Patent Publication Number: US-2023148704-A1

Title: Shoes, devices for shoes, and methods of using shoes

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application is a continuation of U.S. Pat. App. Ser. No. 17/503,793, filed Oct. 18, 2021, which claims priority from U.S. Provisional Pat. App. Ser. No. 63/190,180, filed May 18, 2021, the entire contents of each of which are incorporated by reference herein. 
    
    
     FIELD 
     Embodiments of the present invention relate in general to footwear, and particularly to energy absorption and return systems for use in footwear. 
     BACKGROUND 
     In prior U.S. Pat. No. 10,085,514, filed May 6, 2014, by Goldston et al., which issued on Oct. 2, 2018, a discussion was provided of the desirability of providing for energy shock absorption and energy return by shoes. The entire contents of U.S. Pat. No. 10,085,514 are incorporated by reference herein. 
     SUMMARY OF THE DISCLOSURE 
     A device in accordance with an embodiment for use in a shoe includes a first foot, a second foot, a third foot, and a fourth foot, and a first flexible leg, a second flexible leg, a third flexible leg, and a fourth flexible leg. The first flexible leg extends from the first foot and is curved. The second flexible leg extends from the second foot and is curved. The third flexible leg extends from the third foot and is curved. The fourth flexible leg extends from the fourth foot and is curved. In various embodiments, the first flexible leg, the second flexible leg, the third flexible leg, and the fourth flexible leg are joined together with each other at a common area. The first flexible leg, the second flexible leg, the third flexible leg, and the fourth flexible leg are configured to store energy when a force is applied to the common area, and are configured to return energy when the force is removed from the common area. 
     In various embodiments, the first foot, the second foot, the third foot, the fourth foot, the first flexible leg, the second flexible leg, the third flexible leg, and the fourth flexible leg are formed as a single unit. In some embodiments, the single unit is formed of carbon fiber. In some embodiments, the single unit is formed of one or more of carbon fiber, poly-paraphenylene terephthalamide (known as Kevlar®), styrene, and/or a thermoplastic elastomer such as a polyether block amide (PEBA) material known as Pebax® that is manufactured by ARKEMA. In various embodiments, the common area is at a central location with respect to locations of the first foot, the second foot, the third foot, and the fourth foot. In various embodiments, the common area is raised in height as compared to a corresponding top surface of each of the first foot, the second foot, the third foot, and the fourth foot. In some embodiments, the first flexible leg, the second flexible leg, the third flexible leg, and the fourth flexible leg each comprise one or more of carbon fiber, poly-paraphenylene terephthalamide (known as Kevlar®), styrene, and/or a thermoplastic elastomer such as a polyether block amide (PEBA) material known as Pebax®, or other suitable material. In various embodiments, the device is at least partially located in an opening in a midsole of a shoe. 
     In various embodiments, the device further includes a spring extending from a bottom surface of the common area. In some embodiments, the device further includes a first spring extending from a bottom surface of the first foot, a second spring extending from a bottom surface of the second foot, a third spring extending from a bottom surface of the third foot, and a fourth spring extending from a bottom surface of the fourth foot. In further embodiments, the device includes a fifth spring extending from a bottom surface of the common area. In various embodiments, the first flexible leg and the third flexible leg together form a first arch. In various embodiments, the second flexible leg and the fourth flexible leg together form a second arch. In some embodiments, a center of the first arch and a center of the second arch are joined together at the common area. 
     A shoe in accordance with an embodiment includes a midsole and a device located at least partially in an opening in the midsole. In various embodiments, the device includes a first foot, a second foot, a third foot, and a fourth foot, a first flexible leg that extends from the first foot and is curved, a second flexible leg that extends from the second foot and is curved, a third flexible leg that extends from the third foot and is curved, and a fourth flexible leg that extends from the fourth foot and is curved. In various embodiments, the first flexible leg, the second flexible leg, the third flexible leg, and the fourth flexible leg are joined together with each other at a common area. 
     A method of using a device in a shoe in accordance with an embodiment includes applying force to a common area at which a first flexible leg, a second flexible leg, a third flexible leg, and a fourth flexible leg of the device are joined together to cause a first spring located under a first foot connected to the first flexible leg to compress, and to cause a second spring located under a second foot connected to the second flexible leg to compress, and to cause a third spring located under a third foot connected to the third flexible leg to compress, and to cause a fourth spring located under a fourth foot connected to the fourth flexible leg to compress, and to cause a fifth spring located under the common area to compress, and to cause the first flexible leg, the second flexible leg, the third flexible leg, and the fourth flexible leg to flex to a flexed position, so as to store potential energy. In various embodiments, the method further includes releasing the force from the common area to allow the first spring, the second spring, the third spring, the fourth spring, and the fifth spring to stretch, and to allow the first flexible leg, the second flexible leg, the third flexible leg, and the fourth flexible leg to return back from the flexed position, so as to return energy. 
     A device in accordance with another embodiment for use in a shoe includes a first foot, a second foot, a third foot, and a fourth foot, and a first flexible leg, a second flexible leg, a third flexible leg, and a fourth flexible leg. The first flexible leg extends from the first foot and is curved. The second flexible leg extends from the second foot and is curved. The third flexible leg extends from the third foot and is curved. The fourth flexible leg extends from the fourth foot and is curved. The first flexible leg and the third flexible leg are joined together with each other as a single unit to form a first arch from the first foot to the third foot. The second flexible leg and the fourth flexible leg are joined together with each other as a single unit to form a second arch from the second foot to the fourth foot. The second arch has a center portion that is located under a center portion of the first arch. 
     In various embodiment, the device further includes a spring extending from a bottom surface of the center portion of the second arch. In various embodiments, the device further includes a first spring extending from a bottom surface of the first foot, a second spring extending from a bottom surface of the second foot, a third spring extending from a bottom surface of the third foot, and a fourth spring extending from a bottom surface of the fourth foot. In some embodiments, the device further includes a fifth spring extending from a bottom surface of the center portion of the second arch. 
