JP4630566B2 - Iron-type golf club head for sand wedge and sand wedge having the same - Google Patents

Description

The present invention relates to an iron type golf club head for a sand wedge and a sand wedge provided with the same .

An iron type golf club head in a sand wedge or the like is also used in a bunker. In bunker shots, the effect of explosion shots (shots that explode the sand in the bunker and launch the ball with sand) (hereinafter also referred to as the explosion effect) allows the ball to escape from the bunker to the outside of the bunker and at the appropriate initial speed. And the backspin amount can be given to the ball. In addition, if the head speed is less reduced by the bunker sand and the head is a so-called detachable head, the ball can easily escape from the bunker, and the backspin amount of the hit ball is relatively increased, so that the ball tends to stop on the green.

  In conventional iron type golf club heads, the lift force that the head receives from the sand (the vertical component of the force that the sole surface receives from the sand) by making the so-called bounce angle relatively large especially in sand wedges that are frequently used in bunker ). Therefore, when the bounce angle is increased, the head is prevented from being excessively submerged in the sand, the head speed is reduced, so that the head becomes a so-called good head and the explosion effect is secured.

By the way, regarding the sole shape of an iron type golf club head, Patent Document 1 discloses an iron type golf club head that minimizes the influence of ground resistance by providing a runner on the sole to reduce the contact area of the head. Proposed. According to Patent Document 1, it is described that the runner is gradually raised from the face side to the back side of the head, thereby minimizing the rebound of the club head by the ground and the piercing to the ground. (See Patent Document 1).
In Patent Document 2, a sole angle (an angle generally referred to as a bounce angle) is set to a plus (positive value) for the entire sole, and one sole angle on the toe side or heel side of the sole is set to the other side. An iron type golf club head having a larger sole angle is disclosed. According to this Patent Document 2, since the sole angle is positive in the entire sole, the contact area between the sole and the ground is reduced, the slipping out is improved, and the sole angle is changed in the toe-heel direction. A difference in resistance from the ground occurs on the heel side, and the head rotates to correct hooks and slices.
JP-A-5-192425 (Claims 1-2, page 3, FIG. 3, FIG. 4) JP 2001-95960 A (Claim 1, FIGS. 1 to 4)

Simply increasing the bounce angle as has been done in the past did not provide sufficient removal performance and explosion effect on bunker shots.
In addition, the iron type golf club head described in Patent Document 1 and Patent Document 2 mainly considers a shot on the lawn, and does not consider any explosion shot in the bunker, especially in the bunker shot. Dropping performance and explosion effect were not enough.

  In conducting the present invention, as a result of detailed examination of the behavior of the head in the vicinity of the impact, particularly the behavior of the sand at the time of explosion shot, there is an influence on the explosion effect and the slipping performance on the toe side and the heel side of the sole part. I found a difference. At the time of hitting the ball, the head with the face open has an impact while gradually closing the face as the downswing progresses, so the face is open at least until just before the impact, and the heel side of the head precedes the toe side. It is in a state. Therefore, when the head contacts the vicinity of the impact, the heel side of the sole tends to contact before the toe side. In particular, in the case of a bunker shot, the impact and the impact are often made with the face open, so that the heel side of the sole portion tends to come in contact before the toe side. Furthermore, especially in explosion shots, instead of catching the ball cleanly (without duffing) as in normal shots, the ball will be hit intentionally in a duffed state. The head will be grounded at this point. Then, as described above, in the situation where the impact is to be achieved while gradually closing the face, the grounding is performed at an earlier stage than the impact, so that the grounding is easily performed with the face open. Therefore, the tendency that the heel side of the sole portion contacts the ground earlier than the toe side becomes stronger.

  In this way, especially in explosion shots, the heel side of the sole tends to come in contact with the heel side before the toe side, so the function of exploding sand is mainly exerted by the heel side of the sole. It is thought that. On the other hand, it can be said that the toe side of the sole part has a relatively small influence on the explosion function compared to the heel side. Conventionally, however, there has been no idea of considering the difference between the toe side and the heel side in the explosion effect. On the other hand, in the present invention, it has been found that the omission performance and the explosion effect can be further enhanced as compared with the prior art from the idea that this difference is not considered in the past.

