WO1999025427A1

WO1999025427A1 - Golf club head face plate

Info

Publication number: WO1999025427A1
Application number: PCT/US1998/024121
Authority: WO
Inventors: William R. Kingston
Original assignee: Ticomp, Inc.
Priority date: 1997-11-14
Filing date: 1998-11-11
Publication date: 1999-05-27
Also published as: AU1401499A

Abstract

A golf club head face plate (20) comprising a bonded sandwich structure. The bonded sandwich structure has an inner layer (24), a core (22) and an outer layer (26). The inner layer or the outer layer can be a titanium alloy or a titanium graphite laminate. The core can be a syntactic core. Also, a method of making a golf club including the step of providing a golf club head face plate having a bonded sandwich structure. Also, a golf club head body where the sole is cast as part of the body rather than being made separately from the body.

Description

GOLF CLUB HEAD FACE PLATE

CROSS-REFERENCE TO RELATED APPLICATIONS

The present Application is a continuation-in-part of co-pending United States Patent Application 08/690,801, filed August 1, 1996, entitled "METHOD OF

PREPARING BETA TITANIUM-FIBER REINFORCED COMPOSITE LAMINATES;" a continuation-in-part of United States Patent Application 08/588,868, filed January 19, 1996, entitled "BETA TITANIUM-FIBER REINFORCED COMPOSITE LAMINATES," now United States Patent 5,578,384, issued November 26, 1996; a continuation-in-part of co-pending United States Patent Application 08/568,530 filed December 7, 1995, entitled "CARBON-TITANIUM COMPOSITES, " a continuation-in-part of United States Patent Application 08/139,091 filed October 18, 1993,^' entitled "TITANIUM AND GRAPHITE FIBER COMPOSITES, " now abandoned; and a continuation-in-part of co-pending PCT Patent Application No. PCT/US96/ 18742, filed November 22, 1996, entitled "BETA TITANIUM-FIBER REINFORCED COMPOSITE LAMINATES; " the contents of each of which are incorporated herein by reference in their entirety.

BACKGROUND Golf is played by striking a golf ball with a golf club to accurately propel the ball a set distance toward a hole. Golf clubs include a shaft having a grip at its upper end and a head at its lower end. Golf clubs are divided into groups according to their form and function. These groups include "woods" and "irons," named because of their original composition.

Drivers, a type of "wood," are frequently used at the beginning of play to propel the golf ball a long distance toward the hole. Drivers are usually currently constructed with a hollow golf club head of cast metal, such as titanium, and having an anteriorly oriented face plate that strikes the golf ball. Such drivers are often called "metal woods. " While golf club heads for metal woods exist in a variety of shapes and materials, there remain several problems with the golf club heads currently available.

For example, a significant amount of energy is lost when the golf club head face plate strikes the ball, thereby decreasing the distance the golf ball is propelled.

Further, the weight of the face plate relative to the rest of the golf club head tends to disadvantageously position the center of gravity of the golf club head forward toward the face plate rather than toward the back of the club head. This tends to decrease the tendency of the golf ball to leave the golf club head on a straight trajectory.

Therefore, there remains a need for a golf club head face plate that imparts more energy to the golf ball when the ball is struck. Further, there remains a need for a golf club head face plate that is lighter so that the center of gravity of the golf club head is moved away from the face plate.

SUMMARY According to one embodiment of the present invention, there is provided a golf club head face plate comprising a bonded sandwich structure. The bonded sandwich structure can include a titanium alloy and can include a syntactic core. According to another embodiment of the present invention, there is provided a method of constructing a golf club head comprising the step of providing a golf club head face plate having a bonded sandwich structure. According to another embodiment of the present invention, there is provided a single-piece golf club head body cast having comprising an upper portion, a sole and an open face to receive a golf club head face plate, wherein the sole is cast as part of the body rather than being made separately from the body.

FIGURES These features, aspects and advantages of the present invention will become better understood with regard to the following description and appended claims in the accompanying figures where:

Figure 1 is a partial, front perspective view of a golf club, according to the present invention;

Figure 2 is a cutaway front perspective view of a golf club head face plate, respectively, according to the present invention; and Figure 3 is a front perspective view of a single-piece golf club head cast according to the present invention, with an opening for a face plate.

