Abstract:
Disclosed herein is a shoe construction for providing increased cushioning effects. The shoe includes a sole, a footbed, and a layer of a plurality of deformable protrusions disposed between at least a portion of the sole and the footbed, particularly in the heel and the forefoot area of the shoe. Each of the protrusions includes a tip facing and freely movable with respect to a lower surface of the footbed. Each of the protrusions also includes a base fixedly attached to the sole so that the base does not move relative to said sole. The protrusions provide cushioning by bending when a foot presses down upon them. An alternate embodiment shows the cushioning sole adapted for use in a sandal.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates to the construction of an article of footwear and more specifically to a cushioning construction for the sole of an article of footwear.  
         [0003]     2. Background of the Invention  
         [0004]     The human foot is a complex and remarkable piece of machinery, capable of withstanding and dissipating many impact forces. The natural padding of fat at the heel, as well as the collapsibility of the arch, help to cushion the foot. Throughout the course of an average day, the feet and legs of an individual are subjected to substantial impact forces. Running, jumping, walking, and even standing exert forces upon the feet and legs of an individual which can lead to soreness, fatigue, and injury.  
         [0005]     Although the human foot possesses natural cushioning and rebounding characteristics, the foot may need extra support to overcome many of the forces encountered during extended periods of activity. Unless an individual is wearing shoes which provide proper cushioning and support, the soreness and fatigue resulting from even low levels of activity on unnatural surfaces is acute, and its onset accelerated. The discomfort for the wearer that results may diminish the incentive for further activity. Equally important, inadequately cushioned footwear can lead to injuries such as blisters; muscle, tendon and ligament damage; and bone stress fractures. Improper footwear can also lead to other ailments, including back pain.  
         [0006]     In light of these problems, numerous attempts have been made to incorporate into the sole of a shoe improved cushioning and resiliency. For example, attempts have been made to enhance the natural elasticity and energy return of the foot by providing shoes with soles which store energy during compression and return energy during expansion. These attempts have included the formation of shoe soles that include springs, gels or foams. However, these solutions are expensive, and tend to lose their effectiveness over time.  
       SUMMARY OF THE INVENTION  
       [0007]     Accordingly, disclosed herein is a shoe construction for providing increased cushioning effects. The shoe includes a sole, a footbed, and a layer of a plurality of deformable protrusions disposed between at least a portion of the sole and the footbed, particularly in the heel and the forefoot area of the shoe. Each of the protrusions includes a tip facing and freely movable with respect to a lower surface of the footbed. Each of the protrusions also includes a base fixedly attached to the sole so that the base does not move relative to said sole. The protrusions provide cushioning by bending when a foot presses down upon them. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES  
       [0008]     The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention.  
         [0009]      FIG. 1  is a lengthwise cross-sectional view of a shoe according to the present invention.  
         [0010]      FIG. 2  is an enlarged transverse cross-sectional view of a shoe according to the present invention, taken along line  2 - 2  of  FIG. 1 .  
         [0011]      FIG. 3  is a lengthwise cross-sectional view of an alternate embodiment of the present invention, applying the present invention to a sandal.  
         [0012]      FIG. 4  is a lengthwise cross-sectional view of a further alternate embodiment of a shoe according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0013]     Specific embodiments of the present invention are now described with reference to the figures, where like reference numbers indicate identical or functionally similar elements.  
         [0014]     Referring now to  FIG. 1 , a shoe  100  according to the present invention is shown in cross-section, the section taken lengthwise (from toe to heel) at the center of shoe  100 . A left foot shoe is shown, but it will be apparent to one of ordinary skill in the art that a right foot shoe is merely a mirror image thereof.  
         [0015]     Shoe  100  generally includes three basic components, an upper  102 , a sole  103 , and a footbed  110 . Upper  102  can be of any material or design known to one of ordinary skill in the art. Common materials used for upper  102  include leather, woven materials such as canvas, and synthetic materials such as vinyl.  
