JP2003047676A - Wood golf club head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimumly set a head center of gravity according to a loft angle. SOLUTION: This wood golf club head comprises two or more kinds of wood golf club heads having the same number but different in the loft angle. The head volume of each golf club head is 250 cm<3> or more. In a head measuring state where the axial line of a shaft insert hole for installing a shaft is arranged within a vertical plane VP1 with a regulated lie angle, and a face surface is placed on a horizontal plane according to a regulated face angle, a head profile line K projected to the horizontal plane has a head tail point P farthest from the vertical plane VP1 backward of the head, which is located closer to the heal side as the loft angle is larger to arrange the head center of gravity on the heal side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wood type golf club head group comprising a plurality of types of wood type golf club heads having the same count and different loft angles.

[0002]

2. Description of the Related Art Wood type golf club heads such as drivers usually have a plurality of types with different loft angles even if they have the same number (# 1 here). And it is being sold. Usually, golfers have different head speeds. Therefore, a golfer with a high head speed has a small loft angle, and a golfer with a low head speed has a large loft angle.

Golfers with high head speeds
Generally, the head tends to return at the time of impact of the ball. Therefore, the head having a smaller loft angle is usually set to the toe side so that the head does not easily return. On the other hand, golfers with a low head speed tend to have difficulty returning, so the center of gravity of the head is set on the heel side, and the head is designed to be easy to return. Further, the design of the center of gravity of the head is usually performed mainly by fixing a weight member having a large specific gravity to the inside of the head.

However, with the recent increase in head volume and the like, the room for fixing the weight member and the like is running out, making it difficult to design an appropriate center of gravity. More specifically, it is difficult to design a large change in the center of gravity of the head.

The present invention has been made in view of such an actual situation, and the rearmost point of the head in the head contour line projected on a horizontal plane is located closer to the heel side as the head having a larger loft angle, and the center of gravity of the head is heeled. The present invention relates to a wood-type golf club head group capable of securing a large amount of movement of the center of gravity, basically arranged on the side.

[0006]

According to a first aspect of the present invention, there is provided a wood type golf club head group comprising a plurality of types of wood type golf club heads having the same count and different loft angles. The head volume of each golf club head is 250 cm ³ or more, the shaft center line of the shaft insertion hole in which the shaft is mounted is arranged in a vertical plane, and the face is inclined with a prescribed lie angle. When the head is placed on a horizontal plane according to the angle, the head contour line projected on the horizontal plane is located at the rearmost point of the head farthest from the vertical plane toward the rear of the head, and the head having a larger loft angle is positioned closer to the heel side. The center of gravity of the head is located on the heel side.

According to a second aspect of the present invention, the loft angles of the wood type golf club heads are α1, ..., αn (unit: °) in order from the smallest loft angle, and the distance of the center of gravity is L1,
, Ln (unit: mm), the following formula (1) is satisfied, and the wood type golf club head group according to claim 1. (Ln-1 -Ln) / (αn -αn-1)> 1.1 (Unit: mm / °) (1)

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 illustrates a head of a driver (# 1) as a wood type golf club head (hereinafter, may be simply referred to as “head”) 1. The head 1 has a face portion 3 having a face surface 2 which is a surface for hitting a ball, a crown portion 4 which is a head upper surface and is connected to an upper edge 2a of the face surface 2, and the face surface 2
The sole portion 5 that connects to the lower edge 2b and forms the bottom surface of the head (see FIG.
Is not visible), and the side portion 6 that connects the crown portion 4 and the sole portion 5 and extends from the toe 2t of the face surface 2 through the back face to the heel 2e of the face surface 2, the face portion 3 and the crown. An example is one provided with a neck portion 7 which is provided in the vicinity of the intersection on the heel side e where the portion 4 and the side portion 6 intersect and to which one end of a shaft (not shown) is mounted. A circular shaft insertion hole 7a is formed in the neck portion 7, and when the head 1 is aligned with the lie angle, the shaft center line CL of the shaft insertion hole 7a can be used as a reference.

The head 1 can be formed of various metal materials such as aluminum alloy, titanium, titanium alloy, and stainless. A titanium alloy having a high specific strength is preferable. In this example, the main part of the head is formed by precision casting of lost wax using Ti-6Al-4V which is an α + β type titanium alloy, and joining the remaining parts to this by welding or the like. However, the present invention is not limited to such an aspect, other materials,
It goes without saying that it can be manufactured by another molding method.

The present invention is directed to a wood type golf club head group including a plurality of types of heads 1 having the same count and different loft angles. The "same count" means that the count numbers displayed on the head 1 are the same. If the loft angle is different, for example, 1 °,
The angle can be changed in equal or irregular angle increments of about 1.5 ° or 2.0 °. In the present embodiment, the wood-type golf club head group S (hereinafter, simply referred to as "head group") is made up of three types of driver heads 1 whose loft angles are changed by 9 degrees, 10 degrees, and 11 degrees in steps of 1 degree. There are some cases). The loft angle used in this specification is a real loft angle that is the inclination of the face surface with respect to the axial center line of the shaft insertion hole CL.

