JP2003220160A - Golf club head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an iron type golf head effectively decreased a resistance from the ground by devising a shape of a curved-surface at the base of the sole of the iron type golf club head. <P>SOLUTION: The iron type golf head has the base 21 of the sole having a curved-surface. The radius of curvature in a tow heel direction of the curved- surface surrounded by a tow side score line 61, a heel side score line 62, a leading edge 31 and a trailing edge 32 is gradually decreased toward the trailing edge 32 from the leading edge 31, and the radius of the curvature in a face back direction is gradually decreased toward a heel side from a tow side. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the shape of the bottom surface of a sole portion of an iron type golf club head.

[0002]

2. Description of the Related Art When a golf ball placed on the ground is hit by a golf club head, if the sole portion comes into contact with the ground, resistance is added from the ground, which reduces the head speed at the moment of impact and swings after hitting. There arises a problem of feeling uncomfortable. As shown in FIG. 7, since the center of gravity 71 of the head is on the toe side of the shaft axis 72, a phenomenon called toe down occurs at the time of impact due to the centrifugal force applied during the downswing. The dotted line portion in FIG. 7 is a state in which toe down is occurring.

However, when the downswing cannot be performed on the correct trajectory, the toe down at the time of hitting becomes insufficient and the heel portion often bites into the ground. In that case, the bottom of the sole part receives resistance from the ground as the heel part digs into the ground, causing unnecessary rotational force in the direction in which the face closes around the heel part, and the head speed decreases at the moment of impact. The state of the head when hitting becomes unstable. As a result, there are problems such as variations in the direction of the ball being hit, a reduction in flight distance, and a poor feeling of swinging after hitting the ball.

Therefore, various techniques have been applied to the shape of the sole portion to reduce the resistance due to contact with the ground and the above-described method for preventing the heel portion from biting into the ground when hitting. became.

For example, the radius of the barge of the sole from the leading edge to the trailing edge is smaller than 20 mm, and the sole round is 130 mm.
It is formed with a curved surface smaller than that, and the barger round is formed with two curved surfaces that are continuous from the face side to the rear surface side, and the boundary portion is formed in a ridge shape in the longitudinal direction of the head, so that An iron type golf club head is disclosed in which the resistance from the ground is reduced (see, for example, Patent Document 1).

[0006]

[Patent Document 1] Japanese Unexamined Patent Publication No. 2-63483 (page 1,
(Fig. 1)

[0007]

The above-mentioned sole shape is
Since the radius of curvature of the round bar and the sole round is very small and the contact area with the ground is small as compared with the usual iron club head, even if the toe down is not sufficient, the bite of the heel portion to the ground is reduced. However, since the radius of curvature of the barger round and the radius of curvature of the sole round are constant and their values are very small, there arises a problem that the head is not stable at the time of hitting the ball.

Further, in the above-mentioned sole shape, as shown in FIG. 8 (based on FIG. 1 of Patent Document 1), when the golf ball 83 placed on the ground is hit, the leading edge 81 and the ground are separated from each other. There is a distance between the golf ball ball 83 and the leading edge 81, not the face surface 82.
Since it hits the ball, it hits the top and the ball does not go up, which causes problems such as variations in the hitting direction and a reduction in flight distance.

In order to solve the problems of the prior art, the present invention devises the shape of the bottom surface of the sole portion of the iron type golf club head to effectively reduce the resistance received from the ground. The purpose is to provide a club head.

[0010]

According to a first aspect of the present invention, there is provided a curved surface shape of a bottom surface of a sole portion of an iron type golf club head, the toe side score line width line, the heel side score line width line, and the leading edge. The radius of curvature in the toe / heel direction on the curved surface surrounded by and the trailing edge is gradually decreased from the leading edge to the trailing edge, and the value of the radius of curvature in the face back direction is changed from the toe side to the heel side. The iron-type golf club head is characterized in that it is gradually reduced toward the front. The distance from the toe side score line width line to the heel side score line width line is not particularly limited, but is generally about 48 mm to 62 mm.