         [0016]     In one embodiment sole  103  includes an outsole  104 , a midsole  106 , and a plurality of protrusions  108 . Outsole  104  is constructed of a resilient, durable material such as rubber. Outsole  104  is intended to provide traction as the ground-engaging surface of shoe  100 . In the embodiment shown in  FIG. 1 , outsole  104  covers the entire lower-most surface of sole  103 . It will be apparent to one skilled in the art that outsole  104  may cover only portions of sole  103 , or could be eliminated entirely.  
         [0017]     As shown in  FIG. 1 , midsole  106  is disposed between outsole  104  and footbed  110 . Midsole  106  provides structure to sole  103 , as well as additional padding between a wearer&#39;s foot and the ground. However, midsole  106  is generally constructed of a material that is less dense than that used for outsole  104 , so that the thickness of sole  103  may be increased, while keeping down the weight of shoe  100 . Examples of materials appropriate for midsole  106  include rubber, ethyl vinyl acetate (EVA), polyurethane (PU), and thermoplastic urethane (TPU).  
         [0018]     In one embodiment midsole  106  is disposed along the entire length of sole  103 . In one embodiment midsole  106  is shaped to include depressions in the heel section and the forefoot section of sole  103 , as shown in  FIGS. 1 and 2 . These depressions create space for the insertion of cushioning protrusions  108  so as to minimize the thickness and bulk of sole  103 . It will be apparent to one of ordinary skill in the art that these depressions may be altered in length, such as to extend the full length of sole  103 , depth, and shape, or even eliminated entirely.  
         [0019]     Cushioning protrusions  108  are disposed between midsole  106  and footbed  110 . Protrusions  108  may be disposed in the heel region of sole  103 , the forefoot region of sole  103 , along the entire length and width of sole  103 , or a combination of these configurations. In the embodiment shown in  FIG. 1 , with protrusions  108  located in a heel region and forefoot region of sole  103 , with no protrusions  108  in an arch region of sole  103 . Instead, an insole layer  105  is stretched across the width of sole  103  in the arch region to increase the stability of shoe  100 . The placement of protrusions  108  will depend upon the desired location of cushioning.  
         [0020]     Referring now to  FIG. 2 , protrusions  108  are shown in cross-section taken along line  2 - 2  in  FIG. 1 . As can be seen clearly in  FIG. 2 , each protrusion  108  includes a tip  212  and a base  214 . In one embodiment, a vertical axis  216  of protrusions  108  passing through tip  212  is set at a right angle to base  214 , i.e., protrusions  108  do not slant towards either a toe region or a heel region of shoe  100 . Although other alignments of protrusions  108  are possible, this alignment of protrusions  108  facilitates the proper bending thereof.  
         [0021]     Tip  212  touches but is moveable with respect to a lower surface of footbed  110 . In the embodiment shown in  FIG. 2 , base  214  is fixedly attached to midsole  106 . In this embodiment, protrusions  108  are formed on a sheet, so that the sheet may be trimmed to an appropriate size to be inserted into the depressions created in midsole  106 . However, protrusions  108  could also be individually formed and attached directly to midsole  106 , although this process would be very labor intensive and achieving a uniform layer of protrusions could be difficult without skilled technicians. In either case, base  214  of protrusion  108  is attached to midsole  106 , either directly or indirectly as part of the sheet, so that base  214  does not move with respect to midsole  106 . In one embodiment, base  214  is permanently affixed, such as by cement, although base  214  may alternatively be more temporarily affixed, such as by a temporary adhesive or by hook and loop fasteners such as Velcro®. Such a temporary attachment would allow for custom designs for changing the hardness of protrusions  108  upon demand or to allow for easy replacement of protrusions  108 .  
         [0022]     In addition to attaching protrusions  108  to an upper surface of midsole  106 , protrusions  108  may be molded as an integrated part of midsole  106 . In another embodiment, not shown, protrusions  108  are attached to or integrally molded with outsole  104  so that tips  212  face or even touch footbed  110 . Midsole  106  may still be used in this embodiment, where protrusions  108  would project through coordinating windows or holes cut into midsole  106  to touch a lower surface of footbed  110 .  