DESCRIPTION According to one embodiment of the present invention, there is provided a golf club head face plate designed to increase the natural frequency of the face plate so that the natural frequency of the face plate more closely matches the natural frequency of the golf ball than the natural frequency of a face plate made of conventional material. According to another embodiment of the present invention, there is provided a golf club head face plate which comprises a bonded sandwich structure. According to still another embodiment of the present invention, there is provided a method of playing golf which includes the step of striking a golf ball with a golf club head having a face plate designed to increase the natural frequency of the face plate so that the natural frequency of the face plate more closely matches the natural frequency of the golf ball than the natural frequency of a face plate made of conventional material. According to still another embodiment of the present invention, there is provided a method of playing golf which includes the step of striking a golf ball with a golf club head having a face plate which comprises a bonded sandwich structure. According to still another embodiment of the present invention, there is provided a single-piece golf club head cast according to the present invention, with an opening for a face plate.

The effectiveness of a golf club in accurately propelling a golf ball a long distance is in part due to properties of the golf ball, properties of the force applied to the golf ball through the golf club head, properties of the golf club head face plate striking the ball and the interaction between these properties. In general, the more energy lost when the ball is struck by the golf club head face plate, the less distance the golf ball is propelled. Therefore, when attempting to propel a golf ball a long distance, it is advantageous to minimize energy loss when the golf ball is struck in order to increase the distance the golf ball is propelled. In general, the natural frequency of the rebound of a golf ball is more rapid than the natural frequency of the rebound of the golf club head face plate. Energy is lost when the golf ball is struck because the golf ball will leave the golf club head face plate before the golf club head face plate fully rebounds. Therefore, one method of decreasing energy loss during the strike is to increase the natural frequency of the face plate so that the natural frequency of the face plate more closely matches the natural frequency of the golf ball than the natural frequency of a face plate made of conventional material.

Generally, the natural frequency of the rebound of a material is proportional to the square root of (the stiffness of the material (k) divided by the mass of the material (m)). Therefore, increasing the natural frequency of the rebound of a golf club head face plate can be accomplished by increasing the stiffness of the face plate, by decreasing the mass of the face plate, or by both.

According to one embodiment of the present invention, there is provided a golf club head face plate that comprises a bonded sandwich structure. The golf club head face plate has a higher natural frequency of the rebound that more closely matches the natural frequency of the rebound of a golf ball. In use, the golf club head face plate decreases the energy loss when a golf ball is struck, thereby causing the golf ball to be propelled a longer distance.

Referring now to Figures 1 and 2, there is shown a partial, front perspective view of a golf club and a cutaway front perspective view of a golf club head face plate, respectively, according to the present invention. The golf club 10 comprises a head body 12 having a front face 14 and an upwardly extending tubular neck portion 16 attached to a shaft 18. The front face 14 comprises a golf club head face plate 20 according to one embodiment of the present invention.

The golf club head face plate 20 comprises a bonded sandwich structure having a core layer 22 between an inner layer 24 and an outer layer 26. The outer layer has an external ball striking surface. The golf club head face plate 20 has an increased flexural stiffness to weight ratio, and hence an increased natural frequency of the rebound, that is higher than solid titanium or aluminum. The bonded sandwich structure places one layer in compression, one layer in tension, and the core in shear and localized compression. The core layer 22 can be any light weight sandwich panel core having suitable properties as will be understood by those with skill in the art with reference to the disclosure herein. For example, the core layer 22 can be a honeycomb core such as 5052 Rigicell™ Aluminum Corrugated Honeycomb, (available from Hexcel, Dublin, CA, designated CR-ALC-18-5052-.006 (R2)). In a preferred embodiment, the core layer 22 comprises a syntactic core such as SynCore 9823.1 (available from Hysol Aerospace Products, Pittsburg, CA). The inner layer 24 and the outer layer 26 can be any suitable material, and can be of identical materials or different materials, as will be understood by those with skill in the art with reference to the disclosure herein. For example, the inner layer 24 and the outer layer 26 can be a material selected from the group consisting of a metal, a ceramic, a fiber reinforced composite, and a hybrid laminate of alternating layers of metal, composite or ceramic. In one embodiment, both the inner layer 24 and the outer layer 26 comprise one or more titanium alloys such as TIMETAL^® 15-3 (Ti 15V-3Cr-3Al-3Sn) (available from Titanium Metals Corporation, Denver, CO). In addition, both the inner layer 24 and the outer layer 26 can be a laminate such as a titanium graphite laminate. In a preferred embodiment, both the inner layer 24 and the outer layer 26 comprise a beta titanium-fiber reinforced composite laminate having a layer of beta titanium alloy and a layer of fiber reinforced composite, wherein the layer of beta titanium alloy has a yield strength to modulus of elasticity ratio that is substantially similar to the strength to modulus of elasticity ratio of the layer of fiber reinforced composite, as disclosed in co-pending United States Patent Application 08/690,801, filed August 1, 1996, incorporated herein by reference in its entirety.