According to a second aspect of the present invention, the bottom surface of the sole portion of the iron type golf club head is curved, and the distance from the toe side score line width line, the heel side score line width line and the leading edge is 6 mm. The value of the radius of curvature in the toe / heel direction on the curved surface surrounded by the curve and the curve whose distance from the trailing edge is 3 mm is gradually reduced from the leading edge to the trailing edge, and the radius of curvature in the face back direction is reduced. The iron-type golf club head is characterized in that the value is gradually reduced from the toe side to the heel side. In the invention of claim 2, the distance from the toe side score line width line, the heel side score line width line, and the leading edge is 6 mm.
Is limited to the curved surface surrounded by the curved line of 3 mm and the curve with a distance of 3 mm from the trailing edge in order to correspond to the shape of the sole portion chamfered on the leading edge and / or the trailing edge as described later. Is.

[0012]

1 is a perspective view showing a bottom surface 21 of a sole portion of a golf club head 1 according to the present invention, and FIGS. 2 and 3 are views of the golf club head 1 as seen from the bottom surface 21 side of the sole portion. is there. In order to describe the curved surface shape of the sole bottom surface 21, curves A1 to A4 are provided in the toe / heel direction on the sole bottom surface 21 and curves B1 to B7 are provided in the face back direction, as described later.

The toe side score line width line used in the description of the present invention means a toe side end portion of the score line which is perpendicular to both the ground and the face surface when the golf club head is in contact with the lie angle. When the length of the score line is various, it is a line of intersection between the plane passing through the end portion on the most toe side) and the bottom surface of the sole portion. The heel side score line width line is perpendicular to both the ground and the face surface when the golf club head is in contact with the lie angle, and is on the heel side end of the score line (when the score line has various lengths. Is the end on the heel side)
It is a line of intersection between the plane passing through and the bottom surface of the sole portion.

The shapes of the leading edge 31 and the trailing edge 32 when viewed from the bottom side of the sole portion are not limited to the linear shapes as shown in FIGS. 2 and 3, but may be the curved shapes as shown in FIG. is there. In order to deal with such a shape, the curves A1 to A4 are defined as follows in the present invention.

As shown in FIGS. 2 and 4, the intersection of the leading edge 31 and the toe side score line width line 61 is M
1, the intersection of the leading edge 31 and the heel side score line width line 62 is M2, and the straight line connecting M1 and M2 is the reference line A0. A curve with a distance of 6 mm from the reference line A0 is A1, and a curve with a distance of 9 mm is A2. "Curve with a distance of 6 mm from the leading edge"
Means the curve A1, and the "region where the distance from the leading edge is 6 mm or more and 9 mm or less" means the curve A1.
It is an area between the curve A2 and the curve A2.

Similarly, on the trailing edge 32 side, the intersection on the toe side between the trailing edge 32 and the toe side score line width line 61 is M3, and the trailing edge 32 is shown.
And the intersection of the heel side score line width line 62 with M4,
A straight line connecting M3 and M4 is defined as a reference line A00. A curve with a distance of 6 mm from the reference line A00 is A3, and a curve with a distance of 3 mm is A4. "Curve with a distance of 3 mm from the trailing edge" means curve A4, and "the distance from the trailing edge is 3 mm or more and 6 m.
The "area equal to or less than m" is an area sandwiched between the curve A3 and the curve A4.

The curves B1 to B7 are defined as follows. Toe side score line width line 61 is B1, a curve with a distance of 10 mm from toe side score line width B2 is B2, heel side score line width line 62 is B7, and a curve with a distance of 10 mm from heel side score line width line 62 is B6, curve B2
The curve in the center between the curve B6 and the curve B6, and the curve B2 and the curve B4
The central curve between and is B3, and the central curve between the curves B4 and B6 is B5. Therefore, the area in the toe-heel direction from the curve B2 to the curve B6 is divided into four equal parts by the curves B3, B4 and B5. The method of defining the curves B1 to B7 is the same when the leading edge 31 and / or the trailing edge 32 shown in FIG. 4 are curved.

When viewed from the sole bottom 21 side, the curve A
1 and A2 are parallel, and curves A3 and A4 are parallel. The curves B1 to B7 are parallel to each other. Curve A
1 to curve A4 and curve B1 to curve B7 are shown in FIG. 2 and FIG.
When viewed from the bottom surface 21 side of the sole portion as shown in FIG.

