Golf club head

A golf club putter head comprising:

• a top portion, a sole portion, a front portion with a striking surface, a heel side portion, and a toe side portion, wherein the heel side portion and the toe side portion extend rearwardly from the front portion and initially diverge outwardly from the front portion before converging toward one another;
• a central portion extending rearwardly from the front portion with a toe side gap separating a portion of the central portion from the toe side portion and extending through the sole portion and the top portion, and a heel side gap separating a portion of the central portion from the heel side portion and extending through the sole portion and the top portion;
• a face portion plane intersects a horizontal ground plane to define a ground center location, a ground center X-axis, and a ground center Y-axis, with the ground center Y-axis separating a toe-side of the putter head from a heel-side of the putter head;
• a center of gravity having a CG x-axis, a CG y-axis, and a CG z-axis;
• a putter head geometric center;
• a heel side outboard extension extending from the heel side portion and located at least partially behind a geometric center vertical plane containing the putter head geometric center and is parallel to the ground center X-axis;
• a toe side outboard extension extending from the toe side portion and located at least partially behind the geometric center vertical plane;
• a forward maximum external perimeter width between the opposed heel side portion and the toe side portion, measured parallel to the ground center X-axis, located at a forward maximum width location between the geometric center vertical plane and the striking surface;
• a forward minimum external perimeter width between the opposed heel side portion and the toe side portion, measured parallel to the ground center X-axis, located at a forward minimum width location closer to the striking surface than the forward maximum width location, where the forward minimum external perimeter width is less than the forward maximum external perimeter width;
• a rearward maximum external perimeter width between a heelwardmost point on the heel side outboard extension and a toewardmost point on the toe side outboard extension, measured parallel to the ground center X-axis;
• a rearward minimum external perimeter width between the opposed heel side portion and the toe side portion, measured parallel to the ground center X-axis, located at a rearward minimum width location rearward of the forward maximum width location and forward of the rearward maximum external perimeter width, where the rearward minimum external perimeter width is less than the forward maximum external perimeter width, and the rearward minimum external perimeter width is less than the rearward maximum external perimeter width;
• wherein:
• a moment of inertia about the CG z-axis (Izz) of 4000-14000 g·cm2;
• an effective footprint defined as an area occupied by an outermost silhouette of the golf club putter head projected onto a X-Y plane;
• an actual footprint less than the effective footprint, and the actual footprint defined as the area occupied by an actual silhouette of the golf club putter head projected onto the X-Y plane;
• and
• a footprint ratio of 0.7-0.9, with the footprint ratio defined as the actual footprint divided by the effective footprint.

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 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 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 central gap creating an opening extending through the sole portion and the top portion, wherein the central gap has a central gap geometric center and the central gap geometric center is positioned rearward of the head center of gravity;
• and
• wherein the golf club putter head has:
• a CGy location of no more than 50 mm as measured from the ground center location along the ground center Y-axis;
• 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;
• 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;
• and
• a footprint ratio of 0.7-0.9, with the footprint ratio defined as the actual footprint divided by the effective footprint.

A golf club putter head, comprising:

• a golf club putter head geometric center;
• a 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 formed of a sole portion material;
• 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 located rearward of the CG, a portion of the sole plate forward edge is located forward of the CG, and the sole plate is formed of a sole plate material different than the sole portion material;
• 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 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 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;
• 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;
• 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 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.