The present invention has been made in view of such a situation, and in consideration of the difference in function at each position in the toe and heel directions of the sole portion, an iron type golf for sand wedge having excellent pull-out performance and high explosion effect. It is intended to be a club head.

In the iron-type golf club head for sand wedge of the present invention, a position 25 mm away from the face center position to the toe side is a toe side reference position, and a position 25 mm away from the face center position to the heel side is a heel side reference position. When the face has a positive bounce angle in the toe / heel direction range from the toe side reference position to the heel side reference position, the bance angle at the heel side reference position is larger than the bounce angle at the toe side reference position. the sole surface of the heel side from the center position, and have a groove-like portion extending inclined toward the heel side from the toe side as it goes from the trailing edge side to the leading edge side,
A straight line passing through two contour lines existing on both sides of the groove-shaped portion and perpendicular to the groove direction line, and on the inner surface of the groove portion in a cross-sectional view of the section perpendicular to the groove direction line. The angle between the point and the tangent at the point located at the midpoint of the groove depth is not less than 20 degrees and not more than 40 degrees,
The length of the groove-shaped portion in the longitudinal direction is 10 mm or more, the groove width of the groove-shaped portion is 7 mm or more and 17 mm or less, and the groove depth of the groove-shaped portion is 0.5 mm or more and 2.0 mm or less. And
The groove-shaped portion constitutes a concave portion toward the head outer surface side, and the cross-sectional line of the groove-shaped portion is a smooth curve.
The bounce angle is increased from the toe side to the heel side in the toe-heel direction range from the toe side reference position to the heel side reference position, and
The sole width and is characterized that you have been largely from the toe side toward the heel side at the toe-heel direction ranging from the toe side reference position to the heel side reference position.
In this manner, the sole surface has a positive bounce angle in the toe-heel direction range of 25 mm from the center of the face to the toe side and the heel side from the face center position. The removal performance is not impaired. Since the bounce angle at the heel side reference position is larger than the toe side reference position, the grounding resistance at the toe side reference position can be reduced while sufficiently ensuring the explosion effect at the heel side reference position of the sole. Further, the groove-like portion provided on the heel side increases the sand discharging ability in explosion shots.

  Further, if the sole surface on the toe side of the face center position is a convex curved surface or flat surface toward the head outer surface side and is formed of a smooth surface, the toe side portion is caught when swinging. In addition, an increase in resistance due to an increase in unnecessary contact area can be suppressed, and the ground resistance is reduced.

According to the present invention, since the bounce angle is made different between the toe side and the heel side of the sole portion, and the groove-like portion that can enhance the sand discharging performance is provided on the heel side, the removal performance and the explosion effect are excellent. An iron type golf club head for a high sand wedge can be obtained.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a front view of an iron type golf club head (hereinafter, also simply referred to as a head) 1 according to an embodiment of the present invention as viewed from the face surface 2 side. The face surface 2 is provided with a plurality of face lines 3 at a predetermined pitch in a direction substantially parallel to the toe-heel direction. The toe side end of this face line 3 (when the toe side end positions in the toe / heel direction are different among the plurality of face lines 3, the toe side end of them is the same) and the heel side end (several sides) When the toe / heel direction position of the heel side end differs between the face lines 3, the toe / heel direction center position of the heel side end with the end of the heel side is the face center position fc (one-dot chain line in FIG. 1) Is shown). Further, the head 1 extends from the lower edge of the face surface 2 to the rear of the head, the sole surface 5 constituting the bottom surface of the head 1, the sole portion 4 having this as the outer surface, and the shaft extending from the heel side portion of the face surface 2. And a hosel 11 having a shaft hole 10 for bonding. The surface (outer surface) of the sole portion 4 is the sole surface 5. The sole surface 5 and the back face 12 form a continuous surface via the trailing edge 7. The leading edge 6 and the trailing edge 7 are boundary lines between the sole surface 5 and other head outer surfaces (the face surface 2 and the back face 12).