In some iron type golf club heads,
You can also see the leading edge chamfered for the purpose of preventing the leading edge from sticking to the ground at the time of impact with down blow and for design purposes.
There is also a trailing edge chamfered for the purpose of preventing the swinging feeling from being deteriorated when the trailing edge comes into contact with the ground after impact (especially in a head with a wide sole width). In most cases, the chamfered head described above has a flat chamfered surface, and if such a chamfered surface is included, the radius of curvature of the curved surface cannot be measured. The chamfered surface on the leading edge side is 5m from the leading edge
Most of them are around m, so in the present invention, the region of 6 mm or more and 9 mm or less from the leading edge was set as the radius of curvature measurement region. The chamfered surface on the trailing edge side is almost 2 mm from the trailing edge, so 3 m from the trailing edge.
A region of m or more and 6 mm or less was set as a radius of curvature measurement region.

The radius of curvature used in the present invention is the radius of the arc when the above curves are approximated to one arc.

An Earl gauge (made by Uchida Yoko) was used to measure the radius of curvature. Apply various R-gauges in parallel with the curves (curve A1 to A4 and B1-C7) of the measurement area on the bottom of the sole, and set the value of the radius gauge closest to the curve on the bottom of the sole to the radius of curvature. Value.

The shape of the bottom surface 21 of the sole portion of the golf club head 1 according to the present invention is a curved surface surrounded by the score line width 6, the leading edge 31 and the trailing edge 32, and has a leading radius of curvature in the toe / heel direction. It gradually decreases from the edge 31 toward the trailing edge 32. Using the above curve, curve A1
The radius of curvature gradually decreases from the curve A4 to the curve A4. Further, the radius of curvature in the face back direction is gradually reduced from the toe side to the heel side. If the above curve is used, the radius of curvature gradually decreases from the curve B1 to the curve B7.

The bottom surface 21 of the sole portion having the radius of curvature as described above.
If the curved surface is formed, unlike the conventional product shown in FIG. 8, the face toe area 51 has a shape close to a flat surface, and the distance between the leading edge 31 and the ground is short, so that it is effective in preventing top striking. Since the back heel region 52 has a rounded curved surface, the resistance received from the ground by the heel portion 4 can be reduced even when the toe down is insufficient at the time of hitting the ball, so that the head speed is reduced due to the resistance from the ground and the face is closed. It is possible to solve problems such as unnecessary rotation force and poor swinging feeling.

In the present invention, in the above curved surface, the toe in the area (distance between the curve A1 and the curve A2) whose distance from the leading edge 31 is 6 mm or more and 9 mm or less.
The value of the radius of curvature in the heel direction is 200 mm or more and 280 mm
It is as follows. Within the region, the curves A1 to A2
Although the value of the radius of curvature gradually decreases toward, the value of the radius of curvature is included in the range from 200 mm to 280 mm at any place in the region.

In the above area, the larger the radius of curvature is, the more the area on the side of the leading edge 31 becomes a curved surface, so that the horizontal lie shown in FIG.
At the time of impact, the distance between the leading edge 31 and the ground becomes short, and top hitting can be prevented. However, when the value of the radius of curvature is 280 mm or more, the radius of curvature is too large. Therefore, in the case of a toe-up lie shown in FIG. 5 (b), the toe portion easily pierces the ground at the time of impact,
The toe-down lie shown in FIG. 5C causes a problem that the golf club head is not stable at the time of impact such that the heel portion is likely to be stuck into the ground at the time of impact.

As the radius of curvature is smaller, the region on the side of the leading edge 31 has a more rounded curved surface, so that the ease of hitting with a lie with a toe up or a lie with a toe down improves. However, if the value of the radius of curvature is 200 mm or less, the radius of curvature is too small, and the region on the leading edge 31 side has an excessively rounded curved surface, which makes it difficult to hit with a horizontal lie. Further, since the mass distributed to the sole portion is decreased and the position of the center of gravity is increased, the operability of the club is deteriorated. As in the present invention, the value of the radius of curvature in the toe / heel direction is set to 200.
The above problems can be solved by setting the thickness to be ≧ mm and 280 mm. Such an effect can be achieved by setting the radius of curvature to 220 mm.
Especially when it is set to 260 mm or less.

