JPH0241002Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to the improvement of a head for a golf club.
In particular, the object is to provide an excellent alternative to wooden heads.

In the past, persimmon trees were mainly used for golf heads, but although they can be used as heads due to their dimensions, the production volume is very small and it is difficult to obtain them, and since they are made of wood, they are easily affected by moisture, so it is difficult to obtain them. There are also concerns about poor balance and cracking, and in recent years, the use of plastic has been considered. Therefore, the fiber content is 5 to 60% by weight, and the fiber length is 0.2 to 35%.
Carbon fiber-reinforced plastics or glass fiber-reinforced plastics of mm are attracting attention, and golf clubs made from such fiber-reinforced plastics have a specific elasticity and hardness that have a significant impact on flight distance and hitting sound, compared to conventional persimmon wood. Comparable to the manufactured wood head. However, the inventors of the present invention have found that the rigidity is insufficient to withstand the large bending moment that acts on the neck portion of the head when the club is swung, and cracks are likely to occur in this neck portion due to bending strain.

The golf club head made of fiber-reinforced plastic according to the present invention can solve the above-mentioned problem in bending rigidity at the neck part, and the reinforcing fibers on the whole or surface of the neck part are stronger than the reinforcing fibers in other parts. This structure is characterized in that long fiber roving is used and the length direction of the long fibers is made to match the length direction of the neck portion.

The present invention will be explained below with reference to the drawings.

In FIG. 1, 1 is a head for a golf club, 1a indicates a neck portion, and the neck portion 1a is
It is molded from carbon or glass fiber-reinforced plastic (fiber direction matches the length direction of the neck) using long fibers (60 to 200 mm) as fibers, and the main body part 1b of the head other than the neck part is made of short fibers (60 to 200 mm) as fibers. 0.2 to 35 mm) from carbon or glass fiber reinforced plastic. 3 is a metal soul plate, which has a circular hole 31 as shown in FIG. 2A, or a long hole 3 as shown in FIG. 3A.
2,... (the circular holes 31,... are both inversely tapered as shown in Fig. 2B, and the elongated holes 32,... are both inversely tapered as shown in Fig. 3B), and the main body of the head is inserted into these holes. 1b
The fiber-reinforced plastic is digging in.

In the above, the amount of carbon or glass fiber in the fiber-reinforced plastic of the club main body 1b is 5 to 5.
60% by weight, and the fiber length is 0.2 to 35mm, with a specific elasticity comparable to that of persimmon wooden wood heads.
As described above, it has hardness. Further, the carbon or glass fiber of the fiber-reinforced plastic of the neck portion 1a has a length in the neck length direction.
Since long fibers of 60 to 200 mm are used, the bending rigidity of the neck part 1a can be increased, and therefore, the bending strain of the neck part is reduced in response to the bending moment that acts on the neck part due to the weight of the head when swinging the club. can be made sufficiently small.

In the above embodiment, the entire neck portion is molded from long fiber reinforced plastic.
As shown in the cross section), the part 10b excluding the surface of the neck part is molded with short fiber reinforced plastic, and the surface 10a of the neck part is covered with carbon roving or glass roving A, and the longitudinal direction of the roving is aligned with the longitudinal direction of the neck part. It is also possible to embed it so that it matches the . In the above, the average inner diameter of the neck (inner diameter of the shaft insertion hole) is d ₁ and the average outer diameter is
d ₂ and the Young's modulus per long fiber is e, then the bending stiffness (EI) ₁ of the neck in the example in which the reinforcing fibers in the entire neck are made of long fibers is the density of the long fibers.
As a ₁ , it is evaluated as (EI) ₁ = π(d ₂ ⁴ − d ₁ ⁴ )/64ea ₁ −.

In addition, the bending stiffness (EI) ₂ of the neck part in the example in which the reinforcing fibers on the surface of the neck part (average outer diameter: d ₂ , average inner diameter: d ₃ ) are long fibers is calculated by assuming that the density of the long fibers is a ₂ , (EI) ₂ = π(d ₂ ⁴ − d ₃ ⁴ )/64ea ₂ −.

On the other hand, as shown in FIG. 5 as a comparative example, the core part A of the neck part 100a (average inner diameter: d ₁ , average outer diameter:
The bending stiffness (EI) ₃ of the neck when the reinforcing fibers in d ₄ ) are long fibers is given by the density of the long fibers a ₃ , (EI) ₃ = π(d ₄ ⁴ − _{d 1} ⁴ )/64ea It can be evaluated as _3- .

Therefore, in all of the above cases, if the amount of long fibers used is the same, a ₁ (d ₂ ² − _{d 1} ² )=a ₂ (d ₂ ² −d ₃ ² )=a ₃ (d ₄ ² −d ₁ ² )=
Since K, (EI) ₁ = eπK/64 (d ₂ ² + d ₁ ² ) −′ (EI) ₂ = eπK/64 (d ₂ ² + d ₃ ² ) −′ (EI) ₃ = eπK/64 ( d ₄ ² + d ₁ ² ) −′.

Since d ₃ > d ₁ , I ₂ > I ₁ and d ₂ >
Since d ₄ , I ₁ > I ₃ , and therefore (EI) ₂ > (EI) ₁ > (EI) ₃ .

In this way, when the surface or the entire neck portion is made of long fibers, the bending rigidity can be increased for the same amount of fibers, compared to when only the core portion is made of long fibers.

As mentioned above, the golf club head according to the present invention is made of fiber-reinforced plastic, and the fibers on the entire or surface of the neck are made of longer fibers than the fibers of other parts, and the direction of the long fibers is adjusted. Since the neck part is made to match the length direction, the bending rigidity of the neck part can be sufficiently increased, and the amount of long fibers used can be relatively small, and the occurrence of cracks due to bending strain at the neck part can be well prevented.
FRP golf club heads can be provided at low cost.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a golf club head according to the present invention, FIGS. 2A and 3A are explanatory diagrams each showing another embodiment of the present invention, and FIGS. 2B and 3B are respectively FIG. 2A is an explanatory diagram showing the b-b cross section in FIG. 3A, FIG. 4A is an explanatory diagram showing another embodiment of the present invention, and FIG.
FIG. 5 is an explanatory diagram showing a comparative example. In the figure, 1a, 10a, and 100a are network portions, and 1b and 10b are other portions.

Claims (1)

[Scope of utility model registration request] In a golf club head made of fiber-reinforced plastic, the reinforcing fibers on the entire or surface of the neck are made of longer fibers than the reinforcing fibers in other parts, and the longitudinal direction of the long fibers is the same as the longitudinal direction of the neck. A head for a golf club characterized by matching the head.