     A shoe in accordance with another embodiment includes a midsole and a device located at least partially in an opening in the midsole. The device includes a first foot, a second foot, a third foot, and a fourth foot, and a first flexible leg, a second flexible leg, a third flexible leg, and a fourth flexible leg. The first flexible leg extends from the first foot and is curved. The second flexible leg extends from the second foot and is curved. The third flexible leg extends from the third foot and is curved. The fourth flexible leg extends from the fourth foot and is curved. The first flexible leg and the third flexible leg are joined together with each other to form a first arch from the first foot to the third foot. The second flexible leg and the fourth flexible leg are joined together with each other to form a second arch from the second foot to the fourth foot. The second arch has a center portion that is located under a center portion of the first arch. In various embodiments, the device further includes a first spring extending from a bottom surface of the first foot, a second spring extending from a bottom surface of the second foot, a third spring extending from a bottom surface of the third foot, a fourth spring extending from a bottom surface of the fourth foot, and a fifth spring extending from a bottom surface of the center portion of the second arch. 
     A method in accordance with an embodiment of using the device in a shoe includes applying force to the center portion of the first arch to cause force to be applied to the center portion of the second arch, and to cause the first spring located under the first foot connected to the first flexible leg to compress, and to cause the second spring located under the second foot connected to the second flexible leg to compress, and to cause the third spring located under the third foot connected to the third flexible leg to compress, and to cause the fourth spring located under the fourth foot connected to the fourth flexible leg to compress, and to cause the fifth spring located under the center portion of the second arch to compress, and to cause the first flexible leg, the second flexible leg, the third flexible leg, and the fourth flexible leg to flex to a flexed position, so as to store potential energy. In various embodiments, the method further includes releasing the force from the center portion of the first arch to allow the first spring, the second spring, the third spring, the fourth spring, and the fifth spring to stretch, and to allow the first flexible leg, the second flexible leg, the third flexible leg, and the fourth flexible leg to return back from the flexed position, so as to return energy. In various embodiments, the center portion of the second arch is located below the center portion of the first arch. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    shows a shoe in accordance with an embodiment. 
         FIG.  2    shows an exploded view of a shoe including a device in accordance with an embodiment. 
         FIG.  3 A  shows the device from  FIG.  2    for use in a shoe in accordance with an embodiment. 
         FIG.  3 B  shows another embodiment of a device that includes a center spring for use in a shoe. 
         FIG.  3 C  shows another embodiment of a device that includes four side springs for use in a shoe. 
         FIG.  3 D  shows another embodiment of a device that includes a center spring and four side springs for use in a shoe. 
         FIG.  4 A  shows another embodiment of a device for use in a shoe. 
         FIG.  4 B  shows another embodiment of a device that includes a center spring for use in a shoe. 
         FIG.  4 C  shows another embodiment of a device that includes four side springs for use in a shoe. 
         FIG.  4 D  shows another embodiment of a device that includes a center spring and four side springs for use in a shoe. 
         FIGS.  5 A,  5 B, and  5 C  show example states of the device of  FIG.  4 B , where  FIG.  5 A  shows an uncompressed state,  FIG.  5 B  shows a state when the device is under pressure, and  FIG.  5 C  shows a state when the device has bounced back. 
         FIG.  6    shows a portion of an embodiment of a shoe illustrating exemplary locations at which one or more devices in accordance with any of the embodiments may be located. 
         FIG.  7    is a flowchart of a method in accordance with an embodiment. 
         FIG.  8    is a flowchart of a method in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    shows a shoe  100  in accordance with an embodiment. The shoe  100  includes an outsole  202 , a midsole  203 , an upper  204 , and a fastening member  205 . The shoe  100  has various portions, including a forefoot portion  101 , a ball portion  102 , an arch portion  103 , and a heel portion  104 . The outsole  202  is designed to be placed on the ground in normal operation of the shoe  100 . The upper  204  includes an opening for a foot of a user and means for tightening the shoe  100  around the foot of the user, such as the fastening member  205 , which may be, for example, laces, a zipper, or the like. 
     The forefoot portion  101  of the shoe  100  is located at the front of the shoe  100 , and the forefoot portion  101  may support the toes of a foot of a human when the foot of the human is inserted into the shoe  100 . The ball portion  102  is located adjacent to the forefoot portion  101 , and the ball portion  102  may support the ball of a foot of a human when the foot of the human is inserted into the shoe  100 . The arch portion  103  is located adjacent to the ball portion  102 , and may provide support to an arch of a foot of a human when the foot of the human is inserted into the shoe  100 . The heel portion  104  is located adjacent to the arch portion  103  and at the rear of the shoe  100 , and may provide support to a heel of a foot of a human when the foot of the human is inserted into the shoe  100 . 
       FIG.  2    shows an exploded view of the shoe  100  in accordance with an embodiment. The shoe  100  includes the outsole  202 , the midsole  203 , an insole  216 , and a device  231 . In various embodiments, the shoe further includes a plate  222 . The insole  216  is located above the plate  222 . There is a cavity or opening  217  in the midsole  203  into which at least a portion of the device  231  is insertable. For example, the device  231  may be positioned within the opening  217  in the midsole  203  such that bottom surfaces of the device  231  contact a top surface of the outsole  202 . In some embodiments, the opening  217  is a partial opening in the midsole  203  forming a cavity in which the device  231  may be positioned such that bottom surfaces of the device  231  contact a surface of the midsole  203  within the cavity. Though not shown in  FIG.  2   , the shoe  100  can have other elements such as the upper  204  and the fastening member  205  as shown in  FIG.  1   . Referring to  FIGS.  1  and  2   , the shoe  100  also has the forefoot portion  101 , ball portion  102 , arch portion  103 , and heel portion  104  in a longitudinal direction. 