Referring now to Figure 3, there is shown is a front perspective view of a single-piece golf club head cast 28 according to the present invention made as part of a golf club head. The golf club head cast 28 has an open face 30 to receive a golf club head face plate (not shown) and to remove any material remaining in the body 28 after the casting process. In this embodiment, the sole of the golf club head 32 is cast as part of the golf club cast 28 head rather than made separately and attached to the remainder of the golf club head body. An upwardly extending tubular neck 34 portion is also provided to receive a shaft, not shown.

EXAMPLE #1

Comparison of Energy Loss During a Strike Between a Conventional Face Plate and

Face Plates According to Embodiments of the Present Invention Golf club head face plates constructed according to the present invention were tested against a control golf club head face plate as follows. A control golf club head face plate, the "Control Plate, " was constructed consisting of a titanium alloy plate of Ti 6A1-4V having a thickness of about 0.115 inches.

Two test golf club head face plates were also constructed according to the present invention. The first test face plate, "Test Plate #1," consisted of a core of SynCore 9823.1 (Hysol Aerospace Products) and both an inner and an outer layer of TIMETAL^® 15-3 (Ti 15V-3Cr-3Al-3Sn) in the cold rolled condition (165 KSI yield, 10.5 MSI modulus, available from Titanium Metals Corporation). The core of SynCore 9823.1 was bonded to the inner and outer layers using AF163M (available from 3M Aerospace Materials Department, St. Paul, MN). Thicknesses of the core, and inner and outer layers were about 0.19 inches and about 0.02 inches each, respectively, giving Test Plate #1 a total thickness of about 0.23 inches. The second test face plate, "Test Plate #2, " consisted of a core of SynCore 9823.1 (Hysol Aerospace Products) and inner and outer layers of a titanium graphite laminate. The laminate consisted of TIMETAL^® 15-3 (Ti 15V-3Cr-3Al-3Sn) having a thickness of about 0.009 inches, in the same cold rolled condition as in Test Plate #1 but laminated to three piles of SP381-T800, each 0.005 inches thick (available from 3M

Aerospace Materials Department, St. Paul, MN). The three piles of SP381-T800 were oriented in 0°, 90°and 0°. The three piles of SP381-T800 were bonded to the TIMETAL^® 15-3 using AF163M (available from 3M Aerospace Materials Department, St. Paul, MN). Thicknesses of the core, and inner and outer layers were about 0.18 inches and about 0.025 inches each, respectively, giving Test Plate #2 a total thickness of about 0.23 inches.

The Control Plate was cut to about 4 by 2.5 inches. Test Plate #1 and Test Plate #2 were cut with a water jet into the shape of a golf club head face plate approximately 3.25 inches long, 1.5 inches in maximum height and 1.375 inches in average height. Test Plates #1 and #2 were then mounted into a titanium rectangular fixture approximately the same size as the Control Plate. The portion of the Control Plate equivalent to Test Plate #1 and #2 weighed about 38 grams. The unmounted Test Plate #1 weighed approximately 24 grams. The unmounted Test Plate #2 weighed approximately 20 grams. Energy loss during the strike was determined by firing a golf ball at each plate at 85 mph and 105 mph and measuring the velocity of the ball before and after hitting each plate, according to the formula: energy loss = (v,² - v₂ ²)/2 where V_j is the velocity of the golf ball before hitting the plate and v₂ is the velocity of the golf ball after hitting the plate.