         [0023]     Protrusions  108  are formed of a softer material than that of midsole  106 , as the cushioning is a result of the ability of protrusions  108  to bend and deform in response to the application of a downward force, such as a step, as will be described in greater detail herein. Appropriate materials are similar to those mentioned above with respect to midsole  106 , such as rubber, EVA, thermoplastic rubber (TPR), silicone, thermoplastic elastomers such as SEBS, and urethane, although the density of the materials must be chosen to allow for the cushioning effect from the bending of protrusions  108 . If the material is too hard, then protrusions  108  will not bend to a sufficient degree to cushion; if the material is too soft, then protrusions  108  will spread outwardly or crush (as opposed to bending), and the material will wear too quickly. In one embodiment, the durometer for the material in the present invention is in the range of 45-75 on the Asker C scale. However, if protrusions  108  are situated closer to the foot, e.g., if a thin footbed is used, then the material will be softer, so that the bottom of the foot is not irritated.  
         [0024]     In one embodiment, protrusions  108  are conical in shape, with tip  212  (i.e., the apex of the cone) facing the bottom surface of footbed  110 . Other shapes for protrusions  108  are also possible.  
         [0025]     Referring again to  FIG. 1 , the height of protrusions  108  must be sufficient to allow for bending. For the example durometer range noted above (45-75 on the Asker C scale) of the material, a range of the height of protrusions  108  is between 5 mm to 9 mm. Shorter than 5 mm and protrusions  108  may not bend. Greater than 9 mm and sole  103  becomes prohibitively bulky. However, it will be apparent to those skilled in the art that heights outside of this range are acceptable, such as if a shoe with a platform or otherwise thick sole is being designed or if materials outside of the noted durometer range are used.  
         [0026]     The width of protrusions  108  will vary with the height, so that appropriate bending may occur. For the embodiment described above using cone-shaped protrusions, a range of appropriate diameters of base  214  is from approximately 3 mm to 6 mm. Again, this dimension will vary widely, depending upon the shape of protrusions  108 , the material used, and the desired amount of bending.  
         [0027]     The number and arrangement of protrusions  108  will vary depending upon the dimensions thereof and the level of desired cushioning. Protrusions  108  must be spaced far enough apart so that the bending of protrusions  108  is not inhibited. For the purposes of example only, in one embodiment protrusions  108  are arranged in symmetrical rows. If each conical protrusion  108  is approximately 6 mm high and the diameter of base  214  is approximately 4 mm wide, then the concentration of protrusions  108  is slightly greater than one per centimeter.  
         [0028]     Footbed  110  is disposed above protrusions  108 . Footbed  110  reduces the tactile sensation of tips  212  of protrusions  108  on the wearer&#39;s foot. In one embodiment, footbed  110  includes several layers. In one embodiment, main layer  107  is made of a resilient material, such as PU, with a felt or other soft material as the uppermost layer  109 . The heel of footbed  110  may include a heel cup  111  made of a harder, more rigid material to provide additional reduction of the point sensation caused by the tips  212  of protrusions  108 . Such materials include plastic, rubber, non-woven synthetic or natural materials or a tightly woven or knitted material.  
         [0029]     In one embodiment, footbed  110  is removable, i.e., footbed  110  is not fixedly attached to shoe  100  or sole  103  at any point, but it is merely inserted into shoe  100  and held in place by frictional forces. Alternatively, footbed  110  may be attached to shoe  100  or sole  103  along the periphery thereof, such as by cementing or stitching. However, tips  212  of protrusions  108  should still be freely movable with respect to footbed  110 .  
         [0030]     The cushioning mechanism of protrusions  108  will now be described with reference to  FIG. 2 . As a wearer steps down, pressure is applied to footbed  110 . Footbed  110  translates this force to protrusions  108 , in particular, those protrusions  108  in the vicinity of the force. As tips  212  of protrusions  108  are not attached to footbed  110 , protrusions  108  are free to bend and deform to cushion the step. Footbed  110  is sufficiently thick and the bottom material is sufficiently stiff to reduce or eliminate the irritating tactile sensation of tips  212  on the sole of the wearer&#39;s foot. However, a massaging sensation due to the movement of protrusions  108  beneath footbed  110  may remain.  
