angle
of approximately 90 degrees, in its relationship to the leg, in
anticipation of the person's heavy body weight being totally
concentrated upon the heel of the foot upon impact with the soft
sand ahead.
[0016] Wearers of conventional, rigid sole sandals avoid the
foot-sinking problem by simply engaging in short-stride steps only.
This action results in the outstretched legs and feet being
positioned at a much lesser angles, and consequently very little
foot sinking.
[0017] The foot-sinking problem can also be better understood by
analyzing the performance of a conventional, walking shoe during
the various stages of a full-stride walking cycle.
[0018] When wearing conventional walking shoes or jogging sneakers,
while engaged in full-stride walking or jogging on very soft sand,
as the sandal-wearer's upper body moves forward to take a step, a
foot is thrust forward in the air above the sand's surface. But,
before that leading foot makes contact with the soft sand ahead,
the heel of the trailing foot instinctively arcs upward, away from
the surface of the soft sand, in preparation for that foot being
lifted airborne off the soft sand and thrust forward toward its own
next step.
[0019] As the foot's heel arcs upward, the sandal-wearer's total
body weight becomes concentrated totally upon the ball joints of
the toes, and with a small amount concentrated upon the toes
themselves. As the sandal-wearer's upper body continues its move
forward, and the leading leg is nearing completion of its airborne
stepping action forward, the heel of the trailing foot arcs upward
even higher, and the angle of each of the sandal-wearer's
outstretched legs, in their relationship to the vertical, becomes
quite pronounced--roughly 15 to 25 degrees. But, before the heel of
the trailing foot completes its arcing movement upward, the sole of
that shoe reaches its maximum degree of flexibility, thereby
causing the front portion of the shoe sole to cease flexing and
begin tilting downward into the soft sand as the heel continues its
arcing movement upward.
[0020] By the time the heel completes its upward arc, the front
portion of the foot's shoe sole has tilted downward in front at an
angle of roughly 15 to 25 degrees, and there is an insufficient
number of square-inches of sole surface area in contact with the
soft sand to support the body's full weight. As a result, 1.25
inches to 2.5 inches, more or less, of foot sinking results before
there are enough square-inches of sole surface area in contact with
the soft sand to support the body's weight.
[0021] Had the trailing foot been positioned at a much lesser
angle, as it is during short-stride walking, very little less foot
sinking would have occurred. The amount of foot sinking that occurs
on very soft sand is directly proportional to the angle of the shoe
sole, in its relationship to the surface of the soft sand, and is
indirectly proportional to the square-inch surface area of that
portion of the shoe sole that remains in contact with the soft
sand.
[0022] Wearers of the conventional, flexible-sole shoes being
discussed, are forced to walk with short strides, vs. full strides,
to cause the shoe sole to be positioned at a much lesser angle, and
consequently cause much less foot sinking to occur before enough
square-inches of sole surface area are in contact with the soft
sand to support the body's weight. In this particular instance,
immediately following the foot sinking that occurs with the
trailing foot, the beach walker's full-body weight is instinctively
shifted away from the ball joints of the toes portion of the
trailing foot, forward to the heel of the leading foot, as it
strikes the soft sand ahead while being positioned at a 15 to 25
degree angle, at the completion of its airborne stepping action
forward, as explained more fully in the next paragraph.
[0023] When the leading foot strikes the soft sand, its angular
orientation to the surface of the soft sand, causes it to sink down
into the soft sand until enough square-inches of the sole's surface
area come in contact with the soft sand to support the
sandal-wearer's full-body weight. The amount of foot sinking that
occurs depends upon the severity of the foot angle and the body
weight of the individual. The less the angle, the less the foot
sinking, and the less the body weight, the less the foot sinking;
but the sinking normally ranges from roughly 1.25 inches to 2.5
inches.
[0024] The phenomena of the sandal-wearer's foot changing its angle
of orientation, in its relationship to the sand's surface, occurs
during short-stride walking cycles also, but to a much lesser
extent. In explanation, when a leg is thrust forward in the air
toward a new step forward, the human body instinctively locks the
foot of that leg at its most natural anatomical angle
(approximately 90 degrees), in its relationship to the leg, in
anticipation of the body's full weight being concentrated upon the
heel of the sandal-wearer's foot when the foot and sandal contact
the soft sand ahead. And, during full-stride walking, because the
leg is thrust forward at a 15 to 25 degree angle, in its
relationship to vertical, the sandal-wearer's foot and sandal sole
strike the soft sand at approximately that same 15 to 25 degree
angle, in its relationship to the soft sand.
[0025] During short-stride walking the leg is thrust forward at a
much lesser angle; and, consequently, the sandal-wearer's foot and
sandal sole strike the soft sand at roughly that same lesser angle,
thereby causing a much smaller amount of foot sinking to occur. It
should be noted that the support capability of a square-inch of a
shoe's sole on very soft sand is diminished by almost the same
percentage as the angle of the sole, in its relationship to the
sand's surface. A 15- to 25-degree angle reduces the support
capability of the footwear sole by 16.7 to 27.8 percent. A
45-degree angle reducing the support capability of a sole by 50
percent. A hypothetical 90-degree angle reduces the support
capability of a sole by 100 percent.
[0026] Also, when a shoe's sole makes contact with very soft sand
at the completion of the airborne stage of a full-stride, stepping
action forward, its 15- to 25-degree angle orientation with the
sand, causes only a miniscule amount of surface contact to take
place initially along the back edge of the shoe sole. The small
area of surface contact results in almost no initial sand
resistance. But, as the body's heavy weight forces the sandal's
sole to sink down deeply into the soft sand, more and more of the
shoe's sole surface area comes in contact with the soft sand, until
there are enough square-inches of sole contact with the soft sand
to support the body's full weight, and the sinking stops.
[0027] For example, when contact is made with the foot positioned
at an 18-degree angle, the shoe's sole must sink down approximately
1.625 inches before 5 linear inches of the shoe's sole come into
contact with the soft sand. When contact is made with the foot
positioned at a 25-degree angle, the sandal sole must sink down
approximately 2.3 inches before 5 linear inches of sole come in
contact with the soft sand. The actual number of linear inches
needed to support a sandal-wearer's full weight, of course, depends
upon the shoe's width, the sandal's angular orientation, and the
body weight of the sandal-wearer.
[0028] Although hinged, multi-section, rigid sole footwear dates
back to several patents of the early 1900s (and possibly before),
the idea has never been employed for any purpose other than to
alleviate the foot discomfort caused by the inflexibility of
rigid-sole sandals and clogs. In those early patents, the hinged,
two-part (or more) rigid sole systems introduced flexibility to
rigid sole footwear, making the walking process much less
cumbersome and much more comfortable by making the movements of the
sole conform more to the foot's movement, thereby eliminating most
of the thong pressures created by one-piece, rigid sole
footwear.
[0029] In the present invention, however, the flexibly-hinged,
three-part, rigid sole system not only eliminates foot discomfort,
but also works in tandem with the novel idea of added extra sole
length behind the sandal-wearer's heel to make possible the
employment of inverted mechanical leverage to greatly reduce deep
foot sinking.
[0030] The present invention, with its extended sole length and
extra sole width, looks like an over-sized sandal and is quite
unconventional and strange-looking, but it functions exceptionally
well, and allows beach- and desert-lovers to walk normally on very
soft sand with almost the same degree of ease and comfort as
walking on firmer surfaces. With the present invention there is no
need to be confined to short-stride steps to avoid foot sinking,
and there is no need to concentrate on one's walking in an effort
to lessen foot sinking.
[0031] Thus, a sand walking sandal solving the aforementioned
problems is desired.
SUMMARY OF THE INVENTION
[0032] A hinged sandal for walking on sand having a forward sole
section with a foot receiving portion located thereon and an
extended forward sole width portion extending outward and laterally
from the foot receiving portion. A rearward sole section has a foot
receiving portion located thereon, an extended rearward sole width
portion extending outward and laterally from the foot receiving
portion, and a rearward sole section length extension projecting
rearward from the foot receiving portion, wherein the extended
rearward sole width portion and the rearward sole section length
extension are integral with the rearward sole section. A flexible
hinge joins the forward and rearward sole sections together
allowing each of the sole sections to angularly rotate about the
flexible hinge independent of each other. A foot retaining thong or
footwear retaining straps are mounted on the foot receiving portion
for securing a user's foot to the hinged sandal.
[0033] The first objective of the present invention is to provide
an improved sandal that will allow full-stride walking on very soft
sand without the deep foot sinking and thong pressure discomforts
that have forever been deficiencies of all known one-part, rigid
sole sandals and clogs, which are the footwear of choice for the
overwhelming majority of people when walking on soft sand. The two
causes of foot sinking when walking on very soft sand are: (1) the
heavy body weight of the sandal wearer, and (2) the instinctive
positioning of the sandal wearer's foot at an angle, in its
relationship to the soft sand, during several stages of the
full-stride walking cycle. The angle occurs as the outstretched
leading foot strikes the soft sand ahead during a stepping action
forward, and as the outstretched trailing foot is being lifted up
off the soft sand to begin its next step forward.
[0034] The present invention circumvents the angle of the foot
problem by having a flexibly-hinged, three-part, rigid sole system
that has extra sole length added behind the heel of the
sandal-wearer's foot to employ the principles of inverted
mechanical leverage to force the three sole sections to lie down
flatly upon the soft sand whenever they are supporting any
significant amount of body weight, thereby eliminating the problem
of deep foot sinking.
[0035] The thong pressure discomfort problem is eliminated by
adding flexibility to the one-part rigid sole by dividing it into
three, flexibly-hinged, rigid sole sections, which are more
compatible with the flexing actions of the foot.
[0036] Additional sole width has been added to each of the three
sole sections to increase the number of square inches of sole
surface area for each of the three sections. This additional width
reduces the amount of body weight pressure supported
per-square-inch of sole surface area for each of the three sole
sections, thereby reducing foot sinking even more. The present
invention makes all walking on very soft sand almost as comfortable
and easy as walking on firm surfaces with conventional footwear,
except for the occasional tilting of the foot sometimes caused by
sand surface irregularities.
[0037] Although the hinged, multi-sectioned, rigid sole idea dates
back to a hand full of clog patents of the early 1900s, the idea
has never been employed for any purpose other than for smoother
walking and to alleviate the foot discomfort that is caused by
thong pressures created during the full-stride walking cycle as a
result of the rigid sole's inflexibility. In those early patents,
the hinged, two-section (or more) sole systems eliminated the thong
pressures by incorporating flexibility into the rigid sole of the
clog by dividing the traditional one-part sole into two or more
parts, each joined by some form of hinge. In the present invention,
however, the flexibly-hinged, three-part, rigid sole idea is
combined with the simple, but crucially important, concept of
adding extra sole length behind the sandal-wearer's heel to make
possible the employment of inverted mechanical leverage to solve
the deep foot-sinking problem--a totally "new and unique" concept
for which a patent is being sought. Adding additional sole width
simply reduces the foot sinking even more.
[0038] The second objective of the present invention is to provide
a sandal for use with walking shoes and jogging sneakers, that will
allow full-stride walking and jogging on very soft sand without
deep foot sinking. This is accomplished by designing a sandal with
a flexibly-hinged, three-part, rigid-sole system that is
significantly lengthened behind the heel of the sandal-wearer's
foot. The design features interact to employ inverted mechanical
leverage to eliminate the deep foot sinking which is a deficiency
of all known conventional footwear when engaged in full-stride
walking on very soft sand. The problematic foot sinking is reduced
even further by designing the sandal sole system with extra sole
width to reduce the amount of body weight supported per-square-inch
of sole. All of the above-listed design/construction features work
together to eliminate all but an insignificant amount of foot
sinking.
[0039] The foot sinking that occurs with conventional footwear is
primarily the result of the angle of the foot, in its relationship
to the sand's surface, during two stages of the walking cycle. The
angling occurs once when the walker is engaged in an airborne step
forward. During this stage of the walking cycle, the angle of the
out-stretched leading leg (in its relationship to the vertical)
causes the foot and shoe to strike the soft sand ahead at a 15- to
25-degree angle, more or less, in its relationship to the sand's
surface. When this occurs, the body's full weight is concentrated
upon the heel of the leading foot and shoe, causing the back
portion of the shoe to sink down deeply into the soft sand, 1.25 to
2.5 inches, or more, before enough square-inches of shoe surface
area come in contact with the soft sand to support the body's full
weight.
[0040] The problematic angle of the shoe occurs a second time
during the walking cycle with the opposite, trailing foot as the
leading foot is being thrust in the air toward its next stepping
action forward. As this action is occurring, the heel of the
trailing foot and the heel of the shoe instinctively arc upward
together, above the surface of the soft sand, in anticipation of
their own next step forward. Just before the heel of the leading
foot makes contact with the surface of the soft sand ahead, the
heel of the trailing foot and the heel of the shoe arc up even
higher, causing the back portion of the shoe to rise high above the
surface of the soft sand, which causes the front portion of the
shoe to angle downward, and sink deeply into the soft sand until
enough square-inches of the shoe sole's surface area once again
come in contact with the soft sand to support the body's full
weight. The reduced square-inch area of sole contact with the soft
sand causes the sinking to occur. Also relevant is the fact that
the support capability of every square-inch of a sole's bottom
surface, that is in contact with soft sand, is diminished by almost
the same percentage as the angle of the sole, in its relationship
to the sand's surface. A 25-degree angle reduces the support
capability of the footwear sole by 27.8 percent, and a 45-degree
angle reducing the support capability of a sole by 50 percent,
etc.
[0041] With the present invention, however, the outcome of the same
two stages of the walking cycle, described above, is dramatically
different. During the stage when the sandal-wearer is taking an
airborne step forward, the leading foot strikes the soft sand ahead
at exactly the same angle as with conventional footwear. With the
present invention, however, the sandal-wearer's heel functions as a
weighted fulcrum of an inverted mechanical lever, with the
sandal-wearer's full-body weight forcing the sandal's rear sole
section to instantly plop down firmly and flatly upon the soft sand
within a split second after contact is made with the soft sand,
which results in an insignificant amount of foot sinking. This
action occurs even while the sandal-wearer's foot and shoe remain
positioned at the angle that it was in when the plop-down action
occurred.
[0042] As the walking cycle continues, the sandal-wearer's upper
body continues moving forward until it passes directly over the
leading foot. This movement forward causes the leading foot to arc
downward from its angular orientation until it is flatly positioned
upon the soft sand, and no longer at an angle. As the foot is
arcing downward, it functions as a weighted fulcrum of an inverted
lever, forcing the middle sole section and the forward sole section
of the sandal sole to lie down flatly upon the soft sand, one after
the other, in succession, where roughly 1/2 of the body's weight,
which had been totally concentrated upon the heel, now becomes
concentrated mostly upon the ball joints of the toes, and with a
small amount upon the toes themselves, and distributed throughout
the entire forward sole section.
[0043] During the other relevant stage of the walking cycle, when
the sandal-wearer's leading foot is engaged in an airborne step
forward, the heel of the trailing foot arcs upward above the sand
in anticipation of that foot being lifted up off the soft sand, and
thrust forward in the air toward its next step. During this arcing
action of the heel, the rear sole section's elastic foot-strap
assembly keeps the rear sole section pulled snugly up beneath the
sole of the sandal-wearer's shoe as the heel reaches its maximum
angle upward.
[0044] And, because of the flexibly-hinged, three-part, rigid-sole
system, the heel's arcing action leaves the forward sole section of
the sandal completely undisturbed, and positioned firmly and flatly
upon the soft sand, supporting the body's full weight until that
weight is removed when it shifts forward to the opposite foot. When
the leading foot strikes the soft sand ahead, at the completion of
its airborne step forward, the body's full weight is instinctively
shifted off of the trailing foot, totally forward to the leading
foot.
