Patent ID: 6551200
Filing Date: 2003-04-22
Classification: A63B

Abstract:
A golf club head comprising:a body having a planar upper portion, said upper portion having a top edge and a substantially constant thickness, and a rearwardly extending lower portion, said lower portion having a bottom edge, wherein a front surface of said lower portion and a front surface of said upper portion together form a substantially planar striking face having a loft angle measured from a vertical axis, said striking face having a length, and wherein a rear side of said lower portion having at least a first recess adjacent a toe end and at least a second recess adjacent a heel end; wherein a lateral axis at the junction of said upper and lower portions of said body extends from said toe end to said heel end, with a reference point being defined at a mid portion of said lateral axis, between about 50% and about 75% of the height of the striking face, measured from said bottom edge to said top edge, said reference point being located less than about 70% of the face height if said loft angle is less than about 56 degrees, and wherein a central axis is defined substantially parallel to said lateral axis, at approximately 50% of the face height; wherein said first recess comprises a first volume and said second recess comprises a second volume, said first and second recesses extending downwardly at least to said central axis, and wherein the portions of the body that define said first and second recesses each have a stifffiess approximately the same as the stiffness of said upper portion, while the remainder of said lower portion has a stiffness at least 50% greater than the stiffness of said upper portion; wherein a central region of said lower portion, located below said reference point, has a maximum stiffness that is at least about 20 times the stiffness of said upper portion, and wherein regions located below said first and second recesses each have a maximum stiffness at least about 10 times the stiffness of said upper portion, wherein a stiffness zone is located within said central region, at said central axis and extending halfway toward said lateral axis, between said first and second recesses, at least about 10% of the length of said striking face, such that a relative stiffness is established between said central region and said upper portion and between said central region and said first and second recesses.