Method and apparatus for injection moulding rubber soles having at least two layers

Abstract From the Canadian patent

Process for injection moulding rubber or rubber-mixture soles having at least two layers and connecting them to one another and if required to a shoe upper. First the rubber mixture for the bottom sole layer is injected into an enlarged mould cavity and the latter is made smaller to match the volume of the bottom sole layer; once the rubber mixture has partially solidified the upper delimitation means for the bottom sole layer is removed and is replaced by a last. The rubber mixture for the inner sole layer is infected into the thus created mould cavity. By displacing the bottom sole layer upwards, the mould cavity is made smaller to match the size of the inner sole layer; after partial …