FIELD OF THE INVENTION
The present invention pertains to footwear and is particularly
applicable to a shoe having a sole with embedded padding and an elevated heel.
A variety of different structures exist for the construction
of a shoe's sole. However, improvements in existing structures still are desirable.
For example, the present inventor has discovered that problems often have arisen
when a designer has attempted to include padding in the sole of a shoe, particularly
if the sole is very thin.
SUMMARY OF THE INVENTION
The present invention addresses this problem by providing
a shoe that has a multi-layered sole with embedded padding. More specifically, at
least one of the layers includes a sheet of base material having a hole through
its central region, such that the hole is surrounded by the base material, and a
cushioning pad attached to the base material so as to fill the hole. In one representative
embodiment, the cushioning pad is approximately the same size and shape as the hole,
and the perimeter of the pad is stitched to the perimeter of the hole. As a result
of such construction, padding is provided in a manner that tends to resist damage
The foregoing summary is intended merely to provide a brief
description of the general nature of the invention. A more complete understanding
of the invention can be obtained by referring to the claims and the following detailed
description of the preferred embodiments in connection with the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is an exploded view of a shoe according to a representative
embodiment of the present invention.
Figure 2 is a cross-sectional view of the front portion
of a shoe sole according to a representative embodiment of the present invention.
Figure 3 is a perspective view of a shoe's midsole according
to a representative embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
The following discussion describes a shoe 10 according
to a representative embodiment of the present invention. As shown in the drawings,
shoe 10 includes a sole 20, a heel 50 and an upper 60. In accordance with customary
styles, a shoe having a separate heel 50 often also will have a very thin sole 20.
Referring initially to Figure 1, the sole 20 of shoe 10
includes a plurality of layers. The bottom layer, or outsole, 22 preferably is made
of natural or synthetic leather, but instead may be made of any other material,
preferably one that is sufficiently durable for extended outdoor use, adequately
shape-retaining, but still resilient enough to provide a desired amount of comfort.
Next is a padding layer 24 which, e.g., may be 1 mm (millimeter) thick of padding
On top of padding layer 24 is an insole board 30 which
preferably is comprised of a base material 32, such as 2 mm thick serrated cardboard.
Preferably, a region of insole board 30 (more preferably, the metatarsal region)
is coated with a thin layer of material 33, which preferably is glued or otherwise
bonded onto the base material 32. In the preferred embodiments of the invention,
material 33 is a fabric or fibrous material, although other types of material instead
may be used. Although not shown in the drawings, layer 33 preferably is applied
to both the top and bottom sides of insole board 30.
Cut into the base material 32 and the coating 33 (if provided),
again preferably in the metatarsal region of insole board 30, is a hole 34. As shown,
hole 34 preferably is almost as wide as insole board 30 and generally covers the
entire metatarsal region. In the present embodiment, hole 34 is approximately rectangular,
although other shapes instead may be used.
A cushioning pad 36 is provided and preferably is attached
around its entire periphery to corresponding points around the periphery of hole
34. In the preferred embodiments, cushioning pad 36 is stitched to the base material
32 around the perimeter of hole 34. The use of an appropriate coating 33 (e.g.,
fabric or a fibrous material) often can increase the durability of the attachment
created by such stitching. However, if the base material 32 itself is sufficiently
durable (e.g., made from leather or synthetic leather), a separate coating 33 might
not provide much additional benefit.
In any event, cushioning pad 36 preferably is approximately
the same size and shape as hole 34, at least in terms of length and width. More
preferably, cushioning pad 36 is just slightly smaller in length and width than
hole 34 so as to match and just fit within the hole 34. However, because the material
forming cushioning pad 36 preferably is more compressible than the base material
32, it often will be desirable to use a cushioning pad 36 that is thicker than the
surrounding base material 32 in its ordinary (i.e., uncompressed) state, but which
compresses to approximately the same thickness as (or slightly thicker than) base
material 32 when the expected amount of weight is applied (e.g., the weight of the
expected wearer, or some multiple thereof to account for the extra force produced
when the wearer is walking or running). Pad 36 may be formed of any desired cushioning
material, such as a gauze-like fabric.
