Abstract:
An inflatable cushioning device, comprising an fluid-tight, enclosed area, wherein said enclosed area is bordered by a first generally flat surface, a second generally flat surface and at least one bellowed surface, such that said bellowed surface will collapse when a force is applied. The cushioning device may comprise an inflation mechanism for selectively introducing air into the enclosed area. The present invention also includes an athletic shoe comprising the bellowed cushioning device. The present invention also includes a process for making the bellowed cushioning device out of various layers of sheets.

Description:
[0001]     This application is a non-provisional application claiming priority to U.S. Patent Application No. 60/488,389 filed Jul. 21, 2003, the contents of which are incorporated herein in its entirety. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates to cushioning devices for use in footwear, and to an article of footwear having a bellowed cushioning area.  
         [0004]     2. Background Art  
         [0005]     Athletic footwear must provide stable and comfortable support for the body while subject to various types of stress that occur during the various foot movements associated with athletic activity.  
         [0006]     One of the problems associated with 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.  
         [0007]     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. This results in discomfort for the wearer which diminishes 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. Thus, it is essential to have cushioning footwear when engaging in athletic activity. Further, any cushioning system added to athletic shoes must be inexpensive and simple to use.  
         [0008]     Proper footwear should complement the natural functionality of the foot, in part by incorporating a sole which absorbs shocks and returns energy to the foot. However, different levels of cushioning may be desired depending on the type of activity. Accordingly, it is desirable to provide a shoe which can provide a varying level of support and cushioning in the sole of the foot.  
       BRIEF SUMMARY OF THE INVENTION  
       [0009]     The present invention resolves the above stated problems by providing an cushioning device comprising an air-tight, enclosed area defined by a first generally flat surface, a second generally flat surface and at least one bellowed surface. The bellowed surface collapses upon the force of the foot upon it to provides both cushioning and rebounding characteristics. In one embodiment, the cushioning device has an inflation mechanism for selectively introducing air into said enclosed area such that the level of support can be adjusted by the individual wearer. Further in one embodiment, the cushioning device is wedge-shaped with the first and second generally flat surfaces in close proximity at a first end and being separated by the bellowed surface at a second end.  
         [0010]     The enclosed area is generally defined by an N number of sheets, including a first sheet, a second sheet, a third sheet, a fourth sheet and so on up to an Nth sheet. The first sheet is attached to the second sheet, the second sheet is attached to the third sheet, the third sheet is attached to the fourth sheet, and so on up to an Nth sheet. The first and Nth sheets are the first and second generally flat surfaces of the cushioning device while the intermediate sheets form the bellowed surface. In one embodiment, all but the first and Nth sheets are horseshoe shaped, such that the enclosed area is a single large cavity. In another embodiment, the enclosed area is made up of a plurality of chambers, wherein the first sheet and the second sheet form a first chamber, the third sheet and the forth sheet form a second chamber and so on. In this embodiment, a hole may be place in all but the first and Nth sheets such that each chamber is fluidly interconnected.  
         [0011]     The sheets are formed from a fluid impermeable material, such as thermoplastic polyurethane.  
         [0012]     The present invention contemplates an article of foot wear comprising a cushioning device comprising an enclosed area defined by a generally flat surface, a second generally flat surface and at least one bellowed surface.  
         [0013]     The present invention also contemplates a process for manufacturing a bellowed cushioning device comprising providing four or more fluid impermeable sheets and attaching the sheets together to form a first generally flat surface, a second generally flat surface and a bellowed surface defining an fluid tight enclosed area. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES  
       [0014]     The foregoing and other features and advantages of the present invention will be apparent from the following, more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings in which:  
         [0015]      FIG. 1  is a side view of a shoe including an inflated cushioning device according to the present invention;  
         [0016]      FIG. 2  is a side view of a shoe including a deflated cushioning device according to the present invention;  
         [0017]      FIG. 3  is a top view of the sheets forming one embodiment of a cushioning device of the present invention;  
         [0018]      FIG. 4  is an exploded cross section view of a cushioning device of the present invention made from the sheets of  FIG. 3 .  
         [0019]      FIG. 5  is a side view of a cushioning device of the present invention formed from the sheets of  FIG. 3  constructed as in  FIG. 4 ;  
         [0020]      FIG. 6  is a top view of the sheets forming another embodiment of a cushioning device of the present invention.  