     In various embodiments, the plate  222  is a carbon fiber plate. Also, in various embodiments, the plate  222  has a same or similar shape as the insole  216  in length and width directions. In some embodiments, the plate  222  has a shorter length than the insole  216 . In various embodiments, the plate  222  extends across substantially an entire length of the shoe  100 . For example, in some embodiments, the plate  222  extends within an area bounded by a wall of the midsole  203  at the back of the shoe  100  to a wall of the midsole  203  at the front of the shoe  100 . In various embodiments, the plate  222  extends from the heel portion  104  of the shoe  100   and through the arch portion  103  and the ball portion  102  of the shoe  100  and into the forefoot portion  101  of the shoe  100 . In some embodiments, there is a sockliner positioned above the insole  216  that is on an opposite side of the insole  216  from the plate  222 . In various embodiments, the insole  216  comprises an ethylene-vinyl acetate (EVA) material, or the like. In various embodiments, the midsole  203  comprises a thermoplastic elastomer such as a polyether block amide (PEBA) material, such as the PEBA material known as Pebax® that is manufactured by ARKEMA. In some embodiments, a Shore type A durometer value of the midsole  203  is less than 40. In some embodiments, a Shore type A durometer value of the midsole  203  is greater than 40. 
     In various embodiments, the device  231  is an energy storage and return device that acts as a trampoline to store potential energy when compressed by a foot of a human wearing the shoe  100 , and then to return energy to the foot of the human as the foot of the human is lifted. In various embodiments, a rear end of the device  231  is positioned near a half-way point of a length of the shoe  100  and the device  231  extends all the way to near a front of the shoe  100  where it would be under the toes of a user of the shoe  100 . In various embodiments, the device  231  extends from a position in the arch portion  103  of the shoe  100  and through the ball portion  102  of the shoe  100  and into the forefoot portion  101  of the shoe  100  to near a front of the forefoot portion  101  of the shoe  100 . In some embodiments, the device  231  is positioned entirely within the forefoot portion  101  of the shoe  100 . In some embodiment, the device  231  is positioned entirely within the ball portion  102  of the shoe  100 . In some embodiments, the device  231  is positioned entirely within the heel portion  104  of the shoe  100 . Other positions of the device  231  within the shoe  100  are also possible. 
     In various embodiments, the plate  222  is glued or otherwise affixed to the device  231 . For example, a top surface of the device  231  in various embodiments is glued to a bottom surface of the plate  222  during manufacture. In various embodiments, the plate  222  is affixed, such as being permanently affixed, to the device  231  such that the plate  222  works together with the device  231  to provide energy return to a user using the shoe  100 . In various embodiments, the plate  222  is affixed to the device  231  such that an energy return of the plate  222  works with a kinetic release of the device  231  when a user is using the shoe  100 . In some embodiments, the plate  222  is omitted from the shoe  100 , and the device  231  has an upper surface in contact with a bottom surface of the insole  216 . 
       FIG.  3 A  shows the device  231  from  FIG.  2    for use in a shoe in accordance with an embodiment. The device  231  includes an energy storage and return structure  240 . The energy storage and return structure  240  includes a first foot  261 , a second foot  262 , a third foot  263 , and a fourth foot  264 , and a first flexible leg  251 , a second flexible leg  252 , a third flexible leg  253 , and a fourth flexible leg  254 . The first flexible leg  251  extends from the first foot  261  and is curved. The second flexible leg  252  extends from the second foot  262  and is curved. The third flexible leg  253  extends from the third foot  263  and is curved. The fourth flexible leg  254  extends from the fourth foot  264  and is curved. The first flexible leg  251 , the second flexible leg  252 , the third flexible leg  253 , and the fourth flexible leg  254  are joined together with each other at a common area  380 . In various embodiments, the first flexible leg  251 , the second flexible leg  252 , the third flexible leg  253 , and the fourth flexible leg  254  are joined together with each other at the common area  380  by being manufactured as a single unit. The first flexible leg  251 , the second flexible leg  252 , the third flexible leg  253 , and the fourth flexible leg  254  are configured to store energy when a force is applied to the common area  380 , and are configured to return energy when the force is removed from the common area  380 . 
     In various embodiments, the first foot  261 , the second foot  262 , the third foot  263 , the fourth foot  264 , the first flexible leg  251 , the second flexible leg  252 , the third flexible leg  253 , and the fourth flexible leg  254  are formed as a single unit. In some embodiments, such a single unit is formed of carbon fiber. In some embodiments, such a single unit is formed of one or more of carbon fiber, rubber, poly-paraphenylene terephthalamide (known as Kevlar®), styrene, and/or a thermoplastic elastomer such as a polyether block amide (PEBA) material known as Pebax®. In various embodiments, the energy storage and return structure  240  is formed of one or more of carbon fiber, rubber, poly-paraphenylene terephthalamide (known as Kevlar®), styrene, and/or a thermoplastic elastomer such as a polyether block amide (PEBA) material known as Pebax®, or other material that allows for flexing and returning from a flexed state. In various embodiments, the common area  380  is at a central location with respect to locations of the first foot  261 , the second foot  262 , the third foot  263 , and the fourth foot  264 . In various embodiments, the common area  380  is raised in height as compared to a corresponding top surface of each of the first foot  261 , the second foot  262 , the third foot  263 , and the fourth foot  264 . In some embodiments, the first flexible leg  251 , the second flexible leg  252 , the third flexible leg  253 , and the fourth flexible leg  254  each comprise one or more of carbon fiber, rubber, poly-paraphenylene terephthalamide (known as Kevlar®), styrene, and/or a thermoplastic elastomer such as a polyether block amide (PEBA) material known as Pebax®. In various embodiments, the device  231  is at least partially located in an opening in a midsole of a shoe. 
