JPH0575B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to golf clubs, and more particularly to golf clubs with improved club head construction.

Description of the Prior Art Regarding the performance of a golf club, it is desired that the golf club be able to fly a longer distance and have excellent directional stability. By the way, it has been known that if the club head is made of a material with higher hardness, the flight distance can be increased. however,
Conversely, when a hard club head is used, it has the disadvantage of lacking directional stability.

On the other hand, it has been found that a golf club with excellent directional stability can be obtained by constructing the club head from a softer material. However, in this case, contrary to the above-mentioned hard club head, there were drawbacks such as a lack of long distance and a drawback of being easily scratched.

As mentioned above, "directional stability" and "flying distance"
It was extremely difficult to achieve both.

OBJECT OF THE INVENTION The purpose of the invention is to eliminate the above-mentioned drawbacks,
The objective is to provide a golf club that can satisfy both "directional stability" and "flying distance."

Composition of the Invention In summary, the present invention includes a head having a multilayer structure consisting of an internal member and an external member that tightly surrounds the internal member over its entire surface. Only internal parts
It is made of a superelastic alloy that undergoes thermoelastic martensitic transformation, and the external members are made of steel, stainless steel,
A golf club, characterized in that it is made of a metal selected from the group consisting of copper alloys and copper alloys. In this invention, the interior of the club head is made of an alloy that produces stress-induced martensite due to stress when the ball is hit, and the superelastic behavior of the alloy when the ball is released can be used to increase flight distance. The objective is to improve ball retention due to the flexibility of the golf ball, that is, to improve directional stability by increasing the contact area between the golf ball and the club head and extending the contact time.

Examples of the above-mentioned "alloys that cause thermoelastic martensitic transformation" include NiTi alloys containing 50 to 60% by weight of Ni and the remainder being Ti, or Ni or up to 10% of the Ti containing Cu, Al, or V. , Fe,
NiTi alloys substituted with one or more elements selected from the group consisting of Co, Zr, etc., or An, Al, Ni, Si, Sn Examples include copper alloys containing one or more elements selected from the group consisting of , Be, Ga, Ge, Zr, etc. In addition, if it is an alloy that can cause thermoelastic martensitic transformation,
Any alloy can be used in this invention.

Preferably, the alloy constituting the internal member is
Constructed from materials manufactured by a powder sintering process. Thereby, a club head with better directionality can be constructed.

The "external member" can be made of various conventionally used metals or alloys such as copper alloys.

Effects of the Invention As described above, the present invention includes an internal member and a head having a multilayer structure of an external member tightly surrounding the internal member on its entire surface, and the internal member undergoes thermoelastic martensitic transformation. Since it is made of an alloy, stress-induced martensite is generated in the inner member in response to stress when the golf ball is hit, and normal elastic deformation occurs in the outer member. Since stress-induced martensite is more flexible than the normal austenite phase, it deforms easily, and along with the deformation, the external member also deforms elastically so that the golf ball slightly bites into it. As a result, the contact area between the golf ball and the club head is increased, resulting in better ball retention. Therefore, it is possible to obtain a golf club that has far superior directional stability compared to conventional golf clubs. In addition, when the golf ball leaves the club head, a repulsive force is obtained due to the superelastic behavior based on the unloading of the stress-induced martensite, and the golf ball itself is connected to an external member that is harder and has a larger coefficient of restitution. Because of the contact, it is possible to apply a larger repulsive force to the golf ball compared to the conventional repulsive force based on mere elastic behavior, and therefore, it is possible to obtain a greater "flying distance" than a conventional golf club. It becomes possible. As described above, the golf club of the present invention can achieve the "flying distance" which was difficult to achieve at the same time.
It satisfies both the requirements of "direction stability" and "directional stability", and provides an ideal golf club. Furthermore, in the golf club of the present invention, the golf ball is repelled by the superelastic behavior associated with the unloading of stress-induced martensite, so that a ball hitting point range with excellent directionality within the face portion of the club head, ``the so-called sweet spot.'' ” has been dramatically expanded, and the so-called ball retention is good, making it possible to easily apply backspin.

