Golf Club Head

The present invention relates in general to golf clubs, and more particularly to a golf club head.

Golf clubs are typically divided into three main classes--the putters, irons and woods. The woods are generally used to hit the golf ball a long distance and the woods are traditionally constructed from wood, such as persimmon. Today, however, many woods are constructed from metal, which are generally referred to as metal woods. Metal woods allow the weight of the club head to be balanced and weight distributed around the periphery of the club head, which allows the location and size of the sweet spot of the club head to be adjusted.

A conventional metal wood is shown in U.S. Pat. No. 4,432,549 issued to Zebelean which discloses a metal driver that is cast in two parts. The first part or body includes a face plate, top crown, and sides which surround a large opening; and the second part includes a sole plate or bottom surface which is configured to fit into the large opening in the first part of the club head. After casting, the sole plate is welded to the body to form the golf club head of the metal driver. This golf club head, however, is unsatisfactory because it includes two components that must be welded together, which involves a significant amount of time and increases cost of the club head. Additionally, the lie, loft and face angle of the club head often undesirably changes because the independently formed components do not always mate in an identical manner, and the sole plate is not always welded to the body at the same angle. Thus, significant resources must be used to test and eliminate defects that occur because the sole plate and the body are not always joined at the same manner, which further increases the complexity of the manufacturing process.

Conventional metal woods which require welding the sole plate to the body are unsatisfactory because not all welds are identical. For example, differences in penetration and sealing of a weld affect the strength and structural integrity of the club head, which changes the characteristics of the club head. Welding also undesirably increases the weight and the thickness of the club head, and the differently sized welds cause an unequal weight distribution in a club head. This added weight is disadvantageous because a light-weight club head is important, and the weight is desirably positioned only in specific locations. Additionally, welding not only introduces variables during the manufacture of a single club head, it also causes variation between different club heads. Further, pieces of the weld inside the club head may break off during play. These pieces, which are located inside the sealed club head, rattle every time the club is used. The annoying rattle requires additional time, effort, money and materials to correct.

Conventional club heads are finished with a large degree of care to create the desired appearance and esthetics. For example, golf club heads are often subjected to the expensive and time consuming steps of grinding, sanding, sand blasting, polishing, tumbling and painting to finish the club head. Conventional club heads require that these steps be completed after the components are welded together because the high temperature welding will destroy or mar a finished club head. Disadvantageously, it is difficult to modify or customize the club head after it is welded together. For example, the Zebelean patent discloses filling the hollow club head with a hardening material, such as polyurethane. The Zebelean patent explains that, after the sole plate is welded to the body and the club head is finished, an opening is drilled through the center of the sole of the club head to insert the hardening material. Various types of plugging screws are used to close the opening. This golf club head is unsatisfactory because drilling the opening, filling the club head with the hardening material and sealing the opening often damages or mars the polished surface of the club head. Further, the plugging screw alters the weight and balance of the club head.

Another conventional golf club head is shown in U.S. Pat. No. 4,021,047 issued to Mader which discloses a two piece metal club head held together by mechanical fasteners. The Mader patent discloses a sole plate, face plate and hosel which are cast out of a unitary piece of metal. A wood or plastic cap fits along the top of the face plate and extends to the rear surface of the club head to form a crown and rear capping piece. The cap is attached by two screws which extend through the sole plate and hollow cavity of the club head. This golf club head, however, is unsatisfactory because the mechanical fasteners tended to loosen during play, add unnecessary weight to the club head and the weight is added to the club head in undesired locations.

Another conventional golf club head is shown in U.S. Pat. No. 5,292,129 issued to Long, et al. The Long patent discloses a metal golf club head which is reinforced by three ribs which extend between the internal surface of the striking face and the internal surface of the top side to reinforce both the striking face and the top side. This golf club head is unsatisfactory because the sole plate must be welded to the body of the golf club, and the reinforcement ribs are not interconnected to the sole plate. Disadvantageously, this allows sole plate to deform and buckle when striking a golf ball.

Therefore, there is a need for a golf club head without these significant disadvantages. In addition, there is a need for an improved golf club head which does not require welding or mechanical fasteners to attach the top crown or sole plate to the face plate.

