Patent Publication Number: US-6669577-B1

Title: Golf club head with a face insert

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     Not Applicable 
     FEDERAL RESEARCH STATEMENT 
     Not Applicable 
     BACKGROUND OF INVENTION 
     1. Field of the Invention 
     The present invention relates to a golf club head. More specifically, the present invention relates to a golf club head with a face insert. 
     2. Description of the Related Art 
     High performance drivers employ relatively thin, high strength face materials. These faces are either formed into the curved face shape then welded into a driver body component around the face perimeter, or forged into a cup shape and connected to a body by either welding or adhesive bonding at a distance offset from the face of up to 0.75 inch. The faces formed from sheet material have an advantage in slightly superior material properties over cup-shape faces forged from round bar, and noticeably lower production costs. 
     However, in the formed sheet approach, the position of the weld and the structural characteristics of the surrounding body component have greater bearing on the stiffness of the face than with cup-shape faces. The stiffness of the face affects both the performance of the face-in terms of golf ball rebound speed and the durability of the face under repeated impact loading. 
     In a popular embodiment of the sheet-formed face insert driver, the weld between the formed face insert and the investment cast driver body is located on the striking face, a small distance from the face perimeter. 
     It is common practice for the face insert to be of uniform thickness and to design the surrounding driver body component to be of equal thickness. In this way there is continuity of face thickness across the weld. 
     Several patents discloses face inserts. Anderson, U.S. Pat. Nos. 5,624,437, 5,094,383, 5,255,918, 5,261,663 and 5,261,664 disclose a golf club head having a full body composed of a cast metal material and a face insert composed of a hot forged metal material. 
     Viste, U.S. Pat. No. 5,282,624 discloses a golf club head with a cast metal body and a forged steel face insert with grooves on the exterior surface and the interior surface of the face insert and having a thickness of 3 mm. 
     Rogers, U.S. Pat. No. 3,970,236, discloses an iron club head with a formed metal face plate insert fusion bonded to a cast iron body. 
     Galloway, et alii, U.S. Pat. No. 6,354,962 discloses a golf club head of a face cup design. 
     However, none of the prior art patents disclose a means for achieving material properties and cost savings of the face inserts with the performance properties of the face-cup design. 
     SUMMARY OF INVENTION 
     The present invention overcomes the problems of the prior art by providing a golf club head that has a body with a striking plate insert in which the body has a front wall perimeter region that is thinner than the striking plate insert. This allows the golf club head of the present invention to have similar performance to a golf club head with a face cup design while having the material properties and cost savings of a golf club head with a face insert. 
     Having briefly described the present invention, the above and further objects, features and advantages thereof will be recognized by those skilled in the pertinent art from the following detailed description of the invention when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is an exploded view of the components of a preferred embodiment of the golf club head of the present invention. 
     FIG. 2 is a front view of a golf club head of the present invention. 
     FIG. 3 is a top plan view of a golf club head of the present invention. 
     FIG. 4 is a side view of the heel end of a golf club head of the present invention. 
     FIG. 5 is side view of the toe end of a golf club head of the present invention. 
     FIG. 6 is a bottom plan view of a golf club head of the present invention. 
     FIG. 7 is a rear view of a golf club head of the present invention. 
     FIG. 8 a front view of a golf club head of the present invention showing the perimeter region in dashed lines. 
     FIG. 9 is a cross-sectional view along line  9 — 9  of FIG.  3 . 
    