In the present invention, in the above curved surface, the value of the radius of curvature in the toe-heel direction is set in the region where the distance from the trailing edge 32 is 3 mm or more and 6 mm or less (the region sandwiched between the curve A3 and the curve A4). 200 mm over 140 mm
mm or less. In the area, the value of the radius of curvature gradually decreases from the curve A3 to the curve A4, but the value of the radius of curvature is 140 m at any place in the area.
It is included in the range from m to 200 mm.

If the value of the radius of curvature is 200 mm or more, the radius of curvature is too large.
Has a shape close to a flat surface, and the resistance received from the ground by the heel portion 4 is large when the toe down is insufficient at the time of hitting the ball, so that the head speed is lowered, unnecessary rotational force generated in the direction in which the face is closed, and swinging feeling are deteriorated. The problem arises.

Further, the smaller the radius of curvature in the above area is, the more rounded the curved surface of the back heel area 52 becomes, so that the easiness of hitting with a lie with a raised toe or a lie with a lowered toe is improved and a hit ball is hit. At times, even when the toe down is not sufficient, the resistance received by the heel portion 4 from the ground can be reduced. However, the value of the radius of curvature is 1
If the radius is less than 40 mm, the radius of curvature will be too small, and the mass distributed to the back heel side will be insufficient, and the center of gravity of the golf club head will move toward the toe side and the top edge side, which will reduce the operability of the club. Occurs. As in the present invention, the value of the radius of curvature in the toe / heel direction is set to 140
The above-mentioned problem can be solved by setting the thickness to be 200 mm or more and 200 mm or less. The effect is to set the radius of curvature to 160 mm.
Especially when it is 180 mm or less.

In the present invention, in the above-mentioned curved surface, in a region where the distance from the toe side score line width 61 is 0 mm or more and 10 mm or less (the region sandwiched between the curves B1 and B2), the radius of curvature in the face back direction is The value is 60 mm or more and 80 mm or less. In the area, the value of the radius of curvature gradually decreases from the curve B1 to the curve B2, but the value of the radius of curvature is 60 m at any place in the area.
It is included in the range from m to 80 mm.

The larger the radius of curvature in the above area, the more the toe side area of the head becomes a curved surface. Therefore, in the horizontal lie shown in FIG. 6A, the leading edge 31 at the time of impact and the ground surface. The distance to and becomes shorter, and top strikes can be prevented. However, if the value of the radius of curvature is 80 mm or more, the radius of curvature becomes too large,
The mass distributed to the toe side increases and the center of gravity shifts to the toe side, which reduces the operability of the club, and in the lie with the ball hitting direction shown in Fig. 6 (b), the leading edge is on the ground. In the lie shown in FIG. 6 (c) in which the ball is easily stabbed and the hitting direction is lowered, there is a distance between the leading edge and the ground, which causes a problem that the player is likely to hit the top.

When the value of the radius of curvature is 60 mm or less, the curved surface becomes more rounded than necessary. Therefore, in a horizontal lie, there is a distance between the leading edge and the ground at the time of impact, and it is easy to hit the top. Cause problems. When the value of the radius of curvature in the face back direction is set to 60 mm or more and 80 mm or less as in the present invention, the above problems can be solved.

Further, in the present invention, in the above curved surface,
In the region where the distance from the heel side score line width line 62 is 0 mm or more and 10 mm or less (the region between the curve B6 and the curve B7), the value of the radius of curvature in the face back direction is 1
It is set to 0 mm or more and 30 mm or less. In the region, the value of the radius of curvature gradually decreases from the curve B6 to the curve B7, but the value of the radius of curvature is included in the region of 10 mm or more and 30 mm or less at any place in the region.

The radius of curvature in the above area is set to 30 m.
If it is m or more, the radius of curvature is too large, so that the back heel region 52 becomes a curved surface close to a flat surface, and if the toe down is insufficient at the time of hitting, the heel portion receives a large resistance from the ground, the head speed is lowered, and the face is closed. There arises a problem that the unnecessary rotational force generated in the direction and the feeling of swinging are deteriorated.

