# Patent

## Title
Golf club head and method of making same

## Abstract

A golf club head, preferably a putter head, has a body fitted with inserts having a density greater than that of the club head body. Two cavities are formed in the body and are accessible only through a front face of the body. One cavity is adjacent a heel region of the body, and the other cavity is adjacent a toe region of the body. In a preferred embodiment, the inserts and the cavities are provided with a suitable draft angle. The inserts are bonded within the cavities and are subsequently finished using a milling process or the like so that a front surface of each insert is substantially flush with the front face of the body.

## Background
BACKGROUND OF THE INVENTION
This invention relates generally to golf equipment and, in particular, to a golf club head and a method of making the golf club head.
It is often desirable to incorporate heel and toe weighting into a golf club head to increase the moment of inertia of the club head. This increased moment of inertia tends to decrease club head twisting in the event the golfer strikes the golf ball off-center. In an effort to increase the moment of inertia, prior art club heads generally utilize a low-density material (such as aluminum) for a club head body in conjunction with a higher density material for heel and toe weights. U.S. Pat. No. 4,508,350, for example, discloses a golf club putter having a high polar moment of inertia provided by forming the club head body of aluminum. Similarly, U.S. Pat. No. 4,915,385 discloses metallic (e.g., copper) heel and toe weights used in conjunction with a lower-density (e.g., aluminum) club head.
SUMMARY OF THE INVENTION
The present invention provides a golf club head having a body fitted with inserts having a density greater than that of the body. Two cavities are formed in the body, one in or adjacent to a heel region of the body, and another in or adjacent to a toe region. In a preferred embodiment, the inserts and cavities are provided with a suitable draft angle and are subsequently finished by using a milling process or the like.



DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a golf club head in accordance with the present invention;
FIGS. 2A, 2B and 2C are enlarged cross sectional views showing a portion of the golf club head shown in FIG. 1; and
FIG. 3 is an enlarged perspective view of a portion of the golf club head of FIG. 1.