  The toe-heel direction is defined as the direction of the line of intersection between the plane including the face surface 2 and the horizontal plane when the head 1 is placed on the horizontal plane at a predetermined lie angle and loft angle. sell. In this case, when the face surface is not a plane, the direction of the intersecting line between the plane perpendicular to the perpendicular line from the head center of gravity to the face surface and the horizontal plane can be the toe-heel direction. Further, the face-back direction can be a direction perpendicular to the toe-heel direction and parallel to the horizontal plane in the reference state. The toe side and the heel side are the toe side and the heel side in the toe-heel direction. In the head 1 shown in FIG. 1, the toe / heel direction coincides with the installation direction of the face line 3, but it goes without saying that they may not coincide with each other.

  2A is a view of the head 1 as viewed from the sole surface 5 side, and FIG. 2B is a cross-sectional view taken along line BB in FIG. 2A. As shown in these drawings, the sole portion 4 of the head 1 has a groove-like portion 8 that extends inclinedly from the toe side toward the heel side as it goes from the trailing edge 7 side to the leading edge 6 side. ing. The groove portion 8 constitutes a concave portion toward the head outer surface side. As shown in FIG. 2 (b), the cross-sectional line of the groove-like portion 8 is a smooth curve, and the groove-like portion 8 and the portion other than the groove-like portion 8 are continuous with a smooth curve. The outline 8b of the shaped part 8 is not clearly visible. Therefore, in FIG. 2A and the like, the outline 8b of the groove 8 is indicated by a broken line. The groove-shaped portion 8 is provided on the heel side sole surface 52 that is the sole surface 5 on the heel side with respect to the face center position fc (see FIG. 3A).

  As shown in FIGS. 1 and 3A, a position (toe / heel direction position) 25 mm away from the face center position fc to the toe side is a toe side reference position tk, and 25 mm away from the face center position fc to the heel side. The position (toe / heel direction position) is set as the heel side reference position hk. At this time, the head 1 has a positive bounce angle θ in a toe-heel direction range 20 (shown by broken line hatching in FIG. 3A) from the toe side reference position tk to the heel side reference position hk.

Here, the bounce angle θ is defined by the following (A) as shown in FIG.
(A) In a reference state in which the head is placed on a horizontal plane at a predetermined lie angle and loft angle, the face surface 2 (if the face surface 2 is not a plane, a plane perpendicular to the perpendicular line from the head center of gravity to the face surface) The angle formed between the tangent 13 and the horizontal plane 14 at the center point c in the face-back direction of the sole surface 5 in a cross-sectional view taken along a plane perpendicular to the horizontal plane.
As the bounce angle θ increases, the amount of sand that collides with the sole surface 5 when the head 1 is traveling in the bunker sand tends to increase, so the force that the sole surface 5 receives from the sand increases. Cheap. At this time, the vertical component (lifting force) of the force that the sole surface 5 receives from the sand prevents the head 1 from excessively sinking into the sand, thereby improving the explosion effect and weakening the ground resistance. Effect (hereinafter also referred to as a Vance effect) is achieved.
The bounce angle θ is determined at each position in the toe / heel direction, but the center point c in the face / back direction in the definition of the bounce angle θ is located in the groove-shaped portion 8. Since the center point c is located on the inner surface 81 of the groove-shaped portion 8 (the wall surface of the groove-shaped portion 8 or the like), the above-defined bounce angle θ is not necessarily appropriate as an index of the Vance effect. Absent. Therefore, in this case, a groove direction line 16 that is a tangent at the center point 15t of the valley line 15 that is a set of the deepest cross-section points of the groove 8 and indicates the installation direction of the groove 8 is considered (see FIG. 2A). ), And the definition of the bounce angle can be as follows.
(B) In a reference state in which the head is placed on a horizontal plane at a predetermined lie angle and loft angle, the face-back direction of the sole surface 5 in a sectional view taken along a plane parallel to the groove direction line 16 and perpendicular to the horizontal plane Angle formed by the tangent at the center point and the horizontal plane (not shown).

  In the head 1, the bounce angle θ at the heel side reference position hk is larger than the bounce angle θ at the toe side reference position tk. The bounce angle θ changes substantially continuously in the toe / heel direction range 20 from the toe side reference position tk to the heel side reference position hk. The bounce angle θ increases as the distance from the toe side toward the heel side in the toe / heel direction range 20 increases.