     In various embodiments, the first flexible leg  251  and the third flexible leg  253  together form a first arch  255  from the first foot  261  to the third foot  263 . In various embodiments, the second flexible leg  252  and the fourth flexible leg  254  together form a second arch  256  from the second foot  262  to the fourth foot  264 . In some embodiments, a center of the first arch  255  and a center of the second arch  256  are joined together as part of a single unit at the common area  380  and are angled with respect to each other. 
     The first flexible leg  251  has a top surface  301  and a bottom surface  302 . The second flexible leg  252  has a top surface  321  and a bottom surface  322 . The third flexible leg  253  has a top surface  341  and a bottom surface  342 . The fourth flexible leg  254  has a top surface  361  and a bottom surface  362 . The first foot  261  has a top surface  311  and a bottom surface  312 . The second foot  262  has a top surface  331  and a bottom surface  332 . The third foot  263  has a top surface  351  and a bottom surface  352 . The fourth foot  264  has a top surface  371  and a bottom surface  372 . The common area  380  has a top surface  381  and a bottom surface  382 . 
     With reference to  FIGS.  2  and  3 A , in various embodiments, the device  231  is located at least partially within the opening  217  in the midsole  203  of the shoe  100  such that the bottom surface  312  of the first foot  261 , the bottom surface  332  of the second foot  262 , the bottom surface  352  of the third foot  263 , and the bottom surface  372  of the fourth foot  264  are flat on a top surface of the outsole  202 . In various embodiments, the device  231  is located entirely within the opening  217  in the midsole  203  of the shoe  100 . In various embodiments, a first portion of a bottom surface of the plate  222  is glued to the top surface  381  of the common area  380  of the device  231 , and a second portion of the bottom surface of the plate  222  lays on a surface of the midsole  203  of the shoe  100 . Also, in various embodiments, the insole  216  lays on a top surface of the plate  222 . 
     A method of using the device  231  in the shoe  100  in accordance with an embodiment includes applying force, such as from a foot of a human user, to the common area  380  at which the first flexible leg  251 , the second flexible leg  252 , the third flexible leg  253 , and the fourth flexible leg  254  of the device  231  are joined together to cause the first flexible leg  251 , the second flexible leg  252 , the third flexible leg  253 , and the fourth flexible leg  254  to flex to a flexed position, so as to store potential energy. In various embodiments, the method further includes releasing the force from the common area  380 , such as by lifting the foot of the human user, to allow the first flexible leg  251 , the second flexible leg  252 , the third flexible leg  253 , and the fourth flexible leg  254  to return back from the flexed position, so as to return energy to the foot of the human user. In various embodiments, the force is applied to the common area  380  from the foot of the human user by the foot of the human user pressing on the insole  216  to cause the plate  222  to apply the force to the common area  380 . 
       FIG.  3 B  shows a device  232  in accordance with another embodiment. With reference to  FIGS.  3 A and  3 B , the device  232  is similar to the device  231  and includes the energy storage and return structure  240  of the device  231 , but the device  232  also includes a center spring  395  that is positioned on the bottom surface  382  of the common area  380 . The label numbers in  FIG.  3 B  that are the same as label numbers in  FIG.  3 A  denote the same structures. In various embodiments, the spring  395  is a coil spring. In various other embodiments, the spring  395  is a wave spring or other type of spring. The spring  395  provides for additional energy storage and return when the device  232  is used in a shoe. 
     With reference to  FIGS.  2  and  3 B , the device  232  can be used in place of the device  231   in the shoe  100 . In some embodiments, a bottom of the spring  395  would be in contact with a top surface of the outsole  202  when the device  232  is positioned at least partially within the opening  217  in the midsole  203  of the shoe  100 . Also, in various embodiments, the bottom surface  312  of the first foot  261 , the bottom surface  332  of the second foot  262 , the bottom surface  352  of the third foot  263 , and the bottom surface  372  of the fourth foot  264  are flat on a top surface of the outsole  202  when the device  232  is positioned at least partially within the opening  217  in the midsole  203  of the shoe  100 . In various embodiments, the device  232  is located entirely within the opening  217  in the midsole  203  of the shoe  100 . In various embodiments, a first portion of a bottom surface of the plate  222  is glued to the top surface  381  of the common area  380  of the device  232 , and a second portion of the bottom surface of the plate  222  lays on a surface of the midsole  203  of the shoe  100 . Also, in various embodiments, the insole  216  lays on a top surface of the plate  222 . 
     A method of using the device  232  in the shoe  100  in accordance with an embodiment includes applying force, such as from a foot of a human user, to the common area  380  at which the first flexible leg  251 , the second flexible leg  252 , the third flexible leg  253 , and the fourth flexible leg  254  of the device  232  are joined together to cause the center spring  395  to compress, and to cause the first flexible leg  251 , the second flexible leg  252 , the third flexible leg  253 , and the fourth flexible leg  254  to flex to a flexed position, so as to store potential energy. In various embodiments, the method further includes releasing the force from the common area  380 , such as by lifting the foot of the human user, to allow the center spring  395  to expand from the compressed state and to allow the first flexible leg  251 , the second flexible leg  252 , the third flexible leg  253 , and the fourth flexible leg  254  to return back from the flexed position, so as to return energy to the foot of the human user. In various embodiments, the force is applied to the common area  380  from the foot of the human user by the foot of the human user pressing on the insole  216  to cause the plate  222  to apply the force to the common area  380 . 
       FIG.  3 C  shows a device  233  in accordance with another embodiment. With reference to  FIGS.  3 A and  3 C , the device  233  is similar to the device  231  and includes the energy storage and return structure  240  of the device  231 , but the device  233  further includes a first spring  391   extending from the bottom surface  312  of the first foot  261 , a second spring  392  extending from the bottom surface  332  of the second foot  262 , a third spring  393  extending from the bottom surface  352  of the third foot  263 , and a fourth spring  394  extending from the bottom surface  372  of the fourth foot  264 . The label numbers in  FIG.  3 C  that are the same as label numbers in  FIG.  3 A  denote the same structures. In various embodiments, the first spring  391 , the second spring  392 , the third spring  393 , and the fourth spring  394  are coil springs. In various other embodiments, the first spring  391 , the second spring  392 , the third spring  393 , and the fourth spring  394  are wave springs or other types of springs. The first spring  391 , the second spring  392 , the third spring  393 , and the fourth spring  394  provide for additional energy storage and return when the device  233  is used in a shoe. 
