US Patent 7704430 Method for making a tread assembly

A method for making an article of footwear is disclosed. The method can include a number of steps where various molds are used to attach or mold a tread element onto a substrate or matrix lining. The tread element can be formed by compressing a rubber block between various molding members to cause the resulting rubber material to flow through at least one injection cavity, which penetrates through holes in the matrix lining, into at least one lug cavity disposed on the side of the matrix lining opposite to the injection cavity. The rubber material eventually enters the lug cavity and becomes attached to the matrix lining.