In FIG. 2, each head 1 of the head group S of this embodiment is arranged with the axial center line CL of the shaft insertion hole 7a in the vertical in-plane VP1 as shown in FIGS. In the head measurement state in which the face surface 2 is tilted at the specified lie angle β and the face surface 2 is placed on the horizontal surface HP with the specified face angle δ, the head contour line K projected on the horizontal surface HP is measured.
(K1, K2,
K3) is shown. Further, FIG. 6 shows an enlarged head contour line K of a head having a loft angle of 9 °.

In the head contour lines K1, K2, K3, the head is located farthest from the vertical plane VP1 to the rear of the head (the distance N perpendicular to the vertical plane to the head contour line is maximum as shown in FIG. 6). The last points P1, P2, P3 are
The head with a larger loft angle is positioned closer to the heel. That is, the head rearmost point P2 having a loft angle of 9 ° is set to be closer to the heel side than the rearmost point P1 of the head having a loft angle of 8 °, and the loft angle is more than the rearmost point P2 of the head having a loft angle of 9 °. The head end point P3 of 10 ° is set to the heel side.

In the head group S, a head having a larger loft angle is provided with the head rearmost point P on the heel side. Specifically, in the head contour line K shown in FIG. , A head length B that is a length along a vertical plane VP1 between the heel end point PH forming the most heel side, and a length along the vertical plane VP1 between the heel end point PH and the head rearmost point P. Ratio with A (A / B)
However, it means that the larger the loft angle α, the smaller the head. The heel side end PT substantially forms a boundary with the neck portion 7.

As described above, in each head 1 of the head group of the present embodiment, the head rearmost point P is located closer to the heel side as the head having the larger loft angle α is positioned at the loft angle α.
Change according to. Since the weight distribution is relatively large in the vicinity of the rearmost point of the head, the center of gravity G of the head can be moved by moving the rearmost point P of the head. Therefore, the larger the loft angle α, the more weight can be distributed to the heel side, and the center of gravity G of the head can be distributed closer to the heel side.

The volume and mass of the head 1 included in the head group S and the length of the neck portion 7 may be set to be substantially the same or may be different. However, it is necessary to set the head volume of each head to 250 cm ³ or more. When the head volume is less than 250 cm ³ , even if the head rearmost point P is moved to the heel side and the head shape is changed as described above, the movement of the center of gravity of the head does not follow such a change in the head shape. The center of gravity of the head cannot be effectively changed significantly. From this viewpoint, the head volume of each head 1 is 270 cm ³ or more, more preferably 300 cm ³ or more, and further preferably 310 to 450 cm ^3.
It is desirable to set the degree.

In each head 1 of the head group S,
If the rearmost point P of the head is too close to the heel side, or conversely, it is too close to the toe side, the shape of the head becomes peculiar, and a sense of discomfort tends to occur when the head is held. From such a viewpoint, the ratio (A / B) is, for example, 0.35 to 0.65, and more preferably 0.45 to 0.65.
It is desirable to set it to 0.60. Further, as shown in FIG. 6, in the head contour line K, a toe side curve C1 that joins the head rearmost point P and the toe side end PT, and a heel side curve C2 that joins the head rearmost point P and the heel side end PH. Is not particularly limited, but it is desirable to form smoothly using various curves such as a single arc, a compound arc, or an elliptic curve.

Although not particularly limited, as described above, by changing the position of the rearmost point P of the head,
The loft angle of the head group S is α1 in order from the smallest loft angle.
, .Alpha.n (unit: .degree.) And the distance of the center of gravity of the head is L1, ..., Ln (unit: mm), it becomes possible to set so as to satisfy the following formula (1). (Ln-1 −Ln) / (αn −αn-1)> 1.1 (unit: mm / °) (1) The center of gravity distance means the shaft insertion hole 7a of the shaft insertion hole 7a as shown in FIG. It is the shortest length from the axis center line CL (or its extension) to the center of gravity G of the head.

Generally, the center-of-gravity distance L becomes smaller as the center of gravity G of the head gets closer to the heel side, but according to this embodiment, the change of the center-of-gravity distance L per 1 ° of the loft angle is expressed by the above equation (1). The amount can be limited to more than 1.1 mm, and a larger movement of the center of gravity of the head can be realized. The head group consisting of conventional large-sized heads is almost
The value of -Ln) / (αn-αn-1) is smaller than 1.1 (mm / °). It is particularly preferable to satisfy the following formula (2), more preferably the following formula (3). (Ln-1-Ln) / (αn-αn-1) ≧ 1.2 (unit: mm / °) (2) (Ln-1-Ln) / (αn-αn-1) ≧ 1.5 ( Unit: mm / °) (3)

The center of gravity distance L is, for example, 20 to 45.
mm, and more preferably from 28 to 38 mm. When the center-of-gravity distance L exceeds 45 mm,
Even a golfer with a high head speed tends to have difficulty returning the head. On the other hand, if it is less than 20 mm, the golfer with a low head speed tends to return too much, which results in a hit ball. It tends to impair directional stability.