     With reference to  FIGS.  2  and  3 C , the device  233  can be used in place of the device  231  in the shoe  100 . In some embodiments, a corresponding bottom of each of the first spring  391 , the second spring  392 , the third spring  393 , and the fourth spring  394  would be in contact with a top surface of the outsole  202  when the device  233  is positioned at least partially within the opening  217  in the midsole  203  of the shoe  100 . In various embodiments, the device  233  is located entirely within the opening  217  in the midsole  203  of the shoe  100 . In various embodiments, a first portion of a bottom surface of the plate  222  is glued to the top surface  381  of the common area  380  of the device  233 , and a second portion of the bottom surface of the plate  222  lays on a surface of the midsole  203  of the shoe  100 . Also, in various embodiments, the insole  216  lays on a top surface of the plate  222 . 
     A method of using the device  233  in the shoe  100  in accordance with an embodiment includes applying force, such as from a foot of a human user, to the common area  380  at which the first flexible leg  251 , the second flexible leg  252 , the third flexible leg  253 , and the fourth flexible leg  254  of the device  233  are joined together to cause the first spring  391 , the second spring  392 , the third spring  393 , and the fourth spring  394  to compress, and to cause the first flexible leg  251 , the second flexible leg  252 , the third flexible leg  253 , and the fourth flexible leg  254  to flex to a flexed position, so as to store potential energy. In various embodiments, the method further includes releasing the force from the common area  380 , such as by lifting the foot of the human user, to allow the first spring  391 , the second spring  392 , the third spring  393 , and the fourth spring  394  to expand from the compressed state and to allow the first flexible leg  251 , the second flexible leg  252 , the third flexible leg  253 , and the fourth flexible leg  254  to return back from the flexed position, so as to return energy to the foot of the human user. In various embodiments, the force is applied to the common area  380  from the foot of the human user by the foot of the human user pressing on the insole  216  to cause the plate  222  to apply the force to the common area  380 . 
       FIG.  3 D  shows a device  234  in accordance with another embodiment. With reference to  FIGS.  3 A and  3 D , the device  234  is similar to the device  231  and includes the energy storage and return structure  240  of the device  231 , but the device  234  further includes the first spring  391  extending from the bottom surface  312  of the first foot  261 , the second spring  392  extending from the bottom surface  332  of the second foot  262 , the third spring  393  extending from the bottom surface  352  of the third foot  263 , the fourth spring  394  extending from the bottom surface  372  of the fourth foot  264 , and the center spring  395  that is a fifth spring extending from the bottom surface  382  of the common area  380 . The label numbers in  FIG.  3 D  that are the same as label numbers in  FIG.  3 A  denote the same structures. In various embodiments, the first spring  391 , the second spring  392 , the third spring  393 , the fourth spring  394 , and the center spring  395  are coil springs. In various other embodiments, the first spring  391 , the second spring  392 , the third spring  393 , the fourth spring  394 , and the center spring  395  are wave springs or other types of springs. The first spring  391 , the second spring  392 , the third spring  393 , the fourth spring  394 , and the center spring  395  provide for additional energy storage and return when the device  234  is used in a shoe. 
     With reference to  FIGS.  2  and  3 D , the device  234  can be used in place of the device  231  in the shoe  100 . In some embodiments, a corresponding bottom of each of the first spring  391 , the second spring  392 , the third spring  393 , the fourth spring  394 , and the center spring  395  would be in contact with a top surface of the outsole  202  when the device  234  is positioned at least partially within the opening  217  in the midsole  203  of the shoe  100 . In various embodiments, the device  234  is located entirely within the opening  217  in the midsole  203  of the shoe  100 . In various embodiments, a first portion of a bottom surface of the plate  222  is glued to the top surface  381  of the common area  380  of the device  234 , and a second portion of the bottom surface of the plate  222  lays on a surface of the midsole  203  of the shoe  100 . Also, in various embodiments, the insole  216  lays on a top surface of the plate  222 . 
     A method of using the device  234  in the shoe  100  in accordance with an embodiment includes applying force, such as from a foot of a human user, to the common area  380  at which the first flexible leg  251 , the second flexible leg  252 , the third flexible leg  253 , and the fourth flexible leg  254  of the device  234  are joined together to cause the first spring  391 , the second spring  392 , the third spring  393 , the fourth spring  394 , and the center spring  395  to compress, and to cause the first flexible leg  251 , the second flexible leg  252 , the third flexible leg  253 , and the fourth flexible leg  254  to flex to a flexed position, so as to store potential energy. In various embodiments, the method further includes releasing the force from the common area  380 , such as by lifting the foot of the human user, to allow the first spring  391 , the second spring  392 , the third spring  393 , the fourth spring  394 , and the center spring  395  to expand from the compressed state and to allow the first flexible leg  251 , the second flexible leg  252 , the third flexible leg  253 , and the fourth flexible leg  254  to return back from the flexed position, so as to return energy to the foot of the human user. In various embodiments, the force is applied to the common area  380  from the foot of the human user by the foot of the human user pressing on the insole  216  to cause the plate  222  to apply the force to the common area  380 . 
