Abstract:
A golf club head has a main body portion formed by an investment casting of material such as stainless steel, beryllium copper, titanium, and aluminum. The face plate of the head is formed of a forged metal, such as forged carbon steel, this plate being welded to the face portion of the casting to form an integral assembly therewith. The forged metal face plate affords a more solid impact and feel to the club which provides better control. Also, it has very high strength. Preferably, the head consists of cast stainless steel, and the face plate of forged stainless steel, both steels being of the same composition. Face plate metal is preferably re-distributed toward the toe and heel of the head.

Description:
This application is a continuation-in-part of application Ser. No. 549,973, filed Jul. 9, 1990 , now U.S. Pat. No. 5,094,38 which is a continuation-in-part of application, Ser. No. 492,973 filed Mar. 13, 1990, now U.S. Pat. No. 5,024,437 which is a continuation-in-part of Ser. No. 364,698 filed Jun. 12, 1989 now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to golf clubs and more particularly to an improved face plate construction for a golf club head. 
     The heads of golf clubs are generally formed in a one-piece casting of durable materials, such as stainless steel, beryllium copper, aluminum, etc. A head of this type is described in U.S. Pat. No. 4,021,047 issued May 3, 1977, to R. J. Mader. The use of face plates made of a different material than that of the main body of the club head has been disclosed in the prior art in both irons and &#34;wood&#34;-type drivers, which are often made of cast metal. Such prior art club heads are described in U.S. Pat. No. 4,792,140 issued Dec. 20, 1988, to Yamaguchi et al.; U.S. Pat. No. 4,534,558 issued Aug. 13, 1985, to Yoneyama; U.S. Pat. No. 3,218,072 issued Nov. 16, 1965, to Burr; and British Patent No. 1.227.948 issued Apr. 15, 1971, to Haines et al. In the heads of all of these prior art patents, the face plate is of a plastic material, such as a resin or a carbon fiber composite. It has been found that the use of a forged metal for the face plate of the club head results in a stronger head and in a more solid impact with a golf ball and better &#34;feel&#34; which provides better ball flight control. However, forged metal is not amenable to casting, which mitigates against its use for forming the entire head. Also, forged metal tends to have a high density which would make for a club head having excessive weight. 
     SUMMARY OF THE INVENTION 
     The golf club head of the present invention provides an improvement over prior art heads in that it utilizes a face plate of forged metal. This end result is achieved without greatly increasing the cost or weight of the driving head by forming the main body of the head in an investment casting of a material such as stainless steel, beryllium copper, titanium, or aluminum, and then attaching a face plate of a forged metal selected from the class consisting of forged carbon steel, forged stainless steel, forged beryllium copper, and forged titanium, by suitable means such as welding. 
     It has been found that forged metal face plates have an inherently greater strength than cast metal face plates with a more uniform hardness over the hitting area of the plate. This is in view of the low porosity, high density and homogeneous grain structure of such a material which makes for a more solid plate. On the other hand, cast metal is desirable for the main body of the club head in view of its lighter weight, which tends to keep down the overall weight of the club head. It is essential that the face plate be solidly attached to the main body of the head by means such as welding to make for a solidly integrated head structure. 
     It is therefore an object of this invention to provide a golf club head having a face plate of a forged metal which gives more solid impact resistance and feel, to provide better control. 
     It is another object to provide a face plate that provides added heel and toe region weighting to a golf club, to enhance control of ball stroking; and it is an object to provide such a face plate that also consists of forged material. 