DESCRIPTION OF THE INVENTION
With reference to FIG. 1, a golf club head 100, preferably a golf putter head, in accordance with a preferred embodiment of the present invention includes a body 102 having a front face 112, a bottom surface or “sole” 114, a heel region 106, and a toe region 104. Body 102 is typically attached to a shaft 110 via a suitable hosel 108 and is suitably formed such that it includes two cavities (or “pockets”) 130 and 132 located in toe and heel regions 104 and 106, respectively. Inserts 120 and 122 are configured to be received within, attached to, or otherwise integrated with body 102 such that they substantially fill the respective cavities 130 and 132.
In the preferred embodiment, cavities 130 and 132 are configured to receive the respective inserts 120 and 122 only through openings in front face 112, and are held in place via any suitable bonding technique—e.g., epoxy, interference fit, or the like. In the preferred embodiment, cavities 130 and 132 (as well as inserts 120 and 122) are formed with a suitable “draft” (e.g., a five degree draft) to facilitate placement of inserts 120 and 122, as described in further detail below. Further in accordance with the preferred embodiment, after inserts 120 and 122 are placed in cavities 130 and 132, the front surfaces 214 (FIG. 2A) of inserts 120 and 122 are milled or otherwise finished so that these front surfaces 214 are flush with face 112.
Body 102 generally comprises any suitable metal, plastic, composite material, or combination thereof selected in accordance with various criteria as described in further detail below. For example, body 102 may be made of a metallic material having a relatively low density, e.g., titanium or a high-purity titanium alloy having a density of approximately 3.0 g/cm3 to 7.0 g/cm3. Alternatively, the body 102 may be made of a composite or plastic material having the desired characteristics. Depending upon the selected material or materials, body 102 may be fabricated using any suitable process now known or later developed, including a variety of conventional casting methods such as investment-casting, powdered-metal processing, and/or metal machining. Body 102 is preferably formed using a suitable casting process and thereafter milled to finish the various exposed surfaces, as described in further detail below.
In the preferred embodiment, cavities 130 and 132 are configured with respect to body 102 such that inserts 120 and 122 form a portion of face 112 of body 102 and are placed at the opposite ends of body 102, i.e. in the heel and toe regions 106 and 104 of the body 102. This placement of the inserts 120, 122 increases the moment of inertia of club head 100 when inserts 120 and 122 are fabricated from a material having a density that is greater than that of body 102. In this regard, inserts 120 and 122 may be fabricated using any suitable material, including various metals, plastics, composite materials, or any combination thereof. In the preferred embodiment, inserts 120 and 122 are formed of a material such as tungsten having a density ranging from approximately 15.0 g/cm3 to 20.0 g/cm3.
It is usually advantageous to fit club head 100 with inserts 120 and 122 having substantially the same weight. The present invention, however, also contemplates the use of inserts 120 and 122 having different weights and/or manufactured from different materials. This might be advantageous, for example, to compensate for non-symmetrical features of club head 100 or to align the center of gravity of club head 100 with the geometric center of front face 112. Inserts 120 and 122 may be fixed within respective cavities 130 and 132 using any suitable method now known or later developed, including the use of adhesives and/or conventional metal-joining operations such as soldering, brazing, and the like. In the preferred embodiment, inserts 120 and 122 are affixed within cavities 130 and 132 by using a conventional epoxy adhesive.
FIGS. 2A, 2B and 2C depict the placement of insert 120 within cavity 130, as seen in a cross sectional view. As shown in FIG. 2A, cavity 130 has a bottom wall 209 and side walls 210. In the preferred embodiment, the side walls 210 are provided with a draft angle α (e.g., a draft angle of approximately five degrees). It will be appreciated that the mating side surfaces 212 of insert 120 would have the same draft angle. Insert 120 also has a bottom surface 216. As shown in FIG. 2B, insert 120 is suitably placed within cavity 130 such that it substantially fills the cavity 130. In the preferred embodiment, a layer 218 of epoxy adhesive is applied to the bottom wall 209 and the side walls 210 of cavity 130 in order to provide permanent bonding of the insert 120 within cavity 130.
It will be understood that portions of the front surface 214 of insert 120 may not be flush (e.g., at points 220 and 222 in FIG. 2B) with respect to front face 112 of the body 102. Accordingly, the surface 214 is preferably milled or otherwise finished so that the surface 214 as shown in FIG. 2C is flush with front face 112. It will be appreciated that the steps illustrated in FIGS. 2A-2C would also be performed for the insert 122.
FIG. 3 shows the insert 120 as having an inner arcuate surface 306 and an outer arcuate surface 308. It will be understood that the outer arcuate surface 308 generally follows the contour of the toe region 104 of the body 102. The insert 120 is preferably configured such that there is more mass in portion 304 that is below horizontal midline 310 than in the portion 302 that is above horizontal midline 310. It is preferable that, given the total height of insert 120 (as viewed from the front relative to the body 102), the insert weight is concentrated such that the center of gravity 320 of insert 120 is below horizontal midline 310. This configuration of insert 120 assists in lowering the center of gravity of the club head 100.
Although the invention has been described herein in conjunction with the appended drawings, those skilled in the art will appreciate that the scope of the invention is not so limited. For example, while the present invention has been described in terms of golf putters, many other types of golf clubs would profit from the present invention, including irons, metal woods, etc. Moreover, while titanium and tungsten have been cited as preferred materials for the body and inserts respectively, it will be appreciated that any suitable material now known or later developed may be used in connection with the present invention, including various metals, alloys, composites, ceramics, and the like. These and other modifications in the selection, design, and arrangement of the various components and steps discussed herein may be made without departing from the scope of the invention as set forth in the appended claims.

