Note: Descriptions are shown in the official language in which they were submitted.
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HIGH HEELED SHOE DESIGN
This invention relates to a new and improved design
for high heeled pump or fashion shoes. The invention is
particularly, though not exclusively, applicable to such
shoes having heels in the height of at least one and
three-quarter inches preferably in the range of one and
three-quarters to two inches or more.
Prior art high heeled shoes in current use have a
reputation of being extremely uncomfortable and there is
,.survey information indicating that as many as 20Y of the
users of such shoes experience foot pain related to the
shoes immediately and the majority of users experience
such pain after as little as four hours of use. This
discomfort results from the wearer's foot sliding
forwards in the shoe with the consequence that th.e
wearer's toes are jammed in the toe portion of the shoe.
One attempt at reducing the discomfort resulting
from the wearing of high heeled shoes is found in U.S.
Patent 2,465,817 in which, in the toe portion of the
shoe, a concave depression 22 is arranged to receive the
ball portion of the wearer's foot and a convex mound
portion 24 is provided forward of that concave portion
whereby the weight of the wearer is supported mainly, if
not entirely, by the ball portion of the foot and by the
heel of the foot with the wearer's weight mainly on the
ball portion of the foot. Such an arrangement is said
to permit very high heels, as high as four inches,
without discomfort to the wearer as the ball portion of
the foot is received in the concave depression of the
shoe thereby preventing the foot from sliding forward in
the shoe. As will be seen from this patent, the heel
seat proposed in the construction disclosed is at a very
substantial angle to the ground plane, that angle being
of the order of 45 degrees. As a consequence, very
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little of the wearer's weight will actually be supported
by the heel seat with the wearer's weight, as stated
above, being carried mainly on the ball portion of the
foot. This results in excessive weight being borne by
the metatarsal with the likelihood that there will be
excessive pressure on the head of the metatarsal
resulting in metartarsalagia. In any event this design
will result in substantial discomfort and a reduction in
foot flexibility.
w Other examples of prior art will be found in U.S.
Patents 1,593,398, 2,254,353, 2,370,789, 2,641,066,
2,852,865, 4,631,841 and RE 18,237.
It is an object of the present invention to provide
a comfortable high-heeled pump or fashion shoe capable
of being used for extended periods without discomfort.
According to the invention there is provided a high
heeled shoe defining ground plane and having a heel seat
disposed at an .angle of from approximately 0 degrees
relative to sa id ground plane to an inclination upwardly
and rearwardly of approximately 3 degrees relative to
said ground plane.
The invention will now be described, by way of
example, with reference to the accompanying drawings, in
which:
Figure 1 is a diagrammatic cross sectional view of
a high heeled shoe according to the present invention;
and
Figure 2 is a diagrammatic representation showing a
comparison of relevant angles to the ground plane of a
shoe according -to the present invention such as that
shown in Figure 1 and current high heeled shoes having
similar heel heights.
With reference to Figure 1 there is shown in ghost
the bone structure of a foot. This structure comprises
the tarsus 1, the metatarsus 2 and the phalanges 3. The
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tarsus 1 is supported by the heel seat 4 while the
metatarsus extends over the shank S to the ball of the
foot 6 where the metatarsus joins the base of the
p,halanges 3. The ball of the foot underlying the heads
of the metatarsals, forming the metatarsus, and the
phalanges are supported by the toe region 7 of the shoe.
The shoe illustrated in Figure 1 has a heel height
of from approximately one and three-quarter inches to
approximately two inches or more. The particular shoe
10' illustrated ins based on a U.S. standard ladies' shoe
size 7. The shoe is shown on a ground plane 8 from
which the heel height to the heel seat 4 is measured.
The heel seat 4 may be parallel with the ground plane or
inclined upwardly and rearwardly of the shoe at an angle
of up to approximately 3 degrees relative to the ground
plane and is preferably at an upward and rearward
inclination of approximately 2 degrees. This angle is
referenced X in Figures 1 and 2. The metatarsus is
angled downwardly and forwardly of the shoe from the
heel seat with the first metatarsal at an angle of
approximately 30 degrees plus/minus 3 degrees relative
to the ground plane, preferably at an angle of
approximately 30 degrees plus/minus 1 1/2 degrees and
more preferably at an angle of approximately 30
degrees. This angle is reference Y in Figures 1 and 2.
In the toe region of the shoe the great toe is
inclined upwardly and forwardly by the upward and
forward inclination of the toe region at an angle of
approximately S 1/2 degrees plus/minus 1 degree relative
to the ground plane. This angle is reference Z in
Figures 1 and 2.
