GOLF CLUB HEAD AND METHOD OF FABRICATING STRIKING PLATE

Abstract

A golf club head including a head body and a striking plate is provided. The head body has an opening. The striking plate is disposed at the opening and has a striking surface. The striking plate includes a first crystallization phase region and at least a second crystallization phase region. The second crystallization phase region is located in the first crystallization phase region. The second crystallization phase region extends from the striking surface to an interior of the striking plate. The elastic modulus of the second crystallization phase region is smaller than that of the first crystallization phase region.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application serial no. 95139354, filed Oct. 25, 2006. All disclosure of the Taiwan application is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to a golf club head and a method of fabricating a striking plate, and more particularly to a golf club head with a striking plate having a crystallization phase region with a low elastic modulus and a method of fabricating the striking plate.

2. Description of Related Art

With the prevailing of sports in today's society, golf has become one of the favorite sports widely accepted by the mass, and more and more people are participating in the golf sports. Golf clubs can be classified into wooden clubs, iron clubs, putters, and so on according to various fields and usage.

As for the wooden club, the golf club head is usually fabricated by first forming a head body made of a metal material or together with carbon fiber, and then, integrating a striking plate for striking a golf ball with the head body as a whole. The golf club head has a specific specification and limitation in size and weight, so as to provide a desired controlling and striking effect when striking the golf ball. Therefore, depending upon different requirements in use, in the design of the golf club head, the basic architecture of the head body and the striking plate or the combination constitution thereof is generally changed to achieve the optimal design.

The region with a high coefficient of restitution (COR) of the homogeneous and uniform striking plate is usually located in the center region, and the COR of the striking plate is gradually reduced as being far away from the center region. As far as the COR of the striking plate is concerned, the larger the region with a high COR of the striking plate of the golf club head is, the better the striking effect of the striking plate is. Therefore, in the conventional design of striking plate of the golf club head, the thickness of the plate is reduced to increase the striking restitution capability, but meanwhile the durability of the striking plate is degraded. The striking plate may be easily damaged after a long time of striking as the thickness is reduced. How to simply and effectively increase the striking restitution capability of the striking plate without degrading the durability has become an urgent problem to be solved in the design of the golf club head.

SUMMARY OF THE INVENTION

The present invention is directed to a gold club head, wherein the striking plate has a larger region with a high COR.

The present invention is also directed to a method of fabricating the striking plate, so as to enlarge the region of the striking plate with a high COR.

The present invention provides a golf club head, which comprises a head body and a striking plate. The head body has an opening. The striking plate is disposed at the opening and has a striking surface. The striking plate comprises a first crystallization phase region and at least a second crystallization phase region. The second crystallization phase region is located in the first crystallization phase region and extends from the striking surface to an interior of the striking plate. The elastic modulus of the second crystallization phase region is smaller than that of the first crystallization phase region.

In an embodiment of the present invention, a crystallization phase of the first crystallization phase region includes β-type or α-β-type.

In an embodiment of the present invention, a crystallization phase of the second crystallization phase region includes α′-type or α″-type.

In an embodiment of the present invention, the elastic modulus of the first crystallization phase region may be larger than or equal to 100 GPa.

In an embodiment of the present invention, an absolute value of the difference between the elastic modulus of the first crystallization phase region and that of the second crystallization phase region may be larger than or equal to 5 GPa and smaller than or equal to 10 GPa.

In an embodiment of the present invention, the striking plate is made of a Ti alloy.

The present invention provides a method of fabricating the striking plate, which is applicable for a golf club head. The method of fabricating the striking plate comprises the following steps. First, a plate body is provided, and a crystallization phase of the plate body is a first crystallization phase. Next, a part of the plate body is heated. Next, the heated part of the plate body is quenched, so as to make the crystallization phase of the part of the plate body be transformed into a second crystallization phase.

In an embodiment of the present invention, the step of heating the part of the plate body may be achieved by irradiating the plate body with a high-energy laser beam.

In an embodiment of the present invention, the step of heating the part of the plate body may be achieved by irradiating the plate body with an electron beam.

In an embodiment of the present invention, the step of quenching the heated part of the plate body may be achieved by water cooling, air cooling, or furnace cooling.

In an embodiment of the present invention, a cooling rate of quenching the heated part of the plate body is higher than or equal to 10° C. per second.

In an embodiment of the present invention, the first crystallization phase includes β-type or α-β-type.

In an embodiment of the present invention, the second crystallization phase includes α′-type or α″-type.

In an embodiment of the present invention, the plate body is made of a Ti alloy.

Based on the above, since the striking plate of the present invention has the second crystallization phase region with a lower elastic modulus, on the whole, the striking plate of the present invention has a larger region with a high COR. In addition, in the method of fabricating the striking plate of the present invention, the second crystallization phase region with low elastic modulus is formed in the plate body by partially heating and quenching, without degrading the durability of the striking plate, so the region of the striking plate with a high COR is enlarged. In addition, in the method of fabricating the striking plate of the present invention, the method of irradiating with the laser beam or the electron beam may be adopted to partially heat the plate body, so the method of fabricating the striking plate of the present invention is simple and the manufacturing cost is low.