One aspect of the invention is a golf club head with a unitary, one-piece body including a face plate, top crown and sole plate. Advantageously, the face plate, sole plate and top crown of the golf club are always correctly positioned in the desired configuration, and this eliminates variations in lie, loft and face angle. Significantly, the golf club head of the present invention does not require welding or other types of fasteners to attach the sole plate or top crown to the face plate. Because welding or mechanical fasteners are not required, the manufacturing process is simplified and more of the weight of the golf club can be distributed in the desired locations.

Another aspect is a golf club head with a reinforcement structure which strengthens the face plate of the golf club head. Preferably, the reinforcement structure includes one or more ribs which are integrally formed with the top crown, face plate and sole plate of the club head. Advantageously, the reinforcement structure strengthens the top crown, face plate and sole plate of the club head. Thus, the club head does not significantly deform when the face plate strikes the golf ball. In addition, the reinforced club head provides increased elasticity or rebound to the club face, which results in more energy transferred to the golf ball so that the ball can travel a greater distance.

In one embodiment of the invention, the golf club head includes a unitary, one-piece body having a top crown, a face plate, a sole plate and a side skirt. The side skirt includes an opening which provides access to an interior portion of said one-piece body, and a cap is configured to cover the opening in the side skirt.

In another embodiment of the invention, the golf club head includes a face plate and a sole plate which are integrally connected to form a single unit. The club head also includes a top crown connected to the face plate, and a side skirt is connected to the top crown, face plate and sole plate. The face plate, sole plate, top crown and side skirt form a generally hollow body.

In a further embodiment of the invention, a method of making a golf club head includes forming a unitary one-piece body including a face plate, a top crown, a sole plate, a side skirt, and an opening in said side skirt; forming a side skirt cap configured to cover the opening in the side skirt; and attaching the side skirt cap to the body. Preferably, the one-piece body further includes a reinforcement structure which reinforces the face plate.

These and other features of the present invention will now be described with reference to the drawings of preferred embodiments, which are intended to illustrate and not to limit the invention, in which:

FIG. 1 is a perspective front view of a golf club head in accordance with an embodiment the present invention;

FIG. 2 is an exploded perspective back view of the golf club head shown in FIG. 1, illustrating the cap removed from the skirt;

FIG. 3 is a cross-sectional side view along lines 3--3 of the golf club head shown in FIG. 2;

FIG. 4 is a bottom plan view of the golf club head shown in FIG. 1 with a portion of the top crown cut away, illustrating the reinforcement structure; and

FIG. 5 is the bottom plan view of the golf club shown in FIG. 4, illustrating reinforcing material on the inner surface of the face plate.

As shown in FIG. 1, the golf club head 10 includes a face plate 12 which is adapted to strike a golf ball. The face plate 12 includes a plurality of grooves 14 which preferably extend the majority of the length of the face plate, and the grooves 14 may be generally U-shaped or V-shaped in configuration. The grooves 14 preferably conform to the United States Golf Association ("USGA") rules, but any grooves or no grooves may also be used. The club head 10 also includes a top crown 16, a hosel or neck 18 which is configured to receive a shaft 20 (shown in phantom), and a sole plate 22. The hosel 18 includes an opening 19 and the upper portion of the hosel preferably extends between about 1/4 inch (0.6 cm) and 1 inch (2.5 cm), and more preferably about 1/2 inch (1.2 cm), above the upper surface of the top crown 16. Alternatively, the club head 10 may include a longer or shorter hosel 18, or no hosel. Preferably, the opening 19 in the hosel 18 extends through the club head 10 and sole plate 22, and the shaft 20 is inserted through the opening and finished flush with the bottom surface of the sole plate 22. The hosel 18 may also be a blind hosel in which the opening 19 extends through only a portion of the club head 10 and not through the sole plate 22.

The golf club head 10 shown in the accompanying figures and described below is a driver or one wood, but the club head may also be any other type of wood. In addition, the golf club 10 shown in the accompanying figures and described below is an "over-sized" golf club which is larger in size than a traditional golf club, but the club head may also be, for example, a "mid-sized" or "regular-sized" club head. Further, the club head 10 may be connected to any type of desired shaft 20, such as steel, graphite, titanium, or composite materials, and the shaft may be any desired size and length.