## Claims

1. A method of making a golf club head, said method comprising:
(a) forming a body from a first material having a first density, said body having a heel region, a toe region, a front face, a first cavity in said heel region, and a second cavity in said toe region, wherein said first and second cavities are accessible only through said front face;
(b) forming a first insert and a second insert from a second material having a second density greater than said first density,
(c) placing and affixing said first insert within said first cavity;
(d) placing and affixing said second insert within said second cavity;
(e) finishing a front surface of said first insert and a front surface of said second insert so that the front surfaces of said first and second inserts are substantially flush with said front face; and
(f) forming each of said first and second inserts with a height and a horizontal midline perpendicular to said height so that a portion of each of said inserts located below said horizontal midline has a mass greater than a portion of each of said inserts located above said horizontal midline.

2. The method of claim 1, further comprising affixing said first and second inserts within said first and second cavities by using adhesive.

3. The method of claim 1, further comprising finishing the front surfaces of said first and second inserts by utilizing a milling process.

4. The method of claim 1, further comprising forming each of said first and second cavities with a plurality of side walls, each of said side walls having a draft angle.

5. The method of claim 4, further comprising forming each of said first and second inserts with a plurality of side surfaces for mating with the side walls of said first and second cavities, each of said side surfaces having said draft angle.

6. The method of claim 5, further comprising forming each of said first and second cavities with a bottom wall and forming each of said first and second inserts with a bottom surface.

7. The method of claim 6, further comprising applying a layer of adhesive to the bottom and side walls of said first and second cavities before said first and second inserts are placed in said first and second cavities.

8. A golf club head comprising:
a body formed of a first material having a first density, said body having a heel region, a toe region, a front face, a first cavity in said heel region, and a second cavity in said toe region, said first and second cavities being accessible only through said front face;
each of said first and second cavities having a plurality of side walls, each of said side walls having a draft angle;
a first insert and a second insert formed of a second material having a second density greater than said first density, said first and second inserts being placed in said first and second cavities, respectively;
each of said first and second inserts having a plurality of side surfaces for mating with the side walls of said first and second cavities, each of said side surfaces having said draft angle; and
each of said first and second inserts has a height and a horizontal midline perpendicular to said height so that a portion of each of said inserts located below said horizontal midline has a mass greater than a portion of each of said inserts located above said horizontal midline.

9. The golf club head of claim 8, further comprising a layer of adhesive applied to the side walls of said first and second cavities for bonding said first and second inserts in said first and second cavities.

10. The golf club head of claim 8, wherein said first and second cavities each have a bottom wall, and wherein said first and second inserts each have a bottom surface.

11. The golf club head of claim 8, wherein each of said first and second inserts has a front surface that is substantially flush with the front face of said body.

12. A method comprising:
(a) forming a body from a first material having a first density, the body having a heel, a toe, a front face, a first cavity adjacent to the heel, and a second cavity adjacent to the toe, wherein the first and second cavities are accessible only through the front face;
(b) forming each of the first and second cavities with a plurality of side walls, the side walls having a draft angle;
(c) forming a first insert and a second insert, each with a plurality of side surfaces for mating with the side walls of the first and second cavities, the side surfaces having the draft angle, and wherein the first insert and the second insert are formed from a second material having a second density greater than the first density;
(d) placing and affixing the first insert within the first cavity, wherein the center of mass of the first insert lies below a horizontal midline of the body; and
(e) placing and affixing the second insert within the second cavity, wherein the center of mass of the second insert lies below the horizontal midline of the body.

13. The method of claim 12, further comprising finishing a front surface of the first insert and a front surface of the second insert so that the front surfaces of the first and second inserts are substantially flush with the front face.

14. The method of claim 13, further comprising finishing the front surfaces of the first and second inserts by utilizing a milling process.

15. The method of claim 12, further comprising forming each of the first and second inserts with a height and a horizontal midline perpendicular to the height so that a portion of each of the inserts located below the horizontal midline has a mass greater than a portion of each of the inserts located above the horizontal midline.

16. The method of claim 12, further comprising forming each of the first and the second inserts with a perimeter having a partial convex surface and a partial concave surface.

17. The method of claim 12, further comprising forming each of the first and the second inserts from a material having the second density in a ratio at least 2.5:1 to the first density.

18. The method of claim 12, wherein the draft angle of the walls comprises the draft angle to about 5.0°.