In order to make aforementioned features and advantages of the present invention comprehensible, a preferred embodiment accompanied with figures is described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic exploded view of a golf club head according to an embodiment of the present invention.

FIG. 2 is a schematic side view of the striking plate of FIG. 1.

FIGS. 3A to 3C are schematic process flow views for fabricating the striking plate of FIG. 1.

DESCRIPTION OF EMBODIMENTS

Referring to FIGS. 1 and 2, FIG. 1 is a schematic exploded view of a golf club head according to an embodiment of the present invention, and FIG. 2 is a schematic side view of the striking plate of FIG. 1. The golf club head 200 of this embodiment includes a head body 210 and a striking plate 220. The head body 210 has an opening 212. In this embodiment, the head body 210 may be a shell, and integrally formed by a common metal material (e.g., stainless steel) by way of lost-wax casing.

Alternatively, in other embodiments of the present invention, the head body 210 may be made of composite material of metal and high molecular plasticizing material or high strength fiber material (e.g., carbon fiber), and it is fabricated by the following steps. A crown (not shown) is separately prefabricated by injection molding or thermal compression molding, and then, the crown is embedded into another part of the metal shell. Alternatively, a carbon fiber pre-preg may be directly adhered on the hollow portion of the metal shell, and then heated by the use of a mold and an air bag so as to forming the body 210.

The striking plate 220 is disposed at the opening 221, for composing the golf club head 200 together with the head body 210. The striking plate 220 has a striking surface 222, and the striking plate 220 includes a first crystallization phase region 224 and at least one second crystallization phase region 226 (two second crystallization phase regions are schematically shown in FIG. 1). The second crystallization phase regions 226 are located in the first crystallization phase region 224, and extend from the striking surface 222 to an interior of the striking plate 220, and the elastic modulus of each second crystallization phase region 226 is smaller than that of the first crystallization phase region 224. In this embodiment, the second crystallization phase regions 226 are usually located outside of the center region 228 of the striking plate 220.

In this embodiment, a crystallization phase of the first crystallization phase region 224 includes β-type or α-β-type. The so-called β-type crystallization phase indicates that the crystallization mode is body-centered cubic lattice (BCC lattice), and the so-called α-β-type crystallization phase indicates that the crystallization modes include hexagonal close-packed lattice (HCP lattice) and BCC lattice. Moreover, a crystallization phase of each second crystallization phase region 226 includes α′-type or α″-type. The so-called α′-type crystallization phase indicates a hexagonal martensite, the so-called α″-type crystallization phase indicates an orthorhombic martensite, and both of them are incomplete-transformation crystallization phases formed due to quick cooling. Under the incomplete-transformation phase, the Ti alloy has a low elastic modulus.

It should be noted that, the so-called elastic modulus is Young's modulus, with the metric unit as Pascal (Pa for short). The elastic modulus of the material (usually a single atom metal or alloy) is inversely proportional to the COR, that is, the lower the elastic modulus of the material is, the higher the COR is. Therefore, not only the center region 228 of the striking plate 220 of this embodiment has a relatively high COR, but the second crystallization phase regions 226 of the striking plate 220 also have a relatively high COR, on the whole, the striking plate 220 has a larger region with high COR. In addition, in this embodiment, the elastic modulus of the first crystallization phase region 224 may be larger than or equal to 100 GPa (i.e., 100*10⁹ Pa), and a absolute value of the difference between the elastic modulus of the first crystallization phase region 224 and that of the second crystallization phase region 226 may be larger than or equal to 5 GPa and smaller than or equal to 10 GPa.

It should be noted that, in this embodiment, the striking plate 220 may be made of Ti alloy, for example, Ti-6Al-4V alloy, that is, the Ti alloy with the components of 90 wt % Ti, 6 wt % Al, and 4 wt % V. However, in another embodiment, the striking plate 220 is made of other kinds of Ti alloys, for example, Ti-8Al-1Mo-1V, Ti-6Al-2Sn-4Zr-2Mo, Ti-6Al-6V-2Sn, Ti-6Al-2Sn-4Zr-6Mo, Ti-8Mn, Ti-10V-2Fe-3Al, Ti-11.5Mo-6Zr-4.5Sn, Ti-15Mo-5Zr-3Al, and Ti-13V-11Cr-3Al.

Referring to FIG. 1, it should be noted in this embodiment that, the head body 210 and the striking plate 220 may be bonded through embedding and/or soldering. Furthermore, before the striking plate 220 is positioned, the solder may be pre-coated on the bonding surface of the head body 210 and the striking plate 220. Then, the striking plate 220 is disposed at the opening 212 of the head body 210, and then soldered such that the solder is melted and cooled so as to form a soldering layer (not shown) for connecting the head body 210 with the striking plate 220. Moreover, in another embodiment, first, the striking plate 220 is disposed at the opening 212 of the head body 210, and then, the solder is coated on the seam at the bonding position of the head body 210 and the striking plate 220, and after the solder is melted into the bonding surface, the soldering layer (not shown) is formed by cooling and solidification.

