Upper for an article of footwear with auxetic configuration
An article of footwear includes an upper with openings arranged in an auxetic configuration. The upper includes at least two openings that differ in size. Regions of the upper with larger openings may expand more than regions of the upper with smaller openings.
1. An upper for an article of footwear, comprising:
a first region and a second region of the upper, wherein the second region is different from the first region;
a plurality of openings extending through a portion of a thickness of the upper, the plurality of openings arranged to provide the upper with an auxetic property, the plurality of openings including:
a first opening provided in the first region, the first opening having a first perimeter length;
a second opening provided in the second region, the second opening having a second perimeter length that is greater than the first perimeter length; and
an intermediate set of openings disposed between the first opening and the second opening; and
wherein the perimeter length of each of the plurality of openings progressively increases from the first perimeter length of the first opening to the second perimeter length of the second opening across the intermediate set of openings.
2. The upper according to claim 1 , wherein the auxetic property is a negative Poisson's ratio, such that if a portion of the upper is tensioned in a first direction, that portion expands from a neutral state to an expanded state both in the first direction and in a second direction that is orthogonal to the first direction.
3. The upper according to claim 2 , wherein the second region is characterized by a greater expansion in the second direction than that of the first region when exposed to a similar tension.
4. The upper according to claim 1 , wherein the first opening has a first opening boundary that includes:
a first vertex, a second vertex, a third vertex, a fourth vertex, a fifth vertex, and a sixth vertex;
a first edge extending from the first vertex to the second vertex;
a second edge extending from the second vertex to the third vertex;
a third edge extending from the third vertex to the fourth vertex;
a fourth edge extending from the fourth vertex to the fifth vertex;
a fifth edge extending from the fifth vertex to the sixth vertex; and
a sixth edge extending from the sixth vertex to the first vertex.
5. The upper according to claim 4 , wherein when in an undeformed state:
the first vertex has a corresponding first interior vertex angle that is greater than 180 degrees;
the second vertex has a corresponding second interior vertex angle that is less than 90 degrees;
the third vertex has a corresponding third interior vertex angle that is greater than 180 degrees;
the fourth vertex has a corresponding fourth interior vertex angle that is less than 90 degrees;
the fifth vertex has a corresponding fifth interior vertex angle that is greater than 180 degrees; and
the sixth vertex has a corresponding sixth interior vertex angle that is less than 90 degrees.
6. The upper according to claim 4 , wherein at least one of the first edge, the second edge, the third edge, the fourth edge, the fifth edge, and the sixth edge are curved.
7. The upper according to claim 1 , wherein the first region is adjacent a throat opening of the upper and the second region is part of a forefoot portion of the upper.
8. The upper according to claim 1 , wherein the first region is adjacent a throat opening of the upper and the second region is part of an arch portion of the upper.
9. The upper according to claim 1 , wherein the upper is made of two or more layers.
10. The upper according to claim 1 , wherein the second region is more proximate to a throat opening of the upper than is the first region.