Golf club head

Abstract

Disclosed herein is a driver-type golf club head that has a strike face. The strike face has a central region, defined by a 40 mm by 20 mm rectangular area centered on a geometric center of the strike face and elongated in a heel-to-toe direction. The driver-type golf club head is configured such that after 500 impacts of a standard golf ball at the geometric center of the strike face, where at each impact the standard golf ball has a velocity of 52 meters per second, the CT of the strike face at any point within the central region is less than 256 microseconds and the CT at the geometric center of the strike face is no more than five microseconds different than the initial CT value.

1 . A driver-type golf club head, comprising:
 a forward portion, comprising a strike face;   a rearward portion, opposite the forward portion;   a crown portion;   a sole portion, opposite the crown portion;   a heel portion;   a toe portion, opposite the heel portion;   a hollow interior region defined by the forward portion, the rearward portion, the crown portion, the sole portion, the heel portion, and the toe portion;   at least one of a crown opening, formed in the crown portion, or a sole opening, formed in the sole portion, each one of the crown opening and the sole opening is open to the hollow interior region; and   an insert covering each one of the at least one crown opening, to form part of the crown portion, and the sole opening, to form part of the sole portion, the insert is made of a non-metal material having a density between about 1 g/cm 3  and about 2 g/cm 3 ;   wherein:
 the strike face is void of through-apertures open to the hollow interior region; 
 a volume of the driver-type golf club head is between 350 cm 3  and 500 cm 3 ; 
 the golf club head has a center-of-gravity (CG) with an x-axis coordinate, on an x-axis of a head center face origin coordinate system of the golf club head, between −7 mm and 7 mm and a y-axis coordinate, on a y-axis of the head center face origin coordinate system of the golf club head, between 25 mm and 50 mm, and a z-axis coordinate, on a z-axis of the head center face origin coordinate system of the golf club head, less than 2 mm; 
 the strike face of the forward portion has a central region, defined by a 40 mm by 20 mm rectangular area centered on a geometric center of the strike face and elongated in a heel-to-toe direction; 
 a summation of a moment of inertia of the golf club head about a z-axis of a head center-of-gravity coordinate system (Izz) and a moment of inertia of the golf club head about an x-axis of the head center-of-gravity coordinate system (Ixx) is between about 740 kg·mm 2  and about 1,100 kg·mm 2 ; 
 a characteristic time (CT) of the strike face, within the central region, is no more than 257 microseconds; 
 before the strike face impacts a golf ball, the CT of the strike face, at the geometric center of the strike face, has an initial CT value of at least 244 microseconds; and 
 the driver-type golf club head is configured such that after 500 impacts of a standard golf ball at the geometric center of the strike face, where at each impact the standard golf ball has a velocity of 52 meters per second, the CT of the strike face at any point within the central region is less than 256 microseconds and the CT at the geometric center of the strike face is no more than five microseconds different than the initial CT value. 
   
     
     
         2 . The driver-type golf club head according to  claim 1 , wherein:
 the strike face, the forward portion, at least part of the crown portion, at least part of the sole portion, at least part of the heel portion, and at least part of the toe portion form a one-piece monolithic construction and are made of the same material;   a minimum thickness of the forward portion at the strike face is between 1.5 mm and 2.5 mm;   a maximum thickness of the forward portion at the strike face is less than 3.7 mm; and   an interior surface of the forward portion, opposite the strike face, is not chemically etched and has an alpha case thickness of no more than 0.30 mm.   
     
     
         3 . The driver-type golf club head according to  claim 1 , wherein:
 the forward portion further comprises a strike plate that defines the strike face;   the forward portion comprises a plate opening;   the strike plate encloses the plate opening;   the strike plate is made of a first alloy of a metallic material, the first alloy having a first ultimate tensile strength;   the forward portion, other than the strike plate, is made of a second alloy of the metallic material, the second alloy having a second ultimate tensile strength that is less than the first ultimate tensile strength by at least 10%;   the first ultimate tensile strength is at least 1,000 MPa;   a minimum thickness of the strike plate is between 1.5 mm and 2.5mm;   a maximum thickness of the strike plate is less than 3.7 mm; and   an interior surface of the strike plate, opposite the strike face, is not chemically etched and has an alpha case thickness of no more than 0.30 mm.   
     
     
         4 . The driver-type golf club head according to  claim 3 , wherein the first ultimate tensile strength is at least 1,100 MPa. 
     
     
         5 . The driver-type golf club head according to  claim 3 , further comprising a body that defines the forward portion, other than the strike plate, wherein:
 the plate opening is formed in the body; and   the strike plate is one of welded, bonded, or brazed to the body.   
     
     
         6 . The driver-type golf club head according to  claim 1 , wherein:
 the forward portion further comprises a strike plate that defines the strike face;   the forward portion comprises a plate opening;   the strike plate encloses the plate opening; and   the strike plate is made of a non-metal material having a density between 1 g/cm 3  and 2 g/cm 3 .   
     
     
         7 . The driver-type golf club head according to  claim 6 , further comprising a body that defines the forward portion, other than the strike plate, wherein:
 the plate opening is formed in the body; and   the strike plate is adhered to the body.   
     
     
         8 . The driver-type golf club head according to  claim 6 , wherein the non-metal material of the strike plate comprises a fiber-reinforced polymer. 
     