As shown in FIG. 3A, the sole width wh at the heel side reference position hk is wider than the sole width wt at the toe side reference position tk. The sole width wc at the face center position fc is wider than the sole width wt and narrower than the sole width wh. Further, in the entire sole portion 4, the sole width continuously changes in the toe-heel direction. In addition, the sole width increases from the toe side to the heel side in almost the entire region in the toe / heel direction range 20.
The sole width is a linear distance from the leading edge 6 to the trailing edge 7 at each position in the toe / heel direction.

The toe side sole surface 51, which is the sole surface on the toe side with respect to the face center position fc, is configured by a smooth surface. Further, the toe side sole surface 51 is not provided with the groove-like portion 8, and the whole is formed of a convex curved surface or flat surface toward the head outer surface side. The entire toe / heel direction range 20 from the toe side reference position tk to the heel side reference position hk is also a smooth surface. Further, the entire sole surface 5 is a smooth surface, and the groove-like portion 8 and a portion other than the groove-like portion 8 are continuous with the smooth surface.
The smooth surface is an arbitrary point on the intersection line when considering the intersection line with any plane perpendicular to the horizontal plane in the reference state where the head is placed on the horizontal plane at a predetermined lie angle and loft angle. Can be defined as a surface with tangent. However, it is permissible to provide minute irregularities, holes, design marks, etc. within a range that hardly impairs the effects of providing the smooth surface described above. For example, it is usually provided on the sole surface of an iron type golf club head. Numbered letters (including numbered numbers) and brand letters stamped are allowed.

The operational effects of the head 1 configured as described above will be described.
As described above, especially in the explosion shot, the heel side portion of the sole portion 4 has a very strong tendency to come in contact before the toe side portion, so the function of exploding sand is mainly the heel of the sole surface 5. It is thought that it is demonstrated by the side. Therefore, regarding the heel side of the sole surface 5, it is considered that the explosion effect is enhanced by relatively increasing the bounce angle θ.
On the other hand, it can be said that the toe side of the sole surface 5 has a relatively small influence on the explosion function compared to the heel side. Therefore, if the bounce angle θ is increased on the toe side of the sole surface 5, the action of increasing the resistance force from the ground contact surface (sand, etc.) is greater than the effect of increasing the explosion effect, and as a result, the slipping performance is reduced. It is thought that it becomes.

  The head 1 has a positive bounce angle in a range that is particularly easily grounded on the sole surface 5, that is, a range in the toe-heel direction from the toe side reference position tk to the heel side reference position hk. As a result, the explosion effect and the removal performance are not impaired. The bounce angle θ at the heel side reference position hk is larger than the bounce angle θ at the toe side reference position tk, and the bounce angle θ in the toe / heel direction range 20 from the toe side reference position tk to the heel side reference position hk. Therefore, the ground resistance on the toe side can be reduced while sufficiently ensuring the explosion effect on the heel side of the sole. That is, as described above, since the degree of influence on the explosion effect and the slipping performance differs between the toe side and the heel side of the sole portion 4, the bounce angle θ is relatively large at the heel side reference position hk in consideration of this point. Thus, the ground resistance can be suppressed by relatively reducing the bounce angle θ at the toe side reference position tk while enhancing the explosion effect.

Further, the explosion effect is enhanced by the groove-shaped portion 8 provided on the heel side sole surface 52. As described above, especially in explosion shots, the heel side of the sole surface 5 is more likely to come into contact with the heel side compared to the toe side. The grounding pressure of the non-grooved portion (portion other than the grooved portion 8) at the time of contact is increased. If it does so, it will become easy for the sole part 4 to enter sand, and the initial reaction force which the sole part 4 receives from sand at the time of initial contact will become comparatively low. Then, when the sole portion 4 enters the sand and almost the entire inner surface 81 (see FIG. 2B) of the groove-shaped portion 8 comes into contact with the sand, the sole surface 5 is present due to the presence of the groove-shaped portion 8. Since the contact area between the sand and the sand becomes large, excessive contact due to excessive increase of the contact pressure can be prevented (dive can be prevented. In order to enhance the explosion effect, the sole surface 5 needs to enter the sand to some extent. Yes, but at the same time, it is necessary not to get too much into the sand, because if you don't get into the sand to some extent, the amount of sand that will explode (explode) cannot be secured, and it will get too deep In this case, the swinging-out becomes worse and the explosive force for scattering the sand is reduced.As described above, the groove portion 8 is provided in the portion on the heel side that makes initial contact with the sand, thereby providing the sole portion. There are those somewhat easily enter the sand, enhanced explosion effect by and suppressing the entry of the excessive sand.

