Abstract:
An article of footwear has an upper and a sole. The sole has at least one inflatable bladder wherein said at least one inflatable bladder has an inflated state and a deflated state. A ground engaging surface of the sole has a first profile in the deflated state and a second profile in the inflated state. The first profile is different from the second profile. Varying the profile of the ground engaging surface varies the amount of cushioning in the sole so that the shoe can serve as a multipurpose shoe for activities requiring different amounts of cushioning.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to footwear, and more particularly to an athletic shoe having an inflatable ground engaging surface. 
     2. Background Art 
     One of the problems associated with footwear, especially athletic shoes, has always been striking a balance between support and cushioning. 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. 
     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 and forefoot, as well as the flexibility of the arch, help to cushion the foot. 
     An athlete&#39;s stride is partly the result of energy which is stored in the flexible tissues of the foot. For example, a typical gait cycle for running or walking begins with a “heel strike” and ends with a “toe-off”. During the gait cycle, the main distribution of forces on the foot begins adjacent to the lateral side of the heel (outside of the foot) during the “heel strike” phase of the gait, then moves toward the center axis of the foot in the arch area, and then moves to the medial side of the forefoot area (inside of the foot) during “toe-off”. During a typical walking or running stride, the achilles tendon and the arch stretch and contract, storing and releasing energy in the tendons and ligaments. When the restrictive pressure on these elements is released, the stored energy is also released, thereby reducing the burden which must be assumed by the muscles. 
     Although the human foot possesses natural cushioning and rebounding characteristics, the foot alone is incapable of effectively overcoming many of the forces encountered during athletic activity. Unless an individual is wearing shoes which provide proper cushioning and support, the soreness and fatigue associated with athletic activity is more acute, and its onset accelerated. The discomfort for the wearer that results may diminish the incentive for further athletic 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. 
     Proper footwear should complement the natural functionality of the foot, in part, by incorporating a sole (typically including an outsole, midsole and insole) which absorbs shocks. However, the sole should also possess enough resiliency to prevent the sole from being “mushy” or “collapsing,” thereby unduly draining the energy of the wearer. 
     In light of the above, numerous attempts have been made to incorporate into a shoe improved cushioning and resiliency. For example, attempts have been made to enhance the natural resiliency 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 such as ethylene vinyl acetate (EVA) or polyurethane (PU). However, all of these tend to either break down over time or do not provide adequate cushioning characteristics. 
     Another concept practiced in the footwear industry to improve cushioning and energy return has been the use of fluid-filled systems within shoe soles. These devices attempt to enhance cushioning and energy return by transferring a pressurized fluid between the heel and forefoot areas of a shoe. The basic concept of these devices is to have cushions containing pressurized fluid disposed adjacent the heel and forefoot areas of a shoe. 
     However, a cushioning device which is pressurized with fluid at the factory is comparatively expensive to manufacture. Further, pressurized fluid tends to escape from such a cushioning device, requiring large molecule fluids such as Freon gas to be used as the inflating fluid. A cushioning device which contains air at ambient pressure provides several benefits over similar devices containing pressurized fluid. For example, generally a cushioning device which contains air at ambient pressure will not leak and lose air, because there is no pressure gradient in the resting state. 
     Athletes often need different amounts of cushioning in the soles of their shoes for different activities and consequently require a different pair of shoes for each activity. Accordingly, there is a need in the art to have a single shoe that can vary the amount of cushioning in the sole for activities requiring different amounts of cushioning. 
     BRIEF SUMMARY OF THE INVENTION 
     Disclosed herein is a sole for an article of footwear comprising at least one inflatable bladder wherein the at least one inflatable bladder has an inflated state and a deflated state. A ground engaging surface of the sole has a first profile in the deflated state and a second profile in the inflated state wherein the first profile is different from the second profile. 
     Also disclosed herein is an article of footwear comprising an upper and a sole wherein the sole comprises at least one inflatable bladder. The at least one inflatable bladder has an inflated state and a deflated state. A ground engaging surface of the sole has a first profile in the deflated state and a second profile in the inflated state wherein the first profile is different from the second profile. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES 
         FIG. 1  is a side view of an exemplary shoe with a ground engaging surface having individual outsole pieces. 
