US Patent 8235844 Hollow golf club head

A hollow golf club incorporating a stress reducing feature including a crown located stress reducing feature, located on the crown of the club head, and a sole located stress reducing feature, located on the sole of the club head. The location and size of the stress reducing features, and their relationship to one another, play a significant role in reducing the peak stress seen on the golf club's face during an impact with a golf ball, as well as selectively increasing deflection of the face.