  Further, since the bounce angle θ at the heel side reference position hk is made larger than the bounce angle θ at the toe side reference position tk, the sole surface 5 is gradually increased from the toe side toward the heel side. , It tends to be a substantially twisted sole surface shape. In the case of such a substantially twisted sole surface shape, when the sand is scattered in front of the head or discharged backward, discharging in a direction slightly toward the heel side than the normal direction of the face surface 2 results in relatively low discharge resistance. Become. Therefore, the sand in front of the sole portion 4 can be discharged through the groove portion 8 with a small discharge resistance by arranging the groove portion 8 in the inclined direction as described above. In particular, in a bunker shot, the ball is hit on an outside-in track, but the groove direction line 16 of the groove-like portion 8 is close to the outside-in track, so that swinging is smoother and the head speed is reduced. The decrease is suppressed and the explosion effect is enhanced. In addition, when considering a total of three bounce angles θ obtained by adding the bounce angle θ at the face center position fc to the bounce angle θ, it is preferable that these are larger on the heel side and smaller on the toe side. That is, it is preferable that the bounce angle θ at the heel side reference position hk is the largest, the bounce angle θ at the face center position fc is next largest, and the bounce angle θ at the toe side reference position tk is smallest. This is because the tendency of the substantially twisted shape of the sole surface 5 described above is further increased.

  The sole width wh at the heel side reference position hk is wider than the sole width wt at the toe side reference position tk. Therefore, the explosion effect at the heel side reference position hk is further enhanced by the relatively wide sole width wh, and at the same time, the ground resistance at the toe side reference position tk is further reduced by the relatively narrow sole width wt. As described above, the heel side shape of the sole surface 5 has a relatively strong influence on the explosion effect, whereas the toe side shape has a relatively strong influence on the grounding resistance than the explosion effect. This is a configuration that takes into account.

  Further, since the toe side sole surface 51, which is the sole surface 5 on the toe side with respect to the face center position fc, is constituted by a smooth surface, when swinging off at the toe side portion having a relatively large influence on the ground resistance. The increase in resistance due to catching and an increase in unnecessary contact area can be suppressed, and the ground resistance is reduced. Further, since the entire toe side sole surface 51 is constituted by a convex curved surface or flat surface and the groove-like portion 8 is not provided on the toe side sole surface 51, the ground resistance is further reduced. The entire toe-heel direction range 20 described above is constituted by a smooth surface, and further, the entire sole surface 5 is constituted by a smooth surface, so that the ground resistance is minimized.

  As described above, the groove-shaped portion 8 plays an important role in the expression of the explosion effect, but as described above, the region having a strong influence on the explosion effect is a region on the heel side with respect to the face center position fc. Therefore, even if the groove-like portion 8 is provided on the toe side sole surface 51, the contribution to the explosion effect is small. A smooth surface composed of a flat surface is advantageous in that the effect of reducing the ground resistance is obtained. Further, if the groove-shaped portion 8 is increased, the shape of the sole surface 5 becomes complicated, which causes a cost increase such as the sole surface 5 being difficult to polish. Therefore, it is preferable not to provide the groove-like portion 8 on the toe side sole surface 51.

  Since the present invention has an effect of enhancing the explosion effect as described above, it is preferably applied to an iron type golf club head and an iron type golf club having many opportunities for taking an explosion shot. Therefore, the head and club of the present invention preferably have a real loft of 42 degrees or more, more preferably 50 degrees or more, and particularly preferably 54 degrees or more.