As best seen in FIGS. 1 and 2, the golf club head 10 includes a heel 24 proximate the hosel 18 and a toe 26 distal the hosel 18, and side skirt 30 which extends around the golf club head 10. The skirt 30 is connected to the sole plate 22, top crown 16 and face plate 12 to form the body 32 of the club head 10. The side skirt 30 also includes an opening 34, and a cap 36 is configured to cover the opening 34. These different parts combine to form the exterior surfaces of the club head 10, and because the club head 10 is substantially hollow, each of these parts has a corresponding inner surface.

The face plate 12 and the top crown 16 or sole plate 22 are preferably formed as a unitary, one-piece component; and more preferably, the face plate 12, top crown 16 sole plate 22 and side skirt 30 are formed as a unitary, one-piece component. Because the face plate 12 and the sole plate 22 are formed as part of the one-piece body 32, the face plate and sole plate are always correctly positioned at the desired configuration and angle. Advantageously, because there is little or no variation between the angle of the face plate 12 and sole plate 22, each club head 10 will have essentially the same loft, lie and face angle.

Additionally, the one-piece body 32 greatly simplifies the manufacturing process because the sole plate 22 does not have to be welded to the face plate 12--this saves time and resources, and reduces the weight of the golf club. Reducing the weight of the club head 10 typically allows a higher club head speed, which results in more power and energy being transferred to the golf ball. Alternatively, instead of reducing the weight of the club head, the weight saved by the one-piece body can be used, for example, to make a larger sized club head and/or the weight can be redistributed within the club head. For example, the weight may be redistributed to change the center of gravity, additional weight may be positioned directly behind the club face, or additional weight may be distributed around the perimeter of the club head.

The club head 10 is preferably fabricated as a unitary, one-piece body 32 by casting, such as investment, die or lost wax casting; but the club head may also be forged, molded, pressed, or constructed by any other known means such as dynamic compaction or isostatic compaction. The one-piece body 32 is preferably constructed from a titanium alloy, such as titanium 6Al-4V, but any metal or metal alloy such as stainless steel or aluminum may also be used. Additionally, any composite or amorphous materials may be used to construct the body 32. Further, all or a portion of the body 32 may also be constructed from plastic or composite materials; and the face plate 12 may include an insert, such as graphite or other materials, on the front face designed to impact the golf ball.

The face plate 12 of the golf club head 10 preferably has a thickness in the range of about 0.06 inches (1.5 mm) to about 0.12 inches (3 mm), and more preferably about 0.08 inches (2 mm). The top crown 16 has a thickness of about 0.04 inches (1 mm), the sole plate 22 has a thickness of about 0.04 inches (1 mm), and the skirt 30 has a thickness of about 0.04 inches (1 mm). Of course, the thickness of either or all of these surfaces may also be larger or smaller depending, for example, upon the desired strength and configuration of the club head 10, or the materials used to construct the club head. The thickness may also be nonuniform and the thickness may vary to distribute the weight in the desired locations of the club head.

The face plate 12 desirably has a width of about 3.5 inches (88 mm) and a height of about 2.4 inches (60 mm), and the sole plate 22 desirably has a length of about 3.6 inches (91 cm). The overall volume of the club head 10 is preferably between about 15 cubic inches (250 cc) and about 18 cubic inches (300 cc). It will be understood the dimensions of the club head 10 may vary, for example, according to the type of club head and whether the club head is over-sized, mid-sized or regular-sized. The face plate 12 and the sole plate 22 are preferably constructed with a lie between about 55.degree. and about 59.degree., and more preferably about 58.degree.; and the soled or rest loft of the golf club is preferably between about 5.degree. and about 13.degree.. The face angle of the club head is preferably between about -1.degree. and about +3.degree., wherein the minus sign indicates the "open" position and the plus sign indicates the "closed" position. Of course, these measurements may vary, for example, according to the type of club head and the preferences of the user. As discussed above, because the face plate 12 and sole plate 22 are desirably constructed as part of a one-piece body 32, these components are always correctly positioned at the desired configuration and angle such that there is little or no variation between club heads. Advantageously, this ensures each club head has the desired shape and characteristics.

