Golf club head

A golf club putter head, comprising:

• a golf club putter head geometric center;
• a golf club putter head center of gravity (CG) having a CG X-axis, a CG Y-axis, and a CG Z-axis;
• a top portion;
• a sole portion having a sole opening and a void extending to a portion of the top portion;
• a sole plate attached to the golf club putter head and closing the sole opening, the sole plate having a sole plate rear edge and a sole plate forward edge, wherein a portion of the sole plate rear edge is curved and located rearward of the CG, and a portion of the sole plate forward edge is straight and located forward of the CG;
• a face portion having a striking surface with a striking surface width and a geometric center separating a heel side and a toe side of the golf club putter head, and the face portion comprising a face portion heel side and a face portion toe side;
• a polymer face insert attached to a portion of the face portion;
• a ground center location located near a bottom edge of the face portion, a ground center X-axis, a ground center Y-axis, a ground center Z-axis;
• a back portion;
• a first toe side portion extending rearwardly from the face portion toe side and flaring outwardly from the striking surface thereby diverging from the ground center Y-axis, and a second toe side portion extending rearwardly from the first toe side portion and joining the back portion;
• a first heel side portion extending rearwardly from the face portion heel side and flaring outwardly from the striking surface thereby diverging from the ground center Y-axis, and a second heel side portion extending rearwardly from the first heel side portion and joining the back portion;
• wherein the second toe side portion and the second heel side portion converge toward one another;
• and
• wherein the golf club putter head has:
• a CGx location between −5.0 mm and 5.0 mm, as measured from a Y-Z plane passing through the ground center location;
• and
• a moment of inertia about the CG z-axis (Izz) that is at least 4,000 g·cm2 and no more than 14,000 g·cm2.

A golf club putter head, comprising:

• a golf club putter head geometric center;
• a top portion;
• a sole portion;
• a face portion having a striking surface with a striking surface width and a geometric center separating a heel side and a toe side of the golf club putter head, and the face portion comprising a face portion heel side and a face portion toe side;
• a ground center location located near a bottom edge of the face portion, a ground center X-axis, a ground center Y-axis, a ground center Z-axis;
• a golf club putter head center of gravity (CG) having a CG X-axis, a CG Y-axis, and a CG Z-axis;
• a back portion;
• a first toe side portion extending rearwardly from the face portion toe side and flaring outwardly from the striking surface thereby diverging from the ground center Y-axis, and a second toe side portion extending rearwardly from the first toe side portion and joining the back portion;
• a first heel side portion extending rearwardly from the face portion heel side and flaring outwardly from the striking surface thereby diverging from the ground center Y-axis, and a second heel side portion extending rearwardly from the first heel side portion and joining the back portion;
• wherein the second toe side portion and the second heel side portion converge toward one another;
• and
• a toe gap located between the striking surface and the back portion on the toe side, said toe gap creating a toe-opening extending through the sole portion and the top portion, the toe gap bounded by a toe side portion and a central body portion, at least a portion of the putter head bounding the toe gap comprising a steel alloy;
• a heel gap located between the striking surface and the back portion on the heel side, said heel gap creating a heel-opening extending through the sole portion and the top portion, the heel gap bounded by a heel side portion and a central body portion, at least a portion of the putter head bounding the heel gap comprising a steel alloy;
• a first weight and a second weight attached to the golf club putter head;
• and
• wherein the golf club putter head has:
• a CGx location between −5.0 mm and 5.0 mm, as measured from a Y-Z plane passing through the ground center location;
• a moment of inertia about the CG z-axis (Izz) that is at least 4,000 g·m2 and no more than 14,000 g·cm2;
• an effective footprint defined as an area occupied by an outermost silhouette of the golf club putter head projected onto an X-Y plane;
• an actual footprint less than the effective footprint, wherein the actual footprint is defined as an area occupied by an actual silhouette of the golf club putter head projected onto the X-Y plane, the actual footprint is 6,000-8,500 mm2;
• and
• a footprint ratio of 0.7-0.9, with the footprint ratio defined as the actual footprint divided by the effective footprint.