[0045] During the two stages of the walking cycle listed above, the
three sole sections are each positioned firmly and flatly upon the
soft sand for the entire time that they are supporting any
significant amount of body weight, thereby nullifying the deep foot
sinking that is normally caused by the angle of the sandal-wearer's
foot. The body weight part of the foot-sinking problem is lessened
by the entire sole system being designed with an extra width of
0.75 inch to 1.5 inches, more or less. This causes the body-weight
pressure per-square-inch of sandal sole surface area to be
significantly reduced, which correspondingly results in even less
foot sinking. The small amount of foot sinking that remains is
totally insignificant.
[0046] These and other features of the present invention will
become readily apparent upon further review of the following
specification and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0047] FIG. 1 is a perspective view of the right foot sandal facing
to the right, as seen from the top, right rear of the sandal.
[0048] FIG. 2 is an overhead view of the right foot sandal facing
to the right and showing the exterior surfaces only.
[0049] FIG. 3 is an overhead view of the right foot sandal facing
to the right, showing the exterior surfaces and a silhouette of a
sandal-wearer's foot correctly positioned on the sandal.
[0050] FIG. 4 is an exploded view of the right foot sandal facing
to the right, as seen from the top, right, rear of the sandal, and
showing the various layers of the sandal sole.
[0051] FIG. 5 is a front elevation view of the right foot sandal
showing a cross-sectional view of the forward sole section, as
identified by line A-A of FIG. 6.
[0052] FIG. 6 is a side elevation view of the right foot sandal
facing to the left that includes a cross-sectional view as
identified by line B-B of FIG. 7.
[0053] FIG. 7 is a bottom view of the right foot sandal facing to
the left, showing the exterior surfaces of the sandal.
[0054] FIG. 8A is the first drawing of a 6-part sequence FIGS. 8A,
8B, 8C, 8D, 8E and 8F depicting the various stages of a full-stride
walking cycle. This drawing depicts the right foot sandal
configuration at the moment that it first touches the surface of
the soft sand after having been thrust forward in the air toward a
new step.
[0055] FIG. 8B is the second drawing of a 6-part sequence FIGS. 8A,
8B, 8C, 8D, 8E and 8F depicting the various stages of a full-stride
walking cycle. This drawing depicts the right foot sandal
configuration a split second after the back end of the rear sole
section strikes the surface of the soft sand.
[0056] FIG. 8C is the third drawing of a 6-part sequence FIGS. 8A,
8B, 8C, 8D, 8E and 8F depicting the various stages of a full-stride
walking cycle. This drawing depicts the right foot sandal
configuration the moment after roughly half, of the sandal-wearer's
body weight has shifted from the heel of the foot, forward to the
ball joints of the toes, and a small amount to the toes
themselves.
[0057] FIG. 8D is the fourth drawing of a 6-part sequence FIGS. 8A,
8B, 8C, 8D, 8E and 8F depicting the various stages of a full-stride
walking cycle. This drawing depicts the right foot sandal
configuration just after the foot's heel has begun its arc upward,
away from the back portion of the sandal's rear sole section.
[0058] FIG. 8E is the fifth drawing of a 6-part sequence FIGS. 8A,
8B, 8C, 8D, 8E and 8F depicting the various stages of a full-stride
walking cycle. This drawing depicts the right foot sandal
configuration as the foot's heel is reaching the highest point of
its arc upward as the sandal-wearer's upper body continues its move
forward toward the next step being taken by the opposite foot.
[0059] FIG. 8F is the sixth drawing of a 6-part sequence FIGS. 8A,
8B, 8C, 8D, 8E and 8F depicting the various stages of a full-stride
walking cycle. This drawing depicts the right foot sandal
configuration just after all of the body's weight has instinctively
shifted forward to the opposite foot, as it is lifted up into the
air, above the soft sand, during the initial phase of its thrust
forward toward a new step.
[0060] FIG. 9 is a perspective rear view of an alternative
embodiment of a left foot sandal facing to the left, as seen from
the top, left, rear of the sandal.
[0061] FIG. 10 is an overhead view of the left foot sandal facing
to the left and showing the exterior surfaces and dashed-line
indications of some non-surface portions.
[0062] FIG. 11 is a side elevation view of the left foot sandal
showing the sandal-wearer's shoe, strapped into position upon the
sandal.
[0063] FIG. 12 is an overhead view of the left foot sandal facing
to the left and showing the exterior surfaces and dashed-line
indications of some non-surface portions.
[0064] FIG. 13 is an overhead view of the sole of the left foot
sandal sole facing to the left and showing no appendages or
attachments, except for the two, flexible, rubber-like hinges.
[0065] FIG. 14 is a bottom view of the sandal sole of the left foot
sandal facing to the left and showing only a small portion of the
tread, which will ultimately extend across the entire length of the
sole.
[0066] FIG. 15A is a side elevation view of the entire rear
stationary foot-strap anchor.
[0067] FIG. 15B is an overhead view of the forward stationary
foot-strap anchor and the rear stationary foot-strap anchor with
the anchoring tongue protrusion on the opposite side shown in
dashed lines.
[0068] FIG. 15C is a bottom view of the forward stationary
foot-strap anchor and the rear stationary foot-strap anchor.
[0069] FIG. 15D is an overhead view of the forward stationary
foot-strap anchor and the rear stationary foot-strap anchor with
the forward and rear stud-mate attachment shown attached beneath
the hooked stud.
[0070] FIG. 15E is a side view elevation of the forward stationary
foot-strap anchor shown with the forward stud-mate attachment that
is affixed to the end of the truncated forward foot-strap
assembly.
[0071] FIG. 15F is an end elevation view of the forward stationary
foot-strap anchor shown with a cross-sectional side view of the
forward stud-mate attachment shown attached beneath the hooked
stud, as identified by line A-A of FIG. 15E.
[0072] FIG. 16A is a cross-sectional side view of the forward
adjustable foot-strap anchor and the rear adjustable foot-strap
anchor, as identified by line B-B in FIG. 16B.
[0073] FIG. 16B is an overhead view of the surface features of the
forward adjustable foot-strap anchor and the rear adjustable
foot-strap anchor.
[0074] FIG. 16C is an overhead view of the two cavities that secure
the forward adjustable foot-strap anchor, and the rear adjustable
foot-strap anchor to the sandal sole.
[0075] FIG. 16D is a bottom view of the surface elements of the
forward adjustable foot-strap anchor, and the rear adjustable
foot-strap anchor.
[0076] FIG. 16E is a side view of the forward adjustable foot-strap
anchor and the rear adjustable foot-strap anchor with a locking arm
shown in a vertical assembly view.
[0077] FIG. 16F is a side view of multiple, sequential images
showing the locking-arm stud of the locking arm in various stages
of being lifted up and out of its locked position.
[0078] FIG. 16G is an elevation view of the outer end side of the
forward adjustable foot-strap anchor attached to the forward
stud-mate attachment which is a component part of the forward
foot-strap assembly.
[0079] FIG. 16H is an elevation view of the inner end side of the
forward adjustable foot-strap anchor attached to the forward
stud-mate attachment which is a component part of the forward
foot-strap assembly.
[0080] FIG. 17A is the first drawing of an 9-part series FIGS.
17A-17I, depicting the face of a buckle for adjusting the length of
the elastic strap portion of the forward foot-strap assembly, and
of the rear foot-strap assembly 8.
[0081] FIG. 17B is the second drawing of a 9-part series FIGS.
17A-17I, depicting the serrated edges of the buckle edges where the
wide, elastic strap loops around within the buckle.
[0082] FIG. 17C is the third drawing of a 9-part series FIGS.
17A-17I, depicting an end view of the buckle for adjusting the
length of the elastic strap portion of the forward foot-strap
assembly, and of the rear foot-strap assembly.
[0083] FIG. 17D is the fourth drawing of a 9-part series FIGS.
17A-17I, depicting an end view of the buckle for adjusting the
length of the elastic strap portion of the forward foot-strap
assembly, and of the rear foot-strap assembly.
[0084] FIG. 17E is the fifth drawing of a 9-part series FIGS.
17A-17I, depicting a cross-sectional side view, as identified by
line A-A of FIG. 17A, of the buckle for adjusting the length of the
elastic strap portion of the forward foot-strap assembly, and of
the rear foot-strap assembly.
[0085] FIG. 17F is the sixth drawing of a 9-part series FIGS.
17A-17I, depicting a cross-sectional side view A, as identified by
line A-A of FIG. 17A, of the buckle for adjusting the length of the
elastic strap portion of the forward foot-strap assembly, and of
the rear foot-strap assembly.
[0086] FIG. 17G is the seventh drawing of a 9-part series FIGS.
17A-17I, depicting a rectangular clasp for keeping the two sections
of the elastic strap held together.
[0087] FIG. 17H is the eighth drawing of a 9-part series FIGS.
17A-17I, depicting a rectangular clasp for keeping the two sections
of the elastic strap held together.
[0088] FIG. 17I is the final drawing of a 9-part series FIGS.
17A-17I, depicting a rectangular clasp for keeping the two sections
of the elastic strap held together, and secured to a wide foam
rubber cushion for comfort and to lessen wear and tear on the
elastic strap.
[0089] FIG. 18A is the first drawing of a 5-part series FIGS.
18A-18E depicting various drawings of the heel back stop mechanism.
This drawing is a rear view elevation of the heel back stop showing
all of the exterior surfaces and dashed-line indications of some
opposite-surface portions, and includes a cross-sectional view of
the truncated sandal sole that surrounds the anchoring tongue
protrusion.
[0090] FIG. 18B is the second drawing of a 5-part series FIGS.
18A-18E depicting various drawings of the heel back stop mechanism.
This drawing is an overhead view showing the exterior surfaces and
dashed-line indications of some non-surface portions.
[0091] FIG. 18C is the third drawing of a 5-part series FIGS.
18A-18E depicting various drawings of the heel back stop mechanism.
This drawing is a bottom view showing the exterior surfaces only,
specifically including the anchoring tongue protrusion that fits
down into the cavity provided in the rear sole section.
[0092] FIG. 18D is the fourth drawing of a 5-part series FIGS.
18A-18E depicting various drawings of the heel back stop mechanism.
This drawing is a front view showing the exterior surfaces and
dashed-line indications of some below the surface or opposite
surface portions.
[0093] FIG. 18E is the final drawing of a 5-part series FIGS.
18A-18E depicting various drawings of the heel back stop mechanism.
This drawing is a side view of the exterior surfaces and
dashed-line indications of some non-surface portions. Included are
the anchoring tongue protrusion and the locking arm that fit into
the cavity provided in the rear sole section, which is represented
by a cross-sectional, truncated view.
[0094] FIG. 19A is the first drawing of a 6-part sequence FIGS.
19A-19F depicting the various stages of a full-stride walking cycle
as the sandal-wearer's upper body is moving forward. This drawing
shows the configuration of the left foot sandal the moment before
it strikes the surface of the soft sand after having been thrust in
the air toward a full-stride step forward.
[0095] FIG. 19B is the second drawing of a 6-part sequence FIGS.
19A-19F depicting the various stages of a full-stride walking cycle
as the sandal-wearer's upper body continues moving forward. This
drawing shows the configuration of the left foot sandal the moment
that it strikes the surface of the soft sand after having been
thrust in the air toward a full-stride step forward.
[0096] FIG. 19C is the third drawing of a 6-part sequence FIGS.
19A-19F depicting the various stages of a full-stride walking cycle
as the sandal-wearer's upper body continues moving forward. This
drawing shows the configuration of the left foot sandal a split
second after the back end portion of the rear sole section strikes
the surface of the soft sand.
[0097] FIG. 19D is the fourth drawing of a 6-part sequence FIGS.
19A-19F depicting the various stages of a full-stride walking
cycle. This drawing shows the configuration of the left foot sandal
as the sandal-wearer's upper body continues moving forward during
the walking cycle until it passes directly over the foot.
[0098] FIG. 19E is the fifth drawing of a 6-part sequence FIGS.
19A-19F depicting the various stages of a full-stride walking
cycle. This drawing shows the configuration of the left foot sandal
as the sandal-wearer's upper body continues moving forward, and the
opposite foot begins its airborne thrust forward toward its next
full-stride step.
[0099] FIG. 19F is the final drawing of a 6-part sequence FIGS.
19A-19F depicting the various stages of a full-stride walking
cycle. This drawing shows the configuration of the left foot sandal
just after it has been lifted up in the air, off the soft sand,
during its thrust forward toward its next full-stride step.
[0100] FIG. 20A shows a top view with two cross section views of a
forward stud-mate attachment for attaching to the forward
adjustable foot-strap anchor.
[0101] FIG. 20B shows a top view with two cross section views of a
rear stud-mate attachment for attaching to the rear adjustable
foot-strap anchor.
[0102] FIG. 20C shows a top view with two cross section views of a
forward stud-mate attachment for attaching to the forward
stationary foot-strap anchor.
[0103] FIG. 20D shows a top view with two cross section views of a
rear stud-mate attachment for attaching to the rear stationary
foot-strap anchor.
[0104] Similar reference characters denote corresponding features
consistently throughout the attached drawings.
LIST OF REFERENCE NUMBERS UTILIZED IN THE DRAWINGS
[0105] 1. The forward sole section. [0106] 2. The middle sole
section. [0107] 3. The rear sole section. [0108] 4. The top sole
layer of all three sole sections 1, 2, 3. [0109] 5. The bottom sole
layer of the forward sole section 1. [0110] 6. The bottom sole
layer of the middle sole section 2. [0111] 7. The bottom sole layer
of the rear sole section 3. [0112] 8. The sandal thong. [0113] 9.
The portion of the thong 8 that is positioned in the crook between
the largest toe and adjacent toe of the sandal-wearer's foot.
[0114] 10a. The right side portion of the divided thong strap that
extends across the top, right, front portion of the foot's instep.
[0115] 10b. The left side portion of the divided thong strap that
extends across the top, left, front portion of the foot's instep.
[0116] 11a. The right side portion of the divided thong strap that
extends around the right side portion of the foot's instep. [0117]
11b. The left side portion of the divided thong strap that extends
around the left side portion of the foot's instep. [0118] 12a. The
forward end of the thong 8 that anchors into the middle sole layer
31 of the forward sole section 1. [0119] 12b. The right rear end of
the thong 8 that anchors into the middle sole layer 33 of the rear
sole section 3. [0120] 12c. The left rear end of the thong 8 that
anchors into the middle sole layer 33 of the rear sole section 3.
[0121] 13. The aperture in the top sole layer 4 for allowing
passage of the forward, portion 9 of the thong 8. [0122] 14a. The
right, rear aperture in the top sole layer 4 for allowing passage
of the divided, thong strap ending located on the right, rear side.
[0123] 14b. The left, rear aperture in the top sole layer 4 for
allowing passage of the divided, thong strap ending located on the
left, rear side. [0124] 15. The convexly-embossed, heel position
indicator. [0125] 16. The area of body weight pressure located
beneath the heel of the foot. [0126] 17. The area of body weight
pressure located beneath the ball joints of the toes. [0127] 18.
The area of body weight pressure located beneath the toes. [0128]
19. The slightly angled, leading end of the forward sole section 1
(laterally). [0129] 20. The slightly angled, trailing end of the
rear sole section 3 (laterally). [0130] 21. The flexible hinge
layer (thin rubber-like material). [0131] 22. The alternate
flexible hinge layer (strong, flat, fabric-like layer) (not shown)
(same shape as top sole layer). [0132] 23. The cavity for
containing the flexible hinge 21. [0133] 24. The tapered thickness
of the leading end of the forward sole section 1. [0134] 25. The
leading end, angled thickness of the middle sole section 2. [0135]
26. The trailing end, angled thickness of the middle sole section
2. [0136] 27. The cross-sectional outline indication of a
sandal-wearer's leg cut just above the ankle. [0137] 28. The hidden
line of separation between the forward sole section 1 and the
middle sole section 2. [0138] 29. The hidden line of separation
between the middle sole section 2 and the rear sole section 3.