Further, the smaller the radius of curvature in the above area is, the more rounded the curved surface of the back heel area 52 of the head becomes, so that the resistance received by the heel portion 4 from the ground is reduced even when the toe down is not sufficient at the time of hitting the ball. However, it is difficult to actually manufacture a golf club head having a radius of curvature of 10 mm or less, and even if it is manufactured, it is not practical. When the value of the radius of curvature in the face back direction is 10 mm or more and 30 mm or less as in the present invention, the above problem can be solved.

[0036]

EXAMPLES Tables 1 and 2 below show curves A1 to A4 and curves B of golf club heads in examples of the present invention.
1 shows the value of the radius of curvature of the curve B7.

[0037]

[Table 1] Curvature radii of curves A1 to A4

[0038]

[Table 2] Curvature radii of curves B1 to B7

In order to verify the superiority of this embodiment, a golf club head of the embodiment and the golf club heads of Comparative Product 1 to Comparative Product 15 shown in Table 3 were used to prepare a trial hit club, and a general golfer 10 A trial hit questionnaire was conducted for people.

Table 3 shows the values of the radii of curvature explained in the following (a) to (d) in the golf club heads of Examples and Comparative Products 1 to 15.

(A) The value of the radius of curvature in the toe-heel direction on a curve (curve at the center between the curve A1 and the curve A2) whose distance from the leading edge is 7.5 mm. (B) The value of the radius of curvature in the toe-heel direction on a curve (center curve between the curves A3 and A4) at a distance of 4.5 mm from the trailing edge. (C) The value of the radius of curvature in the faceback direction of the curve (the central curve between the curves B1 and B2) having a distance of 5 mm from the toe side score line width line. (D) The value of the radius of curvature in the face back direction on a curve (curve at the center of the curves B6 and B7) having a distance of 5 mm from the heel side score line width line.

Regarding the sole shapes of the comparative products 1 to 15, only the values of the radii of curvature of the above (a) to (b) are shown, but a smooth curved surface is formed on the entire sole portion as in the embodiment. ing.

In order to clarify the evaluation of the sole shape, the club specifications of the trial hit clubs were adjusted to be equal. The club spec is a 6 iron, club length 37.5 inches, loft angle 29 degrees, lie angle 61 degrees,
Shaft flex SR and club balance D1.

The comparative products 1 to 4 have different values of the radius of curvature in the above (a) from the examples (the purpose of evaluating the regions of the curves A1 to A2). Regarding Comparative product 5 to Comparative product 8, the value of the radius of curvature in (b) is different from that of the example (the purpose of evaluating the regions of the curves A3 to A4). The comparative products 9 to 12 have different values of the radius of curvature in (c) from the examples (the purpose of evaluating the regions of the curves B1 to B2). Comparative product 13 ~
Regarding the comparative product 15, the value of the radius of curvature of (d) is different from that of the example (the purpose of evaluating the regions of the curves B6 to B7).

[0045]

Table 3 Values of the radii of curvature of the above (a) to (d) in Examples and Comparative Examples 1 to 15

The questionnaire items are the following five items. 1. Ease of hitting when touching the ground with a lie with toe up and toe down 2. Ease of hitting with a lie with a higher hitting direction and a lie with a lower hitting direction 3. Ease of hitting with a horizontal lie 4. Resistance from the ground when hitting a ball 5. Club operability Each item is rated on a 5-point scale.
Points, 3 points, 2 points, 1 point. Table 4 shows the results of each item (average score of 10 persons) and the average score of 5 items in the questionnaire.

[0047]

[Table 4] Questionnaire results

As can be seen from the above results, by setting the curved surface shape of the bottom surface of the sole portion to have the radius of curvature as in this embodiment, an overall excellent golf club head can be obtained.

The shape of the bottom surface of the sole portion of the present invention is not limited to a specific count but is effective for all iron type golf club heads.