After the fabrication of the head body 210 of the gold club head 200, and the assembling of the head body 210 with the striking plate 220 is carried out. The method of fabricating the striking plate 220 is described below in detail. FIGS. 3A to 3C are schematic process flow views for fabricating the striking plate of FIG. 1. The method of fabricating the striking plate 220 of this embodiment includes the following steps. First, referring to FIG. 3A, a plate body P is provided, and a crystallization phase of the plate body P is a first crystallization phase. In this embodiment, the first crystallization phase includes β-type or α-β-type.

Next, referring to FIG. 3B, the plate body P is partially heated, that is, a part of the plate body is heated. In this embodiment, the step of partially heating the plate body P may be achieved by irradiating the plate body P with a high-energy laser beam L. In another embodiment, the step of partially heating the plate body P may be achieved by irradiating the plate body P with an electron beam (not shown).

Next, referring to FIG. 3C, the heated part of the plate body P is quenched such that the crystallization phase of the part of the plate body P is transformed into a second crystallization phase to form at least a second crystallization phase region 226 (two second crystallization phase regions are shown in FIG. 3C). Moreover; the step of quenching the heated part of the plate body P may be achieved by water cooling, air cooling, or furnace cooling, and a cooling rate for quenching the heated part of the plate body P may be larger than or equal to 10° C. per second. Furthermore, the second crystallization phase includes α′-type or α″-type.

After the steps of FIGS. 3A to 3C, a striking plate 220 with a first crystallization phase region 224 (with the first crystallization phase) and a plurality of second crystallization phase regions 226 (with the second crystallization phase) are substantially completed. In another embodiment, the appearance or the striking surface 222 of the striking plate 220 may be further processed, so as to make the appearance of the striking plate 220 correspond to the appearance of the opening 212 of the head body 210 (shown in FIG. 1), thus, the striking surface 222 achieves the required surface roughness.

To sum up, the golf club head and the method of fabricating the striking plate of the present invention at least have the following advantages.

First, since the striking plate of the present invention has the second crystallization phase region with a relatively low elastic modulus, that is, the second crystallization phase region is a relatively high COR, on the whole, the striking plate of the present invention has a larger region with a high COR.

Second, since in the method of fabricating the striking plate of the present invention, the second crystallization phase region with a low elastic modulus is formed in the plate body by partially heating and then quenching, without degrading the durability of the striking plate, the region with a high COR of the striking plate is enlarged.

Third, since in the method of fabricating the striking plate of the present invention, the method of irradiating with the laser beam or the electron beam are adopted to partially heat the plate body, the method of fabricating the striking plate of the present invention is simple and the manufacturing cost is low.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.

Claims

1. A golf club head, comprising:

a head body, having an opening; and

a striking plate, disposed at the opening and having a striking surface, wherein the striking plate comprises: a first crystallization phase region; and at least a second crystallization phase region, located in the first crystallization phase region, wherein the second crystallization phase region extends from the striking surface to an interior of the striking plate, and the elastic modulus of the second crystallization phase region is smaller than that of the first crystallization phase region.

2. The golf club head as claimed in claim 1, wherein a crystallization phase of the first crystallization phase region includes β-type or α-β-type.

3. The golf club head as claimed in claim 1, wherein a crystallization phase of the second crystallization phase region includes α-type or α″type.

4. The golf club head as claimed in claim 1, wherein the elastic modulus of the first crystallization phase region is larger than or equal to 100 GPa.

5. The golf club head as claimed in claim 1, wherein an absolute value of the difference between the elastic modulus of the first crystallization phase region and the second crystallization phase region is larger than or equal to 5 GPa and smaller than or equal to 10 GPa.

6. The golf club head as claimed in claim 1, wherein the striking plate is made of Ti alloy.

7. A method of fabricating the striking plate, applicable for a golf club head, comprising:

providing a plate body, wherein a crystallization phase of the plate body is a first crystallization phase;

heating a part of the plate body; and

quenching the heated part of the plate body to transform the crystallization phase of the part of the plate body into a second crystallization phase.

8. The method of fabricating the striking plate as claimed in claim 7, wherein the step of heating the part of the plate body is achieved by irradiating the plate body with a high-energy laser beam.

9. The method of fabricating the striking plate as claimed in claim 7, wherein the step of heating the part of the plate body is achieved by irradiating the plate body with an electron beam.

10. The method of fabricating the striking plate as claimed in claim 7, wherein the step of quenching the heated part of the plate body is achieved by water cooling, air cooling, or furnace cooling.

11. The method of fabricating the striking plate as claimed in claim 7, wherein a cooling rate of quenching the heated part of the plate body is larger than or equal to 10° C. per second.

12. The method of fabricating the striking plate as claimed in claim 7, wherein the first crystallization phase comprises β-type or α-β-type.

13. The method of fabricating the striking plate as claimed in claim 7, wherein the second crystallization phase comprises α′-type or α″-type.

14. The method of fabricating the striking plate as claimed in claim 7, wherein the plate body is made of Ti alloy.