Patent ID: 7731883

Claim:
A method of making tread elements for an article of footwear, comprising the steps of: pressing a matrix lining against a molding base by applying pressure from a first lug cavity rim and a second lug cavity rim on a first side of a central mold; placing a first rubber block and a second rubber block between a molding press and a second side of the central mold; compressing the first rubber block and the second rubber block between the molding press and the second side of the central mold, so that the first rubber block and the second rubber block liquefy; pressing the first lug cavity rim into the matrix lining to permanently form in the matrix lining a first outer periphery indentation having an inside perimeter and an outside perimeter; pressing the second lug cavity rim into the matrix lining to permanently form in the matrix lining a second outer periphery indentation having an inside perimeter and an outside perimeter; wherein first material associated with the first rubber block flows through a first injection cavity disposed in the central mold, the first injection cavity being in fluid communication with a first lug cavity; wherein second material associated with the second rubber block flows through a second injection cavity disposed in the central mold, the second injection cavity being in fluid communication with a second lug cavity; preventing, by pressing the first lug cavity rim into the matrix lining, the first material from escaping from the first lug cavity into the first outer periphery indentation; and preventing, by pressing the second lug cavity rim into the matrix lining, the second material from escaping from the second lug cavity into the second outer periphery indentation; wherein a first tread element formed by the first material has a base defined by the size and shape of the first lug cavity rim and is spaced from a second tread element formed by the second material having a base defined by the size and shape of the second lug cavity rim; wherein the base of the first tread element is disposed within the inside perimeter of the first outer periphery indentation and the base of the second tread element is disposed within the inside perimeter of the second outer periphery indentation; and wherein the matrix lining is exposed between the first tread element and the second tread element.