         FIG. 2  is a plan view of an exemplary sole with a ground engaging surface having individual outsole pieces. 
         FIG. 3A  is a side view of a portion of an exemplary ground engaging surface in an inflated state. 
         FIG. 3B  is a side view of a portion of an exemplary ground engaging surface in a deflated state. 
         FIG. 4  is a side view of an exemplary shoe with a ground engaging surface having an outsole material. 
         FIG. 5  is an plan view of an exemplary lower surface of a midsole. 
         FIG. 6  is a plan view of a first surface of an exemplary inflatable bladder. 
         FIG. 7  is an exploded view of an exemplary inflation mechanism and air transfer manifold incorporated into an exemplary sole. 
         FIG. 8  is an exploded view of an exemplary air pressure regulator incorporated into an exemplary sole. 
         FIG. 9  is a perspective side view of an exemplary barb connector. 
         FIG. 10  is a perspective view of an exemplary one-way valve for use in an exemplary inflation mechanism. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A preferred embodiment of the present invention is now described with reference to the Figures, in which like reference numerals are used to indicate identical or functionally similar elements. Also in the Figures, the left most digit of each reference numeral corresponds to the Figure in which the reference numeral first appears. While specific configurations and arrangements can be used without departing from the spirit and scope of the invention, it will be apparent to a person skilled in the relevant art that this invention can also be employed in other applications. 
     Disclosed herein is a shoe shown generally at  100  in  FIG. 1 . Shoe  100  is intended to be any type of shoe including, without limitation, an athletic shoe, a brown shoe, sandal or a dress shoe. As shown in  FIG. 1 , shoe  100  has an upper shown generally at  102 , a sole shown generally at  104 , a heel area shown generally at  106 , a forefoot area shown generally at  108  and an arch area shown generally at  110 . Sole  104  has a ground engaging surface  112  with an inflatable bladder  114  located above ground engaging surface  112 . Inflatable bladder  114  is adjustable between an inflated state and a deflated state wherein ground engaging surface  112  has a first profile in the deflated state and a second profile in the inflated state. Inflating and deflating inflatable bladder  114  changes the profile of ground engaging surface  112  by extending at least a portion of ground engaging surface  112  away from sole  104 . Shoe  100  also has an air pressure regulator  116  that regulates the air pressure in inflatable bladder  114 . Air pressure regulator  116  adjusts the pressure at which air is released from inflatable bladder  114  through a pressure release valve. Air pressure regulator  116  may be adjusted so the system is fully open (no air stays in inflatable bladder  114 ), regulated (pressure in inflatable bladder  114  varies depending on the setting, as air is allowed to purge through the pressure release valve above the set pressure threshold), or fully closed (inflatable bladder  114  inflates to a maximum inflation pressure and no air is allowed to pass through the pressure release valve). 
     As shown in  FIGS. 1 and 2 , inflatable bladder  114  has a plurality of interconnected chambers  118  that are connected via conduits  120 . Ground engaging surface  112  preferably comprises a plurality of individual outsole pieces  119  which are spaced apart from each other leaving gaps  121  therebetween. Inflatable bladder  114  is visible in gaps  121 . At least one of the plurality of individual outsole pieces  119  extend away from sole  104  when inflatable bladder  114  inflates, thereby altering the profile of ground engaging surface  112  from a first profile in the deflated state as shown in  FIG. 3B  to a second profile in the inflated state as shown in  FIG. 3A . Each chamber  118  has an individual outsole piece  119  associated with it that extends away from sole  104  when chamber  118  is inflated. 