[0050]

According to the iron type golf club head of the present invention, the face toe region has a shape close to a plane and the distance between the trailing edge and the ground is short, so that it is effective in preventing top striking at the time of hitting a ball. . Also, since the back heel area has a rounded curved surface, even if the toe down is not sufficient at the time of hitting, the resistance that the heel receives from the ground can be reduced, so the head speed decreases due to the resistance from the ground, and the face closes. It is possible to solve problems such as unnecessary rotation force and poor swinging feeling. Compared to the conventional iron type golf club head with a constant radius of curvature of the sole, it effectively reduces the resistance from the ground,
It is possible to obtain an iron type golf club head which is excellent overall.

[0051]

[Brief description of drawings]

FIG. 1 is a perspective view showing a golf club head according to the present invention.

FIG. 2 is a view of the golf club head according to the present invention as viewed from the bottom side of the sole portion.

FIG. 3 is a view of the golf club head according to the present invention as viewed from the bottom side of the sole portion.

FIG. 4 is a view showing a golf club head in which a leading edge and a trailing edge are curved when viewed from the bottom side of a sole portion.

5A is a diagram showing a horizontal lie, and FIG.
FIG. 5B is a diagram showing a lie with raised toes.
(C) is a figure which shows the lie | fall of a toe.

6 (a) is a diagram showing a horizontal lie, and FIG.
FIG. 6B is a view showing a lie rising in the ball hitting direction, and FIG.
(C) is a diagram showing a lie falling in the ball striking direction.

FIG. 7 is a diagram showing a toe down of a golf club head.

FIG. 8 is a diagram showing a conventional golf club head.

[Explanation of symbols]

1 golf club head 21 Bottom of sole 31 leading edge 32 trailing edge 4 heel 51 Face toe area 52 Back heel area 61 Toe side score line width line 62 Heel side score line width line 71 Center of gravity 72 Shaft axis 81 Leading Edge 82 Face 83 golf balls M1 intersection M2 intersection M3 intersection M4 intersection A0 reference line A00 reference line A1 curve A2 curve A3 curve A4 curve B1 curve B2 curve B3 curve B4 curve B5 curve B6 curve B7 curve

Claims (5)

[Claims] 1. A toe on a curved surface of a bottom surface of a sole portion of an iron type golf club head, which is surrounded by a toe side score line width line, a heel side score line width line, a leading edge and a trailing edge. An iron-type golf characterized in that the value of the radius of curvature in the heel direction is gradually reduced from the leading edge to the trailing edge, and the value of the radius of curvature in the faceback direction is sequentially reduced from the toe side to the heel side. Club head. 2. A curved surface shape of a sole bottom surface of an iron type golf club head, wherein a distance of 6 mm from a toe side score line width line, a heel side score line width line and a leading edge and a trailing edge The radius of curvature in the toe / heel direction on the curved surface surrounded by the curve having a distance of 3 mm is gradually reduced from the leading edge to the trailing edge, and the radius of curvature in the face back direction is reduced from the toe side to the heel side. Iron type golf club head, which is characterized in that it becomes smaller toward the front. 3. The iron type golf club head according to claim 1 or 2, wherein the value of the radius of curvature in the toe-heel direction is 200 in a region where the distance from the leading edge is 6 mm or more and 9 mm or less.
mm or more and 280 mm or less, and the distance from the trailing edge is 3 mm or more and 6 mm
The value of the radius of curvature in the toe / heel direction in the following areas is 1
An iron type golf club head having a length of 40 mm or more and 200 mm or less. 4. The iron type golf club head according to claim 1, wherein a distance from the toe side score line width line is 0 mm or more 1
The value of the radius of curvature in the face back direction in the region of 0 mm or less is 60 mm or more and 80 mm or less, and the distance from the heel side score line width line is 0 mm.
An iron type golf club head having a value of a radius of curvature in the face back direction of 10 mm or more and 30 mm or less in a region of 10 mm or less. 5. The iron-type golf club head according to claim 1, wherein a curvature radius value in the toe-heel direction is 240 mm in a curve having a distance from the leading edge of 7.5 mm, and The radius of curvature in the toe-heel direction is 170 mm on the curve with a distance of 4.5 mm from the trailing edge, and the radius of curvature in the face-back direction is 5 mm from the score line on the toe side. Is 70 mm, and the radius of curvature in the face back direction is 20 mm in a curve having a distance of 5 mm from the heel side score line width line.