The body 32 of the club head 10 defines a substantially hollow interior portion 40. As shown in FIGS. 2-4, the opening 34 in the side skirt 30 provides access to the interior portion 40. The opening 34 is preferably located substantially opposite the face plate 12, but the opening may be located anywhere in the skirt 30. In addition, the opening 34 may include a portion of the top crown 16 or sole plate 22, or the opening may be entirely located in the sole plate or top crown. The opening 34 is preferably generally rectangular in configuration with a height of about 1 inch (2.5 cm) and a length of about 2 inches (5 cm), but the opening may also have other configurations such as circular or square, or be larger or smaller depending upon the desired size and configuration of the golf club 10.

The cap 36 is preferably configured and sized to cover the opening 34 in the skirt 30. As best seen in FIGS. 2 and 3, the cap 36 has an outer edge 42 with a groove 44 which extends around the outer perimeter of the cap, and the opening 34 in the skirt 30 has an inner edge 46. The groove 44 in the outer edge 42 of the cap 36 is configured to engage the inner edge 46 of the opening 34, such that the inner edge 46 fits securely within the groove 44. Desirably, this creates a "snap" fit between the cap 36 and the opening 34, which releasably secures the cap 36 to the body 32. Additionally, the cap 36 is preferably configured to cover the opening 34 in a manner which creates a generally smooth exterior surface of the skirt 30.

The cap 36 is attached to the opening 34 in the skirt 30 to enclose the substantially hollow internal portion 40. As discussed above, the cap 36 is preferably releasably connected to the skirt 30 by a snap fit; but a press fit, interference fit or fasteners such as bolts, screws and glue may also be used. Desirably, the removable cap 36 provides access to the interior portion 40, even after the club head is finished. Advantageously, because the cap 36 is not welded to the skirt 30, the club head can be finished in any desired manner and then the cap 36 closes the interior portion 40 without damaging or marring the finished surface.

The removable cap 36 advantageously allows materials and/or components to be simply and easily inserted or removed from the finished club head. For example, weight can be added to the heel 24 or toe 26 of the club head 10 to adjust the torque of the golf club head, or weight can be added to lower the center of gravity of the club head. Additionally, weight can be added or removed to balance the club head 10, or to adjust the club head to suit a golfer's particular style or preference. The cap 36 allows additional reinforcement material be added to the club head 10, or removed; and the cap 36 allows materials such as foam or polyurethane to be inserted into the club head 10 before, during or after the manufacturing process. Thus, the removable cap 36 allows the manufacturer, user or others to simply and easily modify and/or repair the club head 10, but the cap 36 may also be permanently connected to the skirt 30 by welding, fusing and the like. Desirably, the cap 36 is constructed in accordance with the rules of the USGA such that the club head can be used in competition.

The cap 36 may be constructed from the same material as the one-piece body 32 and the cap may be cast at the same time the one-piece body. For example, the cap 36 may be produced as part of the body 32, and then the cap may be cut out of the body such that the cap 36 and the opening 34 have precisely the same size and configuration, but the cap can also be constructed separately from the body 32. While the cap 36 may be constructed from the same titanium alloy as the body 32, the cap is preferably constructed from a plastic material, but a wide variety of materials including any of a number of metals, polymers, composites or amorphous materials may be used to construct the cap 36. Further, the cap 36 preferably has a thickness of about 0.04 inches (1 mm), but the thickness may also be larger or smaller depending, for example, upon the desired strength and configuration of the cap 36.

A reinforcement structure 50 is located within the interior portion 40 of the club head 10. The reinforcement structure 50 is desirably positioned behind the face plate 12 and, more desirably, integrally connected to the face plate to form a single unit. The reinforcement structure 50 strengthens the face plate 12 and increases the structural rigidity of the club head 10, which allows the club head to withstand repeated impacts with a golf ball. The structure 50 also helps prevent the energy of the club head from being absorbed (and therefore lost) by deformation of the face plate 12 when the club head 10 strikes the golf ball. The result of such deformation is a loss of energy transfer from the club head 10 to the golf ball, and thus a loss of initial ball velocity which undesirably results in less distance traveled by the golf ball. It will be understood that the club head 10 does not require the use of the reinforcement structure 50.