     
         9 . The driver-type golf club head according to  claim 6 , wherein:
 the strike plate comprises a plurality of plies;   each one of the plies is made of the non-metal material; and   the strike plate has a variable thickness.   
     
     
         10 . The driver-type golf club head according to  claim 6 , wherein:
 the strike plate comprises a base portion and a cover applied onto the base portion;   the cover defines the strike face;   the base portion is made of a fiber-reinforced polymer; and   the cover is made of a fiber-less polymer.   
     
     
         11 . The driver-type golf club head according to  claim 10 , further comprising a body that defines the forward portion, other than the strike plate, wherein:
 the plate opening is formed in the body;   the strike plate is adhered to the body;   the fiber-less polymer comprises polyurethane;   the cover comprises grooves; and   a surface roughness of the cover is greater than a surface roughness of the body.   
     
     
         12 . The driver-type golf club head according to  claim 6 , wherein:
 a maximum thickness of the strike plate, within a preferred impact zone, is between 4.3 mm and 5.15 mm;   the preferred impact zone is centered at a geometric center of the strike face; and   the preferred impact zone has an ovular shape with a height of between 17 mm and 45 mm, in a crown-to-sole direction, and a length of between 28 mm and 65 mm, in a heel-to-toe direction.   
     
     
         13 - 14 . (canceled) 
     
     
         15 . The driver-type golf club head according to  claim 12 , wherein:
 the strike face comprises a toe edge region and a heel edge region outside of the preferred impact zone such that the preferred impact zone is between the toe edge region and the heel edge region;   the toe edge region is closer to the toe portion than the heel edge region;   the heel edge region is closer to the heel portion than the toe edge region;   a thickness of the strike plate transitions from the maximum thickness, within the preferred impact zone, to a toe edge region thickness, within the toe edge region, between 3.85 mm and 4.5 mm; and   the toe edge region thickness is less than the maximum thickness.   
     
     
         16 . The driver-type golf club head according to  claim 12 , wherein the preferred impact zone of the strike face has an area between 500 mm 2  and 1,800 mm 2 . 
     
     
         17 - 18 . (canceled) 
     
     
         19 . The driver-type golf club head according to  claim 6 , wherein:
 a thickness of the strike plate, within a preferred impact zone on the strike face, is variable; and   the preferred impact zone has an ovular shape with a height of between 17 mm and 45 mm, in a crown-to-sole direction, and a length of between 28 mm and 65 mm, in a heel-to-toe direction.   
     
     
         20 . The driver-type golf club head according to  claim 19 , wherein:
 the thickness of the strike plate, within the preferred impact zone, is between 3.5 mm and 5.0 mm;   the thickness of the strike plate, outside of the preferred impact zone, is between 3.5 mm and 4.2 mm; and   the thickness of the strike plate within the preferred impact zone is greater than the thickness of the strike plate outside of the preferred impact zone.   
     
     
         21 . (canceled) 
     
     
         22 . The driver-type golf club head according to  claim 6 , wherein:
 the forward portion further comprises a plate-opening recessed ledge that defines the plate opening;   the strike plate is seatably engaged with the plate-opening recessed ledge of the forward portion; and   the strike plate is adhesively bonded to the plate-opening recessed ledge.   
     
     
         23 . (canceled) 
     
     
         24 . The driver-type golf club head according to  claim 22 , wherein:
 the plate-opening recessed ledge defines a bonding surface to which the strike plate is adhesively bonded; and   a surface area of the bonding surface adhesively bonded to the strike plate is between 850 mm 2  and 1,800 mm 2 .   
     
     
         25 . The driver-type golf club head according to  claim 22 , wherein:
 the plate-opening recessed ledge defines a bonding surface to which the strike plate is adhesively bonded; and   a ratio of a surface area of the bonding surface adhesively bonded to the strike plate to a total surface area of an interior surface of the strike plate, opposite the strike face, is between 0.21 and 0.45.   
     
     
         26 . The driver-type golf club head according to  claim 22 , wherein:
 the strike plate is adhesively bonded to the plate-opening recessed ledge with a layer of adhesive;   the forward portion further comprises a sidewall angled relative to the plate-opening recessed ledge and defining a radially outer periphery of the plate-opening recessed ledge away from a center of the plate opening;   the layer of adhesive is interposed between the plate-opening recessed ledge and the strike plate and interposed between the sidewall and the strike plate;   a thickness of the layer of adhesive between the plate-opening recessed ledge and the strike plate is between 0.25 mm and 0.45 mm; and   a thickness of the layer of adhesive between the sidewall and the strike plate is between 0.15 mm and 0.25 mm.   
     
     
         27 . The driver-type golf club head according to  claim 22 , wherein:
 the strike plate is adhesively bonded to the plate-opening recessed ledge with a layer of adhesive;   the forward portion further comprises a sidewall angled relative to the plate-opening recessed ledge and defining a radially outer periphery of the plate-opening recessed ledge away from a center of the plate opening;   the layer of adhesive is interposed between the plate-opening recessed ledge and the strike plate and interposed between the sidewall and the strike plate; and   a thickness of the layer of adhesive between the plate-opening recessed ledge and the strike plate is greater than a thickness of the layer of adhesive between the sidewall and the strike plate.   
     
     
         28 - 109 . (canceled)