[0139] 30. The tread ribs equally spaced across the entire bottom
surface of the three-part bottom sole layer 5, 6, 7. [0140] 31. The
middle sole layer of the forward sole section 1. [0141] 32. The
middle sole layer of the middle sole section 2. [0142] 33. The
middle sole layer of the rear sole section 3. [0143] 34a. The
weight-reducing cavities of the three-part middle sole layer 31,
32, 33. [0144] 34b. The weight-reducing cavities of the three-part
bottom sole layer 5, 6, 7. [0145] 35a. The cavity in the forward
section of the middle sole layer 31 for anchoring the forward end
12a of the thong 8. [0146] 35b. The cavity in the rear section 33
of the middle sole layer 31, 32, 33 for anchoring the right rear
end 12b of the thong 8. [0147] 35c. The cavity in the rear section
33 of the middle sole layer 31, 32, 33 for anchoring the left rear
end 12c of the thong 8. [0148] 36. The leading end (vertical
portion) of the middle sole section 2 that butts against the
trailing end 42 of the forward sole section 1. [0149] 37. The
trailing end (vertical portion) of the middle sole section 2 that
butts against the leading end 43 of the rear sole section 3. [0150]
38. The triangular, wedge-shaped cutouts of the middle sole section
2. [0151] 39. The triangular, wedge-shaped protrusions created in
the middle sole section 2 by the wedge-shaped cutouts 38. [0152]
40. The curved, right front corner of the forward sole section 1.
[0153] 41. The curved right rear corner of the rear sole section 3.
[0154] 42. The rear end of the forward sole section 1. [0155] 43.
The leading end of the rear sole section 3. [0156] 101. The forward
sole section. [0157] 102. The middle sole section. [0158] 103. The
rear sole section. [0159] 104. The forward flexible hinge. [0160]
105. The rear flexible hinge. [0161] 106. The heel back stop.
[0162] 107. The forward foot-strap assembly. [0163] 108. The rear
foot-strap assembly. [0164] 109. The sole tread ridges. [0165] 10a.
The curved, forward, outer corner of the forward sole section 1, as
seen from above. [0166] 110b. The curved, forward, inner corner of
the forward sole section 1, as seen from above. [0167] 111a. The
curved, rear, outer corner of the rear sole section 103, as seen
from above. [0168] 111b. The curved, rear, inner corner of the rear
sole section 103, as seen from above. [0169] 112. The wide elastic
strap of the two foot-strap assemblies 107, 108. [0170] 113a. The
adjustable buckle of the two foot-strap assemblies 107, 108. [0171]
113b. The cross-sectional thickness of the adjustable buckle 113a
of the two foot-strap assemblies 107, 108. [0172] 114a. The
donut-shape portion of the forward stud-mate attachments 117a for
the forward stationary foot-strap anchors 119a. [0173] 114b. The
donut-shape portion of the rear stud-mate attachments 118a for the
rear stationary foot-strap anchors 119b. [0174] 115a. the
donut-shape portion of the forward stud-mate attachments 117b for
the forward adjustable foot-strap anchors 120a. [0175] 115b. the
donut-shape portion of the rear stud-mate attachments 118b for the
rear adjustable foot-strap anchors 120b. [0176] 117a. The forward
stud-mate attachment for the forward stationary foot-strap assembly
119a. [0177] 117b. The forward stud-mate attachment for the forward
adjustable foot-strap anchor 120a. [0178] 118a. The rear stud-mate
attachment for the rear stationary foot-strap anchor 119b. [0179]
118b. The rear stud-mate attachment for the rear adjustable
foot-strap anchor 120b. [0180] 119a. The forward stationary
foot-strap anchor. [0181] 119b. The rear stationary foot-strap
anchor. [0182] 120a. The forward adjustable foot-strap anchor.
[0183] 120b. The rear adjustable foot-strap anchor. [0184] 121. The
hooked stud portion of the forward stationary foot-strap anchor
119a and the rear stationary foot-strap anchor 119b. [0185] 122.
The hooked stud portion of the forward adjustable foot-strap anchor
120a and the rear adjustable foot-strap anchor 120b. [0186] 123.
The angled, and slightly curved, forward end of the forward sole
section 101, as seen from above. [0187] 124. The angled, and
slightly curved, rear end of the rear sole section 103, as seen
from above. [0188] 125. The angled, and slightly curved, forward
end of the forward sole section 101, as seen from a side view.
[0189] 126. The angled, rear end of the forward sole section 101,
as seen from a side view. [0190] 127. The angled, forward end of
the middle sole section 102, as seen from a side view. [0191] 128.
The angled, rear end of the middle sole section 102, as seen from a
side view. [0192] 129. The angled, forward end of the rear sole
section 103, as seen from a side view. [0193] 130a. The cavity
provided to accommodate the anchoring tongue and T-arm protrusion
133 of the forward adjustable foot-strap anchor 120a. [0194] 130b.
The cavity provided to accommodate the anchoring tongue and T-arm
protrusion 133 of the rear adjustable foot-strap anchor 120b.
[0195] 131a. The recessed shoulder provided for flushly seating the
cover plug 154 of the cavity 130a provided to accommodate the
anchoring tongue and T-arm protrusion 133 of the forward adjustable
foot-strap anchor 120a, as seen from the bottom surface of the
sole. [0196] 131b. The recessed shoulder provided for flushly
seating the cover plug 154 of the cavity 130b provided to
accommodate the anchoring tongue and T-arm protrusion 133 of the
rear adjustable foot-strap anchor 120b, as seen from the bottom
surface of the sole. [0197] 132. The toe-position indicator that
identifies the specified area where the toe end of the shoe needs
to be positioned. [0198] 133. The side view of the anchoring tongue
and T-arm protrusion of the forward adjustable foot-strap anchor
120a, and of the rear adjustable foot-strap anchor 120b, provided
for securing both anchors 120a, 120b to the sole. [0199] 134a. The
anchoring tongue protrusion provided for securing the forward
stationary foot-strap anchor 119a to the forward sole section 101.
[0200] 134b. The anchoring tongue protrusion provided for securing
the rear stationary foot-strap anchor 119b to the rear sole section
103. [0201] 134c. The locking arm for securing the two stationary
foot-strap anchors 119a, 119b to their respective cavities 135 in
their respective sandal sole sections 101, 102. [0202] 135a. The
cavity provided to accommodate the anchoring tongue protrusion and
locking arm 134a, 134b of the two stationary foot-strap anchors
119a, 119b. [0203] 135b. The cross-sectional side view of the
cavity 135a provided to accommodate the anchoring tongue protrusion
and locking arm 134a, 134b of the two stationary foot-strap anchors
119a, 119b. [0204] 136. The recessed shoulder provided for flushly
seating the cover plug 172 of the cavity designed to accommodate
the anchoring tongue protrusion 134a, 134b and locking arm 134c of
the two stationary foot-strap anchors 119a, 119b, as seen from the
bottom surface of the sole. [0205] 137. The small, thin ridges that
minimize the friction between the sandal sole surfaces and the two
adjustable foot-strap anchors 120a, 120b and their anchoring tongue
and T-arm protrusions 133. [0206] 139. The locking arm of the
forward adjustable foot-strap anchor 120a, and of the rear
adjustable foot-strap anchor 120b for securing the lateral
positioning of the anchor. [0207] 140. The locking-arm stud of the
locking arm 139 of the forward adjustable foot-strap anchor 120a,
and of the rear adjustable foot-strap anchor 120b, for securing the
lateral positioning of the anchor. [0208] 141. The thumb-grip
flange of the locking arm 139 of the forward adjustable foot-strap
anchor 120a, and of the rear adjustable foot-strap anchor 120b,
utilized for engaging and disengaging the locking arm 139 and
locking arm stud 140 of the two anchors 120a, 120b. [0209] 142. The
snap-lock stud for securing the locking arm 139 of the forward
adjustable foot-strap anchor 120a, and of the rear adjustable
foot-strap anchor 120b. [0210] 143. The cylindrical hinge-pin of
the locking arm 139 portion of the forward adjustable foot-strap
anchor 120a, and of the rear adjustable foot-strap anchor 120b.
[0211] 145. The gray silhouette of the sandal-wearer's shoe
identifying its correct positioning upon the sandal, as seen from
above. [0212] 146. The cylindrical cavity-sleeve for accommodating
the cylindrical hinge 143 of the locking arm 139 of the forward
adjustable foot-strap anchor 120a, and of the rear adjustable
foot-strap anchor 120b. [0213] 147. The locking-arm shoulder of the
locking arm 139 of the forward adjustable foot-strap anchor 120a,
and of the rear adjustable foot-strap anchor 120b. [0214] 148. The
pressure-activated, snap-lock flange of the two stationary
foot-strap anchors 119a, 119b for use in preventing the accidental
disengagement of the stud-mate attachments when the sandal is not
in use. [0215] 149. The serrated edges of the adjustable buckle
113a where the wide, elastic strap 112 loops around 90-degree plus
angled edges. [0216] 150. The cross-sectional thickness of the
sandal sole. [0217] 151a. The cross-sectional thickness of the
donut-shape portion 114a, 114b of the inner forward stud-mate
attachment 117a, and of the inner rear stud-mate attachment 118a,
shown in their pressure-locked position beneath the hooked studs
121 of the two stationary foot-strap anchors 119a, 119b. [0218]
151b. The cross-sectional thickness of the donut-shape portion
115a, 115b of the outer forward stud-mate attachment 117b, and of
the outer rear stud-mate attachment 118b, shown in their
pressure-locked position beneath the hooked studs 122 of the two
adjustable foot-strap anchors 120a, 120b. [0219] 152a. The cavity
provided to accommodate the locking-arm stud protrusion 140 of the
locking arm 139 of the forward adjustable foot-strap anchor 120a.
[0220] 152b. The cavity provided to accommodate the locking-arm
stud protrusion 140 of the locking arm 139 of the rear adjustable
foot-strap anchor 120b. [0221] 153a. The vertical cross-sectional
thickness of the forward stud-mate attachment 117a of the forward
stationary foot-strap anchor 119a, as identified by line B-B of
FIG. 20C. [0222] 153b. The horizontal cross-sectional thickness of
the forward stud-mate attachment 117a of the forward stationary
foot-strap anchor 119a, as identified by line A-A of FIG. 20C.
[0223] 153c. The vertical cross-sectional thickness of the rear
stud-mate attachment 118a of the rear stationary foot-strap anchor
119b, as identified by line B-B of FIG. 20D. [0224] 153d. The
horizontal cross-sectional thickness of the rear stud-mate
attachment 118a of the rear stationary foot-strap anchor 119b, as
identified by line A-A of FIG. 20D. [0225] 153e. The vertical
cross-sectional thickness of the forward stud-mate attachment 117b
of the forward adjustable foot-strap anchor 120a, as identified by
line B-B of FIG. 20A. [0226] 153f. The horizontal cross-sectional
thickness of the forward stud-mate attachment 117b of the forward
adjustable foot-strap anchor 120a, as identified by line A-A of
FIG. 20A. [0227] 153g. The vertical cross-sectional thickness of
the rear stud-mate attachment 118b of the rear adjustable
foot-strap anchor 120b, as identified by line B-B of FIG. 20B.
[0228] 153h. The horizontal cross-sectional thickness of the rear
stud-mate attachment 118b of the rear adjustable foot-strap anchor
120b, as identified by line A-A of FIG. 20B. [0229] 154. The
cross-sectional side view of the flushly recessed cover plug that
is bonded over each of the two cavities 161 that are provided to
accommodate the anchoring tongue and T-arm protrusion 133 of the
forward adjustable foot-strap anchor 120a, and of the rear
adjustable foot-strap anchor
120b, respectively. [0230] 155. The foam rubber padding for the
heel back stop 106. [0231] 156. The main-body portion of the heel
back stop 106. [0232] 157. The anchoring tongue protrusion of the
heel back stop 106. [0233] 158. The cross-sectional side view of
the underneath side of the top lip of the cavity 130a, 130b, 161
provided for securing the anchoring tongue and T-arm protrusion 133
of the forward adjustable foot-strap anchor 120a, and the rear
adjustable foot-strap anchor 120b within the cavity. [0234] 159.
The locking arm for securing the heel back stop mechanism 106
within the cavity 160a provided in the rear sole section 3. [0235]
160a. The cross-sectional view of the cavity in the rear sole
section 3 designed to accommodate the anchoring tongue protrusion
157 and locking arm 159 of the heel back stop 106, as identified by
line A-A of FIG. 18D. [0236] 160b. The cavity in the rear sole
section 3 designed to accommodate the anchoring tongue protrusion
157 and locking arm 159 of the heel back stop 106. [0237] 161. The
cross-sectional side view of the cavity provided to accommodate the
anchoring tongue and T-arm protrusion 133 of the forward adjustable
foot-strap anchor 120a, and of the rear adjustable foot-strap
anchor 120b. [0238] 162. The cross-sectional side view of the
cavity provided to accommodate the locking-arm stud protrusion 140
of the locking arm 139 of the forward adjustable foot-strap anchor
120a, and of the rear adjustable foot-strap anchor 120b. [0239]
165. The cavity provided to allow a screwdriver to forcibly extract
the heel back stop mechanism 106, if replacement becomes necessary.
[0240] 166. The cavity provided to allow a screwdriver to forcibly
extract the stationary foot-strap anchors 119a, 119b, if
replacement becomes necessary. [0241] 167. The walking/jogging
sneaker of the sandal wearer. [0242] 168. The space separating each
of the three sole sections 101, 102, 103 when connected end-to-end
by the two, flexible hinges 104, 105, as it exists along the top
surface of the three sole sections 101, 102, 103. [0243] 169. The
clasp provided to hold the wide, elastic strap loosely and flatly
together. [0244] 170. The clips provided to secure the long and
wide foam rubber pad 171 in its proper position beneath the rear
foot-strap assembly 108 where it extends across the top of the
foot's instep. [0245] 171. The foam rubber strip that provides
padding beneath the rear foot-strap assembly 108 where it extends
across the top portions of the foot's instep and shoe. [0246] 172.
The cross-sectional view of the flushly recessed cover plug that is
bonded over the cavity 135 provided to accommodate the anchoring
tongue protrusion 134a, 134b of the forward stationary foot-strap
anchor 119a, and the rear stationary foot-strap anchor 119b. [0247]
173. The sub-surface, pressure-activated arm for pushing the
anchoring tongue and T-arm protrusion 133 of the forward adjustable
foot-strap anchor 120a and the rear adjustable foot-strap anchor
120b forward beneath the lip of the cavity 130a & 130b, 161 to
keep the anchors engaged within the cavity. [0248] 174. The
cross-sectional side view of the flushly recessed cover plug that
is bonded over the cavity 160a, 160b provided to accommodate the
anchoring tongue protrusions 157 and locking arm 159 of the heel
back stop 106. [0249] 175. The recessed shoulder provided for
flushly seating the cover plug 74 of the cavity 160b provided to
accommodate the anchoring tongue protrusion 157 and locking arm 159
of the heel back stop 106.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0250] The first embodiment of the present invention, as shown in
FIGS. 1 through 8F, is comprised of a conventional thong 8 and a
flexibly-hinged, three-part, rigid sole system 1, 2, 3, which has
extra sole length added behind the sandal-wearer's heel. These
features interact to enable the employment of inverted mechanical
leverage to eliminate deep foot sinking and thong pressure
discomfort, both of which are long-time deficiencies of
conventional rigid sole sandals and clogs when engaging in
full-stride walking on very soft sand. The three-part sole 1, 2, 3
is also designed extra-wide to reduce foot sinking even more, by
lowering the amount of body weight supported per-square-inch of
sole. A combination of the inverted mechanical leverage action and
the extra sole width virtually eliminates the deep foot sinking
problem; and the flexibly-hinged, three-part sole 1, 2, 3 virtually
eliminates the thong pressure discomfort problem.