         [0021]      FIG. 7  is an exploded cross section view of a cushioning device of the present invention made from the sheets of  FIG. 6 .  
         [0022]      FIG. 8  is a side view of another shoe including an inflated cushioning device of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]     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 is first used. While specific configurations and arrangements are discussed, it should be understood that this is done for illustrative purposes only. A person skilled in the relevant art will recognize that other 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.  
         [0024]     A shoe for a left foot according to the present invention is shown generally at  100  in  FIG. 1 . A corresponding shoe for the right foot would be a mirror image of shoe  100  and therefore, is not shown or described herein. As shown in  FIG. 1 , shoe  100  has a heel area shown generally at  102 , an upper  110 , a sole  120 , and a bellowed cushioning device  130 . Upper  110  has an ankle opening shown generally at  112 , which is designed to receive a wearer&#39;s foot.  
         [0025]     It is preferred that the bellowed cushioning device  130  contain a fluid. Therefore, when pressure is placed on the bellowed cushioning device  130  the bellowed surface  132  collapses, forcing the fluid within into a smaller volume. The collapse of the bellowed surface  132  cushions the foot while the interior volume of fluid provides support for the foot. When the pressure on the bellowed cushioning device  130  is released, the bellowed surface  132  will rebound to its pre-collapsed shape and the fluid within will occupy the entire space.  
         [0026]     The bellowed cushioning device  130  may be filled with any type of gas or liquid. Preferably, the bellowed cushioning device  130  contains air, since it is the most cost-effective fluid. Air may be contained in the bellowed cushioning device  130  at an ambient pressure or it may be pressurized. Preferably, the air within the bellowed cushioning device  130  is pressurized. The greater the pressure of the fluid in the bellowed cushioning device  130  the greater the volume that air occupies when compressed. Therefore, pressurized air will allow less collapse of the bellowed surface  132  than air at ambient pressure.  
         [0027]     Air may be introduced into the bellowed cushioning device  130  at the time of manufacture or the device may include an inflation mechanism. Bellowed cushioning device  130  is shown inflated in  FIG. 1 , and is shown deflated in  FIG. 2 . The inflation mechanism  140  is a device which engages the bellowed cushioning device  130  through an external connection or valve. The inflation mechanism may be an external device such as a pump or a pressurized canister that is connected with bellowed cushioning device  130  when needed. Preferably, however, inflation mechanism  140  is a lightweight, on-board inflation system, as shown in  FIGS. 1 and 2 . An on-board inflation mechanism can be disposed on any area of the shoe provided it is in fluid communication with bellowed cushioning chamber  130 , as would be apparent to one skilled in the art. Such places on the shoe include the tongue, the sole, the vamp or any other part of the upper.  FIGS. 1 and 2  show the inflation mechanism  140  located in a rear portion of the upper. However, this embodiment is merely an example and is not intended to limit the scope of the application.  
         [0028]     The preferred embodiment of  FIG. 1  shows an inflation mechanism  140 . The inflation mechanism  140  includes a one-way valve (not shown) to keep air from escaping bellowed cushioning device  130 . A variety of different inflation mechanisms can be utilized in the present invention. Preferably, the inflation mechanism is small, lightweight, and provides a sufficient volume of air such that only little effort is needed for adequate inflation. For example, U.S. Pat. No. 5,987,779, which is incorporated herein by reference, describes an inflation mechanism comprising a bulb (of various shapes) with a check valve. When the bulb is compressed the check valve causes air within the volume of the bulb to be forced into the bellowed cushioning device  130 . When the bulb is released, the check valve opens to allow ambient air to fill the bulb again.  
         [0029]     Another inflation mechanism, also described in U.S. Pat. No. 5,987,779, is a bulb having a hole in it on top. A finger can be placed over the hole in the bulb upon compression. Therefore, air is not permitted to escape through the hole and is forced into the bellowed cushioning device  130 . When the finger is removed, ambient air is allowed to enter through the hole. U.S. Pat. No. 6,287,225 describes another type of on-board inflation mechanism suitable for the present invention. One skilled in the art can appreciate that a variety of inflation mechanisms designed for use with athletic footwear would be suitable for the present invention. Similarly, various types of one-way valves are suitable for use along with the inflation mechanism  140 . Preferably, the valve will be relatively small and flat, for less bulkiness. As one possible example, U.S. Pat. No. 5,564,143 to Pekar describes a valve suitable for the present invention. The patent describes a valve formed between thermoplastic polyurethane sheets, which is particularly thin and simple to manufacture. One skilled in the art would understand that a variety of suitable valves are contemplated in the present invention and that the example above is not intended to limit the type of valves that may be used herein.  