As best seen in FIGS. 2 and 3, the reinforcement structure 50 is integrally connected to the face plate 12, top crown 16 and sole plate 22 of the club head 10 as part of the one-piece body 32. Thus, the reinforcement structure 50 advantageously strengthens not only the face plate 12, but also the top crown 16 and sole plate 22. The reinforcement structure 50 allows a thinner face plate 12, top crown 16 and/or sole plate 22 to be used, while retaining the structural integrity of the club head 10. As seen in FIGS. 2-4, the reinforcement structure 50 includes three reinforcing ribs 52A, 52B and 52C which extend vertically along the interior surface 54 of the face plate 12, with one end attached to the inner surface 56 of the sole plate 22 and the other end attached to the inner surface 58 of the top crown 16. The center rib 52B is preferably located proximate the center of the face plate 12 and the other ribs 52A and 52C are spaced about 1/2 inch (1.2 cm) apart. Of course, additional or fewer ribs 52 may be utilized, the ribs may be spaced closer or further apart, and the ribs 52 could be at an angle and even horizontal relative to the face plate 12.

As best seen in FIG. 4, the ribs 52A-C each have a thickness of about 0.04 inches (1 mm) and a generally rectangular cross-section, but the thickness and configuration of the ribs may vary depending, for example, upon the desired strength of the ribs. The individual ribs may also have different shapes and characteristics. As seen in FIG. 2, the inner portion 60 of the ribs 52 is curved with a first, upper radius of curvature 62 and a second, lower radius of curvature 64. The upper radius of curvature 62 is preferably between about 2 inches (5 cm) and about 4 inches (10 cm); and the lower radius of curvature 62 is preferably between about 2 inches (5 cm) and about 4 inches (10 cm); but the radius of curvature may be larger or smaller. Desirably, the length of the rib from the inner surface 54 of the face plate to the inner section 60 of the rib 52 is between about 1/4 inch (0.6 cm) and about 1/2 inch (1.2 cm) proximate the center of the rib; while the length of the rib proximate top crown 16 is between about 1/2 inch (1.2 cm) and about 1 inch (2.54 cm); the length of the rib proximate the sole plate 22 is between about 1/2 inch (1.2 cm) and about 1 inch (2.54 cm). Desirably, the curved inner section 60 of the rib 52 decreases the weight of the club head 10, but the ribs may also be straight or have another configuration.

As shown in FIG. 5, the club head 10 may also include reinforcing material 66 which is installed in the inner portion 40 of the club head, preferably behind the face plate 12. The reinforcing material 66 further increases the rigidity of the face plate 12, and may be used with or without the ribs 52. The reinforcing material 66 is preferably constructed from a carbon material, such as graphite, but any material which increases the rigidity of the face plate may be utilized. Advantageously, the reinforcing material 66 can be added after the club head 10 is constructed and finished, without damaging the finished surfaces, because the reinforcing material may be inserted through the opening 34 in the one-piece body 32 of the club head 10.

The present invention also includes a method of making substantially identically-shaped golf club heads 10. The method includes forming the face plate 12, top crown 16, sole plate 22 and skirt 30 as a unitary, one-piece body 32. The onepiece body is desirably formed by investment lost was casting, but the body may also be formed by die casting, injection molding, dynamic compaction, isostatic compaction, forging, lamination and the like. Desirably, the reinforcing ribs 52 are constructed as part of the unitary one-piece body 32. The cap 36 covers the opening 34 in the body 32 to seal the inner portion 40 of the club head. Advantageously, the cap 36 provides access to the inner portion 40 of the club head 10, for example, to change the weight of the club head or increase the strength of the club head.

Although this invention has been described in terms of certain preferred embodiments, other embodiments apparent to those of ordinary skill in the art are also within the scope of this invention. Accordingly, the scope of the invention is intended to be defined only by the claims which follow.