[0251] The inverted mechanical leverage principles being employed
in the present invention relate to the commonly understood use of a
long, rigid beam to lift a very heavy object by placing one end of
the rigid beam under the object, and placing a rock, or other
supporting fulcrum, beneath the beam at a point less than half the
length of the beam away from the object. The mechanical leverage
action created causes the heavy object to be lifted when downward
pressure is applied at the opposite end of the beam. The mechanical
leverage action causes the energy expended to lift the heavy object
to be less than the energy required to lift the heavy object
without the assistance of mechanical leverage. The energy advantage
of this leverage example is not particularly significant to the
present invention, but the basic mechanical leverage action is.
With the present invention, the leverage action being employed is
inverted mechanical leverage, with the forward sole section 1 and
the rear sole section 3 of the sandal acting as two independent,
flat levers joined lengthwise by a flexible hinge 21 and a middle
sole section 2. The sandal-wearer's heel and ball joints of the
toes (and the toes themselves) each act as weighted fulcrums for
their respective sole sections 1 & 3--see FIGS. 8A-8F. The
pressure from the sandal-wearer's body weight, when applied as a
weighted fulcrum by the ball joints of the toes, and the toes
themselves, to the forward sole section 1, and when applied by the
sandal-wearer's heel to the rear sole section 3 forces each sole
section 1, 3 to lie down firmly and flatly upon the soft sand. The
pressure of the sandal-wearer's body weight then holds the affected
sole section 1, 3 firmly and flatly upon the soft sand until the
body weight pressure is removed. The use of inverted mechanical
leverage in the functioning of the present invention is the primary
intellectual property for which a patent is being sought.
[0252] The functioning of the present invention and a detailed
description of the various component parts that make it possible
are explained in the paragraphs below, and are accompanied by
detailed mechanical drawings for reference.
[0253] The flexibly-hinged, three-part, rigid sole system 1, 2, 3
is comprised of three, flexibly-hinged, rigid sole sections 1, 2,
3, hereafter referred to as the forward sole section 1, the middle
sole section 2, and the rear sole section 3. The three sole
sections 1, 2, 3 are aligned one after the other in a linear
fashion from front to rear. The flexible hinge 21 that joins the
three sole sections 1, 2, 3 is designed to allow the sections to
arc upward, in their relationship to one another, much like the
stiff cardboard pages of a baby's picture book when it is lying
open on a flat surface FIG. 8E, but does not allow downward
movement when any two or three of the sole sections are positioned
in a common plane FIG. 8F.
[0254] When the three sole sections 1, 2, 3 are positioned in the
same plane FIG. 8F, downward movement is restricted by the butting
together 42, 36, 37, 43 of the thicknesses of the three sole
sections 1, 2, 3 that occur beneath the flexible hinge 21. The
butting is needed to keep the three sole sections 1, 2, 3 within
the same plane when the sandal-wearer's foot and sandal are
airborne, to prevent the rear sole section 3 and middle sole
section 2 from hanging down below the plane of the forward sole
section 1 due to gravitational forces. The three sole sections 1,
2, 3 are designed with extra width FIG. 3 (roughly 0.75 to 1.5
inches) added to the outer side of the each sandal to increase
their overall square-inch sole surface areas in an effort to reduce
the amount of body weight supported per square inch of sole. The
additional sole width is asymmetrically added to the right side of
the right foot sandal, and to the left side of the left foot
sandal, as opposed to equal amounts being added to both sides of
each foot. By not adding any extra sole width to the inner sides of
the feet, it allows the sandal-wearer's feet, when walking, to
operate just as closely together as they normally do when wearing
conventional shoes and sandals, which is crucial for carefree and
comfortable walking.
[0255] The amount of extra sole width that can be added is
restricted by the amount of extra weight that the additional width
creates, and also by the amount of extra sole width that market
research determines is likely to be acceptable to prospective
buyers. The middle sole layers 31, 32, 33 and the bottom sole
layers 5, 6, 7 will have an extensive array of weight-reducing
cavities 34a, 34b throughout, to help reduce the weight of the
three sole sections 1, 2, 3 as much as possible, without
jeopardizing the strength required of the sole system to support
the weight of the heaviest sandal-wearer anticipated without any
significant flexing of the sole sections 1, 2, 3.
[0256] Working models of the present invention indicate that the
sandal, with its extra width and increased weight, functions
exactly as intended, but only when weight-reducing cavities 34a,
34b are distributed throughout the middle sole layers 31, 32, 33
and the bottom sole layers 5, 6, 7, in a similar fashion to those
shown in FIGS. 4, 5, 6. It should be noted that the extra width of
the sandal sole is not required for the inverted mechanical
leverage action to function successful in eliminating most of the
deep foot sinking that occurs during full-stride walking, but it
should also be noted that any amount of additional sole width
reduces the foot sinking significantly more than without it, by
lowering the amount of body weight supported per-square-inch of
sole. A combination of the inverted mechanical leverage action and
the additional sole width (approximately 0.75 inch to 1.5 inches),
causes the amount of foot sinking to be greatly reduced to the
point of being totally insignificant and unnoticeable by the
sandal-wearer when walking.
[0257] When the present invention is viewed from above, the leading
end 19 of the forward sole section 1 of a right foot sandal is
designed to angle slightly backward, from the left side of the
sandal to the right side; whereas the trailing end 20 of the rear
sole section 3 is designed to angle slightly forward, from the left
side of the sandal to the right side. Both angles enable the
sandal-wearer to make arced changes in direction, while walking,
that are either large diameter arcs or moderate diameter arcs, but
not small diameter arcs, which are problematic.
[0258] During small-diameter changes in direction, the front and
rear outer corners 40, 41 of the sandal sole cause stability
problems. With the present invention, during airborne steps forward
stability is jeopardized if the outer portion of the back end 41 of
the rear sole section 3 strikes the sand prior to that portion of
the sole that is located directly behind the sandal-wearer's heel.
No problem is created, however, if they both strike the sand
simultaneously.
[0259] Conversely, when a sandal-wearer's foot is lifted up off the
soft sand as it is being thrust forward toward a new step,
stability is jeopardized if the outer portion 40 of the front end
19 of the forward sole section 3 lifts off the soft sand later than
the portion that is located directly in front of the
sandal-wearer's toes. No problem is created, however, if they both
lift off the soft sand simultaneously.
[0260] The angle of the back end 20 of the rear sole section 3 has
the additional function of accommodating the slight amount of
flay-footedness of most people, as opposed to people with feet that
are positioned precisely straight forward when walking. People with
very pronounced flay-footedness, can expect to experience stability
problems with the present invention, unless they take care to
engage in only large-diameter directional changes, or have the
angle at the rear end 20 of the rear sole section 3 increased.
[0261] The stability problem caused by small-diameter changes in
direction when engaged in full-stride walking, and the
sandal-wearer's inability to descend boardwalk stairways easily are
the only known deficiencies of the present invention, but they are
not considered serious, considering the invention's enormous
advantage in eliminating deep foot sinking in very soft sand during
full-stride walking.
[0262] The forward sole section 1, when viewed from the side, is
designed with its front end thickness tapered 24, top to bottom,
not too unlike the curve at the forward end of most conventional
snow skis, to greatly reduce the fine sand spray that is flipped up
into the air during each step of the walking cycle.
[0263] The middle sole section 2 is unnecessary for the sandal to
function as intended, but was added primarily for marketing appeal
purposes to make the sandal's mechanical action appear less extreme
and, consequently, less strange looking to outside observers, by
providing more flexibility to the sole system 1, 2, 3. The angular
surface portion 25 of the forward end thickness of the middle sole
section 2, is connected to the trailing end 42 of the forward sole
section 1 by a highly-flexible hinge 21, forming a long, narrow,
triangular notch between the thicknesses of the two surfaces 42,
25. The inverted, v-shaped notch 42, 25 that is formed, angles
downward and backward in the direction of the rear of the sandal,
starting from a point roughly midway down the thickness of the
middle sole section 2, and extends down to the bottom surface of
the section 2. Its function is to provide a space to accommodate
the sand that squeezes out from beneath the two sole sections 1, 2
during the walking cycle. Its purpose is to prevent that sand from
interfering with the clean butting of the two sole sections 1, 2
when they are positioned within the same plane.
[0264] A second inverted, v-shaped notch 26, 43 (a mirror image of
the one just described) is formed between the rear end of the
middle sole section 2 and the forward end of the rear sole section
3, and has the same function as the front-end notch just described.
The purpose of the two points of butting between the three sole
sections 1, 2, 3 is to prevent the middle sole section 2 and the
rear sole section 3 from hanging down below the plane of the
forward sole section 1 when the foot is lifted airborne during its
thrust forward toward another step in the walking cycle FIG. 8F.
The area of the butting 36, 42, 37, 43 between the three sole
sections 1, 2, 3 is designed with a row of relatively small,
triangular, wedge-shaped, cutout notches 38, FIGS. 7 & 8 that
are located directly above the two large, inverted, v-shaped
notches 36, 42, 37, 43 that are directly below the flexible hinge
21, along the front end 36 and back end 37 of the middle sole
section 2.
[0265] The row of cutout notches 38 are similar in shape to the
large, jagged, zigzag teeth of fabric scissors used by the clothing
industry, however, these notches 38 are much thicker than the
notches of fabric scissors, and each pointy tooth 39, that is
created between each cutout notch 38 is similar in shape to a
thick, wedge-shaped slice cut out of a birthday cake. The purpose
of the notches 38 is to prevent any sand that may occasionally find
its way into the butting area 36, 42, 37, 43, such as sticky wet
sand during a surprise thunderstorm, from preventing the three sole
sections 1, 2, 3 from butting together cleanly as intended. Because
of the notches 38, most of the invading sand is squeezed out by the
pointy, wedge-shaped teeth 39 that are formed between the
triangular, wedge-shaped notches 38.
[0266] The rear sole section 3 is designed with extra sole length
added behind the sandal-wearer's heel (approximately 1.125 to 1.5
inches). During a full-stride walking cycle, when the leading foot
is completing an airborne stepping action forward FIGS. 8A &
8B, the interaction of the extra-long rear sole section 3 with the
flexibly-hinged, three-part, rigid sole system, triggers an
inverted mechanical leverage action that occurs within a split
second, forcing the entire rear sole section 3 to plop down flatly
and firmly upon the soft sand. This initial plop-down action is
followed by an arcing downward motion upon the soft sand by the
forward, toes portion of the foot, forcing the forward sole section
1, and the middle sole section 2 also, to lie down flatly and
firmly upon the soft sand, as a result of inverted mechanical
leverage action. A more detailed description of the inverted
mechanical leverage action is included further along in this
section.
[0267] The three sole sections 1, 2, 3 are comprised of three major
layers 4, 31, 32, 33, 5, 6, 7 and one inset, flexible hinge layer
21. They are: (1) a top sole layer 4 which is a one-part layer
common to all three sole sections 1, 2, 3; (2) a middle sole layer
31, 32, 33 which is divided between the three sole sections 1, 2,
3; (3) a bottom sole layer 5, 6, 7 which is divided between the
three sole sections 1, 2, 3; and (4) a one-part, inset,
highly-flexible hinge layer 21 which is inset flush into the
three-part, middle sole layer 31, 32, 33.
[0268] Each of the layers 4, 31, 32, 33, 5, 6, and 7 are explained
in detail below.
[0269] The top sole layer 4 is a relatively thin, flat,
single-piece layer of foam rubber, or other material with similar
properties, which has the purpose of providing a firm cushioning
for the sandal-wearer's foot; and to possibly serve as a
highly-flexible hinge (to hopefully eliminate the highly-flexible
hinge 21 shown in the drawings FIGS. 4 & 6) that is needed to
connect the three sole sections 1, 2, 3, if a material with the
necessary characteristics can be found. To function as the hinge,
the top sole layer must allow each of the sole sections 1, 2, 3 to
flex freely and easily, in relationship to one another, for tens of
thousands of flexes without cracking, tearing or stretching
excessively. The top sole layer 4 is not too unlike some of the
thicker (verses thinner) present-day computer mouse pads
(approximately 1/4-inch thick, more or less) and has roughly the
same moderate firmness that will provide sufficient cushioning for
the sandal-wearer's foot without compressing more than 2/3 to 3/4
of its thickness under the weight of the heaviest sandal-wearer
anticipated. The layer 4 will be glued, or otherwise bonded, to the
layer, or layers, beneath it.
[0270] A very shallow, thin, convexly-embossed (or imprinted) heel
position indicator 15 will be molded into the top surface of the
top sole layer 4 with the center, back portion of the heel position
indicator 15 positioned significantly forward (approximately 1.125
inches) from the back edge of the rear sole section 3. The center,
forward portion of the heel position indicator 15 is positioned
even further away (approximately 1.5 inches) from the back edge of
the rear sole section 3. The purpose of this indicator 15 is to
strongly communicate to prospective buyers that this sandal is not
meant to be fitted to a person's foot in the traditional manner
with the foot's heel positioned almost to the end of the sandal
sole.
[0271] The correct positioning of the foot's heel upon the
three-part sole system 1, 2, 3, as indicated by the heel position
indicator 15, is well forward of the back edge (approximately 1.125
to 1.5 inches) of the rear sole section 3. This distance is crucial
for the success of the inverted mechanical leverage action in
eliminating the deep foot-sinking problem. The heel position
indicator 15 performs no other function than to be a
prominently-displayed visual indicator to prospective buyers of the
correct positioning of the foot's heel upon the sandal to prevent
any person from instinctively assuming that the proper sandal size
for their foot is one in which the heel is conventionally
positioned very near the back edge of the sandal sole.
[0272] The hinge sole layer 21 is a thin, wide strip of highly
flexible rubber, or other material with similar properties, that is
very strong and durable, and which has non-stretching and
non-cracking characteristics. Its final thickness is expected to be
not too unlike the thickness of an old-fashioned, car tire inner
tube (approximately 1/8 inch). The layer is designed to be inset
into the top surface 23, FIG. 4 of the three-part, middle sole
layer 31, 32, 33. An alternate hinge may be used to replace the
inset hinge 21. It is the top sole layer 4, if a foam rubber
material can be found that will allow it to function not only as a
cushion for the foot, but also as a highly-flexible, strong and
durable hinge with non-stretch and non-cracking
characteristics.
[0273] A second alternate hinge may be a thin, contiguous layer of
a highly-flexible, strong and durable cloth, or rubber, or
polyester, or other material with similar properties, which has
non-stretch and non-cracking characteristics, If chosen as the
hinge, it would be glued, or otherwise bonded, between the top sole
layer 4 and the middle sole layer 31, 32, 33, and likely have the
same contour shape as the top sole layer 4.
[0274] The middle sole layer 31, 32, 33 is a relatively thin layer
(approximately 1/4 inch, more or less) of very strong, rigid
plastic, or other material with similar properties. The layer is
divided into three parts 31, 32, 33--one part for the forward sole
section 1, one part for the middle sole section 2, and one part for
the rear sole section 3. The thickness of the material ultimately
selected will be determined by the strength needed to maintain 90%,
more or less, of its rigidity when supporting the weight of the
heaviest sandal-wearer anticipated. A very small amount of flexing
is allowable without any serious loss of support capability upon
very soft sand. The layer also has numerous, closely spaced,
cylinder-like, weight-reducing cavities 34a that are arranged
throughout the layer in a geometrically organized fashion.