     These and other objects and advantages of the invention, as well as the details of an illustrative embodiment, will be more fully understood from the following specification and drawings, in which: 
    
    
     DRAWING DESCRIPTION 
     FIG. 1 is a side elevational view of a first embodiment of the invention; 
     FIG. 2 is a bottom plan view of the first embodiment; 
     FIG. 3 is a top plan view illustrating the face plate employed in the first embodiment; 
     FIG. 4 is a top plan view of the first embodiment; 
     FIG. 5 is a side elevational view of a second embodiment of the invention; 
     FIG. 6 is a bottom plan view of the second embodiment; 
     FIG. 7 is a front perspective view of the second embodiment; 
     FIGS. 8-10 are sections taken in elevation to show plate and head attachment; 
     FIG. 11 is an enlarged section showing welding and finishing; 
     FIG. 12 is a vertical section taken through a metal wood head, showing another embodiment of the invention; 
     FIG. 13 is a section taken on lines 13--13 of FIG. 1; 
     FIG. 14 is a front face view of the metal wood of FIG. 12, partly broken away; 
     FIG. 15 is a view like FIG. 13 showing a modification; 
     FIG. 15a is a perspective view of the FIG. 15 face plate; and 
     FIG. 16 is a view like FIG. 13, showing an iron incorporating the invention. 
    
    
     DETAILED DESCRIPTION 
     Referring to FIGS. 1-4, a first embodiment of the invention is illustrated. Face plate 11, which is fabricated of a material selected from the class consisting of forged carbon steel, forged stainless steel, forged beryllium copper, and forged titanium, has a lip portion 11a formed thereon. The main body 12 of the club head is formed by the investment casting of a material, such as stainless steel, beryllium copper, titanium, aluminum, etc. Main body portion 12 has a slot 12a formed therein and a recessed portion 12b which matingly receives face plate 11 with lip portion 11a fitting into slot 12a. Face plate 11 is solidly integrated with main body portion 12 by weld joints 14 formed along the perimeter of the face plate. In this manner, the face plate is solidly integrated with the casting. 
     Referring now to FIGS. 5-7, a second embodiment of the invention is illustrated, this embodiment being a &#34;wood&#34;-type driver. The main body portion 12, as for the previous embodiment, is formed by investment casting from a material such as stainless steel, beryllium copper, titanium, aluminum, etc. The face plate 11, as for the previous embodiment, is fabricated of forged metal selected from the same class of materials as for the first embodiment. The face plate 11 is abutted against the front surface of the casting and solidly joined thereto along weld joints 14, which run along the perimeter of the face plate thereby integrating the face plate with the casting. 
     For best results, both the head and the face plate consist of the same high strength material, i.e., stainless steel. One such steel is 17-4 PH forged stainless steel. This facilitates best weld connection of these parts and resistance to separation upon repeated sharp impacts with golf balls. See in this regard FIGS. 8-11, showing connection of these parts. 
     In FIG. 8, the peripheral slot 12b is shown formed in a thickened portion 12c of the cast stainless steel head which projects forwardly. See arrow 15. The slot and thickened portion 12c extend in a loop about the open end of the head, which is hollow at 16 Thickness &#34;t&#34; of the main wall extent of the head, rearward of 12c, is typically within the range 0.50 and 0.070 inches, except that the sole plate is typically between 0.085 and 0.100 inches. Head looping lip 12d overhangs the slot 12b, which is generally L-shaped in cross section. See FIG. 11. 
     FIG. 9 shows the forged stainless steel plate 11 looping periphery 11a closely fitted into the looping slot 12b; and FIG. 11 also shows this as well as the plate wall 11b abutting the looping ledge 12e which constitutes one wall of the slot. 
     FIG. 11 also shows weld material 14 applied to the elements 12d and 11a, and penetrating the clearance between 11a and 12d. After grinding, as along finish line 17, the looping peripheral edge of the head and plate is forwardly convexly rounded, as at 20 in FIG. 10, some weld material remaining, as in the clearance. A high strength, rigid connection is thereby effected between the high strength, compatible stainless steel elements 11 and 12, with element 11 being forged for extremely high strength and resistance to failure as by crack formation, and resistance to deformation, in use. 
     Forged plate 11 is preferably of uniform thickness, within the range 0.090 and 0.130 inches, and thicker than sole plate 13. 
