JPH08252343A - Golf club head - Google Patents

Abstract

PURPOSE: To increase the volume of a golf club head and lower the center of gravity of the head to improve the flying distance and directional stability by forming at least a shell part in the golf club head consisting of the shell part and a sole part with a Mg-Li alloy having a specified specific gravity value. CONSTITUTION: At least a shell part 1 in a club head is casted by use of a sand mold, plaster mold, metal mold or lost wax mold with a Mg-Li alloy having a specific gravity not more than 1.6. The Mg-Li alloy is excellent in mechanical strength, cutting property, flowing property, and welding property, and the shell part 1 can be casted without causing a casting defect. The dead head part 3 of the shell part 1 after casting is removed, and an opening part is machined to form a stepped part 4 for fitting a sole part. A sole part 2 is fitted to the stepped part 4 of the shell part 1 and engaged by a screw 5. The sole part 2-may be formed of the same Mg-Li alloy as the shell part 1 or a wear resisting material such as stainless sleel. As the screw 5, a proper one such as aluminum can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a golf club head comprising a shell portion and a sole portion, which is called a wood club, among golf club heads.

[0002]

2. Description of the Related Art Conventionally, golf club heads called wood clubs have been made of lightweight materials such as stainless steel, titanium alloy, titanium alloy, aluminum alloy, and magnesium alloy. The purpose of forming a golf club head in a wood club with a lighter material is to increase the volume with the same weight, thereby lowering the center of gravity of the head and improving flight distance and directional stability. .

Among the various weight-reducing alloys mentioned above, the magnesium alloy has the smallest specific gravity as compared with other materials, and it can be said that it is the most suitable from the viewpoint of satisfying the recent demand for weight reduction of golf club heads. For example, JP-A-6-2
Japanese Patent No. 96714 describes a method of manufacturing a shell portion and a sole portion from a magnesium alloy by a precision casting method, and obtaining a golf club head by welding these, and by using a magnesium alloy having a small specific gravity as a material, a large size is obtained. It has been shown that it is possible to reduce the thickness.

However, in the golf club head described in the above publication, the general-purpose AZ91 alloy as a magnesium alloy has a specific gravity of 1.80, and even if the golf club head made of aluminum or titanium can be made lighter in weight. When the volume of the conventional club head made of titanium or aluminum is set to 200 cc, the weight reduction is about 240 cc at most, which is an improvement of 20% as compared with the conventional club head. It has been demanded.

The object of the present invention is to increase the volume by about 40% as compared with the conventional golf club head, further lower the center of gravity of the head, and improve flight distance and directional stability. It is to provide a golf club head capable of

[0006]

The golf club head of the present invention comprises a golf club head comprising a shell portion and a sole portion, at least the shell portion of which is made of an Mg-Li alloy having a specific gravity of 1.6 or less. By the above, the above-mentioned object is achieved.

In the present invention, the Mg-Li alloy means an alloy containing magnesium and lithium as main components and having a specific gravity of 1.6 or less, and may contain, for example, aluminum, silver or zinc. The content of magnesium, lithium and lithium or the content of other additive elements can be used as long as the specific gravity of these alloys is within the range of 1.6 or less. Mg-L targeted by the present invention
The upper limit of the specific gravity of the i alloy is set to 1.6 because a known magnesium alloy, typically AZ91, has a head volume of 300 cc, which exceeds 10% by weight. It is calculated from the product of 80 times 0.9, that is, 1.8 × 0.9 = 1.62. A specific example of the composition of the Mg-Li alloy is shown in Table 1, and mechanical properties (tensile strength, elongation) and specific gravity are also shown.

[0008]

[Table 1]

The present invention will be described below with reference to the drawings.
FIG. 1 (a) shows a shell portion 1 of a golf club head according to the present invention formed of an Mg-Li alloy, which is cast by a sand mold, a plaster mold, a mold, a lost wax mold or the like. Mg-Li alloy has mechanical strength, machinability, fluidity,
It has excellent weldability, and the shell portion 1 can be cast by the various casting methods described above without causing casting defects and the like. FIG. 1A shows a shell portion 1 in a cast state after casting, and 3 shows a riser portion. FIG. 1B shows a state in which the riser portion 3 is removed and the opening is machined to form a step portion 4 for fitting the sole portion. The sole portion 2 is fitted into the step portion 4 of the shell portion 1 and locked with the screw 5. The state is shown in FIG. 1 (c). The sole portion 2 may be the same Mg-Li alloy as the shell portion 1 or may be formed of a wear resistant material such as stainless steel. The screw 5 may be made of aluminum or any other suitable material.
Since the Mg-Li alloy according to the present invention has excellent weldability, the shell portion 1 and the sole portion 2 may be joined by welding or the like instead of screwing. Before locking the sole portion 2 to the shell portion 1, a balancer is attached inside the shell portion 1 to adjust the center of gravity. The weight of the golf club head thus formed is preferably 190 to 200 g.

[0010]

EXAMPLE A molten alloy containing Li: 9% by weight, Al: 1% by weight, and the balance Mg as an alloy composition was cast into a sand mold, and FIG.
A casting such as that of (a) was obtained. As can be seen from Table 1, the alloy used has a specific gravity of 1.50 and a tensile strength of 245 PMa.
It has an elongation of 15%, excellent machinability and can be welded. Then, the shell part 1 was formed by machining as shown in (b) → (c) of FIG. The obtained shell part had a head volume of 300 cc and a weight of 155 g. Next, the sole portion 2 made of the same alloy was formed by casting, the balancer was attached inside the shell portion 1, and then the sole portion 2 was screwed to the shell portion 1 using four aluminum screws 5. The final weight of the golf club head after mounting the center of gravity in this manner was 195 g.

[0012]

According to the present invention as described above, since at least the shell portion of the golf club head is formed by using the Mg-Li alloy having a small specific gravity, the shell portion can be made light and thin, and the head can be achieved. The head volume can be improved by more than 40% without increasing the weight, the center of gravity can be easily adjusted by the balancer, and the head volume can be increased to increase the hit zone and flight distance and direction stability. Can be improved.

[Brief description of drawings]

FIG. 1 is a process explanatory view when manufacturing a golf club head according to the present invention.

[Explanation of symbols]

 1 shell part 2 sole part 3 riser part 4 step part 5 screw part

Claims (1)

[Claims] 1. A golf club head comprising a golf club head including a shell portion and a sole portion, wherein at least the shell portion is formed of a Mg—Li alloy having a specific gravity of 1.6 or less.