         [0030]     As seen in  FIGS. 1 and 2 , shoe  100  further includes a deflation valve  142  disposed in upper  110  to enable air to be released. However, a deflation valve  142  is not required. The one-way valve used in conjunction with inflation mechanism  140  provides a method to avoid over inflation of the system. In particular, if the pressure in bellowed cushioning device  130  is equal to the pressure exerted by inflation mechanism  140 , no additional air will be allowed to enter the system. In fact, when an equilibrium is reached between the pressure in bellowed cushioning device  130  and the pressure of the compressed inflation mechanism  140 , the one-way valve which opens to allow air movement from inflation mechanism  140  to bellowed cushioning device  130  may remain closed. Even if this valve does open, no more air will enter the system. Any one-way valve will provide a similar effect, as would be known to one skilled in the art.  
         [0031]     In another embodiment, small perforations may be formed in the outside surfaces of bellowed cushioning device  130  to allow air to naturally diffuse out of bellowed cushioning device  130  when a predetermined pressure is reached. The material used to make bellowed cushioning device  130  may be of a flexible material such that these perforations will generally remain closed. If the pressure in bellowed cushioning device  130  becomes greater than a predetermined pressure, the force on the outside surfaces of bellowed cushioning device  130  will open the perforations and air will escape. When the pressure in bellowed cushioning device  130  is less than this predetermined pressure, air will escape very slowly, if at all, from these perforations.  
         [0032]     As an alternative, deflation valve  142  may be a check valve, or blow off valve, which will open when the pressure in bellowed cushioning device  130  is at or greater than a predetermined level. In each of these situations, bellowed cushioning device  130  will not inflate over a certain amount no matter how much a user attempts to inflate the shoe.  
         [0033]     One type of check valve has a spring holding a movable seating member against an opening in bellowed cushioning device  130 . When the pressure from the air inside the bladder causes a greater pressure on the movable seating member in one direction than the spring causes in the other direction, the movable seating member moves away from the opening allowing air to escape bellowed cushioning device  130 . In addition, any other check valve is appropriate for use in the present invention, as would be apparent to one skilled in the art. As an example, the VA-3497 Umbrella Check Valve (Part No. VL1682-104) made of Silicone VL1001M12 and commercially available from Vernay Laboratories, Inc. (Yellow Springs, Ohio, USA) may be a preferred check valve. Further, any check valve would be appropriate for use in any embodiment of the present invention.  
         [0034]     In another embodiment, deflation valve  142  may be a release valve. A release valve is useful to provide the wearer with a greater degree of control in varying the level of support and cushion of bellowed cushioning device  130 . One release valve may be similar to the check valve described above, but capable of being adjusted by the user. For example, the valve may have a mechanism for increasing or decreasing the tension in the spring, such that more or less air pressure, respectively, would be required to overcome the force of the spring and move the movable seating member away from the opening in bellowed cushioning device  130 . Another type of release valve is a plunger type valve. This type of valve also uses a spring to hold a seating member against a hole on the inside of bellowed cushioning device  130 . A plunger type device is attached to the seating member, such that when the plunger is depressed the seating member is forced away from the hole to allow air to escape. As would be apparent to one skilled in the art, any type of release valve is appropriate for use in the present invention, as would be apparent to one skilled in the art, and any release valve would be appropriate for use in any embodiment of the present invention.  
         [0035]     Bellowed cushioning device  130  may include more than one type of deflation valve  142 . For example, bellowed cushioning device  130  may include both a check valve and a release valve. Alternatively, bellowed cushioning device  130  may contain a deflation valve  142  which is a combination release valve and check valve. The deflation valve  142  and inflation mechanism  140  may be molded as a unitary single piece as shown by the crossmarks  380  and  381  in piece  352  of  FIG. 3 .  
         [0036]     Bellowed cushioning device  130  may be formed as a unitary structure. The entire structure may be blow molded or injection molded from a thermoplastic material. An injection molded or blow molded bellowed cushioning device  130  will likely be somewhat rigid. Another alternative is forming bellowed cushioning device  130  from a plurality of thin, flexible, durable thermoplastic sheets, such as a polyurethane film available from J.P. Stevens &amp; Co., Inc., Northampton, Mass.  
