Systems and methods for adjusting friction

Abstract

A shoe comprises an upper portion, a sole, and a sheet of material. The upper portion is configured to receive a foot of a user. The sole is attached to the upper portion. The sheet of material is coupled to the sole. The material includes a substrate and one or more movable projections. The one or more movable projections are configured to extend from the substrate. The one or more movable projections are configured to move between a first orientation and a second orientation relative to the substrate, in response to the sole of the shoe moving between a generally flat configuration and a generally flexed configuration. The movable projections can have a triangular shape, a concave shape, a convex shape, a rectangular shape, or a barbed shape; and can be arranged in a one-direction pattern, a three-column pattern, a half pattern, a 16x2 pattern, or a checkerboard pattern.

What is claimed is: 
     
         1 . A material for adjusting an amount of friction between the material and an object, the material comprising:
 a substrate; and   one or more movable projections configured to extend from the substrate, the one or more movable projections being configured to move between a first orientation relative to the substrate and a second orientation relative to the substrate, in response to movement of the substrate.   
     
     
         2 . The material of  claim 1 , wherein when the movable projections are in in the first orientation, the movable projections are coplanar with the substrate. 
     
     
         3 . The material of  claim 1 , wherein when the movable projections are in the second orientation, the movable projections extend from the substrate at an angle relative to the substrate. 
     
     
         4 . The material of  claim 3 , wherein the angle is greater than 0 degrees and less than or equal to 90 degrees. 
     
     
         5 . The material of  claim 1 , wherein the substrate is movable between a first configuration and a second configuration, the first configuration having a first curvature and the second configuration having a second curvature greater than the first curvature. 
     
     
         6 . The material of  claim 5 , wherein when the substrate is in the first configuration, the movable projections are in the first orientation relative to the substrate. 
     
     
         7 . The material of  claim 5 , wherein when the substrate is in the second configuration, the movable projections are in the second orientation relative to the substrate. 
     
     
         8 . The material of  claim 5 , wherein the movable projections are configured to move between the first orientation and the second orientation in response to the substrate moving between the first configuration and the second configuration. 
     
     
         9 . The material of  claim 5 , wherein the first curvature is about zero, such that the first configuration is a generally flat configuration. 
     
     
         10 . The material of  claim 9 , wherein the second configuration is greater than zero, such that the second configuration is a generally flexed configuration. 
     
     
         11 . The material of  claim 9 , wherein when the substrate is in the first configuration and the movable projections are in the first orientation, the substrate and the movable projections form a generally flat contact area between the material and the object, the generally flat contact area having a first coefficient of friction. 
     
     
         12 . The material of  claim 11 , wherein when the substrate is in the second configuration and the movable projections are in the second orientation, the substrate and the movable projections form a generally rough contact area between the material and the objection, the generally rough contact area having a second coefficient of friction that is greater than the first coefficient of friction. 
     
     
         13 . The material of  claim 1 , wherein the movable projections are integrally formed with the substrate. 
     
     
         14 . The material of  claim 13 , wherein the movable projections are formed from a plurality of cuts in the substrate. 
     
     
         15 . The material of  claim 14 , wherein the plurality of cuts in the substrate are formed from a periodic array of cuts. 
     
     
         16 . The material of  claim 1 , wherein the movable projections are coupled to the substrate. 
     
     
         17 . The material of  claim 1 , wherein the movable projections are formed in a first side of the substrate, and wherein a second opposing side of the substrate includes an adhesive material. 
     
     
         18 . The material of  claim 1 , wherein the movable projections each have a concave shape, a triangle shape, a convex shape, a rectangular shape, a square shape, a barbed shape, or any combination thereof. 
     
     
         19 . The material of  claim 1 , wherein the movable projections are arranged in a plurality of offset rows, the plurality of rows including a first row, a second row positioned adjacent to the first row, and a third row positioned adjacent to the second row, such that the second row is positioned between the first row and the third row. 
     
     
         20 . The material of  claim 19 , wherein each movable projection in the first row is aligned with a corresponding movable projection in the third row, and wherein each movable projection in the second row is not aligned with any corresponding movable projections in the first row or the third row. 
     
     
         21 . The material of  claim 19 , wherein when the movable projections are in the second orientation relative to the substrate, all of the movable projections extend away from the substrate and in an identical direction along the substrate. 
     
     
         22 . The material of  claim 1 , wherein the movable projections are arranged in a plurality of groups along the substrate. 
     
     
         23 . The material of  claim 22 , wherein the plurality of groups includes a first group and a second group positioned adjacent to the first group 
     
     
         24 . The material of  claim 23 , wherein when the movable projections in the first group are in the second orientation relative to the substrate, each of the movable projections in the first group extends away from the substrate and in a first direction along the substrate. 
     
     
         25 . The material of  claim 24 , wherein when the movable projections in the second group are in the second orientation relative to the substrate, each of the movable projections in the second group extends away from the substrate and in a second direction along the substrate, the second direction being opposite the first direction. 
     
     
         26 . The material of  claim 23 , wherein the plurality of groups includes a third group positioned adjacent to the second group, such that the second group is positioned between the first group and the third group. 
     
     
         27 . The material of  claim 26 , wherein when the movable projections in the third group are in the second orientation relative to the substrate, each of the movable projections in the third group extends away from the substrate and in the first direction along the substrate. 
     
     
         28 . The material of  claim 22 , wherein the movable projections in each group are arranged in a plurality of offset rows, the plurality of rows including a first row, a second row positioned adjacent to the first row, and a third row positioned adjacent to the second row, such that the second row is positioned between the first row and the third row. 
     