     Alternatively, as shown in  FIG. 4 , the ground engaging surface  412  may be an outsole  411  that substantially covers inflatable bladder  114 . The outsole material may be a lightweight, flexible, and expandable material including, but not limited to rubber or cast polyurethane or a textile or suitable flexible substrate, such that when inflatable bladder  114  is inflating outsole  411  expands to accommodate the profile of inflatable bladder  114  in its inflated state. As shown in  FIG. 4 , the edge  415  of outsole material may wrap around and attach to a side of shoe  400  or sole  404  so that inflatable bladder  114  is not visible. Alternatively, the edge of the outsole material may be attached to inflatable bladder  114  such that inflatable bladder  114  is visible from a side view of shoe  400 . The outsole material may also be a non-woven material, textile, or film layer. The outsole material may have treads or lugs  413  formed thereon through direct injection, casting, cementing, or other known methods. 
     Alternatively, the ground engaging surface may be the inflatable bladder. When the ground engaging surface is incorporated with the inflatable bladder, the inflatable bladder has a first surface facing the upper and a second surface that is the ground engaging surface. Treads or lugs may be applied to the ground engaging surface through direct injection, casting, cementing, or other known methods. 
     In one embodiment, the inflatable bladder is located between a lower surface of a midsole and the ground engaging surface.  FIG. 5  shows an exemplary lower surface  502  of a forefoot portion of midsole  500  and  FIG. 6  shows an exemplary inflatable bladder  600  for a forefoot region. Lower surface  502  of midsole  500  may have a recess  504  to correspond to a shape of inflatable bladder  600  for storing inflatable bladder  600  in its deflated state above the ground engaging surface in order to minimize the thickness of the sole when inflatable bladder  600  is in its deflated state and locate inflatable bladder  600  with respect to midsole  500 . It is noted that while only the forefoot region of the lower surface of the midsole is depicted, the heel region may have a similar recess corresponding to an inflatable bladder covering the heel region. 
     Inflatable bladder  600  has a first surface  602  that faces midsole  500  and a second surface (not shown) that faces the ground engaging surface. Inflatable bladder  600  has a welding flange  606  with an inside edge  608  defining a boundary of at least one inflatable chamber  610 . Air may enter and leave inflatable bladder  600  through barb connectors attached at locations  612 . First and second surfaces of inflatable bladder  600  may be directly attached to lower surface  502  of midsole  500  or the ground engaging surface, respectively. Alternatively, either first or second surface may have one or more plates  604  attached thereto that are then attached to lower surface  502  of midsole  500  or the ground engaging surface, respectively. When first surface  602  has one or more plates  604 , lower surface  502  of midsole  500  may have additional recesses  506  corresponding to the shape of plates  604  that act as locating features for mounting plates  604  to midsole  500 . Plates  604  may be a polymeric material, such as thermoplastic polyurethane. Plates  604  provide a mounting surface between inflatable bladder  600  and midsole  500 . 
     Plates  604  are strategically shaped, positioned, and made of suitable materials to control the profile of inflatable bladder  600  in its inflated state, to control the height of inflation, and locate inflatable bladder  600  with respect to midsole  500 . The greater the offset between an edge of plate  604  and an edge of inflatable bladder  600 , the greater the thickness of inflation. The offset can also be varied to result in a tapered thickness or offset of inflation, either an increase in thickness or offset along a length of an inflatable bladder or a decrease in thickness along a length of an inflatable bladder. For example, the offset can be varied to result in less inflated thickness at a toe of a shoe and more inflated thickness as the forefoot region curves away from the toe. 
     When plates  604  are present on a surface of inflatable bladder  600 , portions of the surface of inflatable bladder  600  not covered by plates  604  are preferably not attached to the midsole or ground engaging surface or anything else. This allows the unattached portions of the inflatable bladder to move away from the midsole and ground engaging surface. However, there may be cases where it is preferred that certain portions of inflatable bladder  600  that are not covered by plates  604  be bonded to midsole  500 , for example in the toe area or to an air transfer manifold  726 . 
     Plates  604  are made from a polymeric material including, but not limited to, thermoplastic polyurethane. Plates  604  may be applied to inflatable bladder  600  through a variety of methods including, but not limited to, casting, silkscreen printing, or laminating through RF welding, direct injection, or cold cementing. Another exemplary method for attaching plates  604  to inflatable bladder  600  includes applying a 3 mil film of low melting temperature adhesive film to a substrate of plate material, cutting out the formed assembly to a desired shape, and then affixing the adhesive side to the inflatable bladder through conventional methods including, without limitation, RF welding or heat pressing. Subsequently plates  604  may be cold cemented or otherwise attached to the midsole or other surface. 
