GOLF CLUB HEAD WITH IMPROVED INERTIA PERFORMANCE
A golf club head that is capable improving on the inertia properties of a golf club head all while also improving the Center of Gravity (CG) location is disclosed herein. More specifically, the golf club head in accordance with the present invention achieves a relative low Moment of Inertia (MOI) about the Z-axis (MOI-Z) as well as a relatively low MOI about the Shaft-axis (MOI-SA), all combined with a high MOI about the X and Y-axis (MOI-X and MOI-Y) and maintaining a consistently and relatively low CG location measured along a direction tangent to the hosel axis along the X-Y plane (CG-B).
1 . A golf club comprised of a golf club head, a shaft having a shaft axis coupled to the golf club head at a first end of the shaft and a grip coupled to the shaft at a second end of the shaft, wherein the golf club head comprises:
a frontal portion comprised of metal comprising a striking face having a face center located at a forward portion of said golf club head;
a non-metallic rear portion located aft of said striking face comprising a crown at an upper portion of said golf club head and a sole on a bottom portion of said golf club head; and
wherein an x-axis is defined as a horizontal axis tangent to said face center with a positive x direction towards a heel of said golf club head, a y-axis is a horizontal axis orthogonal to said x-axis with a positive x direction towards said crown, and a z-axis being orthogonal to both said x-axis and said y-axis with a positive z direction extending forward,
a plurality of support members extending from the crown to the sole of the rear portion and from a back edge toward a front edge of the rear portion, essentially perpendicular to the striking face, a first support member being located near a central portion of said golf club head in a heel-to-toe orientation, extending substantially in line, along the z-axis, with said face center; and
wherein said golf club head has a MOI-Y to MOI-Z ratio of greater than about 1.5.
2 . The golf club of claim 1 , wherein the first support member has a first maximum height parallel to the y-axis, a first maximum depth parallel to the z-axis and a first thickness and the first depth is greater than the first maximum height and the first thickness is between 0.5 mm and 1.5 mm.
3 . The golf club of claim 2 , wherein the first support member has a plurality of angled strut members that form angles α in between the strut members of between 30 degrees and 100 degrees.
4 . The golf club of claim 2 , wherein a second support member is on a toe side of the first support member, between 20% and 70% of a distance from the first support member and a furthest toe edge, and a third support member is on a heel side of the first support member, between 20% and 70% of a distance from the first support member and a furthest heel edge.
5 . The golf club of claim 4 , wherein the golf club head has a CG and a CG-C, being a distance the CG is back, parallel to the z-axis, from the shaft axis, of between 14 mm to 21 mm.
6 . The golf club of claim 5 , wherein said golf club head has a MOI-X to MOI-Z ratio of greater than about 1.20.
7 . A golf club comprised of a golf club head, a shaft having a shaft axis coupled to the golf club head at a first end of the shaft and a grip coupled to the shaft at a second end of the shaft, wherein the golf club head comprises:
a frontal portion comprised of metal, comprising a striking face having a face center located at a forward portion of said golf club head;
a rear portion comprising a thermoplastic material selected from the group consisting of polyetherimide, polyether ether ketone, polyphenylene sulfide, polysulfone, polyacryletherketone, polyetherketoneketone and polyvinyl chloride and located aft of said striking face comprising a crown at an upper portion of said golf club head and a sole on a bottom portion of said golf club head; and
wherein an x-axis is defined as a horizontal axis tangent to said face center with a positive x direction towards a heel of said golf club head, a y-axis is a horizontal axis orthogonal to said x-axis with a positive x direction towards said crown of said golf club head, and a z-axis being orthogonal to both said x-axis and said y-axis with a positive z direction extending forward,
at least one first weighting member located near a central portion of said golf club head in a heel-to-toe orientation, substantially in line along the z-axis with said face center; and
a plurality of support members comprising a thermoplastic material selected from the group consisting of polyetherimide, polyether ether ketone, polyphenylene sulfide, polysulfone, polyacryletherketone, polyetherketoneketone and polyvinyl chloride, and extending from the crown to the sole and from a back edge toward a front edge of the rear portion, extending essentially perpendicular to the striking face, a first support member being located near a central portion of said golf club head in the heel-to-toe orientation, extending substantially in line, along the z-axis, with said face center.
8 . The golf club of claim 7 , wherein said rear portion and the plurality of support members are comprised of polyphenylene sulfide having a crystallinity of greater than 40%.
9 . The golf club of claim 7 , wherein said rear portion and the plurality of support members are comprised of polyphenylene sulfide having a crystallinity between about 40% and 60%.
10 . The golf club of claim 7 , wherein said rear portion and the plurality of support members are comprised of polyphenylene sulfide having a crystallinity of greater than 40% and glass filler in an amount of between about 20% and 50%.
11 . A method of forming a golf club comprising the steps of:
forming a frontal portion comprised of a crown return, a sole return and a striking face, comprised of titanium;
forming a rear portion and a plurality of support members therein by:
forming a wax rear portion with a plurality of tabs on an inner surface thereof;
forming a plurality of wax support members;
coupling the wax support members to the plurality of tabs in the wax rear portion to form a final rear wax; and
using the final rear wax to cast the rear portion and the plurality of support members from titanium; and
welding the rear portion to the frontal portion.