    
     DETAILED DESCRIPTION 
     As shown in FIGS. 1-8, the golf club head of the present invention is generally designated  20 . The golf club head  20  of FIGS. 1-8 is a driver; however, the golf club head of the present invention may alternatively be a fairway wood. The golf club head  20  has a body  22  that is preferably composed of a metal material such as titanium, titanium alloy, stainless steel, or the like, and is most preferably composed of a cast titanium alloy material. The body  22  is preferably cast from molten metal in a method such as the well-known lost-wax casting method. The metal for casting is preferably titanium or a titanium alloy such as 6-4 titanium alloy, alpha-beta titanium alloy or beta titanium alloy for forging, and 6-4 titanium for casting. Alternatively, the body  22  is composed of 17-4 steel alloy. Additional methods for manufacturing the body  22  include forming the body  22  from a flat sheet of metal, super-plastic forming the body  22  from a flat sheet of metal, machining the body  22  from a solid block of metal, electrochemical milling the body from a forged pre-form, and like manufacturing methods. 
     The golf club head  20 , when designed as a driver preferably has a volume from 200 cubic centimeters to 600 cubic centimeters, more preferably from 300 cubic centimeters to 450 cubic centimeters, and most preferably from 350 cubic centimeters to 420 cubic centimeters. A golf club head  20  for a driver with a body  22  composed of a cast titanium alloy most preferably has a volume of 380 cubic centimeters. Alternatively, when the golf club head  20  is designed as a driver with a body  22  composed of stainless steel, the golf club head preferably has a volume of 275 cubic centimeters. The volume of the golf club head  20  will also vary between fairway woods (preferably ranging from 3-woods to eleven woods) with smaller volumes than between drivers. 
     The golf club head  20 , when designed as a driver preferably has a mass no more than 215 grams, and most preferably a mass of 180 to 215 grams. When the golf club head  20  is designed as a fairway wood, the golf club head preferably has a mass of 135 grams to 180 grams, and preferably from 140 grams to 165 grams. 
     The body  22  has a crown  24 , a sole  26 , a ribbon  28 , and a front wall  30  with an opening  32 . The body  22  preferably has a hollow interior  34 . The golf club head  20  has a heel end  36 , a toe end  38  an aft end  37 . A shaft, not shown, is placed within a hosel, not shown, at the heel end  36 . In a preferred embodiment, the hosel is internal to the body  22 , and the shaft extends to the sole  30 . 
     The golf club head also has striking plate insert  40  that is attached to the body  22  over the opening  32  of the front wall  30 . The striking plate insert  40  preferably is composed of a formed titanium or steel material. Such titanium materials include pure titanium and titanium alloys such as 6-4 titanium alloy, SP-700 titanium alloy (available from Nippon Steel of Tokyo, Japan), DAT 55G titanium alloy available from Diado Steel of Tokyo, Japan, Ti 10-2-3 Beta-C titanium alloy available from RTI International Metals of Ohio, and the like. Other metals for the striking plate insert  40  include high strength steel alloy metals and amorphous metals. Such steel materials include 17-4PH, Custom 450, 455,465 and 465+ stainless steels, AERMET 100 and AERMET 310 alloy steels, all available from Carpenter Specialty Alloys, of Pennsylvania, and C35 maraging steels available from Allvac of North Carolina. Such amorphous metals include beryllium based alloys such as disclosed in U.S. Pat. No. 5,288,344, which pertinent parts are hereby incorporated by reference, quinary metallic glass alloys such as disclosed in U.S. Pat. No. 5,735,975, which pertinent parts are hereby incorporated by reference, and ternary alloys as disclosed in  Calculations of Amorphous - Forming Composition Range For Ternary Alloy Stems And Analyses Of Stabilization Of Amorphous Phase And Amorphous - Forming Ability, Takeuchi and Inoue,  Materials Transactions, Vol. 42, No. 7, p 1435-1444 (2001), which pertinent parts are hereby incorporated by reference. A striking plate insert  40  composed of an amorphous metal is attached through electron beam welding, brazing or press-fitted for attachment to the body  22 . As shown in FIG. 1, the striking plate insert  40  typically has a plurality of scorelines  45  thereon. 
     As shown in FIG. 1, the striking plate insert  40  is welded to the front wall  30  of the body  22 , thereby covering the opening  32 . A plurality of tabs  47 , preferably three, align the striking plate insert  40  for the welding process. Alternatively, the striking plate insert  40  is press-fitted into the opening  32 . 
     In a preferred embodiment, the striking plate insert  40  has uniform thickness that ranges from 0.040 inch to 0.250 inch, more preferably a thickness of 0.080 inch to 0.120 inch, and is most preferably 0.108 inch for a titanium alloy striking plate insert  40  and 0.085 inch for a stainless steel striking plate insert  40 . 
     The present invention is directed at a golf club head that has a high coefficient of restitution thereby enabling for greater distance of a golf ball hit with the golf club head of the present invention. The coefficient of restitution (also referred to herein as COR) is determined by the following equation: 
     
       
           E =( V   2   −V   1)/(   U   1−   U   2 ) 
       