[0275] The bottom sole layer 5, 6, 7 is a very thick, flat layer of
firm and tough foam rubber, or other material with similar
properties. The layer is divided into three separate parts 5, 6, 7
which together make up the bottom portion of the three sole
sections 1, 2, 3--the forward sole section 1, the middle sole
section 2, and the rear sole section 3. Its final thickness will be
approximately as shown in the drawings (3/4 inch, more or less),
but will ultimately be decided by additional testing of the
specific material chosen and by market appeal considerations. The
material ultimately chosen for this layer must also function to
muffle the harsh, clacking sound that often emanates from rigid,
clog-like footwear when walking on very hard surfaces. The
unusually high thickness of this layer 5, 6, 7 is needed for
walking on very rough and deeply-cratered, soft-sand terrain to
prevent the sand's peaks from spilling over the top edges of the
sandal, except in extreme circumstances. The bottom surface of the
layer 5, 6, 7 will have multiple rows of thin, rib-like protrusions
30 molded into the layer to function as the sandal's tread 30. The
tread 30 is intended to enhance market appeal and to provide
traction on hard surfaces such as parking lots, beach boardwalks,
boardwalk stairways, etc. The tread ribs 30 are similar in looks to
the ribs of an old-fashioned washboard, but much smaller and
positioned laterally across the width of the three sole sections 1,
2, 3, from front to rear, with extra space between them
(approximately 3/32 inch, more or less). The treads 30 have very
little perceivable traction value on very soft sand. The layer also
has numerous, closely spaced, cylinder-like, weight-reducing
cavities 34b that are arranged throughout the layer in a
geometrically organized fashion.
[0276] A thong 8 made of rubber, or other material with similar
properties is employed to secure the sandal sole system 1, 2, 3 to
a person's foot. The particular thong that is employed for this
invention is one that for decades has been used in the manufacture
of a ubiquitous conventional sandal, commonly referred to as
flip-flops, and which is in the public domain. U.S. Pat. No.
3,290,802, filing date Dec. 13, 1966, is an example of the type of
thong to be utilized; however, the extra strap portion shown
crossing horizontally over the instep of the sandal-wearer's foot
is not expected to be needed, pending prototype testing on
sandal-wearers with very thin and narrow feet.
[0277] The forward end 12a of the thong 8 is secured to the middle
sole layer 31 of the forward sole section 1 in the cavity provided
35a. From there it passing upward through an aperture 13 in the top
sole layer 4 where it continues upward, passing through the crook
located between the sandal-wearer's largest toe and adjacent toe.
At the top of the crook the thong divides into two separate thong
straps 10a, 10b before traversing the right and left sides,
respectively, of the top, forward portion of the foot's instep,
before continuing on to wrap around the right and left sides 11a,
11b, respectively, of the instep. The two straps then pass through
their respective right and left side apertures 14a, 14b in the top
sole layer 4 before anchoring themselves into their respective
right and left side cavities 35a, 35b of the middle sole layer 33
of the rear sole section 3, below the right and left sides of the
back portion of the sandal-wearer's instep at points located near
the forward end of the rear sole section 3.
[0278] All three thong endings 12a, 12b, 12c are anchored into
their respective cavities by gluing, or other bonding, or by making
the thong strap endings 12a, 12b, 12c with a flange that is larger
in size than the apertures 13, 14a, 14b that it must pass through
in the sandal sole, as is done with conventional flip-flops, if the
material of the top sole layer is strong enough to prevent the
thong strap endings 12a, 12b, 12c from pulling out.
[0279] The functioning of the present invention is more clearly
understood by viewing the accompanying six sequential drawings
FIGS. 8A through 8F which portray the various stages of a
full-stride walking cycle, with step-by-step descriptive wording as
follows:
[0280] During the 1st and 2nd stages of a full-stride walking cycle
FIGS. 8A & 8B, the upper body of the sandal-wearer moves
forward as it thrusts a leg and foot forward in the air during a
stepping action. When contact is made with the soft sand S ahead
FIG. 8A the outstretched leg is positioned at a 15- to 25-degree
angle, in relationship to the vertical, which causes the foot and
sandal to also strike the soft sand S ahead at roughly the same 15-
to 25-degree angle FIG. 8A, but in their relationship to the sand's
surface S.
[0281] At the moment of initial contact with the soft sand S, the
pressure of the sandal-wearer's full-body weight is concentrated by
the heel of the foot upon the rear sole section 3, not at the back
edge of the heel as is commonly thought, but forward of it at a
point located directly beneath the center of the foot's curved heel
bone (as identified by the large hollow arrows in FIGS. 8A &
8B), a point that is significantly forward, away from the back edge
of the foot's heel (approximately 1.125 inches forward), and well
forward of the back edge of the rear sole section 3 (approximately
2.25 to 2.625 inches forward). The center point of the heel bone
functions as a weighted fulcrum, creating an inverted mechanical
leverage action which forces the entire rear sole section 3 to plop
down flatly and firmly upon the soft sand FIG. 8B a fraction of a
second after the back edge of the rear sole section 3 strikes the
surface of the soft sand, and the body's full weight is applied to
that rear sole section 3.
[0282] And, because the body's weight 16, FIG. 3 upon the rear sole
section 3 is concentrated sufficiently far away from all the edges
of the rear sole section 3, it causes the weight to be distributed
throughout the full dimensions of the section 3, holding it firmly
and flatly upon the soft sand S without any perceivable tilting
(except on very irregular sand surfaces), and without any
significant foot sinking (approximately 0.25 inch). The "plop down"
phenomenon of the present invention occurs even though the
sandal-wearer's foot angle remains instinctively locked at the 15-
to 25-degree angle, more or less, during those first moments of the
sandal's initial contact with the soft sand FIG. 8B when the body's
full weight comes to bear upon the soft sand S.
[0283] Under the same circumstances, however, when conventional,
one-part, rigid sole sandals are worn, the foot sinking that occurs
is much greater (roughly 1.25 to 2 inches, or more) because both
the sandal-wearer's foot and sandal sole remain positioned at the
15- to 25-degree angle during those first moments of initial sand
impact when the body's full weight comes to bare upon the soft sand
S. The inverted mechanical leverage actions that occur during this
1st and 2nd stage of the full-stride walking cycle 8A & 8B, and
during the 3rd stage of the full-stride walking cycle FIGS. 8B
& 8C (explained further below), and during the 5th stage of the
full-stride walking cycle FIGS. 8D & 8E (explained further
below) are this invention's primary intellectual property.
[0284] During the 3rd stage of a full-stride walking cycle FIG. 8C
the sandal-wearer's upper body continues its move forward, and
passes directly over the leading foot (shown in this drawing) as
the trailing foot (unseen in this drawing) begins its airborne
movement forward toward the next step. During that trailing foot's
initial movement forward, the toes portion of the sandal-wearer's
leading foot (shown in this drawing) arcs downward from its 15- to
25-degree angular position FIG. 8B, causing the ball joints of the
toes, and the toes themselves to function in unison as a weighted
fulcrum of an inverted mechanical lever, forcing the forward sole
section 1, and consequently the middle sole section 2 also, to lie
down flatly and firmly upon the soft sand FIG. 8C, causing all
three sandal sole sections 1, 2, 3 of the leading foot to be
positioned flatly and firmly upon the soft sand FIG. 8C, where
roughly half of the sandal-wearer's body weight shifts
instinctively away from the foot's heel 16, FIG. 3 forward to the
ball joints of the toes 17, FIG. 3, and with a small portion
applied to the toes themselves 18, FIG. 3. The large hollow arrows
in the drawings FIGS. 8A-8E identify the center points of the major
body weight concentrations upon the forward sole section 1 and the
rear sole section 3. The small hollow arrows in the drawings FIGS.
8C-8E identify the center points of the minor body weight
concentrations emanating from the toes. NOTE: The major points of
body weight concentration 16, 17, FIG. 3 are located sufficiently
far away from the edges of the forward sole section 1 and from the
rear sole section 3 to cause the sandal-wearer's body weight to be
distributed throughout the full dimensions of those two sole
sections 1, 3, holding them firmly and flatly upon the sand's
surface without tilting towards the inside edge.
[0285] During the 4th stage of a full-stride walking cycle FIG. 8D
the sandal-wearer's upper body continues its move forward as the
now-leading opposite foot, (unseen in this drawing) continues
moving forward in the air toward its next step. The forward
movement of the sandal-wearer's body and leading foot causes the
heel of the sandal-wearer's now-trailing foot (shown in this
drawing) to instinctively arc upward, lifting away from the rear
sole section 3. This lifting up of the foot's heel causes that
portion of the sandal-wearer's body weight, that had been
concentrated upon the foot's heel (roughly half), to shift totally
forward where it is added to the weight already being borne by the
ball joints of the toes, and a small portion by the toes
themselves. The bulk of the body's weight is concentrated
sufficiently far away from the edges of the sole 17, 18, FIG. 3 to
cause the body weight to be distributed throughout the entire
dimensions of the forward sole section 1, holding it flatly and
firmly upon the soft sand without tilting towards the inside
edge.
[0286] As the foot's heel is engaged in its arcing motion upward
FIG. 8D, the forward, top portion of the foot's instep presses
against the thong straps 10a, 10b, causing them to begin
tightening. But, because the sole is comprised of a
flexibly-hinged, three-part, rigid sole system 1, 2, 3, as opposed
to a one-part rigid sole system, and because there is no body
weight pressure holding the rear sole section 3 down against the
sand, the rear sole section 3 easily lifts up and away from the
soft sand when the two divided thong straps 10a, 10b, 11a, 11b
begin to tighten. The lack of resistance, other than the light
weight of the rear sole section itself 3, prevents any significant
thong pressures from building up upon the sandal-wearer's foot, as
it does with conventional, one-part, rigid sole sandals during this
same stage of the full-stride walking cycle, as explained more
fully elsewhere in this application.
[0287] During the 5th stage of a full-stride walking cycle FIG. 8E
the sandal-wearer's upper body continues its move forward as the
opposite foot (unseen in this drawing) nears completion of its
airborne stepping action forward, causing the sandal-wearer's
now-trailing foot (shown in this drawing) to continue lifting the
foot's heel upward and forward even higher than in the previous
drawing FIG. 8E, and up even further away from the soft sand and
the rear sole section 3 in anticipation of its own next step
forward. As the heel continues its movement upward and forward, the
forward portion of the foot's instep continuing its arc upward
also. As it does, it continues applying pressure against the two
divided thong straps 10a, 10b, 11a, 11b. The thong 8 pressure again
causes the two divided thong straps 10a, 10b, 11a, 11b to easily
pull the flexibly-hinged, rear sole section 3 even further up in
its arc away from the soft sand during this stage of the
full-stride walking cycle.
[0288] And, because of the flexible hinge 21 connecting the
three-part sole system 1, 2, 3, the rear sole section 3 continues
to offer almost no resistance to the pulling thong straps 10a, 10b,
11a, 11b, preventing thong 8 pressures from building up
uncomfortably upon the foot. As the sandal-wearer's full-body
weight continues to be concentrated mostly upon the ball joints of
the toes 17, FIG. 3, well away from the edges of the forward sole
section 1, FIG. 3, the weight continues to be distributed
throughout the full dimensions of the forward sole section 1,
holding it flatly and firmly upon the sand's surface. As the
sandal-wearer's body continues its move forward, the body's full
weight instinctively shifts away from the trailing foot (shown in
this drawing), forward to the opposite foot (not shown in this
drawing), as that foot's heel strikes the soft sand ahead at the
completion of its airborne stepping action forward.
[0289] The trailing foot (shown in this drawing) is then lifted up
off the soft sand as it is thrust forward in the air FIG. 8F toward
its next step. In contrast, when conventional, one-part, rigid sole
sandals are in this stage of the full-stride walking cycle the
thong straps tightening up uncomfortably across the top, forward
portion of the sandal-wearer's instep as the foot's instep
approaches the highest points of its arcing motion upward. This
tightening of the thong straps occurs because of the resistance
emanating from the back portion of the one-part, rigid sole system
which is being held down firmly upon the soft sand by the forward
1/3 portion of the sandal sole where the ball joints of the toes
and the toes themselves are applying their heavy body weight
pressure. The strong and uncomfortable thong pressures eventually
become so great that they overcome the heavy, body weight pressures
that are holding the rigid sole down upon the sand, and pull the
back portion of the sole up above the soft sand at an angle of
roughly 15 to 20 degrees, in its relationship with the sand's
surface.
[0290] This action forces the front end portion of the sandal sole
to punch down deeply into the soft sand because of: (1) the body
weight pressure being exerted by the toes portion of the sandal
sole; (2) the sole's reduced square-inch surface area contact with
the soft sand; and (3) the sole's angular orientation, which
reduces the sole's support capabilities. The front end of the
sandal continues to sink deeper into the soft sand (roughly 1.25 to
2 inches, or more) until there are enough square inches of sole
surface contact with the soft sand to once again support the body's
heavy weight and terminate the sinking.
[0291] During the 6th and final stage of a full-stride walking
cycle FIG. 8F the sandal-wearer's upper body continues its move
forward as the body's total weight instinctively shifts away from
the trailing foot (shown in this drawing) to the leading foot (not
shown in this drawing) as it contacts the soft sand ahead at the
completion of its airborne stepping action forward. As this action
is occurring, the trailing foot (shown in this drawing) is
instinctively lifted airborne above the soft sand as it begins its
movement forward toward its next step.
[0292] During this stage of the walking cycle the forward portion
of the divided thong straps 10a, 10b functions as a slightly
off-center (right to left) supporting fulcrum of an inverted
mechanical lever which is composed of the three sole sections 1, 2,
3 functioning as a single, rigid element (because of the butting of
the three sole sections 1, 2, 3). While airborne, gravitational
forces cause the longer, back portion 2, 3 of the sole/lever 1, 2,
3 to hang down slightly below the heel (as shown in the
drawing).
[0293] During this stage, gravitational forces and the butting that
occurs 42, 36, 37, 43 between the three sole sections 1, 2, 3,
causes the three sole sections 1, 2, 3 to stay positioned within
the same plane, and prevents the middle sole section 2 and the rear
sole section 3 from hanging down below the plane of the forward
sole section 1. With gravitational forces applying downward
pressure upon the longer, rear end portion 2, 3 of the sole/lever
1, 2, 3, the supporting fulcrum which is located just above the
ball joints of the toes causes levered pressure to be exerted
upward beneath the toes by the shorter, forward portion of the
sole/lever 1, 2, 3. The small amount of upward pressure being
exerted beneath the toes is unconsciously felt by the toes, which
instinctively lock themselves in their normal, straight-forward
position, and sometimes in a slightly downward position, resisting
the upward pressure; and consequently preventing the sandal sole
from hanging down more than a slight amount beneath the heel (as
seen in the drawing).
[0294] And, because of the extra width of the sandal sole located
on the right side of the right foot and on the left side of the
left foot, the largest and strongest toe of each foot bears the
bulk of the weak leveraged pressure being exerted. The sandal's
overall weight is relatively light, because of the large number of
weight-reducing cavities designed into the sole system, which
causes the upward pressures being exerted against the toes to be
weak enough not to be objectionable, and only barely noticeable,
just as they are with conventional "flip-flops". The buying public
has become quite accustomed to this slight, instinctive, downward
toe pressure when wearing conventional "flip-flops" and other rigid
sole sandals and clogs that are secured to the foot with a
thong.
[0295] The light weight raw materials chosen for the present
invention, and the inclusion of the large number of weight-reducing
cavities 34a, 34b throughout the three sole sections 1, 2, 3 causes
the weight of the sandal sole to be exceptionally light. And,
because the sole system 1, 2, 3 is exceptionally light weight, the
height of the butting areas 42, 36, 37, 43 between the three sole
sections 1, 2, 3 are small and yet still function satisfactorily in
keeping the three sole sections 1, 2, 3 within the same plane when
airborne. This is the stage of the walking cycle in which it should
be obvious to the viewer of the drawings why extreme measures have
been taken in the design of the sandal to restrict the weight to
prevent the sandal from hanging heavily from the foot during the
airborne stage FIG. 8F of the walking cycle. Without the cavities
34a, 34b, the sandal sole would be far too heavy to function
properly.
