Golf club head with flexible sole

Abstract

Described herein are embodiments of golf club heads with flexible soles. In one embodiment, the golf club head includes a body having a crown opposite a sole, a toe opposite a heel, a back end opposite a front end, and a hosel. The golf club head also includes a sole curvature profile comprising a radius of curvature that varies as the sole curvature profile extends between the front end and the back end. The radius of curvature is configured to increase the flexure of the entire golf club head, thereby increasing the internal energy of the golf club head.

1 . A golf club head comprising:
 a body having a front end;   a back end opposite the front end;   a crown;   a sole opposite the crown, the sole defining a sole surface;   wherein a ground plane is tangent to the sole surface when the golf club head is at an address position to strike a golf ball;   a heel;   a toe opposite the heel, and a hosel structure having a hosel axis extending centrally through a bore in the hosel structure;   an internal cavity;   a strikeface positioned at the front end and defining a geometric center, and a loft plane tangent to the geometric center;   wherein the body comprises a composite material;   wherein the geometric center further defines a coordinate system having the geometric center;   the coordinate system comprising an X axis extending through the geometric center between the heel and the toe;   a Y axis extending through the geometric center and perpendicular to the X axis, between the crown and the sole;   a Z axis extending through the geometric center and perpendicular to the X axis and to the Y axis, between the front end and the back end;   the X axis and the Z axis together define an XZ plane extending between the heel and toe and between the front end and the back end;   the Y axis and the Z axis together define a YZ plane extending between the crown and the sole and between the front end and the back end;   a sole transition point defined by an intersection of the sole and the strikeface;   
       an indented region;
 wherein the indented region is defined where the sole veers inward in a direction toward the internal cavity; 
 the indented region comprises a sole curvature profile defined by an intersection of the sole surface and the YZ plane; 
 
       wherein the sole curvature profile comprises a first inflection point and a second inflection point; 
       wherein the sole curvature profile comprises a first concave section extending from the sole transition point to the first inflection point and is concave relative to the XZ plane; 
       a convex section extending from the first inflection point to the second inflection point and is convex relative to the XZ plane; 
       a second concave section extending from the second inflection point to the back end and is concave relative to the XZ plane; 
       wherein:
 the first concave section comprises a radius of curvature (R3); 
 the convex section comprises a radius of curvature (R4); 
 the second concave section comprises a radius of curvature (R5); 
 
       a first inflection point depth is measured in the direction perpendicular to the loft plane between the loft plane and the first inflection point; 
       wherein a first inflection point depth ratio refers to a ratio of the first inflection point depth to a depth of the golf club head; and wherein the first inflection point depth ratio is between 0.25-0.45. 
     
     
         2 . The golf club head of  claim 1 , wherein the depth of the first inflection point is between 0.50-2.50 inches. 
     
     
         3 . The golf club head of  claim 1 , wherein no portion of the sole intersected by the YZ plane includes a radius of curvature greater than 10 inches between the front end and the back end. 
     
     
         4 . The golf club head of  claim 1 , wherein the radius of curvature R3 and the radius of curvature R5 are each equivalent or greater than R4. 
     
     
         5 . The golf club head of  claim 1 , wherein the radius of curvature R3 is at least twice of the radius of curvature R4. 
     
     
         6 . A golf club head comprising:
 a body having a front end;   a back end opposite the front end;   a crown;   a sole opposite the crown, the sole defining a sole surface;   wherein a ground plane is tangent to the sole surface when the golf club head is at an address position to strike a golf ball;   a heel;   a toe opposite the heel, and a hosel structure having a hosel axis extending centrally through a bore in the hosel structure;   an internal cavity;   a strikeface positioned at the front end and defining a geometric center, and a loft plane tangent to the geometric center;   wherein the body comprises a composite material;   wherein the geometric center further defines a coordinate system having the geometric center;   the coordinate system comprising an X axis extending through the geometric center between the heel and the toe;   a Y axis extending through the geometric center and perpendicular to the X axis, between the crown and the sole;   a Z axis extending through the geometric center and perpendicular to the X axis and to the Y axis, between the front end and the back end;   the X axis and the Z axis together define an XZ plane extending between the heel and toe and between the front end and the back end;   the Y axis and the Z axis together define a YZ plane extending between the crown and the sole and between the front end and the back end;   a sole transition point defined by an intersection of the sole and the strikeface;   an indented region;   wherein the indented region is defined where the sole veers inward in a direction toward the internal cavity;   the indented region comprises a sole curvature profile defined by an intersection of the sole surface and the YZ plane;   
       wherein the sole curvature profile comprises a first inflection point and a second inflection point; 
       wherein the sole curvature profile comprises a first concave section extending from the sole transition point to the first inflection point and is concave relative to the XZ plane; 
       a convex section extending from the first inflection point to the second inflection point and is convex relative to the XZ plane; 
       a second concave section extending from the second inflection point to the back end and is concave relative to the XZ plane; 
       wherein:
 the first concave section comprises a radius of curvature (R3); 
 the convex section comprises a radius of curvature (R4); 
 the second concave section comprises a radius of curvature (R5); 
 