     The shoe of the present invention has at least one inflatable bladder. There can be a single inflatable bladder that spans substantially the entire sole. Alternatively, there may be a plurality of inflatable bladders, such as a first inflatable bladder for a heel area and a second inflatable bladder for a forefoot area. Other alternative embodiments with varying numbers and placements of inflatable bladders are also envisioned as would be readily apparent to a person of ordinary skill in the relevant art. 
     One skilled in the art would readily appreciate that the type of inflatable bladder for use in the sole/shoe of the present invention is not limited. One example of an inflatable bladder includes two films of monolayer or multilayer sealable thermoplastic material through which air may not readily pass. Furthermore, the two sealable thermoplastic films may be a multilayer laminate of film and fabric or of film and a non-woven material. The two films utilized to form the inflatable bladder may be the same material or different materials such as a monolayer film and a multilayer laminate. The films of different materials may be cast or coextruded to form the inflatable bladder. An exemplary film includes an outer layer of 12 mil polyester urethane of 50 D Shore hardness, a scrim layer, and an inner layer of 8 mil polyester urethane of 95 A Shore hardness. The material for the scrim layer is present to increase puncture resistance and to increase the tensile strength and may include, but is not limited to, 210 denier nylon of high tenacity or polyester. The outer layer material should be of suitable thickness and hardness to increase puncture resistance of the bladder. The inner layers face each other in an assembled inflatable bladder. 
     The films are sealed around a periphery to form the inflatable bladder. In a preferred embodiment the majority of the peripheral seal is on an inside of the inflatable bladder. Such an inflatable bladder can be made wherein the two films are positioned on top of each other and welded or otherwise sealed along a plurality of the peripheral edges leaving at least one peripheral edge unsealed. The two films are then turned inside out such that the seal is in the interior of the inflatable bladder. Then the remaining peripheral edge(s) is welded or otherwise sealed together to form the inflatable bladder. Alternatively, the peripheral seal is on an outside of the inflatable bladder wherein the two films are positioned on top of each other and welded or otherwise sealed along the peripheral edges. The welding or sealing may include, but is not limited to, RF welding or heat sealing. Inflatable bladders can be shaped to have a plurality of interconnected inflatable chambers  118  with conduits  120  in between as shown in  FIGS. 1 and 2 . A plurality of interconnected inflatable chambers can be formed by thermoforming the films and welding or otherwise sealing the films together at areas other than the periphery. 
     The ground engaging surface may be a variety of materials and may have a variety of forms. The ground engaging surface shown in  FIGS. 1 and 2  with individual outsole pieces  119  can be made from a variety of methods as would be readily apparent to a person of ordinary skill in the relevant art. For example, the ground engaging surface can have the gap areas scored prior to attaching the ground engaging surface to the inflatable bladder. Inflatable bladder  114  may be attached with an adhesive that is screen printed or otherwise applied in a pattern such that the scored areas of the ground engaging surface can be removed after attachment. Alternatively the individual outsole pieces  119  can be individually attached to the bladder with an adhesive. In such an instance, the pieces that extend away from the sole when the bladder is inflated and the pieces that stay in place may be made of different materials. 
     Alternatively, the ground engaging surface may be an outsole material that is lightweight, flexible, stretchable, and expandable material including, but not limited to cast polyurethane, such that when an inflatable bladder is inflating the outsole material stretches and expands to accommodate the profile of inflatable bladder in its inflated state. The ground engaging surface may also be the inflatable bladder, a non-woven material, a textile, or a film. When the ground engaging surface is incorporated with an inflatable bladder, the inflatable bladder has a first surface facing the upper and a second surface that is the ground engaging surface. Any of these ground engaging surfaces may have treads or lugs applied thereto through direct injection, casting, cementing, or other known methods. The treads or lugs may be applied in a discontinuous manner and may move with the ground engaging surface to form different profiles based on the inflation level of the inflatable bladder. 