In test #1, the energy loss was determined for a soft (Balata) ball fired at an initial velocity of 85 mph. The ball lost approximately 43.7% of its energy when striking the Control Face Plate as compared to a 37.1 % loss for Test Plate #1 and a 38.0% loss Test Plate #2. Therefore, there was a decrease in energy loss of about 13% for Test Plate #1 and Test Plate #2 as compared to the Control Plate.

In test #2, the energy loss was determined for a hard (Surlyn) ball fired at an initial velocity of 85 mph. The ball lost approximately 45.3 % of its energy when striking the Control Face Plate as compared to a 38.4% loss for Test Plate #1. Therefore, there was a decrease in energy loss of about 15% for Test Plate #1 as compared to the Control Plate. In test #3, the energy loss was determined for a hard (Surlyn) ball fired at an initial velocity of 105 mph. The ball lost approximately 37.1 % of its energy when striking the Control Face Plate as compared to a 19.0% loss for Test Plate #1. Therefore, there was a decrease in energy loss of about 48.8% for Test Plate #1. EXAMPLE #2

Method of Producing a Golf Club Head Having a Face Plate with a Bonded Sandwich Structure According to the Present Invention A golf club head with a bonded sandwich structure face plate is produced according to the present invention as follows. A one piece golf club head having an open face designed to receive a face plate is cast from a suitable material, such as titanium alloy Ti 6A1-4V. A suitable mold can be purchased from Butler Molds, Carlsbad, CA. The casting can be manufactured by Timet Castings, Pomona, CA. Alternately, a two-piece golf club head consisting of a body having an open face and a sole plate can be cast and the sole plate attached to the body to complete the golf club body. When titanium is used as the casting material, the sole plate can be attached to the body by welding with an inert gas, followed by grinding and polishing the weld. The casting then has any surface flaws repaired and is prepared for painting and bonding, all according to techniques known to those with skill in the art.

The casting of the body will include an open face with a shoulder designed to receive and support the face plate when the face plate is bonded into the golf club body and to maximize the end fixity of the face plate. Ideally, the shoulder is approximately 0.1 inch in width, gradually tapering back to the wall thickness of the remainder of the club body. A bonded sandwich structure golf club head face plate is made according to the present invention. The exact composition of the bonded sandwich structure face plate and thickness of the face plate is selected to produce a minimum energy loss for the expected velocity of the intended user's swing and type of golf ball in order to most closely match the natural frequency of the rebound rate of the golf ball when struck at such a velocity. Energy loss can be determined for various golf club head face plates according to the present invention, by performing testing similar to that performed in Example #1. For example, in order to produce a golf club head face plate described as

Test Plate #1 in Example #1, a 0.040 inch thick TIMETAL^® 15-3 (Ti 15V-3Cr-3Al-3Sn) strip per AMS 4914A (available from Titanium Metals Corporation, Denver, CO) is purchased and rolled into a strip 0.020 inches thick. Without an intermediate anneal, that is, with the titanium in a high strength, low modulus condition, any oil is cleaned from the strip and the surface is sandblasted. Alternately, the strip can be catholic arc coated with a noble metal like platinum. If a high strength, high modulus titanium is needed, the titanium can be heat treated after the platinum coating in a vacuum chamber for about 8 hours at 1000°F (available from Hinderliter Heat Treating in Anaheim, CA).

For a golf club head face plate comprising a standard modulus titanium graphite laminate bonded sandwich structure, the lay-up would be a 0.015 inch thick TIMETAL^® 15-3 in a high modulus, high strength, heat treated condition, AF163-M glue (3M, St. Paul, MN), four plies of SP381-T800 graphite epoxy tape (oriented 0°, 90°, 0°, and 90°) (3M, St. Paul, MN), and 0.180 inches SynCore 9823.1 (Hysol Aerospace Products, Pittsburg, CA, four plies of SP381-T800 graphite tape (oriented 0°, 90°, 0°, and 90°), AF163-M and TIMETAL^® 15-3.