In order to realize a larger movement of the center of gravity G of the head, for example, FIG.
As shown in, the crown portion 4, the sole portion 5, or the side portion 6
In a part of the above, the thickness t2 of the region on the heel side of the rearmost point P of the head can be made larger than the thickness t1 of the region on the toe side of the rearmost point P of the head. A vertical plane VP2 passing through the rearmost point P of the head and perpendicular to the vertical plane VP1.
6 and 7, the heel side region and the toe side region are bounded by the vertical plane VP2. This makes it possible to change the center of gravity G of the head in the set group S even more significantly, in combination with changing the position of the rearmost point P of the head.

For example, in the crown portion 4, the thickness t2 of the heel side region is, for example, 1.05 to 2.0 times, more preferably 1.5 to 2.0 times the thickness t1 of the toe side region.
It is desirable to set it to about 2.0 times. When the thickness changes, the average thickness is set as described above. Further, the sole portion 4 and the side portion 6 can be set in the same manner as above when the thickness is changed.

Further, FIGS. 8A and 8B show still another embodiment of the present invention. 8A is a sectional view taken along the line ZZ of FIG. 3, and FIG. 8B is a sectional view taken along the line YY of FIG. In this example, the vertical plane VP2 passing through the rearmost point P of the head has a crown portion 4, a sole portion 5, and a side portion 6.
The thickness t3 of the intersection F having a predetermined width including a position intersecting with
Is larger than the thickness t4 of the portion on the toe side or the heel side. In other words, it is desirable that the thickness on the vertical surface VP2 be larger than the thickness on the plane parallel to the vertical surface VP2.

Although the embodiment of the present invention has been described in detail above, for example, a weight member having a large specific gravity can be used together. In this case, since the head shape is changed instead of the weight member alone, the effect can be sufficiently exerted even if the lightweight weight member is used. The wood-type golf club head group of the present invention is implemented as a wood-type golf club group with shafts attached.

[0024]

(Embodiment 1) 3 having the basic form shown in FIG.
A group of wood type golf club heads (Examples 1 to 3) consisting of various types of wood type golf club heads were prototyped based on the specifications in Table 1 and the center-of-gravity distance was measured. For comparison, measurements were also performed on a wood type golf club head group outside the present invention. In each head group, the head volume was 320 cm ³ , and the head mass was 188 g, which were set substantially the same. The loft angle was 8 °, 9 °, and 10 ° in each set group. Table 1 shows the head specifications and measurement results.

[0025]

[Table 1]

As a result of the test, it was confirmed that the golf club heads of the examples can have a larger amount of change in the center-of-gravity distance than the conventional examples, and can form a golf club head group applicable to a wider range of golfers. .

[0027]

As described above, according to the first aspect of the invention, in each head of the head group, the head rearmost point having a high weight distribution ratio is located closer to the heel side as the loft angle α is larger. Since the shape of is changed according to the loft angle, the center of gravity of the head can be largely moved following this. Therefore, the larger the loft angle α, the more weight can be distributed to the heel side, and the center of gravity of the head can be located closer to the heel side, and the degree of freedom in designing the head can be greatly improved. .

According to the second aspect of the present invention, by controlling the loft angle of each wood type golf club head of the head group and its center-of-gravity distance by a constant relational expression, a large difference can be achieved between heads having different loft angles. The change of the distance of the center of gravity can be set, and further.

[Brief description of drawings]

FIG. 1 is a perspective view showing a head of this embodiment.

2A to 2C show head contour lines of a wood type golf club head group.

FIG. 3 is a front view showing a measurement state of a head.

FIG. 4 is a side view showing a measurement state of the head.

FIG. 5 is a plan view showing a measurement state of the head.

FIG. 6 is an enlarged view of a head contour line.

FIG. 7 is a sectional view taken along line YY in FIG. 6 showing another embodiment of the present invention.

8A and 8B show another embodiment of the present invention, in which FIG. 8A is a sectional view taken along line ZZ in FIG. 3, and FIG. 8B is a sectional view taken along line YY in FIG.

[Explanation of symbols]

1 Wood type golf club head 2 face 3 face part 4 Crown 5 sole part 6 side part 7 neck

Claims (2)

[Claims] 1. A wood type golf club head group comprising a plurality of wood type golf club heads having the same count and different loft angles, each golf club head having a head volume of 250 cm ³ or more, and In a head measurement state in which the shaft center line of the shaft insertion hole in which the shaft is mounted is arranged in a vertical plane and is tilted at a specified lie angle, and the face surface is placed on a horizontal surface in accordance with the specified face angle, The contour line of the head projected onto the wood is characterized in that the rearmost point of the head, which is most distant from the vertical surface to the rear of the head, is located on the heel side as the head having a larger loft angle, and the center of gravity of the head is arranged on the heel side. Type golf club heads. 2. A loft angle of each of the wood type golf club heads in the order of decreasing α1, ..., αn (unit:
.Degree.), And the distance of its center of gravity is L1, ..., Ln (unit: mm), the following formula (1) is satisfied, and the wood type golf club head group according to claim 1. (Ln-1 -Ln) / (αn -αn-1)> 1.1 (Unit: mm / °) (1)