  As shown in FIG. 2A, in the projected image on the horizontal plane in a reference state where the head is placed on the horizontal plane at a predetermined lie angle and loft angle, the groove direction line 16 and the normal T ( In FIG. 2A, the angle α formed with the line of the face center position fc is preferably 10 degrees or more as the lower limit, 40 degrees or less, and more preferably 30 degrees or less as the upper limit. This is because the explosion shot is often performed on an outside-in trajectory, and this outside-in trajectory has an angle α in the above preferable range in most golf players.

  The length of the groove-shaped portion 8 ranges from the vicinity of the edge portion 6 (for example, a point within 3 mm from the edge portion 6 to the face-back direction) to the vicinity of the trailing edge 7 (for example, 3 mm from the trailing edge 7 to the face-back direction). It is preferable that it extends without interruption to the point within. By doing so, the sand that has passed through the inside of the groove-like portion 8 can reach the vicinity of the leading edge 6 and the trailing edge 7, and the sand in the groove-like portion 8 is easily discharged. Thus, if the groove-like portion 8 is too short, the sand in the groove-like portion 8 tends not to be discharged. Therefore, the length of the groove-like portion 8 in the longitudinal direction is preferably 10 mm or more, and more preferably 12 mm or more.

  The number of the groove-like portions 8 is not particularly limited, but two or more are preferable. If it is less, the effect of providing the groove-like portion 8 tends to decrease. Further, the number of the groove-like portions 8 is preferably 5 or less, and more preferably 3 or less. This is because if the amount is too large, the groove width W (see FIG. 4) tends to be small and the amount of sand entering the inside of the groove-like portion 8 tends to be small. Thus, the groove width W is preferably a predetermined value or more, specifically, 7 mm or more is preferable, and 9 mm or more is more preferable. If the groove width W is too narrow, the amount of sand entering as described above decreases, and the inner surface 81 of the groove-like portion 8 becomes difficult to polish, which may increase the cost. If the groove width W is too large, the groove portion 8 is too flat and the effect of providing the groove portion 8 may be reduced. Therefore, the groove width W is preferably set to 17 mm or less. The groove width W is the maximum value of the distance between the contour lines 8b on both sides in the cross section perpendicular to the groove direction line 16 (maximum value in one groove-shaped portion 8) (see FIG. 4).

  FIG. 4 is an enlarged cross-sectional view of the groove-like portion 8 in a cross section perpendicular to the groove direction line 16. In this cross-sectional view, the maximum distance (one line) from the straight line r passing through the two contour lines 8b (indicated by dots in the cross-sectional view of FIG. 4) existing on both sides of the groove-shaped portion 8 to the valley line 15 is shown. The maximum value in the groove-shaped portion 8) is the groove depth dm. The groove depth dm is preferably 0.5 mm or more, and more preferably 1 mm or more. If the groove depth dm is too shallow, the effect as the groove-shaped portion 8 may be reduced. In addition, if the groove depth dm is too deep, the inner surface 81 of the groove-like portion 8 may be difficult to polish or mold, which may increase the cost. Therefore, the groove depth dm is preferably 2.0 mm or less. 1.5 mm or less is more preferable.

  The angle g formed between the tangent sm at the midpoint mp of the inner surface 81 of the groove-like portion 8 and the straight line r in the sectional view of FIG. 4 is preferably 20 degrees or more, and preferably 40 degrees or less. If this angle g is too large, sand will not easily enter the groove-like portion 8 and the effect of providing the groove-like portion 8 may be reduced, and the inner surface 81 of the groove-like portion 8 will be difficult to polish. On the other hand, if the angle g is too small, the groove-like portion 8 is too flat and the effect of providing the groove-like portion 8 may be reduced.