     In order for a wearer to customize the amount of air in a bladder the bladder is placed in fluid communication with an inflation mechanism and an air pressure regulator.  FIGS. 7-8  illustrate an exemplary arrangement of an inflation mechanism generally shown at  722 . Inflation mechanism  722  consists of an underfoot pump  724  fluidly connected to a manifold  726 , which sits in a manifold seating  728 . Preferably underfoot pump  724 , manifold seating  728  and manifold  726  are injection molded from a polymeric material including, but not limited to, thermoplastic polyurethane, although other methods of formation may be used as would be apparent to a person of ordinary skill in the relevant art. Manifold seating  728  has a bottom surface  730  with an opening  732  that allows access to a plurality of openings  733  in bottom surface  734  of manifold  726 . Underfoot pump  724  sits in an indentation (not shown) on the upper surface of sole  704 . It is noted that while underfoot pump  724  is shown located in a heel region, it can be located anywhere along sole  704 . Sole  704  has an opening  736  for receiving manifold  726  and manifold seating  728  such that a flange  729  of manifold seating  728  prevents manifold  726  and manifold seating  728  from falling through opening  736 . Alternatively, manifold  726  may have a peripheral flange that rests against an upper surface of sole  704  to prevent manifold  726  from falling through opening  736 , thereby eliminating the need for manifold seating  728 . A bottom surface  734  of manifold  726  and manifold seating  728  are flush with opening  736  in sole  704 . Openings  733  on bottom surface  734  of manifold  726  are accessible for receiving barb connectors, as shown generally at  900  in  FIG. 9 , of bladders to fluidly connect the bladders to underfoot pump  724  via manifold  726 . Barb connector  900  has a flange  902 , a body  904  extending from flange  902 , and at least one conical barb  906  at an end of body  904  opposite flange  902 . 
     A bladder may be fluidly connected to one of openings  733  in bottom surface  734  of manifold  726  via a barb connector  900  or other means. The bladder arrangement may include, but is not limited to, a forefoot bladder and a heel bladder or any other arrangement that would have been apparent to a person of ordinary skill in the relevant art. 
     Air enters inflation mechanism  722  through an air intake hole (not shown) in underfoot pump  724  and passes through a one-way valve (not shown) into manifold  726  when underfoot pump  724  is compressed The air intake hole may have an air intake valve and a filter material that prevents moisture and debris from entering into the system. The one-way valve prevents air from flowing back into underfoot pump  724 . Manifold  726  has one or more pathways that direct the air into the bladder, thereby inflating it. The pathways may include flow restrictors locate therein or adjacent entrances to the pathways that limit the airflow to prevent an inflatable heel bladder from being inflated too quickly, thereby eliminating tears in the bladder, and reducing backflow pressures. 
     An exemplary one-way valve is shown generally at  1042  in  FIG. 10 . One-way valve  1042  is preferably a molded piece of a smooth, nonporous material including, but not limited to, polycarbonate that is inserted between underfoot pump  724  and manifold  726 . One-way valve  1042  is generally cylindrical in shape and has a first end  1044  and a second end  1046 . A first extension  1048  and a second extension  1049  extend perpendicularly from an axis of the body of one-way valve  1042  on opposite sides from each other. A first connector arm  1050  with a first end  1052  and a second end  1054  extends from first extension  1048  substantially parallel to the cylindrical body and a second connector arm  1056  with a first end  1058  and a second end  1060  extends from second extension  1049  substantially parallel to the cylindrical body. There is at least one air outlet opening (not shown) along a circumference of the cylindrical body adjacent second end  1046  of one-way valve  1042 . An elastomeric sleeve  1061  surrounds the outlet opening. First end  1044  of one-way valve  1042 , first end  1052  of first connector arm  1050  and first end  1058  of second connector arm  1056  are inserted into an air fitment receptacle (not shown) of underfoot pump  724  such that first and second extension  1048 ,  1049  abut the air fitment receptacle. Second end  1046  of one-way valve  1042 , second end  1054  of first connector arm  1050  and second end  1060  of second connector arm  1056  are inserted into openings in manifold  726  such that manifold  726  abuts first and second extensions  1048 ,  1049 . 