     
     wherein U 1  is the club head velocity prior to impact; U 2  is the golf ball velocity prior to impact which is zero; V 1  is the club head velocity just after separation of the golf ball from the face of the club head; V 2  is the golf ball velocity just after separation of the golf ball from the face of the club head; and E is the coefficient of restitution between the golf ball and the club face. 
     The values of E are limited between zero and 1.0 for systems with no energy addition. The coefficient of restitution, E, for a material such as a soft clay or putty would be near zero, while for a perfectly elastic material, where no energy is lost as a result of deformation, the value of E would be 1.0. The present invention provides a club head  20  preferably having a coefficient of restitution ranging from 0.81 to 0.94, as measured under conventional test conditions. The coefficient of restitution of the club head  20  of the present invention under standard USGA test conditions with a given ball preferably ranges from approximately 0.80 to 0.94, more preferably ranges from 0.82 to 0.89 and most preferably 0.843. 
     The depth of the club head  20  from the striking plate insert  40  to the aft-end  37  preferably ranges from 3.0 inches to 4.5 inches, and is most preferably 3.75 inches. 
     The height, H, of the club head  20 , as measured while in address position, preferably ranges from 2.0 inches to 3.5 inches, and is most preferably 2.50 inches or 2.9 inches. The width, W, of the club head  20  from the toe end  38  to the heel end  36  preferably ranges from 4.0 inches to 5.0 inches, and more preferably 4.7 inches. 
     The front wall  30  has a perimeter region  50  encompassing the opening  32 . The perimeter region extends from the opening  32  to the perimeter  73  of the front wall  30 . The perimeter  73  of the front wall  30  is defined as the transition point where the front wall  30  transitions from a plane substantially parallel to the striking plate insert  40  to a plane substantially perpendicular to the striking plate insert  40 . Alternatively, one method for determining the transition point is to take a plane parallel to the striking plate insert  40  and a plane perpendicular to the striking plate insert  40 , and then take a plane at an angle of forty-five degrees to the parallel plane and the perpendicular plane. Where the forty-five degrees plane contacts the front wall  30  is the transition point thereby defining the perimeter of the front wall  30 . 
     The perimeter region  50  has a reduced thickness in order to provide a stepped thickness for the impact portion of the golf club head  20 , including the striking plate insert  40 . The perimeter region  50  preferably has a uniform thickness that ranges from 0.040 inch to 0.190 inch, more preferably a thickness of 0.070 inch to 0.0110 inch, and most preferably a thickness of 0.090 inch to 0.105 inch. Alternatively, the perimeter region  50  has a thickness that varies with the thinnest portions away from the striking plate insert  40 . However, the thickness of the perimeter region  50  is always less than the thickness of the striking plate insert  40 . In a preferred embodiment, the thickness of the perimeter region is 0.098 inch. 
     
       
         
           
               
               
               
               
             
               
                 TABLE ONE 
               
               
                   
               
               
                   
                   
                   
                 Durability 
               
               
                 Driver 
                 Thickness 
                 COR 
                 Hits to Failure 
               
               
                   
               
             
            
               
                 Invention 
                 Insert = .108″ 
                 0.843 
                 2500 
               
               
                   
                 Perimeter Region = .098″ 
               
               
                 Standard (i) 
                 Insert = .108″ 
                 0.828 
                 3000 
               
               
                   
                 Perimeter Region = .108″ 
               
               
                 Standard (ii) 
                 Insert = .096″ 
                 0.843 
                 1800 
               
               
                   
                 Perimeter Region = .096″ 
               
               
                   
               
            
           
         
       
     
     Table One illustrates the novelty of the present invention as compared to the prior art. The prior art golf club heads are referenced as Standard (i) and Standard (ii) in Table One. The golf club head  20  of the present invention is referenced as Invention. The prior art club heads have equal thickness from the insert and the perimeter region whereas the golf club head  20  of the present invention has a perimeter region  50  that is thinner than the striking plate insert  40 . Thus, the golf club head  20  of the present invention can achieve a higher COR than a golf club head of the prior art with the same insert thickness. Further, the golf club head  20  of the present invention has greater durability than a golf club head of the prior art with a similar perimeter region thickness. 
     The center of gravity and the moments of inertia of the golf club head  20  may be calculated as disclosed in co-pending U.S. patent application Ser. No. 09/796,951, filed on Feb. 27, 200, now U.S. Pat. No. 6,607,452 entitled High Moment Of Inertia Composite Golf Club, and hereby incorporated by reference in its entirety. In general, the moment of inertia, Izz, about the Z axis for the golf club head  20  will preferably range from 2700 g-cm 2  to 4000 g-cm 2 , more preferably from 3000 g-cm 2  to 3800 g-cm  2 . The moment of inertia, Iyy, about the Y axis for the golf club head  20  will preferably range from 1500 g-cm 2  to 3500 g-cm 2 . 
     From the foregoing it is believed that those skilled in the pertinent art will recognize the meritorious advancement of this invention and will readily understand that while the present invention has been described in association with a preferred embodiment thereof, and other embodiments illustrated in the accompanying drawings, numerous changes, modifications and substitutions of equivalents may be made therein without departing from the spirit and scope of this invention which is intended to be unlimited by the foregoing except as may appear in the following appended claims. Therefore, the embodiments of the invention in which an exclusive property or privilege is claimed are defined in the following appended claims.