Adjustable flex footwear system

Abstract

Disclosed herein is a footwear system with tunable flexibility properties and a process of reversibly modifying the flexibility of footwear. In particular, there is described a footwear system comprising at least two items of footwear and at least two footwear flexibility modulators with anisotropic flexibility properties. In use, the footwear system can be reversibly switched from a stiff configuration to a flexible (i.e. less stiff) configuration. Also disclosed is a method of reversibly modulating the flexibility of footwear.

What is claimed is: 
     
         1 . A footwear system comprising:
 two items of footwear, one for a left foot and one for a right foot of a user; and   at least two footwear flexibility modulators, each of the at least two footwear flexibility modulators configured to be removably located in, on or under at least a portion of each of the two items of footwear,   wherein each of the at least two footwear flexibility modulators has a longitudinal axis and a lateral axis perpendicular to each other, the longitudinal axis and lateral axis defining a plane of the footwear flexibility modulator,   wherein the plane has a first surface and a second surface;   wherein each of the at least two footwear flexibility modulators has anisotropic flexibility properties such that it defines a first flexural stiffness when bending in a first direction and a second flexural stiffness when bending in a second direction opposite the first direction, and wherein the first flexural stiffness is greater than the second flexural stiffness; and   wherein, in use, the footwear system is configured to be worn in one of two configurations:   a) a first configuration in which each of the at least two footwear flexibility modulators is disposed in, on or under at least a portion of each item of footwear with the first surface facing towards or substantially towards a collar region of each item of footwear;   b) a second configuration in which each footwear flexibility modulator is disposed in, on or under at least a portion of each item of footwear with the second surface of the footwear flexibility modulator facing towards or substantially towards the collar region of the upper of each item of footwear;   wherein the footwear flexibility modulator provides a greater resistance to bending during a gait cycle in the first configuration than in the second configuration;   and wherein the footwear system can be reversibly switched from the first configuration to the second configuration by reversing each of the footwear flexibility modulators so that, in use, the opposite of the first or second surfaces of the footwear flexibility modulator faces towards or substantially towards the collar region of the upper of each item of footwear.   
     
     
         2 . A footwear system according to  claim 1 , wherein the first configuration is a stiff configuration and the second configuration is a flexible configuration when bending the footwear flexibility modulators towards the collar region of the upper of the items of footwear. 
     
     
         3 . A footwear system according to  claim 1 , wherein the flexural stiffness in the first configuration of the at least two footwear flexibility modulators is at least 2 times greater than the flexural stiffness in the second configuration. 
     
     
         4 . A footwear system according to  claim 1 , wherein the flexural stiffness in the first configuration of the at least two footwear flexibility modulators is from 2 times to six times greater than the flexural stiffness in the second configuration. 
     
     
         5 . A footwear system according to  claim 1 , comprising at least four footwear flexibility modulators configured to be removably located in, on or under at least a portion of each of the two items of footwear in one of the following combinations:
 a) Only one footwear flexibility modulator in each item of footwear disposed in the first configuration of the footwear flexibility modulator;   b) Only one footwear flexibility modulator in each item of footwear disposed in the second configuration of the footwear flexibility modulator;   c) No footwear flexibility modulator located in, on or under at least a portion of each of the two items of footwear;   d) Two footwear flexibility modulators disposed on top of each other, the uppermost footwear flexibility modulator in the first configuration of the footwear flexibility modulator, and the lowermost footwear flexibility modulator in the second configuration of the footwear flexibility modulator;   e) Two footwear flexibility modulators disposed on top of each other, both of the footwear flexibility modulators disposed in the first configuration of the footwear flexibility modulator;   f) Two footwear flexibility modulators disposed on top of each other, both of the footwear flexibility modulators disposed in the second configuration of the footwear flexibility modulator;   g) Two footwear flexibility modulators disposed on top of each other, the uppermost footwear flexibility modulator disposed in the second configuration of the footwear flexibility modulator and the lowermost footwear flexibility modulator disposed in the first configuration of the footwear flexibility modulator.   
     