     
         29 . The material of  claim 28 , wherein each movable projection in the first row is aligned with a corresponding movable projection in the third row, and wherein each movable projection in the second row is not aligned with any corresponding movable projections in the first row or the third row. 
     
     
         30 . The material of  claim 21 , wherein when the movable projections are in the second orientation relative to the substrate, each of the plurality of groups of movable projections is separated from at least one adjacent group of the plurality of group by a portion of the substrate with no movable projections. 
     
     
         31 . The material of  claim 21 , wherein when the movable projections are in the second orientation relative to the substrate, each of the plurality of groups of movable projections is positioned directly next to at least one adjacent group of the plurality of groups, such that there is no portion of the substrate lacking movable projections that separates each of the plurality of groups from the at least one adjacent group. 
     
     
         32 . The material of  claim 1 , wherein the movable projections are arranged in a plurality of offset rows, the plurality of rows including a first row, a second row positioned adjacent to the first row, and a third row positioned adjacent to the second row, such that the second row is positioned between the first row and the third row. 
     
     
         33 . The material of  claim 32 , wherein when the movable projections in the first row and the second row are in the second orientation relative to the substrate, each of the movable projections in the first row and the second row extends away from the substrate and in a first direction along the substrate. 
     
     
         34 . The material of  claim 33 , wherein when the movable projections in the third row are in the second orientation relative to the substrate, each of the movable projections in the third row extends away from the substrate and in a second direction along the substrate, the second direction being opposite the first direction. 
     
     
         35 . The material of  claim 32 , wherein each movable projection in the first row is aligned with a corresponding movable projection in the third row, and wherein each movable projection in the second row is not aligned with any corresponding movable projection in the first row or the third row. 
     
     
         36 . The material of  claim 32 , wherein when the movable projections are in the second orientation relative to the substrate, each of the plurality of rows of movable projections is positioned directly next to at least one adjacent row of the plurality of rows, such that there is no portion of the substrate lacking movable projections that separates each of the plurality of rows from the at least one adjacent row. 
     
     
         37 . The material of  claim 1 , wherein the movable projections are arranged in a first group, a second group, a third group, and a fourth group, the set of groups forming a generally square or generally rectangular shape. 
     
     
         38 . The material of  claim 37 , wherein the second group is positioned adjacent to the first group along a first axis, wherein the fourth group is positioned adjacent to the first group along a second axis that is perpendicular to the first axis, and wherein the third group is positioned diagonal from the first group along both the first axis and the second axis. 
     
     
         39 . The material of  claim 38 , wherein the movable projections in the first group and the third group extend away from the substrate and in a first direction along the substrate when in the second orientation. 
     
     
         40 . The material of  claim 39 , wherein the movable projections in the second group and the fourth group extend away from the substrate and in a second direction along the substrate when in the second orientation, the second direction being opposite the first direction. 
     
     
         41 . The material of  claim 40 , wherein the first direction and the second direction are opposing directions along the first axis. 
     
     
         42 . The material of  claim 37 , wherein the movable projections in each group are arranged in a plurality of offset rows, the plurality of rows including a first row, a second row positioned adjacent to the first row, and a third row positioned adjacent to the second row, such that the second row is positioned between the first row and the third row. 
     
     
         43 . The material of  claim 42 , wherein each movable projection in the first row is aligned with a corresponding movable projection in the third row, and wherein each movable projection in the second row is not aligned with any corresponding movable projections in the first row or the third row. 
     
     
         44 . The material of  claim 37 , wherein when the movable projections are in the second orientation relative to the substrate, the first group and the second group are separated from the third group and a fourth group by a portion of the substrate with no movable projections that extends along the first axis. 
     
     
         45 . The material of  claim 37 , wherein the movable projections are formed in a periodic array of movable projections, each period of the array of movable projections including one of the first group of movable projections, one of the second group of movable projections, one of the third group of movable projections, and one of the fourth group of movable projections. 
     
     
         46 . The material of  claim 1 , wherein the substrate and the movable projections are formed polyester plastic, spring steel, polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), silicone-based rubber, a plastic, a metal, a polymer, a composite, or any combination thereof. 
     
     
         47 . The material of  claim 1 , wherein the substrate and each of the movable projections has a thickness that is between about 0.002 inches and about 0.05 inches. 
     
     
         48 . The material of  claim 1 , wherein the substrate is configured to be coupled to a sole of a shoe worn by a user, and wherein when the movable projections are in the second orientation relative to the substrate, the movable projections are configured to extend away from sole of the shoe toward a surface on which the user is walking. 
     
     
         49 . The material of  claim 48 , wherein the movable projections are configured to move between the first orientation and the second orientation as the user walks on the surface. 
     
     
         50 . The material of  claim 49 , wherein the movable projections are configured to move from the first orientation to the second orientation in response to the shoe flexing as the user walks, and wherein the movable projections are configured to return to the first orientation from the second orientation when the shoe flattens as the user walks. 
     
     
         51 . The material of  claim 1 , wherein the object is a surface that the material is configured to contact. 
     
     
         52 . A shoe comprising:
 an upper portion configured to receive a foot of a user;   a sole attached to the upper portion; and   a sheet of material coupled to the sole, the material including:
 a substrate; and 
 one or more movable projections configured to extend from the substrate, the one or more movable projections being configured to move between a first orientation relative to the substrate and a second orientation relative to the substrate, in response to the sole of the shoe moving between a generally flat configuration and a generally flexed configuration.