     When underfoot pump  724  is compressed, air flows into an opening  1062  in first end  1044  of one-way valve  1042  and through the valve body to opening  1062 . The force of the air pushes against elastomeric sleeve  1061  covering the outlet opening causing it to expand allowing air to escape out the outlet opening past elastomeric sleeve  1061  and into manifold  726 . When the pressure is released from underfoot pump  724 , elastomeric sleeve  1061  returns to its original, unexpanded state such that air can not flow back into valve  1042  or into underfoot pump  724 . 
     Inflation mechanism  722  described above, is merely exemplary and a variety of other inflation mechanisms can be utilized in the present invention. The inflation mechanism may be an on-board inflation mechanism, for example, a latex bulb which is physically attached to a part of the sole/shoe. Alternatively, the inflation mechanism may be a molded plastic chamber or may be a hand held pump such as one which utilizes CO 2  gas to inflate a bladder. Alternatively, the inflation mechanism may be a portion of a monolithic bladder that is separated from the remainder of the bladder. The isolated portion fluidly communicates with the remainder of the bladder via a one-way valve. The one-way valve allows the isolated portion to act as an inflation mechanism. These alternative inflation mechanisms are described more fully, for example, in U.S. Pub. No. 2006/0162186, which is incorporated herein by reference. 
     Each alternative inflation mechanism requires a one-way valve to be present between the inflation mechanism and the inflatable bladder so that once air enters the inflatable bladder it may not travel backwards into the inflation mechanism. Various types of one-way valves are suitable for use in conjunction with the various alternative inflation mechanisms such as that described more fully in U.S. Pub. No. 2006/0162186, which is incorporated herein by reference. 
     The inflatable bladder inflated by the inflation mechanism may be fluidly connected to other inflatable bladders located throughout the shoe such that the inflation of one inflatable bladder may in turn inflate other inflatable bladders. Each inflatable bladder may have its own check valve and/or air pressure regulator. 
       FIG. 8  illustrates an embodiment wherein pressure regulator  116  is fluidly connected to a bladder via manifold  726 . A protective cover  840  covers and protects bottom surface  734  of manifold  726  and wraps around a medial or lateral side of sole  704  to surround pressure regulator  816 . The material for protective cover  840  may include, without limitation, thermoplastic polyurethane or glass-filled nylon. Pressure regulator  816  may comprise an adjustable knob for setting a desired pressure at which the inflatable bladder is to be maintained. The adjustable knob may be adjustable according to ordinary means including, but not limited to, rotating or sliding. For example, the adjustment may be made over a pressure range of 0 to 20 psi. Additional air present in the system bleeds off when the desired pressure is present and pressure regulator  816  will not allow the bladder to be inflated beyond the desired pressure no matter how much a user attempts to inflate the shoe. Pressure regulator  816  may also contain a provision to allow the inflatable bladder to deflate completely or not inflate at all when the desired pressure is set to 0.0 psi or through actuation of an alternative pressure regulator. A flip top may be used to access pressure regulator  816  as described in U.S. patent application Ser. No. 11/475,254, filed Jun. 27, 2006, which is incorporated herein by reference. The above described pressure regulator is merely exemplary and other pressure regulators could be used, such as a release valve, a check valve or a combination check valve and release valve, as described in U.S. Pub. No. 2006/0162186, which is incorporated herein by reference. 
     The shoe disclosed herein has an inflatable ground engaging surface, which allows the user to change the profile of the ground engaging surface by inflating and deflating the inflatable bladder(s) as desired depending upon the activity the wearer is going to engage in. 
     As noted elsewhere, these example embodiments have been described for illustrative purposes only, and are not limiting. Other embodiments are possible and are covered by the methods and systems described herein. Such embodiments will be apparent to persons skilled in the relevant art(s) based on the teachings contained herein. Thus, the breadth and scope of the methods and systems described herein 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.