For a golf club head face plate comprising a high modulus, height strength, titanium-only skin, the lay-up would be a 0.020 inch thick TIMETAL^® 15-3 in a high modulus, high strength condition, AF163-M, 0.200 inches SynCore 9823.1, AF163-M and another layer of 0.020 inch thick TIMETAL^® 15-3 in a high modulus, high strength condition. Other metals, ceramics, and pre-hardened materials could be used in place of titanium, as appropriate. For a golf club head face plate comprising a high modulus, graphite reinforced, epoxy matrix composite, the lay-up would be 8 plies of SP381-M46 graphite epoxy tape (3M) (oriented 0°, +45°, -45°, 90°, 0°, +45°, -45° and 90°) having a total thickness of 0.45 inches, 0.160 inch thick SynCore 9823.1 and another 8 plies of SP381- M46 (oriented 0°, +45°, -45°, 90°, 0°, +45°, -45° and 90°) having a total thickness of 0.25 inches .

For each face plate, the unbonded lay-up is then placed in a tool (Delta Technology, Brea, CA) having the correct bulge and roll (radius) for the final face plate. The tool containing the lay-up is placed in a heated press, producing a pressure of approximately 100 psi pressure and a temperature of approximately 250 °F for one hour. The finished face plate is removed from the tool, cleaned and inspected.

Next, both the shoulder in the opening of the casting and the edges of the face plate will be coated with a suitable two part glue such as Hysol EA 9309.3NA (Hysol Aerospace Products, Pittsburg, CA). The face plate is placed into the casting and held in place by a fixture for either 8 hours at room temperature or 1 hour at 250 °F. The club head is then cleaned and painted if desired.

Although the present invention has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiments contained herein.

Claims

I CLAIM:

1. A golf club head face plate comprising a bonded .sandwich structure.

2. The golf club head face plate of claim 1, wherein the bonded .sandwich structure includes a titanium .alloy.

3. The golf club head face plate of claim 1, wherein the bonded .sandwich structure includes a syntactic core.

4. The golf club head face plate of claim 1, wherein the bonded .sandwich structure includes a titanium graphite laminate.

5. A golf club head comprising the golf club head face plate of claim 1.

6. A golf club comprising the golf club head face plate of claim 5.

7. A golf club head face plate consisting of a bonded sandwich structure.

8. The golf club head face plate of claim 7, wherein the bonded sandwich structure includes a titanium alloy.

9. The golf club head face plate of claim 7, wherein the bonded sandwich structure includes a syntactic core.

10. The golf club head face plate of claim 7, wherein the bonded sandwich structure includes a titanium graphite laminate.

11. A golf club head comprising the golf club head face plate of claim 7.

12. A golf club comprising the golf club head face plate of claim 11.

13. A method of constructing a golf club head comprising the step of providing a golf club head face plate having a bonded sandwich structure.

14. The method of claim 13, wherein the bonded sandwich structure in the providing step includes a titanium alloy.

15. The method of claim 13, wherein the bonded sandwich structure in the providing step includes a syntactic core.

16. The method of claim 13, wherein the bonded sandwich structure in the providing step is a titanium graphite laminate.

17. A golf club head produced according to the method of claim 13.

18. A method of constructing a golf club comprising the step of providing the golf club head of claim 17.

19. A method of constructing a golf club head comprising the step of providing a golf club head face plate consisting of a bonded sandwich structure.

20. The method of claim 19, wherein the bonded sandwich structure in the providing step includes a titanium alloy.

21. The method of claim 19, wherein the bonded sandwich structure in the providing step includes a syntactic core.

22. The method of claim 19, wherein the bonded sandwich structure in the providing step is a titanium graphite laminate.

23. A golf club head produced according to the method of claim 19.

24. A method of constructing a golf club comprising the step of providing the golf club head of claim 23.

25. A single-piece golf club head body having comprising an upper portion, a sole and an open face to receive a golf club head face plate, wherein the sole is cast as part of the body rather than being made separately from the body.