     
         6 . A footwear system according to  claim 1 , wherein each of the footwear flexibility modulators is shaped to conform to the shape of an insole, midsole or a sole of each of the two items of footwear and wherein, in order to reversibly switch between the first and second configurations, each footwear flexibility modulator is configured to be turned over and disposed in, on or under the other of the two items of footwear so that the opposite layer of the footwear flexibility modulator faces towards the collar region of the upper of each item of footwear. 
     
     
         7 . A footwear system according to  claim 1 , wherein the at least two footwear flexibility modulators are removable footbeds. 
     
     
         8 . A footwear system according to  claim 1 , wherein the at least two footwear flexibility modulators are removable inserts configured to be disposed in each item of footwear between a footbed and an insole. 
     
     
         9 . A footwear system according to  claim 1 , wherein the at least two footwear flexibility modulators are removable inserts configured to be disposed in a recess in the midsole of each item of footwear. 
     
     
         10 . A footwear system according to  claim 1 , wherein the at least two footwear flexibility modulators are removable inserts configured to be disposed in a recess in a sole of each item of footwear. 
     
     
         11 . A footwear system according to  claim 1 , wherein each footwear flexibility modulator is a laminate comprising at least a first layer and a second layer,
 wherein the at least first layer comprises a plate with a modulus of elasticity in the range of approximately 30 ksi-40,000 ksi; and   wherein the at least second layer comprises a fiber reinforced material and having a tensile modulus selected from: about 2 ksi to about 3,000 ksi; about 5 ksi to about 2,000 ksi; about 25 ksi to about 1500 ksi; or about 100 ksi to about 2,000 ksi.   
     
     
         12 . A footwear system comprising at least two reversible footwear flexibility modulator inserts, the at least two reversible footwear flexibility modulator inserts comprising at least two layers: a first layer providing an increased bending resistance in a first bending direction relative to a bending resistance in a second bending direction, the second bending direction being opposite to the first bending direction. 
     
     
         13 . A footwear system according to  claim 12 , wherein the system comprises four footwear reversible footwear flexibility modulator inserts, configured to be inserted in the two items of footwear in one of the following combinations:
 a) Only one footwear flexibility modulator in each item of footwear with the first layer facing towards or substantially towards an upper of each item of footwear;   b) Only one footwear flexibility modulator in each item of footwear with the second layer facing towards or substantially towards an upper of each item of footwear;   c) No footwear flexibility modulator located in, on or under at least a portion of each of the two items of footwear;   d) Two footwear flexibility modulators disposed on top of each other in each item of footwear, the uppermost footwear flexibility modulator in the first configuration of the footwear flexibility modulator, and the lowermost footwear flexibility modulator in the second configuration of the footwear flexibility modulator;   e) Two footwear flexibility modulators disposed on top of each other in each item of footwear, both of the footwear flexibility modulators disposed in the first configuration of the footwear flexibility modulator;   e) Two footwear flexibility modulators disposed on top of each other in each item of footwear, both of the footwear flexibility modulators disposed in the second configuration of the footwear flexibility modulator;   f) Two footwear flexibility modulators disposed on top of each other in each item of footwear, the uppermost footwear flexibility modulator disposed in the second configuration of the footwear flexibility modulator and the lowermost footwear flexibility modulator disposed in the first configuration of the footwear flexibility modulator.   
     