       FIG.  4 A  shows a device  431  in accordance with another embodiment for use in a shoe. The device  431  includes an energy storage and return structure  440 . The energy storage and return structure  440  includes a first foot  461 , a second foot  462 , a third foot  463 , and a fourth foot  464 , and a first flexible leg  451 , a second flexible leg  452 , a third flexible leg  453 , and a fourth flexible leg  454 . The first flexible leg  451  extends from the first foot  461  and is curved. The second flexible leg  452  extends from the second foot  462  and is curved. The third flexible leg  453  extends from the third foot  463  and is curved. The fourth flexible leg  454  extends from the fourth foot  464  and is curved. The first flexible leg  451  and the third flexible leg  453  are joined together with each other as a single unit to form a first arch  455  from the first foot  461  to the third foot  463 . In various embodiments, the first flexible leg  451  and the third flexible leg  453  are joined together with each other by being manufactured as a single unit that is continuous as the first arch  455  from the first foot  461  to the third foot  463 . The second flexible leg  452  and the fourth flexible leg  454  are joined together with each other as a single unit to form a second arch  456  from the second foot  462  to the fourth foot  464 . In various embodiments, the second flexible leg  452  and the fourth flexible leg  454  are joined together with each other by being manufactured as a single unit that is continuous as the second arch  456  from the second foot  462  to the fourth foot  464 . The second arch  456  has a center portion  583  that is located under a center portion  580  of the first arch  455 . 
     In various embodiments, the first foot  461 , the second foot  462 , the third foot  463 , the fourth foot  464 , the first flexible leg  451 , the second flexible leg  452 , the third flexible leg  453 , and the fourth flexible leg  454  are formed of one or more of carbon fiber, poly-paraphenylene terephthalamide (known as Kevlar®), styrene, and/or a thermoplastic elastomer such as a polyether block amide (PEBA) material known as Pebax®. In various embodiments, the energy storage and return structure  440  is formed of one or more of carbon fiber, rubber, poly-paraphenylene terephthalamide (known as Kevlar®), styrene, and/or a thermoplastic elastomer such as a polyether block amide (PEBA) material known as Pebax®, or other material that allows for flexing and returning from a flexed state. In various embodiments, the center portion  580  of the first arch  455  is at a central location with respect to locations of the first foot  461 , the second foot  462 , the third foot  463 , and the fourth foot  464 . In various embodiments, the center portion  580  is raised in height as compared to a corresponding top surface of each of the first foot  461 , the second foot  462 , the third foot  463 , and the fourth foot  464 . In some embodiments, the first flexible leg  451 , the second flexible leg  452 , the third flexible leg  453 , and the fourth flexible leg  454  each comprise one or more of carbon fiber, poly-paraphenylene terephthalamide (known as Kevlar®), styrene, and/or a thermoplastic elastomer such as a polyether block amide (PEBA) material known as Pebax®. In various embodiments, the device  431  is at least partially located in an opening in a midsole of a shoe. 
     The first flexible leg  451  has a top surface  501  and a bottom surface  502 . The second flexible leg  452  has a top surface  521  and a bottom surface  522 . The third flexible leg  453  has a top surface  541  and a bottom surface  542 . The fourth flexible leg  454  has a top surface  561  and a bottom surface  562 . The first foot  461  has a top surface  511  and a bottom surface  512 . The second foot  462  has a top surface  531  and a bottom surface  532 . The third foot  463  has a top surface  551  and a bottom surface  552 . The fourth foot  464  has a top surface  571  and a bottom surface  572 . The center portion  580  of the first arch  455  has a top surface  581  and a bottom surface  582 . The center portion  583  of the second arch  456  has a top surface  584  and a bottom surface  585 . 
     With reference to  FIGS.  2  and  4 A , the device  431  can be used in place of the device  231  in the shoe  100 . In various embodiments, the device  431  is located at least partially within the opening  217  in the midsole  203  of the shoe  100  such that the bottom surface  512  of the first foot  461 , the bottom surface  532  of the second foot  462 , the bottom surface  552  of the third foot  463 , and the bottom surface  572  of the fourth foot  464  are flat on a top surface of the outsole  202 . In various embodiments, a first portion of a bottom surface of the plate  222  is glued to the top surface  581 , and a second portion of the bottom surface of the plate  222  lays on a surface of the midsole  203  of the shoe  100 . Also, in various embodiments, the insole  216  lays on a top surface of the plate  222 . 
     A method of using the device  431  in the shoe  100  in accordance with an embodiment includes applying force to the center portion  580  of the first arch  455  to cause force to be applied to the center portion  583  of the second arch  456 , so as to cause the first flexible leg  451 , the second flexible leg  452 , the third flexible leg  453 , and the fourth flexible leg  454  to flex to a flexed position, so as to store potential energy. In various embodiments, the method further includes releasing the force from the center portion  580  of the first arch  455  to allow the first flexible leg  451 , the second flexible leg  452 , the third flexible leg  453 , and the fourth flexible leg  454  to return back from the flexed position, so as to return energy. In various embodiments, the center portion  583  of the second arch  456  is located below the center portion  580  of the first arch  455 . 
       FIG.  4 B  shows a device  432  in accordance with another embodiment. With reference to  FIGS.  4 A and  4 B , the device  432  is similar to the device  431  and includes the energy storage and return structure  440  of the device  431 , but the device  432  further includes a spring  595  that is positioned on the bottom surface  585  of the center portion  583  of the second arch  456 . The label numbers in  FIG.  4 B  that are the same as label numbers in  FIG.  4 A  denote the same structures. In various embodiments, the spring  595  is a coil spring. In various other embodiments, the spring  595  is a wave spring or other type of spring. The spring  595  provides for additional energy storage and return when the device  432  is used in a shoe. 
     With reference to  FIGS.  2  and  4 B , the device  432  can be used in place of the device  231  in the shoe  100 . In some embodiments, a bottom of the spring  595  would be in contact with a top surface of the outsole  202  when the device  432  is positioned at least partially within the opening  217  in the midsole  203  of the shoe  100 . In various embodiments, the bottom surface  512  of the first foot  461 , the bottom surface  532  of the second foot  462 , the bottom surface  552  of the third foot  463 , and the bottom surface  572  of the fourth foot  464  are flat on a top surface of the outsole  202 . In various embodiments, a first portion of a bottom surface of the plate  222  is glued to the top surface  581 , and a second portion of the bottom surface of the plate  222  lays on a surface of the midsole  203  of the shoe  100 . Also, in various embodiments, the insole  216  lays on a top surface of the plate  222 . 
