US Patent 9138622 Multiple-material iron

The present invention discloses an iron-type golf club head formed from multiple materials that increase torsional stiffness of the club and aid in sound performance. In particular, the iron-type golf club head includes a body having top, sole, heel, toe, and face portions, a rear cavity, and a rear flange extending upwards from the sole portion, and a composite cap comprising a plurality of ribs covering the rear cavity and forming an internal cavity. The ribs can extend from an interior surface to an exterior surface of the composite cap, and in one embodiment, at least one of the ribs extends along an interior surface of the composite cap and hooks over the rear flange.