In Figure 2 the line in ghost illustrates the heel
seat 4 angle X, the inclination Y of the first
metatarsal 2 and the great toe spring Z in the toe
region 7 relative to the ground plane 8. Dimension U
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represents the' heel height. The solid line in Figure 2
represent the corresponding set of angles and
inclination for currently available high heeled shoes
having similar' heel heights to that proposed for the
present invention. In these current shoes the
inclination of the heel seat is upward and backwards
towards the rear of the shoe at an angle L of
. approximately 8 degrees, the inclination of the first
metatarsal downwardly and forward is at an angle M of
" Less than 27 degrees and the great toe is inclined
upwardly and forwardly at an angle N of approximately 1
1/2 degrees. These angles L, M and N are also relative
to the ground plane 8 and relate to a shoe of similar
size, namely II.S. standard ladies' size 7.
The ranges. of angles specified above in the present
inventive shoes result in an included angle between the
toe support region 7 of the shoe and the center line of
the first metatarsal of from approximately 140 1/2
degrees to approximately 148 1/2 degrees.
It is believed that a brief explanation of the
mechanics of t:he foot is appropriate to facilitate an
understanding of the function of the shoe of the present
invention. The foot is capable of functioning in two
separate mechanical fashions so as to support the body
above. Primarily, the foot functions as a beam and
supports the body by bending strain. This mechanism of
support is effective when the force in acting on the
arch (arch flattening force) is relatively low. This
occurs at such times in the step when the center of body
weight falls posterior (behind) the ankle joint. As the
center of weight passes ahead of the ankle joint, as
occurs in a normal step forward, the forces present
begin to cause arch flattening. To counter this, the
foot is capable of initiating a basic change in the
mechanism of support to a truss form of support and is
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then capable of supporting via compression strain.
Since the bones of the foot have been shown to be
extremely strong in terms of compression strength, the
greater the compression strain, the better the arch
support ability. In order for the foot to achieve this
change in support mechanism, the metatarsals must be
buttressed by the bending of the toes. This buttress
effect prevents the metatarsals from sliding forward and
. thus permits the switch from bending to compression
support.
It is this effect which is taken advantage in the
shoe design of the present invention. ey creating a
particular platform surface for the foot, a buttress
effect is initiated in a more effective fashion
preventing the forward sliding of the metatarsal bones
and, as a result, eliminating the subsequent jamming of
the toes into the pointed front of the shoes.
Increasing the angle of bending (extension) of the
toes in the shoes can be accomplished in one of two
ways, the tip of the shoes may be lifted upwards
creating a "genie" type shoe. Although this would be
effective, it mould not be particularly stylish. A more
effective mechanism entails increasing the angle at
which the metaitarsals themselves approach the sole of
the shoe. This has the effect of increasing the bending
of the toes wii:hout creating a "genie" type shoe. This
increase in the angle of the metatarsals relative to the
ground plane is: accomplished by the change in the rear
construction of the shoe (specifically the angle of the
heal seat 4). Since the foot is jointed in a variety of
locations, the plane that the heel bone (calcareous)
takes with the ground will be compensated for by the
pitch of the metatarsals as they approach the ball of
the foot. This; angular relationship is inversely
proportional. The closer the calcareous comes to
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parallel with the ground (provided there is adequate
heel height present), the closer the metatarsals
approach a perpendicular attitude. Thus by providing a
heel seat with a low slope to increase the descent angle
of the metatarsal, the desired buttressing effect is
achieved.
In the present invention, which is directed to shoes
having a heel height above about 1 3/4 inches, the heel
seat is maintained essentially level (up to 3°) with
10respect to the ground irrespective of the heel height.
In all previous shoe designs, the higher the heel of the
shoe, the greater the inclination toward the ground.
This inclination angle increase created an inclined
platform of the foot toward the floor. This increased
angle forced the foot to slide forward and be pinched in
the toe portion of the shoes. The present invention
creates a shoe with the relationship of the heel of the
shoe parallel to the support surface. The metatarsal
angle (corresponding to the shank of the shoe) increases
porportionally to the heel height, e.g. the higher the
heel, the greater the metatarsal angle to the floor. In
a shoe with a heel height over 1 3/4 inches, the
advantage is not of increased metatarsal inclination,
but rather the resulting biomechanical change in
metatarsal inclination due to the maintanance of heel
parallel with the support surface.
This effect is emphasized when the toe region is
angled as specified above in order to increase the
spring angle of the toes. As a consequence of this
particular design, the load distribution between the
foot and the shoe is effected whereby when the wearer is
at rest a greater proportion of the weight of the wearer
is borne by the heel seat rather than being transferred
by the sloping surface of the prior art shoes to the
ball of the foot with consequent problems as referred to
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above. By thca design of the present invention, toe
jamming is preavented and comfort assured.
While the description above has been made with
respect to a 11.S. standard ladies' shoe size 7, the
invention is applicable to the whole usual range of U.S.
standard ladiers' shoe sizes and particularly to those in
the range from size 5 to size 10. With different shoe
sizes the metatarsal inclination will vary within the
range specified With this inclination being close to 33
'degrees for a shoe size 5 and nearer to 27 degrees with
a shoe size 10. The range of angles for the heel seat
and the toe support region given with respect to a size
7 shoe are applicable to shoes in the sizes ranging from
5 to 10.
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