It should be pointed out that the present invention is applicable to a variety of golf clubs in general, such as irons.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 is a front view schematically showing a club head of a golf club in which the present invention is implemented. Since this invention is characterized by the internal structure of the club head, each embodiment will be described below using a diagram corresponding to the sectional view taken along the line A--A in FIG. 1.

Example 1 As shown in the sectional view in FIG. 2, a head 3 consisting of an internal member 1 and an external member 2 was manufactured. In this example, the internal member 1 is made of 56% Ni by weight and the balance is
After hot forging and cold forging a NiTi alloy ingot made of Ti, it is cut into blocks, processed and subjected to a prescribed heat treatment, and the external member 2 is constructed using ordinary steel, as shown in Fig. 3. A 5-iron with a head 3 like this was created. When the flight distance and directional stability of a hit ball were tested using the golf club of this example, it was confirmed that it exhibited much better directional stability and a greater flight distance than conventional golf clubs. Also, when I tried to apply a backspin, the backspin was applied effectively and reliably.

Example 2 As shown in FIG. 3, an internal member 1 and an external member 2
A sandwich wedge was obtained by constructing head 3 consisting of. Internal member 1 is Ni55% by weight, Ti44% by weight
A sandwich wedge having a head 3 in FIG. 3 was prepared by heating and sintering NiTiCu powder containing 1% by weight of Cu and pressed into a desired shape, and combining it with an external member 2 made of steel.

When the sand wedge of Example 2 was actually tested using a golf ball, it was confirmed that it exhibited far superior directional stability and greater flight distance than conventional sand wedges.

Example 3 As shown in FIG. 4, an internal member 1 and an external member 2
A No. 7 iron was made using the head 3 having the following. Internal member 1 is Zn25% by weight, Al5% by weight
A Cu-Zn-Al alloy ingot containing Zn and the remainder being Cu was hot extruded and cold forged, then cut into blocks, machined, and then heat treated. Further, the external member 2 was prepared by cutting stainless steel.

The No. 7 iron 6 having the head 3 of Example 3 was also tested using an actual golf ball, and showed far superior directional stability and superior flight distance compared to the conventional iron. I found out that there was.

Example 4 As shown in FIG. 5, an internal member 1 and an external member 2
A 9-iron was made using head 3 consisting of. Here, as internal member 1, Al14% by weight,
Cu-Al containing 7% by weight of Ni and the balance consisting of Cu
- After pressing the Ni alloy powder into the desired shape,
The inner member 1 was prepared by heating and sintering, and the outer member 2 was prepared by cutting steel.

Example 4 obtained in this way was also tested using a golf ball, and it was found that it exhibited far superior directional stability and was able to achieve a greater flight distance than the conventional 9-iron. was confirmed.

[Brief explanation of drawings]

FIG. 1 is a front view showing the head of a golf club to which the present invention is applied. FIG. 2 is a sectional view of the first embodiment of the invention. FIG. 3 is a sectional view of a second embodiment of the invention. Figure 4 shows
FIG. 3 is a sectional view showing a third embodiment of the invention. FIG. 5 is a sectional view showing a fourth embodiment of the invention. 1... Internal member, 2... External member.

Claims (1)

[Scope of Claims] 1. A head having a multilayer structure consisting of an internal member and an external member that tightly surrounds the internal member on its entire surface, wherein only the internal member is included among the members constituting the head. is made of a superelastic alloy that undergoes thermoelastic martensitic transformation, and the external member is made of a metal selected from the group consisting of steel, stainless steel, and copper alloy. 2 The alloy that causes thermoelastic martensitic transformation may be a NiTi alloy containing 50 to 60% by weight of Ni and the remainder being Ti, or up to 10% of the Ni or Ti may be alloyed with Cu, Al, V, Fe, Co, or Zr. NiTi substituted with one or more elements selected from the group consisting of
The golf club according to claim 1, which is an alloy. 3. The superelastic alloy that undergoes thermoelastic martensitic transformation has copper as its main component and contains Zn, Al, Ni, Si, Sn,
The golf club according to claim 1, which is a copper alloy containing one or more elements selected from the group consisting of Be, Ga, Ge, and Zr. 4. The golf club according to any one of claims 1 to 3, wherein the internal member is a member manufactured by a powder sintering process.