Golf club head with improved characteristic time

Abstract

A driver-type golf club head having a reduced strike face height and a reduced strike face thickness produces a greater golf ball launch speed while maintaining a conforming CT value. In addition, the driver-type golf club head preserves or improves the club head durability, ball flight path optimization, and forgiveness by careful club head mass distribution.

1 . A driver-type golf club head comprising:
 a club head body comprising:
 a crown, a front end, a rear end opposite the front end, a toe end, a heel end opposite the toe end, a sole opposite the crown, and a skirt forming the transition surface between the crown and the sole other than on the front end, each having an inner and outer surface; 
 a strike face located on the front end comprising a geometric center, and is defined by a bulge curvature and a roll curvature; 
 a body width, a body depth, and a body height; and 
 a body center of gravity; 
   wherein:   a loft plane is defined tangent to the geometric center;   a ground plane is defined tangent to the sole when the club head body is in an address position;   an x-axis is defined through the geometric center in a toe portion to heel portion direction parallel to the ground plane;   a y-axis is defined through the geometric center in a crown to sole direction perpendicular to the x-axis;   a z-axis is defined through the geometric in a front end to rear end direction perpendicular to both the x-axis and to the y-axis;   a y′-axis is defined through the center of gravity in a crown to sole direction parallel to the y-axis;   the bulge curvature is the curvature of the strike face in a heel-to-toe direction and comprises a bulge radius, and the roll curvature is the curvature of the strike face in a crown-to-sole direction and comprises a roll radius;   the strike face comprises a strike face perimeter defined at the point where the bulge radius and the roll radius deviate from the bulge curvature and roll curvature respectively;   the strike face perimeter comprises a top edge, a bottom edge, a toe edge, and a heel edge;   the strike face perimeter comprises a top edge point defined by the intersection of the top edge and a YZ plane defined by the y-axis and z-axis;   the strike face perimeter comprises a bottom edge point defined by the intersection of the bottom edge of the strike face perimeter and the YZ plane;   the strike face perimeter comprises a strike face length between 8.15 inches and 8.90 inches;   the strike face comprises a strike face height, measured between the top edge point and the bottom edge point parallel to the loft plane, and the strike face height is between about 1.40 inches and 1.80 inches;   the strike face comprises a strike face volume, measured as the volume bounded by a strike face front surface, a strike face rear surface, and the strike face perimeter projected perpendicular to the loft plane, and the strike face volume is between about 0.410 in 3  and 0.500 in 3 ;   the strike face comprises an area, measured as the area of the strike face front surface bounded by the strike face perimeter, and the strike face area is between about 4.0 and 5.0 in 2 ; and   the strike face comprises a thickness measured as the strike face volume divided by the strike face area, the strike face thickness is between about 0.085 and 0.100 inch.   
     
     
         2 . The driver-type golf club head of  claim 1 , wherein:
 an Iyy is measured as the moment of inertia about the y′-axis, and the Iyy ranges from about 4900 g*cm 2  to 5900 g*cm 2 ; and   a loft angle is defined by the loft plane and the y-axis, and the loft angle is in a range of 7.0 degrees to 16 degrees.   
     
     
         3 . The driver-type golf club head of  claim 1 , wherein:
 the body width is measured between a heelward-most point and a toeward-most point parallel to the x-axis, and the body width is between 4.6 inches and 5 inches;   the body depth is measured between a leading edge and a rearward-most point parallel to the z-axis, and the body depth is between 4.5 and 4.95 inches; and   the body height is measured between the ground plane and a highest point on the crown; and the body height is between about 2.3 and 2.8 inches.   
     
     
         4 . The driver-type golf club head of  claim 1 , wherein:
 a volume of the club head body is greater than about 440 cm 3 ;   a Y GP  is measured from the body center of gravity to the ground plane, parallel to the y-axis, and the Y GP  is between about 0.8 inch and 1.0 inch; and   a CGz is measured from the geometric center to the body center of gravity, parallel to the z-axis, the CGz is between about 1.60 and 1.85 inches.   
     
     
         5 . The driver-type golf club head of  claim 1 , wherein the strike face comprises a strike face width measured as the distance between a heelmost-point of the strike face perimeter to a toeward-most point of the strike face perimeter parallel to the x-axis, and the strike face width is between about 3.5 inches and 4.5 inches. 
     
     
         6 . The driver-type golf club head of  claim 2 , wherein the strike face comprises a top edge point height, measured between the top edge point and the ground plane and parallel to the y-axis, and the top edge point height is between about 1.85 inch and 2.20 inch. 
     
     
         7 . The driver-type golf club head of  claim 3 , wherein the strike face comprises a bottom edge point height, measured between the bottom edge point and the ground plane and parallel to the y-axis, and the bottom edge point height is between about 0.350 inch and 0.385 inch. 
     
     
         8 . The driver-type golf club head of  claim 4 , wherein the strike face comprises a face center height measured between the geometric center and the ground plane and parallel to the y-axis, and the face center height ranges from 1.10 to 1.30 inches. 
     
     
         9 . The driver-type golf club head of  claim 1 , wherein the club head body comprises a crown apex point located at a highest point on the crown in the YZ plane, the crown apex point comprises a height between about 2.15 inches and 2.45 inches measured between the crown apex point and the ground plane parallel to the y-axis. 
     
     
         10 . The driver-type golf club head of  claim 9 , wherein the crown apex point comprises a depth measured between the top edge point and the crown apex point parallel to the z-axis, and the crown apex point depth is between about 0.70 and 0.90 inch. 
     
     
         11 . The driver-type golf club head of  claim 10 , wherein the club head comprises a crown apex angle measured between a first imaginary line parallel to the z-axis and a second imaginary line which intersects both the crown apex point and the top edge point, and the crown apex angle ranges between 18 degrees and 23 degrees. 
     
     
         12 . The driver-type golf club head of  claim 11 , wherein the club head body comprises a sole apex point located at a lowest point on the sole in the YZ plane;
 the sole apex point comprises a depth measured from the bottom edge point to the sole apex point and parallel to the z-axis, and the sole apex point depth ranges from 0.60 to 0.67 inch.   
     
     
         13 . The driver-type golf club head of  claim 12 , wherein the club head body comprises a sole apex angle measured between a third imaginary line parallel to the z-axis and a fourth imaginary line which intersects both the sole apex point and the bottom edge point, and the sole apex angle ranges between 27 degrees and 32 degrees.