[0296] An alternative embodiment to the present invention as shown
in FIGS. 9 through 20D, is comprised of; (1) a flexibly hinged,
three-part, sandal sole system 101, 102, 103 for receiving footwear
of a user; (2) a forward foot-strap assembly 107; (3) a rear
foot-strap assembly 108; and (4) a heel back stop 106. Additional
design characteristic include: (5) extra sole length added to the
rear sole section 3, behind the sandal-wearer's heel; and (6)
additional sole width added to the entire sole system 101, 102,
103. The three, flexibly-hinged, rigid-sole sections 101, 102, 103
and the extra sole length of the rear sole section 3 interact to
enable the employment of inverted mechanical leverage to eliminate
the deep foot sinking that is a known deficiency of all known
conventional footwear when engaged in full-stride walking on very
soft sand. The extra sole width of the three-part sole system 101,
102, 103 is of secondary importance, but it reduces the foot
sinking even more by increasing the square-inch surface area of the
sole system 101, 102, 103, thereby lessening the over-all body
weight supported per-square-inch of sole. A combination of the
inverted mechanical leverage action and the extra sole width,
reduces the foot sinking down to an insignificant level.
[0297] The inverted mechanical leverage principle that is the
primary ingredient of the present invention relates to the commonly
understood use of a long, rigid beam to lift a heavy object by
placing one end of the rigid beam under the object, and placing a
rock, or other supporting fulcrum, beneath the beam at a point
located less than half the over-all length of the beam away from
the object. The leverage action created causes the heavy object to
be lifted up by applying downward pressure to the opposite end of
the beam. With the assistance of the mechanical leverage advantage,
the energy expended to lift the heavy object is less than the
energy required to pick up the heavy object without the use of
leverage. The energy advantage of this leverage example is not
particularly significant to the present invention, but the basic
mechanical action is, when inverted.
[0298] With the present invention, the leverage action being
utilized is inverted, with the forward sole section 101, and the
rear sole section 103 of the sandal, each acting as independent,
flat-surface, inverted levers, and the middle sole section 102,
simply functioning as a spacer between the forward sole section 101
and the rear sole section 103. The shoe's heel acts as a weighted
fulcrum for the rear sole section 103, and the forward portion of
the shoe's sole that is located directly beneath the ball joints of
the toes and the toes themselves, acts as a weighted fulcrum for
the forward sole section 101--see FIGS. 19B, 19C and 19D.
[0299] During a full-stride stepping action forward, when the
airborne foot is completing its step, the pressure from the
sandal-wearer's falling foot, when applied by the sandal-wearer's
shoe heel upon contact with the soft sand, causes the rear sole
section 103 to almost instantly plop down firmly and flatly upon
the very soft sand, where the body's full-weight is supported by
the entire square-inch bottom surface area of the flatly-positioned
rear sole section 3, resulting in an insignificant amount of foot
sinking.
[0300] As the walking action continues, and the angled foot arcs
down flatly upon the soft sand, the pressure being applied by the
front portion of the sandal-wearer's shoe as it is arcing downward,
causes the middle sole section 102 and the forward sole section 1
of the sandal sole system 101, 102, 103 to be pressed down firmly
and flatly upon the soft sand, one after the other, in succession.
The body-weight pressure holds the affected sole sections 101, 102,
103 firmly- and flatly-positioned upon the soft sand until that
pressure is removed.
[0301] With the present invention, whenever any of the three sole
sections are supporting any significant amount of body weight, it
remains positioned firmly and flatly upon the soft sand until that
weight is removed. These inverted mechanical leverage actions
eliminate most of the foot sinking that is caused by two primary
factors when engaged in full-stride walking on very soft sand: (1)
the 18 to 25 degree angle of the sandal-wearer's foot when the back
end of the sandal strikes the soft sand at the completion of every
full-stride, airborne step forward; and (2) the sandal-wearer's
heavy body weight per-square-inch of sole. Those two factors are
the root causes of the foot sinking that occurs during full-stride
walking on very soft sand, whether walking barefooted or wearing
footwear. The present invention's use of inverted mechanical
leverage, combined with the obvious use of extra sole width to
reduce foot sinking, are the key intellectual properties for which
a patent is being sought.
[0302] The functioning of the present invention and a detailed
description of the various component parts that make it possible
are explained in the paragraphs that follow, accompanied by
mechanical drawings for visual reference. Except for the metal
fittings, 119a, 119b, 117a, 118a, the elastic strap portions 112 of
the two foot-strap assemblies 107, 108, and the foam rubber and
rubber parts 171, 155, 104, 105, most parts of the sandal are
designed to be constructed of a very strong, non-brittle plastic
which will likely have a satin-surface finish that is very finely
textured. The look and feel of the plastic will likely be similar
to that found in some, mostly rigid, but not brittle, power hand
tool exterior housings and some newly marketed, sturdy, and tough,
plastic kitchen tongs, spatulas, ladles, etc.
[0303] The flexibly hinged, three-part, sandal-sole system is
comprised of three, rigid-sole sections 101, 102, 103, hereafter
referred to as the forward sole section 101, the middle sole
section 102, and the rear sole section 103. The three sole sections
101, 102, 103 are each aligned flatly and end-to-end, one after the
other, in a linear fashion from the sandal's toe end to the
sandal's heel end 103, with the middle sole section 102 designed
shorter than the other two, and with the separation space between
the three sole sections being 1/8 inch, more or less. The two,
flexibly-hinged joints that link the three sections together are
designed to allow the sole sections 101, 102, 103 to arc upward and
downward, independently in relationship to one another FIGS. 19C
& 19E.
[0304] The three sole sections 101, 102, 103 are designed
extra-wide FIG. 12 with 0.75 inch to 1.5 inches, more or less,
added to the sole's width. The extra sole width is asymmetrically
added to the right side of the right foot sandal, and to the left
side of the left foot sandal, as opposed to equal amounts being
added to both the right and left sides of each foot. By having no
extra width added on the inside of the feet, this asymmetrical
feature allows the sandal-wearer's feet to operate as closely
together while walking, or jogging, as they normally do with
conventional shoes and sandals. The precise amount of extra sole
width will ultimately be decided by the amount of extra sole width
that market research determines is likely to be acceptable to
prospective buyers.
[0305] The amount of foot-sinking that the extra sole width
prevents is not required for the success of the sandal, but when
combined with the leverage action, it does further reduce the
foot-sinking down to an insignificant level, whereas the mechanical
leverage action alone reduces it by only 2/3 to 3/4, but not
totally down to an insignificant level. The added weight and cost
of materials required by the extra sole width will likely lead to
the addition of hidden weight-reducing cavities, not shown in any
of the drawings, although they are not required for the alternative
embodiment to function as intended.
[0306] Partial working models of the present invention, made
without weight-reducing cavities, function exceptionally well and
are not excessively heavy. Also, extra sole width, less than the
1.5 inches shown in these drawings, or no extra width at all, would
result in less of a reduction in foot sinking, but the overall foot
sinking would still be greatly reduced, and likely be considered
"good enough" by prospective buyers consulted during market
research.
[0307] The forward sole section 101 is one of the three, rigid-sole
sections that comprise the sandal sole system 101, 102, 103. When
viewed from the side, it is designed with the forward edge tapered
125, top to bottom, like the curve at the front end of a snow ski,
to reduce the amount of sand spray that is flipped up into the air
any time footwear, is lifted up off very soft sand into the air
when engaging in a step forward in the walking cycle. The forward
sole section 101 is also designed with a very slight curve and a
slight angle 123, left to right, along its forward edge when viewed
from above. The angle enables the sandal-wearer to make arced
changes in direction while walking or jogging. The extra width of
the sandal sole causes large-diameter arcs and moderate-diameter
arcs to be acceptable, but small diameter arcs are not.
[0308] Small-diameter arcs cause stability problems when the
sandal-wearer's foot is being lifted up off the soft sand as it is
being thrust forward toward its next airborne step. The problem
occurs when the front inner corner of the sandal sole, which is
located directly in front of the sandal-wearer's longest toes,
lifts off the soft sand before the front outer corner 110a lifts
off. It is acceptable, however, if the reverse order occurs, or if
the inner and outer corners 110a, 110b both lift off
simultaneously.
[0309] If the present invention is eventually marketed, a strong
caution to prospective buyers of the product will have to accompany
the sandal, warning against engaging in small diameter directional
changes while walking or jogging, to avoid instability and the
possibility of falling.
[0310] The forward sole section 101 is designed with a forward
foot-strap assembly 107 that is stretched snugly, but not tightly,
across the toes portion of the sandal-wearer's shoe, and is
attached to the hooked stud 122 of the forward adjustable
foot-strap anchor 120a on the opposite side of the shoe, securing
the forward 1/3 of the shoe in constant contact with the forward
sole section 1. The strap's snug, but not tight, adjustment allows
the shoe to shift a small amount forward and backward along the top
surface of the sandal sole as the three sandal sole sections 101,
102, 103 flex in relationship to one another during the walking
cycle. This shifting occurs between the narrow confines of the two
foot-strap anchors 119a 119b, 120a, 120b located on each side of
the foot. The shifting occurs only when there is flexing of the
three sole sections 101, 102, 103, and when there is little, or no,
body-weight pressure being concentrated heavily upon the particular
sole sections. When any significant amount of body weight pressure
is being applied to any of the three sole sections 101, 102, 103,
that weight locks the shoe into whatever position that it is in on
that sole section, for the entire time that the pressure is being
applied.
[0311] The thickness of the back end edge 126 of the forward sole
section 101 is designed to be angled backwards from the top surface
to the bottom surface, at approximately 145 degrees, more or less,
down from an imaginary vertical line above. Its purpose is to
extend the bottom surface area as far backwards as possible, in an
effort to maximize the square-inch surface area available to
support the sandal-wearer's body weight. The forward sole section
101 is designed with three cavities 130a, 135, 152a in the top
surface--one for the forward stationary foot-strap anchor 119a, and
the other two for the forward adjustable foot-strap anchor 120a.
These two foot-strap anchors 119a, 120a secure each end of the
forward foot-strap assembly 107, which includes a long and wide
elastic strap 112, which allows it to stretch snugly, but not
tightly, across the toes portion of the sandal-wearer's shoe,
snugly holding the forward 1/3 of the shoe in constant contact with
the forward sole section 1.
[0312] A toe position indicator 132 for the shoes will be embossed,
or otherwise imprinted, or affixed, onto the top surface of the
forward sole section 1. The purpose of this indicator 132 is to
unmistakably communicate to salespersons and prospective buyers of
the sandal exactly what size shoes are required for proper
functioning for that particular size sandal.
[0313] The middle sole section 102 is one of the three, rigid-sole
sections that comprise the sandal sole system 101, 102, 103. It is
designed primarily as a spacer between the forward sole section 101
and the rear sole section 3, and the number of square inches of its
bottom sole surface assists in the sandal's overall resistance to
foot sinking when the foot is positioned flatly upon the soft sand.
Although this middle sole section 102 is shown in the drawings as a
single-element section, it functions equally as well in its job as
a spacer when divided into two or more shorter segments, connected
end to end.
[0314] The sole thickness 127 of the forward end of the middle sole
section 102 angles backwards from the top surface to the bottom
surface, at an angle of approximately 130 degrees, more or less,
down from an imaginary vertical line, to allow a notch of space to
exist between the forward end 127 of the middle sole section 102
and the back end 126 of the forward sole section 101 when both
sections are positioned in the same plane. This space is needed to
allow the two sole sections 1, 102 to flex downward, in
relationship to each other, below the horizontal plane, to
facilitate walking over mounds of sand and also when engaged in one
stage of the walking cycle FIG. 11C. The downward flexing is also
needed when non-cautious sandal-wearers attempt to walk up or down
stairway steps at beach boardwalks, etc., against the
recommendation of the sandal manufacturer.
[0315] The space is also needed to accommodate the small amounts of
soft sand that squeeze out from beneath the sole sections with each
step in the walking cycle. A mirror image of the angular edges just
described also exist between the back end 128 of the middle sole
section 102 and the forward end 129 of the rear sole section 3.
[0316] The rear sole section 103 is one of the three, rigid-sole
sections 101, 102, 103 that comprise the sandal sole system 101,
102, 103. It is designed with extra length added behind the planned
positioning of the sandal-wearer's shoe heel--approximately 1.25 to
1.75 inches, more or less. This extra sole length interacts with
the flexibly-hinged, three-part, sandal sole system 101, 102, 103
to employ inverted mechanical leverage to force the rear sole
section 103 to plop down flatly upon the soft sand at the
completion of the foot's airborne stage of a full-stride, stepping
action forward when the back end of the rear sole section 103
strikes the soft sand ahead. The inverted mechanical leverage
action is explained in more detail elsewhere in this section.
[0317] The rear sole section is also designed with a very slight
curve and a slight angle 124, left to right, along its rear edge
when viewed from above. The angle enables the sandal-wearer to make
arced changes in direction while walking, or jogging. The extra
width of the sandal sole causes large diameter arcs and moderate
diameter arcs to be acceptable, but small diameter arcs are not.
Small-diameter arcs cause stability problems when the
sandal-wearer's foot strikes the soft sand as it is completing its
airborne steps forward during the full-stride walking cycle. The
problem occurs when the rear inner corner of the sandal sole, which
is located directly behind of the sandal-wearer's heel, strikes the
soft sand after the rear outer corner 111 does. It is acceptable,
however, if the reverse order occurs, or if the inner and outer
corners both strike the soft sand simultaneously.
[0318] As explained above, if the present invention is eventually
marketed, a strong caution to prospective buyers of the product
will have to accompany the sandal, warning against engaging in
small diameter directional changes while walking or jogging, to
avoid instability and the possibility of falling.
[0319] The angle of the rear edge 124 of the rear sole section 103
has the additional function of accommodating the small amount of
flay-footedness of most people, as opposed to people with feet that
are positioned precisely straight forward, or are more flay-footed
than is normal. People with very exaggerated flay-footedness, can
expect to experience stability problems with the present invention,
unless they take care to engage in only large diameter directional
changes, or have the angle of the rear edge 124 of the sandal
increased by cutting or filing. The thickness of the forward edge
129 of the rear sole section 103 is designed to be angled forward
from the top surface to the bottom surface, at approximately 145
degrees, more or less, from an imaginary vertical line upward. Its
purpose is to extend as far forward as possible, the bottom surface
area of the rear sole section 103 in an effort to maximize the
square-inch surface area available to support the sandal-wearer's
heavy body weight.
[0320] The rear sole section 103 is designed with four cavities
130b, 152b, 135, 160b in the top surface--one cavity 135 for the
rear stationary foot-strap anchor 119b; and two cavities 130b, 152b
for the rear adjustable foot-strap anchor 120b. The last cavity
160b of the four cavities is for the heel back stop 106. The two
foot-strap anchors 119b, 120b of the rear sole section 103 each
secure one of the two ends of the rear foot-strap assembly 108
which includes a long, wide elastic strap 112 which allows it to
snugly stretch across the instep of the sandal-wearer's foot and
shoe.
[0321] The restraining pressure created by the elastic strap
portion of the rear foot-strap assembly 108 keeps the rear sole
section 103 pulled up snugly and in constant contact with the heel
of the shoe, even during the plop-down stage of the walking cycle
when the rear edge of the shoe's heel shifts forward along the
surface of the rear sole section 3, as explained in the detailed
description of FIGS. 11C and 11E later in this section. The strap's
moderate, but not tight, snugness allows the shoe to shift a small
amount forward and backward along the top surface of the sandal
sole 101, 102, 103 as the three sole sections 101, 102, 103 flex in
relationship to one another during the walking cycle. This
shifting, forward and backward, occurs with the shoe positioned
between the narrow lateral confines of the four foot-strap anchors
119a, 119b, 120a, 120b-one located on each side of the toes portion
of the shoe, and one located on each side of the heel portion of
the foot. The shoe's shifting occurs only during two phases FIGS.
19C & 19E of the full-stride walking cycle when there is
flexing of the three sole sections 101, 102, 103, and when there is
little, or no, body-weight pressure being concentrated heavily upon
the particular sole section(s) involved. When any significant
amount of body weight pressure is being applied to any of the three
sole sections 101, 102, 103; FIGS. 19C & 19E, that weight locks
the shoe into whatever position it is in, on that particular sole
section, for the entire time that the weight is being applied.