       a first inflection point depth is measured in the direction perpendicular to the loft plane between the loft plane and the first inflection point; 
       wherein a first inflection point depth ratio refers to a ratio of the first inflection point depth to a depth of the golf club head; and wherein the first inflection point depth ratio is between 0.25-0.45; 
       the sole curvature profile comprises a nadir and nadir depth ratio; 
       the nadir represents a point on the sole curvature profile that is closest to the XZ plane; 
       the nadir is located on the convex section; 
       wherein the nadir depth ratio is defined as a ratio of a depth of the nadir to a depth of the golf club head; and wherein the nadir depth ratio is between 0.4 and 0.5. 
     
     
         7 . The golf club head of  claim 6 , wherein the depth of the first inflection point is between 0.50-2.50 inches. 
     
     
         8 . The golf club head of  claim 6 , wherein no portion of the sole intersected by the YZ plane includes a radius of curvature greater than 10 inches between the front end and the back end. 
     
     
         9 . The golf club head of  claim 6 , wherein the nadir depth ratio is between 0.45 and 0.60. 
     
     
         10 . The golf club head of  claim 6 , wherein the depth of the nadir is between 2.5 and 3.0 inches. 
     
     
         11 . A golf club head comprising:
 a body having a front end;   a back end opposite the front end;   a crown;   a sole opposite the crown, the sole defining a sole surface;   wherein a ground plane is tangent to the sole surface when the golf club head is at an address position to strike a golf ball;   a heel;   a toe opposite the heel, and a hosel structure having a hosel axis extending centrally through a bore in the hosel structure;   an internal cavity;   a strikeface positioned at the front end and defining a geometric center, and a loft plane tangent to the geometric center;   wherein the body comprises a composite material;   wherein the geometric center further defines a coordinate system having the geometric center;   the coordinate system comprising an X axis extending through the geometric center between the heel and the toe;   a Y axis extending through the geometric center and perpendicular to the X axis, between the crown and the sole;   a Z axis extending through the geometric center and perpendicular to the X axis and to the Y axis, between the front end and the back end;   the X axis and the Z axis together define an XZ plane extending between the heel and toe and between the front end and the back end;   the Y axis and the Z axis together define a YZ plane extending between the crown and the sole and between the front end and the back end;   a sole transition point defined by an intersection of the sole and the strikeface;   an indented region;   wherein the indented region is defined where the sole veers inward in a direction toward the internal cavity;   the indented region comprises a sole curvature profile defined by an intersection of the sole surface and the YZ plane;   
       wherein the sole curvature profile comprises a first inflection point and a second inflection point; 
       wherein the sole curvature profile comprises a first concave section extending from the sole transition point to the first inflection point and is concave relative to the XZ plane; 
       a convex section extending from the first inflection point to the second inflection point and is convex relative to the XZ plane; 
       a second concave section extending from the second inflection point to the back end and is concave relative to the XZ plane; 
       wherein:
 the first concave section comprises a radius of curvature (R3); 
 the convex section comprises a radius of curvature (R4); 
 the second concave section comprises a radius of curvature (R5); 
 
       a first inflection point depth is measured in the direction perpendicular to the loft plane between the loft plane and the first inflection point; 
       wherein a first inflection point depth ratio refers to a ratio of the first inflection point depth to a depth of the golf club head; and wherein the first inflection point depth ratio is between 0.25-0.45;
 the sole curvature profile further comprises a nadir, and a nadir height ratio; 
 the nadir represents a point on the sole curvature profile that is closest to the XZ plane; 
 the nadir is located on the convex section; 
 
       the nadir height ratio is defined as the ratio of the nadir height to the radius of curvature (R3) of the first concave section; and wherein the nadir height ratio is less than 0.33. 
     
     
         12 . The golf club head of  claim 11 , wherein the depth of the first inflection point is between 0.5-2.5 inches. 
     
     
         13 . The golf club head of  claim 11 , wherein no portion of the sole intersected by the YZ plane includes a radius of curvature greater than 10 inches between the front end and the back end. 
     
     
         14 . The golf club head of  claim 11 , wherein the nadir height ratio is less than 0.30.