         [0037]     In one embodiment, these thermoplastic sheets form a series of fluidly connected chambers that make up bellowed cushioning device  130 .  FIG. 3  shows how these sheets are die cut into particular shapes to form the bellowed cushioning device  130 . As shown in  FIG. 3 , bellowed cushioning device  130  may be formed of a first sheet  351 , a second sheet  352 , a plurality of third sheets  353 , and a fourth sheet. The first sheet  351  and the fourth sheet  354 , in this case, make up first and second generally flat surfaces  510 ,  511  (see  FIG. 5 ) for bellowed cushioning device  130 , while second sheet  352  and each of third sheets  353  make up the bellowed surface  132 . However, any number of third sheets  353  can be added to form a bellowed surface  132  of a larger size.  
         [0038]     In one embodiment, the sheets are attached to each other by welding. In a most preferred embodiment, the sheets are attached to each other by radio frequency welding. However, the sheets may be attached by heat welding, ultrasonic welding or any other means for securing thermoplastic sheets together in an airtight manner.  
         [0039]      FIG. 4 . is an exploded cross section view of bellowed cushioning device  130 , which shows how sheets  351 ,  352 ,  353  and  354  are attached. First and second sheets  351  and  352 , as seen in  FIG. 3 , are attached along weld line  357 . First and second sheets  351 ,  352  are attached to form the fluid connection between the inflation mechanism located, in this embodiment, at cross mark  381  and deflation valve located, in this embodiment, at cross mark  380 . Outer edge  356  of first sheet  351  is not welded to any other sheet in order to firmly secure a generally flat surface  510  (see  FIG. 5 ) of bellow cushioning device  130  to other parts of shoe  100 .  
         [0040]     Second sheet  352  is also attached to third sheet  353   a  along an outer weld line  358  to form a first chamber  471 . Third sheet  353   a  is then attached to sheet  353   b , which is identical to sheet  353   a , along an inner weld line  359 . A second chamber  472  is formed when the sheet  353   b  is attached to a fourth sheet  354  along an outer weld line  358 . To form the air tight bellows-like shape of bellowed cushioning device  130 , all sheets are attached together along common bottom weld line  360 . Fourth sheet  354  is not attached to any other sheet to form a second generally flat surface  511  (see  FIG. 5 ).  
         [0041]     One skilled in the art would understand that the distance between inner weld lines  359  and outer weld line  359  can be any length provided that they are uniform throughout each third sheet  353 .  
         [0042]     Chambers  471  and  472  of  FIG. 4  are fluidly interconnected through at least one hole  368  ( FIG. 3 ) between each chamber formed in sheets  352  and  353 . Sheets  351  and  354  do not have these holes because they act as generally flat top and bottom surfaces  510 ,  511  (see  FIG. 5 ) of air tight bellow cushioning device  130 . In an alternative embodiment, only sheets  351  and  354  are welded to each other along bottom weld line  369 . In this embodiment, air is allowed to fluidly move throughout the chambers at the common straight end of bellows cushioning device  130 . In this embodiment, second and third sheets  352  and  353  may be slightly shorter than first and fourth sheets  351  and  354 , provided that they still have a similar overall shape. In this embodiment, holes  368  may or may not be found in each second and third sheets  352 ,  353 .  
         [0043]      FIG. 5  shows a side view of bellowed cushioning device  130 . Alternatively, additional chambers, such as optional chamber  573  can be added by attaching two additional third sheets  353   c  and  353   d  in the same manner described above, and as is shown by the dotted lines in  FIG. 5 . It would be obvious to one skilled in the art how to form any number of optional chambers to the bellow cushioning area by the addition of sheets identical to  354   a ,  354   b , and  355  (such as sheets  354   c ,  354   d  and  355   e  in  FIG. 4 ) between sheet  355  and sheet  356 . One skilled in the art would understand that the addition of such chambers, however, increases the total volume of the bellow cushioning device  130 .  
         [0044]     As seen in  FIG. 5 , bellowed cushioning device  130  is wedge shaped such that bellowed surface  132  decreases in height along its length. In alternate embodiments, bellowed cushioning device  130  may be other shapes, as would be apparent to one skilled in the art, provided that it has at least one bellowed surface  132 .  