[0322] The stationary foot-strap anchor 119a, 119b, of which there
are two, is a mechanism with a hooked stud 121. One of the anchors
is located on the forward sole section 101 and one on the rear sole
section 103, and both are positioned flushly along the right side
of the left sandal, and along the left side of the right sandal,
both within 1/16 inch to 1/8 inch of the shoe's positioning. They
are secured within the cavity 135, FIG. 13 provided in the forward
sole section 101, and in the rear sole section 103 by a locking arm
134c which is part of the two anchors 119a, 119b. The two
stationary foot-strap anchors 119a, 119b function in conjunction
with the two adjustable foot-strap anchors 120a, 120b that are
located on the left side of the left shoe, and on the right side of
the right shoe to provide anchors for the two, foot-strap
assemblies 107, 108. The stationary foot-strap anchors 119a, 119b,
are designed to be thin and to ensure that the sandal-wearer's shoe
is continually positioned within 1/16 to 1/8 inch of the two
stationary foot-strap anchors 119a, 119b, to enable the
sandal-wearer's two feet to operate just as closely together with
the sandals as they do with conventional footwear alone.
[0323] With the present invention, the two sandals never come in
contact with one another during the normal full-stride walking
cycle, and the sandal-wearer never has to walk with his feet held
further apart than is normal. A snap-lock flange 148, as shown in
FIG. 15F, is pressure-activated, has been designed into the
mechanism to ensure that both, the forward stud-mate attachment
117a and the rear stud-mate attachment 118a of the two foot-strap
assemblies 107, 108, remain attached to the anchors, and do not
accidentally disengage even when the foot-strap assembly is hanging
loosely during times when the sandal is not attached to a foot. The
snap-lock flange 148 as shown in FIG. 15F also allows the
foot-strap assemblies to be easily snapped out and in when they
become worn with time and need to be replaced due to excessive
wear.
[0324] The adjustable foot-strap anchor 120a, 120b, of which there
are two, is a mechanism with a hooked stud 122. It is located on
both, the forward sole section 101 and on the rear sole section 3,
and is positioned on the left side of the left shoe, and on the
right side of the right foot, both within 1/16 inch to 1/8 inch of
the shoe. The two adjustable foot-strap anchors 120a, 120b, that
are located on the outer side of the shoe, function in conjunction
with the two stationary foot-strap anchors 119a, 119b that are
located on the inner side of the shoe. These anchors are designed
to ensure that the sandal-wearer's shoe is continually positioned
close enough to the inside edge of the sandal to allow the
sandal-wearer's feet to operate as closely together as they
normally do when wearing conventional footwear, to prevent the
sandals from touching one another when walking or jogging.
[0325] The adjustable foot-strap anchors 120a, 120b are designed to
be laterally adjustable to accommodate every shoe size width.
Unless the sandals are later sold or given away, this adjustment
will be made only once, when the sandal is initially fitted to the
footwear of the sandal wearer at the time of purchase. The
adjustable foot-strap anchors 120a, 120b are designed to enable the
stud-mate attachments 117, 118, of both foot-strap assemblies 107,
108, to be easily engaged and disengaged from beneath the hooked
stud 122 of the adjustable foot-strap anchors 120a, 120b each time
the sandal is attached or detached from the foot.
[0326] The adjustable foot-strap anchors 120a, 120b are designed
with an anchoring tongue and T-arm protrusion 133 that securely
fits down into a cavity 130a, 130b, as shown in FIG. 13, and 161 as
shown in FIGS. 16A, 16E, 16G, 16H provided in the forward sole
section 101 and the rear sole section 102. Another cavity 152a,
152b is provided to accommodate the locking-arm stud 140, FIGS.
16A, 16B, 16D, 16E in one of many different laterally spaced
positions to account for the many different shoe widths. The
adjustable foot-strap anchors 120a, 120b are designed in such a way
that their two plastic parts can be assembled by hand in one easy
step, with no tools required. The locking-arm studs 140, FIGS. 16A,
16B, 16D, 16E of the adjustable foot-strap anchors 120a, 120b can
easily be seated by hand into their respective cavities 152a, 152b
when inserted vertically as shown in FIG. 16E.
[0327] A forward foot-strap assembly 107 and rear foot-strap
assembly 108, each consist of a wide elastic strap 112, roughly 1.5
inches wide, more or less, with a buckle 113a made of a very
strong, rigid plastic, or other material with similar properties.
This buckle 113a will allow the strap's 112 length to be adjusted
to the desired degree of snugness, and to stay adjusted until a
different length, or degree of snugness, is desired. The two
foot-strap assemblies 107, 108 consist of a stud-mate attachment
117a, 117b, 118a, 118b at each of the four ends. Two ends 117a, as
shown in FIG. 20C, and 117b, as shown in FIG. 20A, of which are
made of a very strong, rigid plastic, or other suitable material
with similar properties, and the other two ends of a metallic
material that allows them to have approximately the same strength,
but be much thinner than their plastic counterparts. The metallic
versions are designed with a donut-shaped catch 114a, 114b on one
end that loops beneath the hooked studs 121 of the two, stationary
foot-strap anchors 119a, 119b on the inside edge of the sandal.
[0328] The plastic versions are designed with a donut-shaped catch
115a, 115b on one end that loops beneath the hooked studs 122 of
the two, adjustable foot-strap anchors 120a, 120b on the outer side
of the shoe. The two metallic, stud-mate attachments 117a, 118a of
the two foot-strap assemblies 107, 108 attach beneath the hooked
studs 121 of the two metallic, stationary foot-strap anchors on the
inner side of the foot, then cross over the top of the foot to the
opposite side where the stud-mate attachments 117b, 118b loop
beneath the hooked studs 122 of the two adjustable foot-strap
anchors 120a, 120b located on the outer side of the foot. Once the
two foot-strap assemblies 107, 108 are secured across the top of
the foot, they are tightened snugly, but not tightly, to enable the
shoe's sole to shift forward and backward slightly, as needed,
during the walking process as a result of the flexing of the soles
against each other.
[0329] The moderate degree of snugness of the two, elastic,
foot-strap assemblies 107, 108 is established utilizing the
foot-strap buckle 113a designed for that purpose. When fully
engaged and adjusted, the moderate snugness of the two foot-strap
assemblies 107, 108 insures that the four stud-mate attachments
shown in FIG. 9, 117a, 117b, 118a, 118b of the two, foot-strap
assemblies 107, 108 remain securely engaged beneath the hooked
studs 121, 122 while the sandal is being worn, and prevents their
disengagement until the strap's elastic pressures are relieved by
intentionally applied hand pressure not requiring the loosening of
the buckle 113a. Once the buckle 113a is initially tightened to the
desired degree snugness at time of purchase, it need not be
adjusted again until after many hours of use. The hooked studs 122
of the two adjustable foot-strap anchors 120a, 120b allow for
exceptionally quick and easy attachment and disengagement of the
straps.
[0330] An additional part is a smooth, strong, loose-fitting, cloth
sleeve, with elastic constrictions at each end to keep it securely
positioned near each end of the stud-mate attachments 117a, 118a.
Its function will be to encase and protect the entire foot-strap
assembly 107, 108, except for the donut end portions 114a, 114b,
115a, 115b of each stud-mate attachment 117a, 118a, 117b, 118b, to
reduce wear and tear on the elastic strap portion 112 of the
foot-strap assembly 107, 108, caused by the small amount of rubbing
that occurs during the movement of the foot beneath the foot-strap
assemblies 107, 108 during the walking cycle. This sleeve is
intended to extend the life of the elastic strap 112 of the
foot-strap assemblies 107, 108, which are the weakest parts of the
sandal. The sleeve is not engaged until the strap's tightness has
been initially established at time of purchase. Thereafter, only
one end of the sleeve need be pulled back in the event that an
adjustment is needed with the elastic straps 112 and the buckle
113a.
[0331] A heel back stop 106 is located on the top, back portion of
the rear sole section 3, directly behind the intended placement of
the heel of the sandal-wearer's shoe. It is comprised of a foam
rubber, heel cushion that extends laterally across the top, forward
portion of the plastic, heel back stop 106, which rises
approximately 1.125 inches above the surface of the rear sole
section 3. The actual foam rubber contact point with the back end
of the shoe's heel is at a level located roughly 0.65 inches above
the sole's surface, to account for the large gap (that sometimes
approaches 1/2 inch high) that often exists beneath the back edge
of the heel of a badly worn shoe sole. The foam rubber heel cushion
functions as a pivot point for the back end of the shoe to pivot
against.
[0332] Below the soles surface, an anchoring tongue protrusion 157
fits into a cavity 160a, with a locking arm 159 to secure it snugly
in position. Because of the extended width of the heel back stop
106 it can accommodate the full range of shoe widths. The snap-lock
arm 159 is designed to pressure-snap into the cavity 160a provided,
locking the heel back stop 106 into position upon the rear sole
section 3. A small cavity 165 is provided in the main body portion
156 of the heel back stop 106 to accommodate a screwdriver to be
used to pry out the mechanism for replacement, if needed. The
rounded top edge is designed to be the pivot point between the
shoe's heel and the heel back stop 106 and the adjoining rear sole
section 3, which operate as a single unit, and function like a
flat, inverted mechanical lever during the plop-down stage of the
airborne stepping action of the full-stride walking cycle.
[0333] A description of how the present invention works during a
full-stride walking cycle is described below in step-by-step
detail, accompanied by drawings for visual clarity FIGS.
19A-19F.
[0334] FIG. 19A is the first drawing of a 6-part sequence FIGS.
19A-19F depicting the various stages of a full-stride walking cycle
as the sandal-wearer's upper body continues its move forward. This
drawing shows the configuration of the left foot sandal the moment
before it strikes the surface of the soft sand after having been
thrust in the air toward a full-stride step forward. The angle of
the foot and shoe at this stage is roughly 15 to 25 degrees, in
relationship to the surface of the soft sand, and is a direct
result of the 15 to 25 degree angle of the outstretched leg of the
sandal-wearer, forward of the vertical.
[0335] FIG. 19B is the second drawing of a 6-part sequence FIGS.
19A-19F depicting the various stages of a full-stride walking cycle
as the sandal-wearer's upper body continues its move forward. This
drawing shows the configuration of the left foot sandal the moment
that it strikes the surface of the soft sand after having been
thrust in the air toward a new full-stride step forward. The angle
of the foot and shoe at this stage is approximately 15 to 25
degrees, in relationship to the surface of the soft sand, and is a
direct result of the 15 to 25 degree angle of the outstretched leg,
forward of vertical. A split second after the back edge of the rear
sole section 103 strikes the surface of the soft sand, as the
sandal-wearer's upper body continues its movement forward, it sinks
into the soft sand only about 0.375 inch before enough surface
resistance is created to trigger an inverted mechanical leverage
action upon the flexibly-hinged, three-part sole 101, 102, 103, by
the back edge of the shoe's heel to function as a weighted fulcrum,
as explained more fully in the descriptive text for FIG. 19C in the
next paragraph.
[0336] FIG. 19C is the third drawing of a 6-part sequence FIGS.
19A-19F depicting the various stages of a full-stride walking cycle
as the sandal-wearer's upper body continues its move forward. The
action occurs with the leading foot, when it is positioned far out
ahead of the sandal-wearer's upper body, at the end of the
outstretched leg. During this split-second sequence the back end
portion of the rear sole section 103 strikes the surface of the
soft sand, as seen in FIG. 19B, while positioned at an angle of 15
to 25 degrees, in its relationship to the surface of the soft sand.
The back end of the sandal sinks down into the soft sand
approximately 0.375 inch before an estimated one to two pounds of
sand resistance triggers an inverted mechanical leverage action
upon the flexibly-hinged, rear sole section 103. This action is
triggered by the back edge of the shoe's heel, functioning as a
weighted fulcrum, by applying downward pressure forward of the back
edge of the rear sole section 103, and forcing the rear sole
section 103 to almost instantly arc downward at an angle, away from
the bottom, front portion of the shoe's heel, plopping the entire
rear sole section 103 down flatly upon the soft sand.
[0337] As the split-second sequence is occurring the
sandal-wearer's angled foot begins a much slower downward arc of
its own, as the upper body continues its movement forward, as
explained in the next sequence. The inverted mechanical leverage
action that occurs is made possible, primarily, by the
flexibly-hinged, three-part, sandal sole system 101, 102, 103, and
the forward positioning of the shoe's heel on the extended rear
sole section 103. The top, forward edge of the heel back stop
mechanism 106 also plays an important roll in providing a stable
pivot point for the arcing to occur.
[0338] Note in the drawing that when the rear sole section 103 arcs
downward, away from the forward portion of the shoe's heel, the
back side of the shoe maintains constant contact with the pivot
point at the top, forward edge of the heel back stop mechanism 106,
approximately 1.25 inches above the surface of the rear sole
section 103. Also, the back edge of the shoe's heel maintains
constant contact with the rear sole section 103 as it shifts
forward roughly 3/8 inch, more or less. This phenomena occurs
because of the 15 to 25 degree angular difference that is instantly
created between the shoe's sole and the sandal's rear sole section
103 when the plop down occurs. The instant that the plop-down has
concluded, the rear sole section's downward movement stops abruptly
when the sandal-wearer's body weight becomes fully supported by the
entire surface area of the now flatly-positioned rear sole section
103 and only minimal foot sinking results.
[0339] Immediately prior to the plop-down, the body's full weight,
had been supported by the flatly-positioned forward sole section
101 of the trailing foot, which has a configuration identical to a
mirror image of FIG. 19E. At the peak of the heel's arcing movement
upward, the body's full-weight is shifted forward to the leading
foot shown in FIG. 19C. The inverted mechanical leverage action
being explained above is assisted by the front-to-back, downward
angling, (45 degrees, more or less) of the rear foot-strap assembly
108, which reduces approximately in half, the restraining pressure
being applied by the rear foot-strap assembly 108 to the heel back
stop 106.
[0340] Also, the rear foot-strap assembly's 108 two points of
attachment near the back end of the heel 119b, 120b, FIGS. 3 &
4 are one of the key ingredients to making the plop-down action
successful, not only because its 45-degree angle reduces the
retaining pressure by half, but also because it greatly increases
the mechanical leverage ratio of the heel's downward pressure, when
functioning as a weighted fulcrum upon the rear sole section 103.
The retaining pressure being exerted by the rear foot-strap
assembly 108 is estimated to be 103 pounds, more or less, which is
sufficient to keep the rear sole section 103 sufficiently pulled up
beneath the sole of the shoe, but weak enough to enable the
weighted fulcrum action created by the back edge of the shoe's heel
to easily force the rear sole section 103 to arc downward and away
from the forward portion of the shoe's heel.
[0341] Note that the entire sequence of the rear sole section's
plop-down, just described, occurs within a split-second while the
sandal-wearer's foot and shoe remain positioned at their forward,
upward angle orientation, of approximately 15 to 25 degrees, in
relationship to the surface of the soft sand, until after the
plop-down has occurred, and until after the body's full weight has
been applied to the back edge of the shoe's heel and the soft sand
below. The foot's arc downward from its angular orientation occurs
at a much slower rate of speed than that of the almost
instantaneous plop-down action.
[0342] FIG. 19D is the fourth drawing of a 6-part sequence FIGS.
19A-19F depicting the various stages of a full-stride walking
cycle. This drawing shows the configuration of the left foot sandal
as the sandal-wearer's upper body is continuing its move forward
during the walking cycle until it is passing directly over the
foot, which has arced downward, until it is positioned flatly in
its relationship to the soft sand. This action occurs in the time
frame between FIG. 19C and FIG. 19D. Immediately following the
arced plop-down of the rear sole section 103 that occurs in FIG.
