Cushioning for a sole structure of performance footwear
The present invention is directed toward cushioning for a sole structure for an article of footwear. The cushioning is three-dimensionally (3D) printed cushioning formed from a plurality of cells. Each cell in the plurality of cells includes a lattice of elongate structures that extend symmetrically around an offset axis. The elongate structures of adjacent cells in the plurality of cells connect so that the plurality of cells form a unitary structure and, as the elongate structures of each cell are compressed by a compressive force, the elongate structures of each cell create a lateral shear. As the compressive force is released, the elongate structures return to a rest position, exerting a restorative force on the insole and/or upper of an article of footwear in which the cushioning is included.
1. An article of footwear comprising:
an upper
a sole structure secured to the upper and including cushioning formed from a plurality of cells, wherein each cell in the plurality of cells includes a lattice of elongate structures that extend symmetrically around an offset axis, each offset axis being offset with respect to a vertical axis of its cell, and the elongate structures include:
a first elongate structure that defines a shear assembly configured to create a lateral shear as the lattice of elongate structures of each cell are compressed by a compressive force; and
a second elongate structure that defines a restorative assembly configured to return the lattice of elongate structures to a rest position as the compressive force is released, the restorative assembly driving creation of a restorative force on the upper of an article of footwear in response to the lateral shear.
2. The article of footwear of claim 1 , wherein the elongate structures of adjacent cells in the plurality of cells connect so that the plurality of cells form a unitary structure.
3. The article of footwear of claim 2 , wherein the unitary structure is formed via additive manufacturing.
4. The article of footwear of claim 1 , wherein the restorative force is exerted towards a medial side of the article of footwear.
5. The article of footwear of claim 1 , wherein the restorative force is exerted towards a forward footwear region of the article of footwear.
6. The article of footwear of claim 1 , wherein the elongate structures are segmented beams that each extend diagonally across a reference cube while winding around each other to provide rotational symmetry around the offset axis.
7. The article of footwear of claim 6 , wherein the offset axis extends through a vertical plane that substantially bisects opposing faces of the reference cube.
8. The article of footwear of claim 7 , wherein the vertical axis is a central vertical axis of the reference cube and the offset axis is disposed at an angle in a range of approximately 30 degrees to approximately 60 degrees from the central vertical axis of the reference cube.
9. The article of footwear of claim 6 , wherein the segmented beams each include four segments that are substantially straight and equally sized.
10. The article of footwear of claim 1 , wherein cells of the plurality of cells disposed in a first region of the article of footwear have elongate structures with a first thickness and cells of the plurality of cells disposed in a second region of the article of footwear have elongate structures with a second thickness, thicker than the first thickness, so that the second region provides a reduced amount of the lateral shear as compared to the first region.
11. The article of footwear of claim 1 , wherein the restorative assembly generates return energy to create the restorative force, the return energy being up to approximately 50% of compressive energy transferred to the cushioning by the compressive force.
12. The article of footwear of claim 1 , wherein the shear assembly comprises a horizontal V formed by the first elongate structure and the restorative assembly comprises a vertical V formed by the second elongate structure.
13. The article of footwear of claim 12 , wherein, in response to the compressive force, the vertical V of the restorative assembly compresses and an apex of the horizontal V of the shear assembly moves away from its respective restorative assembly to incrementally lengthen each cell of the plurality of cells.
14. The article of footwear of claim 1 , wherein the elongate structures of adjacent cells in the plurality of cells connect to form a uniform pattern across the cushioning.