     
         14 . A process of reversibly modulating the flexibility of footwear, the process comprising:
 a) providing two items of footwear, one for a left foot and one for a right foot of a user;   b) providing at least two footwear flexibility modulators, each of the at least two footwear flexibility modulators configured to be removably located in, on or under at least a portion of each of the two items of footwear,   wherein each of the at least two footwear flexibility modulators has a longitudinal axis and a lateral axis perpendicular to each other, the longitudinal axis and lateral axis defining a plane of the footwear flexibility modulator,   wherein the plane has a first surface and a second surface;   wherein each of the at least two footwear flexibility modulators has anisotropic flexibility properties such that it defines a first flexural stiffness when bending in a first direction and a second flexural stiffness when bending in a second direction opposite the first direction, and wherein the first flexural stiffness is greater than the second flexural stiffness; and   c) disposing at least one of the at least two footwear flexibility modulators in, on or under at least a portion of each item of footwear such that, in use, one of the first surface or the second surface of the footwear flexibility modulator faces towards or substantially towards a collar region of an upper of each item of footwear;   d) removing the at least two footwear flexibility modulators from the items of footwear;   e) reversing the at least two footwear flexibility modulators;   f) disposing the at least two reversed footwear flexibility modulators in, on or under at least a portion of each item of footwear such that, in use, the other of the first surface or the second surface of each of the at least two footwear flexibility modulators faces towards or substantially towards the collar region of the upper of each item of footwear for modifying the flexibility of the item of footwear; and   g) optionally, repeating steps d) to f) to revert the flexibility properties of each item of footwear.   
     
     
         15 . A process according to  claim 14 , wherein each of the at least two footwear flexibility modulators is shaped to conform to the shape of an insole, footbed, midsole or a sole of each of the two items of footwear and wherein, in order to reversibly modify the flexibility of each item of footwear, in step d) each footwear flexibility modulator is removed from one of the two items of footwear and in step e) is turned over and disposed in, on or under the other of the two items of footwear so that, in use, the opposite layer of the footwear flexibility modulator faces towards or substantially towards a sole of a foot of the user. 
     
     
         16 . A process according to  claim 14 , wherein each of the at least two flexibility modulators is an insert configured to be disposed in an item of footwear between an insole and a footbed and in steps c), f) and g) it is disposed inside each item of footwear directly on a midsole. 
     
     
         17 . A process according to  claim 14 , wherein each of the at least two flexibility modulators is a sole attachment and in steps c), f) and g) it is disposed in a recess in a sole of each item of footwear. 
     
     
         18 . A process according to  claim 14 , wherein the process comprises providing four footwear reversible footwear flexibility modulator inserts, configured to be inserted in a pair of items of footwear in one of the following combinations:
 a) Only one footwear flexibility modulator in each item of footwear in the first configuration of the footwear flexibility modulator;   b) Only one footwear flexibility modulator in each item of footwear in the first configuration of the footwear flexibility modulator;   c) No footwear flexibility modulator located in, on or under at least a portion of each of the two items of footwear;   d) Two footwear flexibility modulators disposed on top of each other in each item of footwear, the uppermost footwear flexibility modulator in the first configuration of the footwear flexibility modulator, and the lowermost footwear flexibility modulator in the second configuration of the footwear flexibility modulator;   e) Two footwear flexibility modulators disposed on top of each other in each item of footwear, both of the footwear flexibility modulators disposed in the first configuration of the footwear flexibility modulator;   e) Two footwear flexibility modulators disposed on top of each other in each item of footwear, both of the footwear flexibility modulators disposed in the second configuration of the footwear flexibility modulator;   f) Two footwear flexibility modulators disposed on top of each other in each item of footwear, the uppermost footwear flexibility modulator disposed in the second configuration of the footwear flexibility modulator and the lowermost footwear flexibility modulator disposed in the first configuration of the footwear flexibility modulator.   
     
     
         19 . A process according to  claim 14 , wherein the flexural stiffness in the first configuration of the at least two footwear flexibility modulators is at least 2 times greater than the flexural stiffness in the second configuration. 
     
     
         20 . A process according to  claim 14 , wherein the at least two footwear flexibility modulators are laminates comprising at least a first layer and at least a second layer, wherein the at least first layer comprises a plate with a modulus of elasticity in the range of approximately 30 ksi-40,000 ksi; and
 wherein the at least second layer comprises a fiber reinforced material and having a tensile modulus selected from: about 2 ksi to about 3,000 ksi; about 5 ksi to about 2,000 ksi; about 25 ksi to about 1500 ksi; or about 100 ksi to about 2,000 ksi.