19C, the angled foot begins its arc downward at a much slower speed
than the almost instant plop-down, from its 15 to 25 degree angle,
until the body-weight pressure has forced the middle sole section
102 and then the forward sole section 101 to lie down flatly upon
the soft sand, in succession, one after the other. It should be
noted that during the walking cycle no significant amount of
body-weight pressure is ever exerted upon any of the three sole
sections 101, 102, 103 until they are positioned flatly upon the
soft sand. This characteristic insures that the maximum number of
square-inches of sole surface is in contact with the soft sand when
the body weight is applied, and that the minimum possible amount of
foot sinking occurs.
[0343] FIG. 19E is the fifth drawing of a 6-part sequence FIGS.
19A-19F depicting the various stages of a full-stride walking
cycle. This drawing shows the configuration of the left foot sandal
as the sandal-wearer's upper body continues its move forward, and
the opposite foot (unseen in this drawing) begins its thrust
forward in the air toward that foot's full-stride step. In
response, the now-trailing leg begins lifting the heel of the
now-trailing foot, shown in the drawing, up in the air above the
soft sand in anticipation of its next stepping action forward. All
the while, the foot's rear foot-strap assembly 108 continues
performing its job of applying mild retaining pressure to the rear
sole section 103, holding it up flatly against the bottom of the
shoe's heel. As the foot's heel lifts upward, the sandal-wearer's
body weight, which the moment before had been divided between the
foot's heel and the ball joints of the toes, and with a small
amount on the toes themselves, shifts totally to the ball joints of
the toes, and a small amount to the toes themselves.
[0344] As the sandal-wearer's upper body continues moving forward,
the outstretched leading leg and the outstretched trailing leg,
each become even more outstretched as the full-stride stepping
action is nearing completion, thereby causing the heel of the
trailing foot to lift up even higher than shown in the drawing.
And, because of the flexing that occurs between the three sole
sections 101, 102, 103 and the shoe, the shoe's heel is forced to
shift backwards on the surface of the rear sole section 3,
reclaiming some, or all, of the space created by the pivoting
action explained in the written descriptions of FIG. 19C above.
[0345] Note that the forward sole section 101 remains firmly and
flatly positioned upon the soft sand during the entire time that it
is supporting any significant amount of the sandal-wearer's body
weight, which maximizes the square-inches of sand contact and
minimizes foot sinking. The flexibly hinged, three-part, sole
system 101, 102, 103 plays a crucial role in making this action
sequence possible.
[0346] FIG. 19F is the sixth drawing of a 6-part sequence FIGS.
19A-19F depicting the various stages of a full-stride walking
cycle. This drawing shows the configuration of the left foot sandal
as the sandal-wearer's upper body continues its move forward, and
just after the foot has been lifted up off the soft sand into the
air during its thrust forward toward its next full-stride step. As
soon as the body-weight pressure is instinctively shifted from the
now-trailing foot (seen in this drawing) forward to the now-leading
foot (not seen in this drawing), the snug retaining pressure being
exerted by the sandal's rear foot-strap assembly 108, shifts the
sandal-wearer's shoe back against the heel back stop 106 where it
had been positioned at the beginning of the walking cycle, as shown
in the drawings of FIGS. 19A & 19B.
[0347] FIG. 16A is a cross-sectional side view of the forward
adjustable foot-strap anchor 120a, and the rear adjustable
foot-strap anchor 120b, as identified by line B-B in FIG. 16B,
shown with a cross-sectional side view 153e of the forward
stud-mate attachment 117b, as identified by line B-B of FIG. 20A.
This mechanism is designed to be made of plastic, or a material
with similar properties.
[0348] Note that the arcing arrows and dashed lines indicate that
the forward stud-mate attachment 117b is designed to enable an
inward and outward, page-like, arcing motion of the forward
stud-mate attachment 117b from its attachment point beneath the
hooked stud 122--up to 60 degrees inward from the vertical and 40
degrees outward from the vertical. Also shown is a sub-surface side
elevation view of the anchoring tongue protrusion 133 and locking
arm 173 of the adjustable foot-strap anchors 120a, 120b, plus a
cross-sectional side view of a truncated portion 150 of the forward
sole section 101, as identified by line B-B of FIG. 16B.
[0349] Note that the cross-sectional thickness of the stud-mate
attachment 153e of the forward foot-strap assembly 107 is seen in
its locked position nestled up beneath, and pressing up against,
the hooked stud 122. The dashed line to the left of the hooked stud
122 also indicates the required angle for the stud-mate attachments
117b, 118b to be positioned at during engagement and disengagement
from underneath the hooked stud 122. The reason that the locked
position beneath the hooked stud 122 is referred to as "locked" is
that the stud-mate attachments 117b, 118b cannot accidentally slip
out from beneath the hooked stud 122 while the sandal is being
worn. It can only be removed "intentionally" by hand pressure
relieving the tension on the foot-strap assemblies 107, 108 and by
arcing the plane of the stud-mate attachments 117b, 118b, like the
page of a book, approximately 40 degrees down from the vertical to
enable it to be slid out from underneath its locked position
beneath the hooked stud 122.
[0350] The anchoring tongue and T-arm protrusion 133 of the two
adjustable foot-strap anchors 120a, 120b extends down into the
specially-designed cavity 130a, 130b of the forward sole section 1,
and the rear sole section 103 where the adjustable foot-strap
anchors 120a, 120b and their anchoring tongue and T-arm protrusion
133 can be slid laterally into one of many different teeth-lock
cavity positions 172a, 172b, made available for anchoring the
adjustable foot-strap anchors 120a, 120b to fit multiple shoe
widths.
[0351] During the initial fitting of the sandal to the purchaser's
foot, when the right side of the left shoe, and the left side of
the right shoe, are positioned up against the two stationary
foot-strap anchors 119a, 119b, the two adjustable foot-strap
anchors 120a, 120b are slid laterally into a position 1/8 inch, or
less, away from the outer side of the sandal-wearer's shoe, to the
nearest teeth-lock location within the cavity 172a, 172b. The
locking-arms 139 and the locking-arm studs 140 of the two
adjustable foot-strap anchors 120a, 120b, are then forced by hand
pressure on the finger-grip flange 141, to arc downward and snap
into one of many teeth-lock cavity 152a, 152b, 162 positions.
[0352] The actual snap-lock stud 142; FIGS. 16B & 16C that the
locking arm 139 snaps down onto when the locking-arm stud 140 is
fully-seated in it's proper teeth-lock cavity 152a, 152b, 162, is
located on the top of the adjustable foot-strap anchor 120a, 120b.
The locking-arm stud shoulder 147; FIG. 16A of the locking arm 139,
is designed to prevent damage to the locking arm 139 during this
engagement process due to the possibility of excessive
hand-manipulated force being applied. The locking-arm stud cavities
152a, 152b, 162 are designed to have greater depth than the length
of the actual locking-arm stud 140, to accommodate excess sand that
may accumulate, and to keep that sand from interfering with the
functioning of the locking-arm stud 140. The locking arm 139 is
attached to the main body of the adjustable foot-strap anchors
120a, 120b by a cylindrical pivot pin 143 that is a contiguous part
of the locking arm 139, and is anchored into the cylindrical,
partial-sleeve cavity 146 where the cylindrical pivot pin 143 and
partial-cavity sleeve 146 function like a conventional door hinge,
and the locking arm 139 functions in a manner similar to a
conventional trap door that arcs upward from the floor.
[0353] The cylindrical pivot pin 143 is designed with the cylinder
shape slightly flattened on the top and bottom, when the locking
arm 139 is positioned in its locked state, enough to allow it to
squeeze down into the open gap of the cylindrical, partial-sleeve
cavity 146 when the locking arm 139 is positioned vertically. Once
inserted into the cylindrical, partial-sleeve cavity 146 during
manufacture, the locking arm 139 becomes locked into the cavity 146
when it is arced downward from its vertical position 5 degrees, or
more, but is then free to arc up and down, up to 85 degrees when
needed, to make shoe width adjustments, if needed. This feature is
one of many designed into the component plastic parts to allow the
standard injection molding process to be used for their formation
and assembly without the use of tools.
[0354] Note that by making the two adjustable foot-strap anchors
120a, 120b adjustable for accommodating all shoe widths, the
required number of different sandal sizes manufactured, and the
total number of sandals needed to be kept in inventory, need only
be 1/4, or fewer, the number required had a different size sandal
been necessary for each shoe size length and width. The functioning
of the two adjustable foot-strap anchors 120a, 120b requires that
it be capable of dealing with pressures from three different
directions--(1) the occasional outward pressures exerted by the
foot against the foot-strap anchors 119a, 119b, 120a, 120b when
directional changes are being made while jogging; and (2) the
upward and inward pressures exerted by the moderately-snug
tightness of the foot-strap assemblies 107, 108.
[0355] The height of the adjustable foot-strap anchors 120a, 120b,
and the stationary foot-strap anchors 119a, 119b was intentionally
designed to be greater than it could have been designed, to ensure
that it prevents the sandal-wearer's shoe, which often has a sole
that curves slightly upward in the front portion, from sliding over
the top of either the forward stationary foot-strap anchor 119a or
the forward adjustable foot-strap anchor 120a, during a change in
direction while jogging, when the sandal-wearer's shoe sometimes
shifts up against the two foot-strap anchors 119a, 120a, located
approximately 1/16 to 1/8 of an inch away from the shoe.
[0356] FIG. 16G is an end elevation view of the forward adjustable
foot-strap anchor 120a connected to the forward stud-mate
attachment 117b, which is the end portion of the truncated forward
foot-strap assembly 107. The top 3/4 portion of the mechanism shown
in the drawing is an elevation of the external surfaces only,
whereas the bottom 1/4 portion is a cross-sectional side view, as
identified by line B-B of FIG. 8B. Note that the small, donut-shape
portion 114a, 151a, as shown in FIG. 20C of the stud-mate
attachment 117b of the forward foot-strap assembly 107 is shown in
its locked position directly beneath the hooked stud 122. See the
"detailed description" above of FIG. 16A for an explanation
regarding the "locked" position of the forward stud-mate attachment
117b, and the rear stud-mate attachment 118b.
[0357] The rear adjustable foot-strap anchor 120b looks identical
to the forward adjustable foot-strap anchor 120a that is shown in
this drawing, except the rear adjustable foot-strap anchor 120b,
would have had the rear stud-mate attachment 118b, FIG. 20B (not
shown in the drawing) instead of the forward stud-mate attachment
117b. Note also that the planes of contact between the cavity walls
130a, 130b, 175 and the anchoring tongue and T-arm protrusion 133
are grooved to minimize the points of contact in an effort to
lessen the friction caused by the inevitable invasion of sand,
explained elsewhere in this application.
[0358] FIG. 17F is the sixth drawing of a 9-part series FIGS.
17A-17I, depicting a cross-sectional side view, as identified by
line A-A of FIG. 17A, of the buckle 113a for adjusting the length
of the elastic strap portion 112 of the forward foot-strap assembly
107, and of the rear foot-strap assembly 108. The elastic strap 112
is shown engaged in the buckle 113a. The configuration of the
elastic strap 112 show it correctly threaded through the buckle.
Its route begins on the left end of the buckle 113a, where it is
attached by sewing, and then extends out toward one end of the
foot-strap assembly 107, 108 where it passes through the clasp 169
and attaches through the wide slot provided in the inner stud-mate
attachment 117a, 118a. It then loops back under in the opposite
direction and passes through the clasp 169 again and travels on
beneath the buckle 113a, and extends all the way toward the
opposite end of the foot-strap assembly 107, 108, where it passes
through a second clasp 169 and attaches through the wide slot
provided in the opposite side stud-mate attachment 117b, 118b and
loops back in the opposite direction, where it again passes through
the second clasp 169 and returns to the buckle 113a where it is
threaded through, and ends up on the other side of the buckle
113a.
[0359] The reason for the continuous looping around of the elastic
strap 112, instead of ending the straps at the two stud-mate
attachments 117, 118 is to eliminate much of the sewing that would
have been required of a non-looping strap. The looping straps show
the addition of two very small and simple plastic, or plastic-like
clasps 169 to hold the top portion of the elastic strap 112, and
the bottom portion of the elastic strap 112, together near each end
so that the top elastic strap 112 and the bottom elastic strap 112
are held together and function as a single strap. The two clasps
170 of the rear foot-strap assembly 108 are likely to be glued, or
otherwise bonded, at opposite ends of a long and wide, 1/4-inch
thick strip of foam rubber. This strip will function as a cushion
between the rear foot-strap assembly 108 and the top portion of the
foot's instep, above the sometimes bulky knot of the shoelaces and
above the top rim of the shoe.
[0360] There is an additional part, not shown in any of the
drawings of this application, which may be added to help protect
the elastic strap 112 of the two foot-strap assemblies 107, 108
from premature wear, and extend their lives. It is a tough, slick,
cloth-like, sleeve, with a tautly stretched, elastic band sewn into
each end. Notches will likely be designed into the stud-mate
attachments 117a, 117b, 118a, 118b located at each end of the two
foot-strap assemblies 107, 108. The elastic endings of the cloth
sleeve would fit into the notches to retain the sleeve pulled over
the entire elastic strap 112 and the buckle 113a.
[0361] FIG. 18A is the first drawing of a 5-part series FIGS.
18A-18E depicting various drawings of the heel back stop mechanism
106. This drawing is a rear view elevation of the heel back stop
106 showing all of the exterior surfaces and dashed-line
indications of some opposite-surface portions, and includes a
cross-sectional view of the truncated sandal sole 150 that
surrounds the anchoring tongue protrusion 157.
[0362] FIG. 18B is the second drawing of a 5-part series FIGS.
18A-18E depicting various drawings of the heel back stop mechanism
106. This drawing is an overhead view showing the exterior surfaces
and dashed-line indications of some non-surface portions. The
portion with lots of small dots represents the foam rubber padding
155 which acts as a cushion for the shoe's heel during the pivot
action which occurs once during every step of the walking cycle
when the top, forward edge of the heel back stop mechanism 106
functions as a pivot point against the back end of the shoe. The
height of the mechanism is approximately 1.25 inches, more or less,
above the surface of the rear sole section. The padding 155 is
expected to be roughly 1/4-inch thick, more or less;
[0363] FIG. 18C is the third drawing of a 5-part series FIGS.
18A-18E depicting various drawings of the heel back stop mechanism
106. This drawing is a bottom view showing the exterior surfaces
only, specifically including the anchoring tongue protrusion 157
that fits down into the cavity 160a provided in the rear sole
section 3.
[0364] FIG. 18D is the fourth drawing of a 5-part series FIGS.
18A-18E depicting various drawings of the heel back stop mechanism
106. This drawing is a front view showing the exterior surfaces and
dashed-line indications of some below the surface or opposite
surface portions. Specifically included are the anchoring tongue
protrusion 157 and the locking arm 159 that fit down into the
cavity 160a provided in the rear sole section 3 which is
represented by a cross-sectional, truncated side view 150;
[0365] FIG. 18E is the fifth drawing of a 5-part series FIGS.
18A-18E depicting various drawings of the heel back stop mechanism
106. This drawing is a side view of the exterior surfaces and
dashed-line indications of some non-surface portions. Included are
the anchoring tongue protrusion 157 and the locking arm 159 that
fit into the cavity 160a provided in the rear sole section 3, which
is represented by a cross-sectional, truncated view 150. The
rounded, top, forward portion of the heel back stop mechanism 106
functions as a cushioned pivot point against the back side of the
shoe's heel at a point located about 1/3 of the way down from the
approximately 1.25 inch height of the mechanism 106. The thickness
of the foam rubber padding 155 is expected to be roughly 1/4 inch,
more or less.
[0366] In this patent application the words sand and soft sand are
meant to refer to very soft sand. It should be noted that the right
foot sandal is a mirror image of the left foot sandal. All linear
measures cited are based upon a sandal designed to fit a size 9D
adult male foot.
[0367] It is to be understood that the present invention is not
limited to the embodiments described above, but encompasses any and
all embodiments within the scope of the following claims.
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