     The method of forming the high strength head includes the steps: 
     a) casting a golf club head main body consisting of metal, 
     b) forging a golf club head face plate consisting of metal, 
     c) weld connecting the forged face plate to the front of the head main body to conform to the front periphery of the body. 
     Further, the a) step typically includes forming a lip 12d at the periphery of the head main body, and the c) step includes weld connecting the periphery 11a of the forged face plate to the lip 12d; and including grinding the weld, the lip and the plate periphery to form a forwardly convex and smooth head surface bounding the periphery of the plate. 
     Referring now to FIGS. 12-14, another embodiment of the invention is illustrated, i.e. a metal wood head having a main body portion 120 of a first metallic material. It may be formed of investment casting material such as stainless steel, beryllium copper, titanium, aluminum, etc. The face plate 121 is formed from a second metallic material, and is forged for high strength. Preferably, the face plate metal is the same as the main body metal, both typically consisting of stainless steel. The forged face plate 121 is peripherally abutted against a front ledge surface of the body (typically a casting), and solidly joined to the latter along weld joint 124, running along the looping peripheral portion of the face plate, integrating the face plate and body portion. 
     Thus, for example, the forged plate 121 has a looping periphery 121a fitting closely into the looping slot 120b, plate wall 121b abutting the looping ledge 120e which constitutes one wall of the slot. The fabrication including welding may be carried out as in FIG. 11, and its description, and a high strength failure resistant club head (metal wood) is thereby formed. The face plate 121 may have the looping peripheral shape of plate 11, and be upwardly convex; downwardly convex, and generally trapezoidal. 
     A feature of the invention is the provision of a face plate having first and second portions and an intermediate portion, the first and second portions of the face plate respectively located closer to said body toe and heel than the intermediate portion. In this regard, the plate first and second portions preferably have greater thickness than the intermediate portion. See first and second plate portions 121f and 121g, the former closest to the head toe 135; and the latter 121g closest to the head heel 136. FIG. 13 shows that the portions 121f and 121g both project toward the space 140 rearward of the plate; and FIG. 14 shows that portion 121f is located between front to rear planes 143 and 144, and portion 121g is located between front to rear planes 145 and 146. Plate intermediate portion 121h lies between planes 143 and 145 for example, and the lateral extent &#34;m&#34; of the intermediate portion 121h may be greater than each of the lateral extents &#34;p&#34; and &#34;q&#34; of the first and second plate portions 121f and 121g. Also, the intermediate portion 121h is centrally thinner than each of the portions 121f and 121g, whereby metal weight of the forged plate is &#34;redistributed&#34; toward the toe and heel of the face plate, and of the club head body, to resist twisting of the club head, and shaft, during impact and striking of a golf ball. As shown, the thickness t 1 , of plate portion 121f progressively and smoothly increases toward plane 144; and the thickness t 2  of plate portion 121g progressively and smoothly increases toward plane 146. Welding 160 at the face plate toe, and 161 at the face plate heel also adds to toe and heel weighting effect. 
     FIG. 15 shows the same construction, except that the thickness of portion 121f increases as an upward stairstep 121f&#39; toward plane 144; and the thickness of portion 121g increases as a stairstep 121g&#39; toward plane 146. Intermediate portion 121h of the plate may have minimum thickness t 3  generally about midway between the increased thickness portions 121f and 121g; and t 3  may be between about 1 to 6 millimeters whereas t 1  and t 2  may each increase to about 4 to 8 millimeters, laterally. Other dimensions may be used. Looping ledge 120e&#39; is slanted or tapered, as in a countersink, in FIG. 15. Other fastening methods (plate to head shell) may be employed. 
     In FIG. 16, a forged face plate 121 may be like that of FIG. 13, and be peripherally attached as by welding at 150 to a looping ledge 151 formed by iron head 152. Note plate weight &#34;redistribution&#34; at 121f  and 121g toward the toe and heel 152a and 152b of the iron head, adding to &#34;anti-twist&#34; effect. Note recess 153 formed by the head body, and into which the thicker plate portions 121f and 121g project.