Golf club head

Abstract

A golf club head includes a loft between 20 degrees and 54 degrees and a main body including a top portion, a sole portion opposite the top portion, a heel portion, a toe portion opposite the heel portion, and a hosel portion extending from the heel portion. The hosel portion includes a hosel bore with an open end for receiving a golf club shaft and an abutment surface configured to support the golf club shaft, and an auxiliary recess extending sole-ward from the abutment surface, the auxiliary recess comprising a volume between 2 cubic centimeters and 3.5 cubic centimeters. The golf club head further includes a striking face defining a virtual face plane and having a face center, a virtual vertical plane perpendicular to the virtual face plane and extending through the face center, and a center of gravity spaced no more than 5 mm from the virtual vertical plane.

We claim: 
     
         1 . A golf club head that, when oriented in a reference position relative to a virtual ground plane, comprises:
 a loft between 20 degrees and 54 degrees;   a main body including:
 a top portion; 
 a sole portion opposite the top portion; 
 a heel portion; 
 a toe portion opposite the heel portion; 
 a hosel portion extending from the heel portion and including:
 a hosel bore with an open end for receiving a golf club shaft and an abutment surface configured to support the golf club shaft; 
 an auxiliary recess extending sole-ward from the abutment surface, the auxiliary recess comprising a volume between 2 cubic centimeters and 3.5 cubic centimeters; and 
 
 a striking face defining a virtual face plane and having a face center; 
   a virtual vertical plane perpendicular to the virtual face plane and extending through the face center; and   a center of gravity spaced no more than 5 mm from the virtual vertical plane.   
     
     
         2 . The golf club head of  claim 1 , wherein the main body is formed of a first material having a first melting point and a first density and the golf club head further comprises an auxiliary component formed of a second material having a second melting point greater than the first melting point and a second density less than the first density, the auxiliary component located at least in part within the auxiliary recess and at least partially encapsulated by the first material. 
     
     
         3 . The golf club head of  claim 2 , wherein the auxiliary component comprises a ceramic material. 
     
     
         4 . The golf club head of  claim 2 , wherein the second density is no greater than 2.5 g/cm 3 . 
     
     
         5 . The golf club head of  claim 2 , wherein the auxiliary component comprises a component mass, Ma, no less than 4.5 g. 
     
     
         6 . The golf club head of  claim 2 , wherein the auxiliary component comprises a component mass, Ma, no less than 5.0 g. 
     
     
         7 . The golf club head of  claim 2 , wherein the auxiliary component comprises a volume no less than 2.5 cc. 
     
     
         8 . The golf club head of  claim 1 , wherein the striking face further includes:
 a central region including the face center, the central region having a first average thickness;   an upper region above the central region, the upper region having a second average thickness;   a toe region toe-ward of the central region, the toe region having a third thickness;   an intermediate region at least partially surrounding the central region and disposed between the central region and each of the upper region and the toe region, the intermediate region having a fourth average thickness that is greater than the first average thickness, the second average thickness, and the third average thickness.   
     
     
         9 . The golf club head of  claim 1 , further comprising a cavity back style head. 
     
     
         10 . A set of golf club heads comprising:
 a first golf club head comprising:
 a first loft between 30 degrees and 54 degrees; and 
 a first main body including:
 a first top portion; 
 a first sole portion opposite the first top portion; 
 a first heel portion; 
 a first toe portion opposite the first heel portion; and 
 a first hosel portion extending from the first heel portion and including:
 a first hosel bore with a first open end for receiving a golf club shaft and a first abutment surface configured to support the golf club shaft; and 
 a first auxiliary recess extending sole-ward from the abutment surface, the first auxiliary recess comprising a volume greater than 2.25 cubic centimeters; 
 
 
   a second golf club head comprising:
 a second loft less than 30 degrees; and 
 a second main body including:
 a second top portion; 
 a second sole portion opposite the second top portion; 
 a second heel portion; 
 a second toe portion opposite the second heel portion; and 
 a second hosel portion extending from the second heel portion and including:
 a second hosel bore with a second open end for receiving a golf club shaft and a second abutment surface configured to support the golf club shaft; and 
 
 
   a second auxiliary recess extending sole-ward from the abutment surface, the second auxiliary recess comprising a volume less than 1 cubic centimeter.   
     
     
         11 . The set of golf club heads of  claim 10 , wherein the second main body further includes a striking face having a face center and including:
 a central region including the face center, the central region having a first average thickness;   an upper region above the central region, the upper region having a second average thickness;   a toe region toe-ward of the central region, the toe region having a third thickness;   an intermediate region at least partially surrounding the central region and disposed between the central region and each of the upper region and the toe region, the intermediate region having a fourth average thickness that is greater than the first average thickness, the second average thickness, and the third average thickness.   
     
     
         12 . The set of golf club heads of  claim 10 , wherein the second hosel bore and the second auxiliary recess extend along a hosel axis of the second hosel. 
     
     
         13 . The set of golf club heads of  claim 10 , wherein the first main body is formed of a first material having a first melting point and a first density and the first golf club head further comprises an auxiliary component formed of a second material having a second melting point greater than the first melting point and a second density less than the first density, the auxiliary component located at least in part within the first auxiliary recess and at least partially encapsulated by the first material. 
     
     
         14 . The set of golf club heads of  claim 10 , wherein the first golf club head and the second golf club head comprise cavity back style golf club heads. 
     
     
         15 . A method of forming a correlated set of golf club heads comprising:
 providing a first golf club head having a first striking face and a first hosel portion including a first hosel bore with a first open end for receiving a golf club shaft and a first abutment surface configured to support the golf club shaft, and an auxiliary recess extending sole-ward from the abutment surface, the auxiliary recess comprising a volume greater than 2.25 cubic centimeters;   applying a coating to at least the first striking face of the first golf club head;   applying a first media blast to the first striking face, the first media blast comprising aluminum oxide having a grit between 180 to 120;   providing a second golf club head having a second striking face and a second hosel portion including a second hosel bore with a second open end for receiving a golf club shaft and a second abutment surface configured to support the golf club shaft, and a secondary bore extending sole-ward from the abutment surface, the secondary bore comprising a volume less than 1 cubic centimeter;   applying the coating to at least the second striking face of the second golf club head; and   applying a second media blast to the second striking face, the second media blast comprising a mix of aluminum oxide and a ceramic media, the aluminum oxide having a grit between 180 and 120.   
     
     
         16 . The method of  claim 15 , wherein the coating comprises chrome plating. 
     
     
         17 . The method of  claim 15 , wherein the second media blast comprises a volumetric ratio of 8:1 to 10:1 aluminum oxide to ceramic media, respectively. 
     
     
         18 . The method of  claim 15 , wherein the correlated set of golf club heads comprise cavity back style golf club heads. 
     
     
         19 . The method of  claim 15 , wherein the first golf club head includes a first main body formed of a first material having a first melting point and a first density and the first golf club head further comprises an auxiliary component formed of a second material having a second melting point greater than the first melting point and a second density less than the first density, the auxiliary component located at least in part within the auxiliary recess and at least partially encapsulated by the first material. 
     
     
         20 . The method of  claim 15 , further comprising laser etching at least a portion of the first striking face of the first golf club head.