Although it is a preferable range of the bounce angle θ, the bounce angle θ at the heel side reference position hk is preferably 8 degrees or more, and more preferably 10 degrees or more. If it is too small, the explosion effect tends to decrease, and it becomes difficult to make the angle larger than the bounce angle θ at the toe side reference position tk. Further, if the bounce angle θ at the heel side reference position hk is too large, the grounding resistance may increase rather than the explosion effect. Therefore, it is preferably 17 degrees or less, more preferably 15 degrees or less.
Further, the bounce angle θ at the toe side reference position tk is preferably 8 degrees or less, and more preferably 4 degrees or less. This is because if it is too large, the grounding resistance tends to increase, and it is difficult to make the angle smaller than the bounce angle θ at the heel side reference position hk. Further, the lower limit of the bounce angle θ at the toe side reference position tk is preferably larger than 0 degree. Even if the bounce angle θ is set to a negative value, the ground resistance is not particularly reduced. On the other hand, the toe side reference position tk is slightly less than the heel side reference position hk, but has a slight bounce effect and explosion effect. This is because the explosive effect and the vance effect are enhanced and the omission performance is improved when the value is larger than that.

The sole width wh at the heel side reference position hk is preferably 17 mm or more, and more preferably 20 mm or more. If it is too narrow, the explosion effect tends to decrease, and it becomes difficult to make the sole width wh wider than the sole width wt at the toe side reference position tk. The upper limit of the sole width wh at the heel side reference position hk is preferably 25 mm or less. This is because if it is too wide, the disadvantage of the increase in grounding resistance due to the increase in the grounding area may become apparent rather than the merit of the explosion effect, and the head weight may become too heavy.
On the other hand, the sole width wt at the toe side reference position tk is preferably 16 mm or less, and more preferably 14 mm or less. If it is too large, the grounding resistance tends to be too large, and it becomes difficult to make the sole width wt smaller than the sole width wh at the heel side reference position hk. The lower limit of the sole width wt at the toe side reference position tk is preferably 10 mm or more. Although the toe side reference position tk is slightly less than the heel side reference position hk, there is a slight bounce effect and explosion effect. Because it gets better.

A total of six types of golf clubs comprising three types of Examples 1 to 3 and three types of Comparative Examples 1 to 3 were evaluated to confirm the effects of the present invention. All the examples and all the comparative examples (hereinafter also referred to as all examples) have common specifications except for the specifications described in Table 1. For example, in all examples, the head is forged with soft iron (S25C), the head weight is 300 g, the club count is a so-called sand wedge (SW), the real loft is 58 degrees, and the shaft, grip, club The length, club balance, etc. are also common. In the example in which the groove-shaped portion 8 is provided, the groove depth dm of the groove-shaped portion 8 is 1.5 mm, the groove pitch between the plurality of groove-shaped portions 8 is 10 mm, and the groove width W is 10 mm. .
The evaluation was conducted by 10 testers with handicap of 0 to 15 and aiming for a pin about 15 yards away, and actually making 5 bunker shots (explosion shots) for each example. evaluated. Table 1 summarizes the specifications and evaluation results of each example.

  Each example and each comparative example will be described supplementarily. In Comparative Example 2 and Examples 1 and 2, each of the two groove-shaped portions is located at the position shown in FIG. 2A on the heel side from the face center position fc. 8 is provided. As shown in FIG. 5, in Example 3, in addition to the two groove-like portions 8 shown in FIG. 2A, two groove-like portions are provided on the sole surface on the toe side from the face center position fc. 8 is provided. The four groove-like portions 8 provided in the third embodiment have an angle α of 30 degrees as shown in Table 1, but the length of each groove-like portion 8 in the longitudinal direction is the sole. The width is appropriately adjusted according to the change in the toe-heel direction. That is, the longitudinal length of the groove-like portion 8 on the toe side with respect to the face center position fc is slightly shorter than the longitudinal length of the groove-like portion 8 on the heel side. In Comparative Example 1 and Comparative Example 3, the groove-like portion 8 is not provided, and there is no concave depression on the sole surface.

  In Table 1, the bounce angle θ1 is the bounce angle θ at the heel side reference position hk, the bounce angle θ2 is the bounce angle θ at the face center position fc, and the bounce angle θ3 is at the toe side reference position tk. The bounce angle θ. The sole width wh is the sole width wh at the heel side reference position hk described above, the sole width wt is the sole width wt at the toe side reference position tk, and the sole width wc is the sole width wc at the face center position fc. is there. The angle α is as described above.