         [0031]     Referring now to  FIG. 3 , an alternate embodiment of the present invention is shown.  FIG. 3  shows a lengthwise cross-sectional view of a sandal  300  including the cushioning sole of the present invention. The construction of sandal  300  is slightly different from that of shoe  100  (as shown in  FIG. 1 ).  
         [0032]     Sandal  300  includes an upper  302  and a sole  303 . As is readily apparent to one of ordinary skill in the art, upper  302  is similar to upper  102  in the embodiment discussed above with respect to  FIG. 1 , although with a relatively open design.  
         [0033]     Sole  303  includes one or several layers. In one embodiment with multiple layers, as is shown in  FIG. 3 , an outsole  304  is a relatively thick layer made of a resilient material such as rubberized or durable EVA. Outsole  304  provides most of the thickness of sole  303 . An insole board  306  is typically a non-woven material disposed between hard outsole  304  to cushioning protrusions  308 , such as PU or EVA. Insole board  306  helps to control excessive motion of the foot for greater stability. For additional stiffness and stability, sole  303  may also include in the heel and arch regions a rigid plate (not shown) made of a material such as plastic or metal.  
         [0034]     It will be apparent to one of ordinary skill in the art that insole board  306  may be eliminated altogether. For such a sole design with only one layer, sole  303  is made of a resilient but lightweight material, such as rubberized EVA, PU, or blown rubber.  
         [0035]     Protrusions  308  are similar to protrusions  108 , described above with respect to the embodiment shown in  FIG. 1 , in that protrusions  308  may be disposed in the heel region of sole  303 , the forefoot region of sole  303 , along the entire length and width of sole  303 , or a combination of these configurations. In the embodiment shown in  FIG. 3 , protrusions  308  are located along the entire length (and width, not shown) of sole  303 .  
         [0036]     As may be with protrusions  108 , in one embodiment protrusions  308  are formed as a sheet, so that the sheet may be cemented to insole board  306 . Protrusions  308  are formed of the same materials as described above with respect to protrusions  108 , namely rubber, EVA, and urethane, with a hardness in one embodiment in the range of 45-75 on the Asker C scale. Also similar to protrusions  108 , protrusions  308  are in one embodiment conical in shape, with a height in a range of 5 mm to 9 mm. All of the variations discussed above with respect to protrusions  108  apply equally to protrusions  308 , such as molding protrusions  308  integrally with sole  303  or insole board  306  or altering the shape of protrusions  308 .  
         [0037]     Finally, a wrapping  310  is attached to outsole  304  around the periphery thereof. Wrapping  310  completely covers protrusions  308  and insole board  306 . Wrapping  310  provides many of the same features as footbed  110 , described above with respect to  FIG. 1 . Wrapping  310  adds an aesthetic and tactile effect, as in a sandal wrapping  310  is more visible than a footbed would be in a closed shoe. Wrapping  310  is in one embodiment made of a non-woven material, such as leather, to provide the same force transfer and tactile-sensation reduction as provided by footbed  110 . Also, in one embodiment, a separate layer of material is affixed to wrapping  310  to reduce further the tactile sensation of protrusions  310  on the wearer&#39;s foot. The attachment of wrapping  310  to outsole  304  can be of any method known in the art, such as by stitching or cementing.  
         [0038]     The cushioning mechanism of protrusions  308  is the same as that described above with respect to protrusions  108  in the embodiment shown in  FIG. 2 .  
         [0039]     Referring now to  FIG. 4 , a further alternate embodiment of the present invention is shown. A shoe  400  includes an upper  402 , a sole  403 , and a footbed  410 . Upper  402  is comparable in form, structure, and materials with upper  102 , described with respect to  FIG. 1 . Similarly, footbed  410  is comparable to footbed  110 , described above with respect to  FIG. 1 .  