     A method of using the device  432  in the shoe  100  in accordance with an embodiment includes applying force to the center portion  580  to cause force to be applied to the center portion  583 , so as to cause the first flexible leg  451 , the second flexible leg  452 , the third flexible leg  453 , and the fourth flexible leg  454  to flex to a flexed position, and to compress the spring  595 , so as to store potential energy. In various embodiments, the method further includes releasing the force from the center portion  580  to allow the first flexible leg  451 , the second flexible leg  452 , the third flexible leg  453 , and the fourth flexible leg  454  to return back from the flexed position, and to allow the spring  595  to expand from the compressed state so as to return energy. 
       FIGS.  5 A,  5 B, and  5 C  show stages of the device  432  during use.  FIG.  5 A  shows the device  432  with the energy storage and return structure  440  and the spring  595  prior to a force being applied.  FIG.  5 B  shows the device  432  with the energy storage and return structure  440  and the spring  595  when the force is applied to place the device  432  under pressure.  FIG.  5 C  shows the device  432  with the energy storage and return structure  440  and the spring  595  when the force has been removed to allow the device  432  to bounce back and return energy. 
       FIG.  4 C  shows a device  433  in accordance with another embodiment. With reference to  FIGS.  4 A and  4 C , the device  433  is similar to the device  431  and includes the energy storage and return structure  440  of the device  431 , but the device  433  further includes a first spring  591  extending from the bottom surface  512  of the first foot  461 , a second spring  592  extending from the bottom surface  532  of the second foot  462 , a third spring  593  extending from the bottom surface  552  of the third foot  463 , and a fourth spring  594  extending from the bottom surface  572  of the fourth foot  464 . The label numbers in  FIG.  4 C  that are the same as label numbers in  FIG.  4 A  denote the same structures. In various embodiments, the first spring  591 , the second spring  592 , the third spring  593 , and the fourth spring  594  are coil springs. In various other embodiments, they are wave springs or other types of springs. The first spring  591 , the second spring  592 , the third spring  593 , and the fourth spring  594  provide for additional energy storage and return when the device  433  is used in a shoe. 
     With reference to  FIGS.  2  and  4 C , the device  433  can be used in place of the device  231  in the shoe  100 . In some embodiments, a corresponding bottom of each of the first spring  591 , the second spring  592 , the third spring  593 , and the fourth spring  594  would be in contact with a top surface of the outsole  202  when the device  433  is positioned at least partially within the opening  217  in the midsole  203  of the shoe  100 . In various embodiments, a first portion of a bottom surface of the plate  222  is glued to the top surface  581 , and a second portion of the bottom surface of the plate  222  lays on a surface of the midsole  203  of the shoe  100 . Also, in various embodiments, the insole  216  lays on a top surface of the plate  222 . 
     A method of using the device  433  in the shoe  100  in accordance with an embodiment includes applying force to the center portion  580  to cause force to be applied to the center portion  583 , so as to cause the first flexible leg  451 , the second flexible leg  452 , the third flexible leg  453 , and the fourth flexible leg  454  to flex to a flexed position, and to compress the first spring  591 , the second spring  592 , the third spring  593 , and the fourth spring  594 , so as to store potential energy. In various embodiments, the method further includes releasing the force from the center portion  580  to allow the first flexible leg  451 , the second flexible leg  452 , the third flexible leg  453 , and the fourth flexible leg  454  to return back from the flexed position, and to allow the first spring  591 , the second spring  592 , the third spring  593 , and the fourth spring  594  to expand from the compressed state so as to return energy. 
       FIG.  4 D  shows a device  434  in accordance with another embodiment. With reference to  FIGS.  4 A and  4 D , the device  434  is similar to the device  431  and includes the energy storage and return structure  440  of the device  431 , but the device  434  further includes the first spring  591  extending from the bottom surface  512  of the first foot  461 , the second spring  592  extending from the bottom surface  532  of the second foot  462 , the third spring  593  extending from the bottom surface  552  of the third foot  463 , the fourth spring  594  extending from the bottom surface  572  of the fourth foot  464 , and the spring  595  that is a fifth spring and that is positioned on the bottom surface  585  of the center portion  583  of the second arch  456 . The label numbers in  FIG.  4 D  that are the same as label numbers in  FIG.  4 A  denote the same structures. In various embodiments, the first spring  591 , the second spring  592 , the third spring  593 , the fourth spring  594 , and the spring  595  are coil springs. In various other embodiments, they are wave springs or other types of springs. The first spring  591 , the second spring  592 , the third spring  593 , the fourth spring  594 , and the spring  595  provide for additional energy storage and return when the device  434  is used in a shoe. 
     With reference to  FIGS.  2  and  4 D , the device  434  can be used in place of the device  231  in the shoe  100 . In some embodiments, a corresponding bottom of each of the first spring  591 , the second spring  592 , the third spring  593 , the fourth spring  594 , and the spring  595  would be in contact with a top surface of the outsole  202  when the device  434  is positioned at least partially within the opening  217  in the midsole  203  of the shoe  100 . In various embodiments, a first portion of a bottom surface of the plate  222  is glued to the top surface  581 , and a second portion of the bottom surface of the plate  222  lays on a surface of the midsole  203  of the shoe  100 . Also, in various embodiments, the insole  216  lays on a top surface of the plate  222 . 