The evaluation items in Table 1 will be described.
The backspin amount is a measure of the backspin amount immediately after hitting the ball (a value rounded to the tens place), and as the backspin amount increases, it tends to stop on the green and becomes relatively close to the pin. The larger the value, the better the result. The run on the green is the distance from the point where the hit ball first landed on the green to the point where the ball stopped. The shorter the run, the easier it is to get closer to the pin.
The good omission is a sensory evaluation of 10 testers about the omission performance of the head, and is an average value evaluated by each tester on a 10-point scale. The higher the score, the better the evaluation was obtained.
The backspin amount and the run value on the green are closely related to the explosion effect. In other words, when the explosion effect is high, the ball easily comes out of the bunker as the sand explodes and the club swings smoothly, increasing the backspin amount and reducing the run on the green, making it easier to get closer to the pin. .
When the evaluation results are compared between the example and the comparative example, all the examples are evaluated as having better omission than all the comparative examples. Similarly, all the examples have a higher backspin amount and fewer runs on the green than all the comparative examples.

1 is a front view of an iron type golf club head according to an embodiment of the present invention as seen from the face side. (A) is the figure which looked at the head of FIG. 1 from the sole surface side, (b) is sectional drawing in the BB line of FIG. 2 (a). 2A is a view as seen from the sole surface side of the head of FIG. 1, as in FIG. 2A, and FIG. 2B is a cross-sectional view of a cross section perpendicular to the face surface of the head. It is sectional drawing of a groove-shaped part. It is the figure which looked at Example 3 from the sole surface side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Iron type golf club head 2 Face surface 4 Sole part 5 Sole surface 51 Toe side sole surface (sole surface toe side rather than the face center position)
52 Sole surface on the heel side (sole surface on the heel side from the center position of the face)
6 Leading edge 7 Trailing edge 8 Grooved portion 20 Toe-heel direction range from toe side reference position to heel side reference position wh Sole width at heel side reference position wt Sole width at toe side reference position fc Face center position tk Toe Side reference position hk Heel side reference position θ Vance angle

Claims (4)

When a position 25 mm away from the face center position to the toe side is a toe side reference position, and a position 25 mm away from the face center position to the heel side is a heel side reference position, the toe from the toe side reference position to the heel side reference position -It has a positive bounce angle in the heel direction range, and the bance angle at the heel side reference position is larger than the bounce angle at the toe side reference position,
The sole surface of the heel side from the face center position, and have a groove-like portion extending inclined toward the heel side from the toe side as it goes from the trailing edge side to the leading edge side,
A straight line passing through two contour lines existing on both sides of the groove-shaped portion and perpendicular to the groove direction line, and on the inner surface of the groove portion in a cross-sectional view of the section perpendicular to the groove direction line. The angle between the point and the tangent at the point located at the midpoint of the groove depth is not less than 20 degrees and not more than 40 degrees,
The length of the groove-shaped portion in the longitudinal direction is 10 mm or more, the groove width of the groove-shaped portion is 7 mm or more and 17 mm or less, and the groove depth of the groove-shaped portion is 0.5 mm or more and 2.0 mm or less. And
The groove-shaped portion constitutes a concave portion toward the head outer surface side, and the cross-sectional line of the groove-shaped portion is a smooth curve.
The bounce angle is increased from the toe side to the heel side in the toe-heel direction range from the toe side reference position to the heel side reference position, and
The sole width, iron type golf club head for sand wedge, characterized that you have been largely from the toe side toward the heel side at the toe-heel direction ranging from the toe side reference position to the heel side reference position. 2. The sand wedge according to claim 1, wherein the sole surface on the toe side relative to the face center position is a convex curved surface or flat surface toward the head outer surface side, and is a smooth surface. Iron type golf club head. The iron type for sand wedge according to claim 1 or 2 , wherein the bounce angle at the heel side reference position is not less than 8 degrees and not more than 17 degrees, and the bance angle at the toe side reference position is greater than 0 degree and not more than 4 degrees. Golf club head. A sand wedge comprising the iron type golf club head for sand wedge according to any one of claims 1 to 3 .

Images