As a result of the foregoing construction, additional cushioning
often can be provided where it is needed most, particularly with respect to shoes
having elevated heels (such as heel 50). At the same time, the way in which cushioning
pad 36 is provided (e.g., within a cut out hole, within a very thin layer of a shoe's
sole and/or with 360° peripheral attachment) often can prevent or reduce shifting
and/or deterioration of the cushioning pad 36. In this regard, the present inventor
has discovered that conventional structures for embedding cushioning in the sole
of a shoe often do not provide adequate support to the cushion itself. As a result,
the forces applied to such conventional cushioning often will dislodge or damage
the cushioning. Such forces typically are applied, e.g., in the ordinary course
of walking or running, and particularly include front-to-rear and rear-to-front
forces. In contrast, it is believed that the structures of the present invention
will tend to significantly reduce such problems.
Immediately above insole board 30 is a relatively thin
and elongated shank 39 that preferably is formed from steel or a similar strong,
rigid, but somewhat flexible metal or other material, thereby providing additional
strength and support and helping to transfer or distribute weight to the heel and
forepart of shoe 10. Examples of some of the alternate materials that may be used
in shank 39 include polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS)
a hard thermoplastic rubber (TPR) or any other stiff, and bend-resistant plastics
or other materials. In the present embodiment, shank 39 is formed as an elongated
substantially rectangular piece. However, other shapes instead may be used to achieve
Immediately above shank 39 is rear midsole portion 40,
which preferably is formed of a thicker and/or more bend-resistant and durable material
than insole board 30, such as a hard polymer. During construction, the rear midsole
portion 40 is bonded to insole board 30, sandwiching shank 39 between them. In addition,
rivets 43 are used to further secure shank 39 to the rear midsole portion 40 and,
in certain embodiments, to insole board 30. The entire combination of insole board
30, shank 39 and rear midsole portion 40 comprises the shoe's midsole 45.
Above the midsole 45 is another padding layer 46 which,
e.g., may be 5 mm thick of latex padding or any other cushioning or padding layer.
Padding layer 46 may or may not include a protective and/or more comfortable outer
layer. Padding layer 46 directly contacts the wearer's foot and sometimes is referred
to as the sock.
Upper 60 may be, e.g., any conventional upper and accordingly
may be formed of natural or synthetic leather or any other natural or synthetic
material. Although shown in the drawings as having a closed construction, it should
be understood that upper 60 instead may have any open or sandal-like construction.
Heel 50 typically is rigid and may be similar or identical
to conventional heels. Typically, heel 50 will elevate the rear portion of shoe
10 by anywhere from 1-4 inches. In the preferred embodiments, heel 50 elevates the
rear portion of shoe 10 by at least 2 inches.
In order to complete the construction of shoe 10, outsole
22, padding layer 24 and midsole 45 may be joined together using stitching, gluing
or any combination of the two. Thereafter, the heel 50 is attached by inserting
a screw 44 through matching holes in midsole 45, padding layer 24, outsole 22 and
heel 50. In addition, extra padding (not shown) may be provided at the position
on midsole 45 that is immediately above where heel 50 attaches to it. In any event,
padding layer 46 is then attached, e.g., using adhesive material. Finally, the upper
60 is attached, again using stitching, gluing or any combination. In one representative
embodiment, upper 60 is provided with a lip (not shown) that extends between layers
of the sole 20. Accordingly, the bonding of the various layers of sole 20 also results
in the bonding of upper 62 the sole 20.
The use of the padding structure according to the present
invention is particularly applicable to a shoe having an elevated heel, such as
shoe 10 shown in the drawings. Such a shoe 10 typically will have a fairly thin
sole portion, e.g., with the front portion of the sole being less than S inch
or even less than R inch thick.
Several different embodiments of the present invention
are described above, with each such embodiment described as including certain features.
However, it is intended that the features described in connection with the discussion
of any single embodiment are not limited to that embodiment but may be included
and/or arranged in various combinations in any of the other embodiments as well,
as will be understood by those skilled in the art.
Similarly, in the discussion above, functionality sometimes
is ascribed to a particular module or component. However, functionality generally
may be redistributed as desired among any different modules or components, in some
cases completely obviating the need for a particular component or module and/or
requiring the addition of new components or modules. The precise distribution of
functionality preferably is made according to known engineering tradeoffs, with
reference to the specific embodiment of the invention, as will be understood by
those skilled in the art.
Thus, although the present invention has been described
in detail with regard to the exemplary embodiments thereof and accompanying drawings,
it should be apparent to those skilled in the art that various adaptations and modifications
of the present invention may be accomplished without departing from the spirit and
the scope of the invention. Accordingly, the invention is not limited to the precise
embodiments shown in the drawings and described above. Rather, it is intended that
all such variations not departing from the spirit of the invention be considered
as within the scope thereof as limited solely by the claims appended hereto.