US Patent 9079081 Iron head

An iron head includes a striking face; a backside surface; a sole surface; a hosel; a recess portion provided in an upper portion of the backside surface; a protruding portion provided at a lower portion of the backside surface and projecting backward; a first hollow portion provided on a heel side of the protruding portion; and a second hollow portion disposed on a toe side and inside the protruding portion. The protruding portion includes a middle portion between the first hollow portion and the second hollow portion. The first hollow portion is disposed away from the second hollow portion by a distance gradually increasing from an upper surface of the protruding portion toward the sole surface.