         [0045]     Another embodiment is described with respect to  FIGS. 6 and 7 .  FIG. 6  shows that bellowed cushioning device  130  can be formed with traditional first sheet  651 , horseshoe-shaped second sheet  652 , a plurality of horseshoe-shaped sheets  653 , and a traditional forth sheet  654 .  FIG. 7  is an exploded cross section view of bellowed cushioning device  130 , which shows how sheets  651 ,  652 ,  653  and  654  are attached. First sheet  651  and horseshoe-shaped second sheet  652 , as seen in  FIG. 6 , are attached along weld line  657 , similar to the earlier described embodiment. Horseshoe-shaped second sheet  652  is also attached to horseshoe-shaped third sheet  653   a  along an outer weld line  658 . Third sheet  653   a  is then attached to another horseshoe-shaped sheet  653   b , which is identical to sheet  653   a , along an inner weld line  659 . Then, horseshoe-shaped sheet  653   b  is attached to a fourth sheet  654  along an outer weld line  658 . To form the air tight bellows-like shape of bellowed cushioning device  130 , all sheets are attached together along common bottom weld line  660 . This alternative embodiment forms one large cavity  771 , rather than a plurality of chambers.  
         [0046]     As air enters bellowed cushioning device  130 , its volume will increase. A natural-state volume, therefore, is initially determined by the amount of air pumped into the bellowed cushioning device  130 . The natural-state volume of the shoe will provide lift to the wearer when standing. This lift may also provide a height advantage to the wearer.  
         [0047]     As the foot exerts downward pressure on bellowed cushioning device  130 , the bellowed surface  132  collapses upon itself, to cushion the foot from the force of this pressure. As this happens the air in bellowed cushioning device  130  compresses, increasing the pressure of the air and decreasing the volume of bellowed cushioning device  130  to a compressed-state volume. However, the compressed air will not allow bellowed cushioning device  130  to completely collapse, thus providing support to the foot with each step. As the foot begins to rise, the pressure of the air expands the volume of bellowed cushioning device  130  back to its natural-state. The release of energy caused by the expansion of air is returned to the foot as bellowed cushioning device  130  springs from its compressed-state volume to its natural-state volume.  
         [0048]     Even when bellowed cushioning device  130  is not inflated, the bellowed configuration is resilient enough to provide a sufficient volume so that bellowed surface  132  will collapse with the downward pressure from a typical step. Therefore, the foot is cushioned by the resiliency of bellowed cushioning device  130  even when it only contains air at ambient pressure.  
         [0049]     Although bellowed cushioning device  130  is shown in  FIGS. 1 and 2  being located in the heel area of the shoe, in alternate embodiments bellowed cushioning device  130  may be located anywhere in shoe  100 , particularly under the forefoot or arch of a wearer&#39;s foot or in the upper.  
         [0050]     Bellowed cushioning device  130  of the embodiments shown in  FIGS. 1 and 2  is located between an upper  110  and a sole  120 . In other embodiments, bellowed cushioning device  130  may also be located within a split in a midsole  870 , as shown in shoe  800  of  FIG. 8 , or in a recess formed within midsole  870 . Bellowed cushioning device  130  may also be located between and upper  110  and midsole  870  or between a midsole and an outsole  872  of a sole  120 . Sole  120  may instead have a thermoformed footplate, as an alternative to a midsole  870 , to which upper  110  is adhered. In this embodiment, bellowed cushioning device  130  may be located between upper  110  and the footplate or between the footplate and outsole  872 . Bellowed cushioning device  130  may even be inserted into a conventional shoe. The bellowed cushioning device  130  may therefore be located in any other position, as would be apparent to one skilled in the art.  
         [0051]     Bellowed cushioning device  130  may be located entirely within the interior of sole  120  or upper  110 , or bellowed cushioning device  130  may have at least its bellowed surface  132  as part of the exterior of a shoe or sole  120  thereof, as shown in  FIGS. 1, 2  and  8 .  
         [0052]     While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that they have been presented by way of example only, and not limitation, and various changes in form and details 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. Additionally, all references cited herein, including issued U.S. patents, or any other references, are each entirely incorporated by reference herein, including all data, tables, figures, and text presented in the cited references.  
         [0053]     The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying knowledge within the skill of the art (including the contents of the references cited herein), readily modify and/or adapt for various applications such specific embodiments, without undue experimentation, without departing from the general concept of the present invention. Therefore, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance presented herein, in combination with the knowledge of one of ordinary skill in the art.