         [0040]     In one embodiment sole  403  includes an outsole  404 , a midsole  406 , and a plurality of protrusions or ridges  408 . Outsole  404  is constructed of a resilient, durable material such as rubber. Outsole  404  is intended to provide traction as the ground-engaging surface of shoe  400 . In the embodiment shown in  FIG. 4 , outsole  404  covers the entire lower-most surface of sole  403 . It will be apparent to one skilled in the art that outsole  404  may cover only portions of sole  403 , or could be eliminated entirely.  
         [0041]     As shown in  FIG. 4 , midsole  406  is disposed between outsole  404  and footbed  410 . Midsole  406  is similar in form and function to midsole  106 , described above with respect to  FIG. 1 . Examples of materials appropriate for midsole  406  include rubber, ethyl vinyl acetate (EVA), polyurethane (PU), and thermoplastic urethane (TPU).  
         [0042]     In the embodiment shown in  FIG. 4  midsole  406  is disposed along the entire length of sole  403 . In this embodiment, midsole  406  is shaped to include depressions in the heel section and the forefoot section of sole  403 . These depressions create space for the insertion of ridges  408  so as to minimize the thickness and bulk of sole  403 . It will be apparent to one of ordinary skill in the art that these depressions may be altered in length, such as to extend the full length of sole  403 , depth, and shape, or even eliminated entirely.  
         [0043]     Ridges  408  are fin-like protrusions extending transversely across shoe  400 . Ridges  408  bend in response to pressure from a wearer&#39;s foot to cushion the step, much like the bending of protrusions  108 , described above. Ridges  408  could be straight, wavy, curved, set at acute or oblique angles to a longitudinal axis of shoe  400 , or any combination of these features. As with protrusions  108 , ridges  408  are attached directly to midsole  406  or are formed as a sheet which is attached to midsole  406 . In another embodiment where midsole  406  is eliminated from the design, ridges  408  are attached to outsole  404 . The attachment of ridges  408  is by any of the methods described above with respect to protrusions  108 , such as by cementing or co-molding.  
         [0044]     In cross-section, ridges  408  have a tip  412 , which is freely movable with respect to footbed  410 , extending to a base  414 , which is fixedly attached to a midsole  406 . In one embodiment, a vertical axis  416  of ridges  408  passing through tip  412  is set at a right angle to base  414 , i.e., ridges  408  do not slant towards either a toe region or a heel region of shoe  400 . Although other alignments of ridges  408  are possible, this alignment of ridges  408  facilitates the proper bending thereof.  
         [0045]     The height and width of ridges  408  is comparable to those of protrusions  108 . Ridges  408 , however, extend nearly the entire width of shoe  400 . Arranged in rows, the concentration of ridges  408  is similar to that of protrusions  108 , slightly more than one per centimeter. The materials used for ridges  408  are similar to those used for protrusions  108 , namely such as rubber, EVA, thermoplastic rubber (TPR), silicone, thermoplastic elastomers such as SEBS, and urethane. The hardness of these materials is also comparable to that of the materials used in protrusions  108 , having a durometer in the range of 45-75 on the Asker C scale. As with protrusions  108 , this range will depend upon the dimensions of ridges  408  as well as the placement of ridges  408  in relation to the wearer&#39;s foot, e.g., a thinner footbed  410  requires a softer material for ridges  408 .  
         [0046]     It will be appreciated by those skilled in the art that the features of the invention may be altered to tailor the characteristics of shoe  100 , sandal  300 , or shoe  400 . For example, the layers of sole  103 , sole  303 , or sole  403  (e.g., outsole  104 , midsole  106 , and projections  108 ) may be made of a variety of materials, including but not limited to plastic, foam, and rubber. The various layers may be secured to each other using any one of the many well known methods in the art, such as cementing, welding, or stitching.  
         [0047]     Construction of the various layers of sole  103 , sole  303 , or sole  403  may be accomplished by any one of the many methods known in the art. For instance, the layers may be formed by injection molding, compression molding, or other suitable methods. Also, it is contemplated that the different layers of sole  103 , sole  303 , or sole  403  described herein can be replaced by one single layer of material, in which the density, flexibility, and pliability may differ throughout the material, or a single material may be used.  
         [0048]     While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents. All patents and publications discussed herein are incorporated in their entirety by reference thereto.