     A method of using the device  434  in the shoe  100  in accordance with an embodiment includes applying force to the center portion  580  to cause force to be applied to the center portion  583 , so as to cause the first flexible leg  451 , the second flexible leg  452 , the third flexible leg  453 , and the fourth flexible leg  454  to flex to a flexed position, and to compress the first spring  591 , the second spring  592 , the third spring  593 , the fourth spring  594 , and the spring  595  so as to store potential energy. In various embodiments, the method further includes releasing the force from the center portion  580  to allow the first flexible leg  451 , the second flexible leg  452 , the third flexible leg  453 , and the fourth flexible leg  454  to return back from the flexed position, and to allow the first spring  591 , the second spring  592 , the third spring  593 , the fourth spring  594 , and the spring  595  to expand from the compressed state so as to return energy. 
       FIG.  6    shows a portion of an embodiment of a shoe  611  illustrating exemplary locations at which one or more devices in accordance with any of the embodiments of  FIGS.  3 A,  3 B,  3 C,  3 D,  4 A,  4 B,  4 C, and  4 D  may be located. Referring to  FIG.  6   , the shoe  611  includes a midsole  613 . In various embodiments, there is an opening  617  in a forefoot portion  614  of the midsole  613 . In various embodiments, there is an opening  618  in a heel portion  615  of the midsole  613 . In various embodiments, there is the opening  617  in the forefoot portion  614  of the midsole  613  and the opening  618  in the heel portion  615  of the midsole  613 . 
     With reference to  FIGS.  3 A,  3 B,  3 C,  3 D,  4 A,  4 B,  4 C,  4 D, and  6   , in various embodiments, any of the devices  231 ,  232 ,  233 ,  234 ,  431 ,  432 ,  433 , and  434  is positionable at least partially within the opening  617  in the forefoot portion  614  of the midsole  613 . In various embodiments, any of the devices  231 ,  232 ,  233 ,  234 ,  431 ,  432 ,  433 , and  434  is positionable at least partially within the opening  618  in the heel portion  615  of the midsole  613 . In various embodiments, one device that is structured such as any of the devices  231 ,  232 ,  233 ,  234 ,  431 ,  432 ,  433 , and  434  is positioned at least partially within the opening  617  in the forefoot portion  614  of the midsole  613 , and another device that is structured such as any of the devices  231 ,  232 ,  233 ,  234 ,  431 ,  432 ,  433 , and  434  is positioned at least partially within the opening  618  in the heel portion  615  of the midsole  613 . 
     In some embodiments, there is no opening in a heel portion of a midsole of a shoe, and there is just a device such as any of the devices  231 ,  232 ,  233 ,  234 ,  431 ,  432 ,  433 , and  434  that is positioned at least partially within an opening in the forefoot portion of the midsole of the shoe. In some embodiments, there is no opening in a forefoot portion of a midsole of a shoe, and there is just a device such as any of the devices  231 ,  232 ,  233 ,  234 ,  431 ,  432 ,  433 , and  434  that is positioned at least partially within an opening in a heel portion of the shoe. Any of the devices  231 ,  232 ,  233 ,  234 ,  431 ,  432 ,  433 , and  434  could be located at other locations within a shoe, such as in any of a forefoot portion, ball portion, arch portion, and/or heel portion of a shoe. Also, different ones of any of the devices  231 ,  232 ,  233 ,  234 ,  431 ,  432 ,  433 , and  434  could be located in a same shoe in different locations. 
       FIG.  7    is a flowchart of a method of using a device in a shoe in accordance with an embodiment. In step  701 , a force is applied to a common area at which a first flexible leg, a second flexible leg, a third flexible leg, and a fourth flexible leg of the device are joined together to cause a first spring located under a first foot connected to the first flexible leg to compress, and to cause a second spring located under a second foot connected to the second flexible leg to compress, and to cause a third spring located under a third foot connected to the third flexible leg to compress, and to cause a fourth spring located under a fourth foot connected to the fourth flexible leg to compress, and to cause a fifth spring located under the common area to compress, and to cause the first flexible leg, the second flexible leg, the third flexible leg, and the fourth flexible leg to flex to a flexed position, so as to store potential energy. In various embodiments, the force is applied to the common area by a user of the shoe. 
     In step  702 , the force is released from the common area to allow the first spring, the second spring, the third spring, the fourth spring, and the fifth spring to stretch, and to allow the first flexible leg, the second flexible leg, the third flexible leg, and the fourth flexible leg to return back from the flexed position, so as to return energy. 
       FIG.  8    is a flowchart of a method of using a device in a shoe in accordance with another embodiment. The device includes a first flexible leg, a second flexible leg, a third flexible leg, and a fourth flexible leg. The first flexible leg and the third flexible leg together form a first arch. The second flexible leg and the fourth flexible leg together form a second arch. 
     In step  801 , the method includes applying a force to a center portion of the first arch to cause force to be applied to a center portion of the second arch, and to cause a first spring located under a first foot connected to the first flexible leg to compress, and to cause a second spring located under a second foot connected to the second flexible leg to compress, and to cause a third spring located under a third foot connected to the third flexible leg to compress, and to cause a fourth spring located under a fourth foot connected to the fourth flexible leg to compress, and to cause a fifth spring located under the center portion of the second arch to compress, and to cause the first flexible leg, the second flexible leg, the third flexible leg, and the fourth flexible leg to flex to a flexed position, so as to store potential energy. In various embodiments, the force is applied to the center portion of the first arch by a user of the shoe. 
     In step  802 , the method includes releasing the force from the center portion of the first arch to allow the first spring, the second spring, the third spring, the fourth spring, and the fifth spring to stretch, and to allow the first flexible leg, the second flexible leg, the third flexible leg, and the fourth flexible leg to return back from the flexed position, so as to return energy. In various embodiments, the center portion of the second arch is located below the center portion of the first arch. 
     The embodiments disclosed herein are to be considered in all respects as illustrative, and not restrictive of the invention. For example, in various other embodiments, additional flexible legs forming additional arches, as well as additional springs could be added to one or more of the devices. The present invention is in no way limited to the embodiments described above. Various modifications and changes may be made to the embodiments without departing from the spirit and scope of the invention.