Golf club set

Abstract

To provide a golf club set which reduces a sense of incongruity at address between club numbers.SOLUTION: A golf club set 2 includes at least three golf clubs 4 having different loft angles. Each golf club 4 respectively has a golf club head 61-1, 62-1, 63-1 with a hitting face 12a and a crown portion 14. The crown portion 14 of each head respectively has an upper heel line 100, 200, 300 extending from a heel side toward a toe side in a region within 10 mm from an upper edge 12c of the hitting face toward a back side. Each of the upper heel lines has a lowest point F, a point F1 spaced 10 mm from the bottom point F toward the toe side, and a point F2 spaced 5 mm from the bottom point F toward the heel side. A curvature radius R1 of a circle passing through the lowest point F, the point F1, and the point F2 increases as the loft angle increases.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This invention relates to a set of golf clubs. [Background technology]

[0002] A golf club set typically includes multiple clubs with different loft angles. Each club is used depending on the desired distance and other factors.

[0003] Japanese Patent Publication No. 2016-7253 discloses a golf club set that takes into account the characteristics of each club number. In this golf club set, the swing resistance is reduced in the higher numbered clubs, and the address stability and low center of gravity are achieved in the lower numbered clubs. The club number is the designation given to each club that makes up the golf club set, and usually includes a number, except for wedges. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2016-7253 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The inventors have discovered that in a set of golf clubs, a sense of discomfort occurs at address between clubs. They further discovered that this discomfort is caused by a line located near the heel side of the upper edge of the clubface. This discomfort can make addressing the ball difficult. This discomfort can lead to swing inconsistencies and mis-shots.

[0006] One of the objectives of this invention is to provide a golf club set that reduces the feeling of discomfort when addressing the ball between clubs. [Means for solving the problem]

[0007] In one embodiment, a golf club set comprises at least three golf clubs with different loft angles. Each golf club has a golf club head comprising a striking face and a crown. The crown of each head has an upper heel line extending from the heel side to the toe side in an area within 10 mm back from the upper edge of the striking face. The upper heel line has a lowest point F, a point F1 located 10 mm toe-side from the lowest point F and being the toe-side end of the upper heel line, and a point F2 located 5 mm heel-side from the lowest point F and being the heel-side end of the upper heel line. When the radius of curvature R1 of a circle passing through the lowest point F, point F1, and point F2 is defined in a projection line obtained by projecting the upper heel line onto a plane perpendicular to the face-back direction, the radius of curvature R1 increases as the loft angle increases. [Effects of the Invention]

[0008] One possible aspect is the provision of golf club sets that reduce the feeling of discomfort when addressing the ball between clubs. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is an overall view of the golf club set according to the present invention. [Figure 2] Figure 2(a) is an explanatory diagram regarding the definition of the outer edge of the striking face, and Figure 2(b) is an example of a cross-sectional line of the outer surface of the head relating to that definition. [Figure 3] Figure 3 shows a plan view and a front view of the head (H4) according to the set of the first embodiment. [Figure 4] Figure 4 shows a plan view and a front view of the head (H5) according to the set of the first embodiment. [Figure 5] Figure 5 shows a plan view and a front view of the head (H6) according to the set of the first embodiment. [Figure 6] Figure 6 shows a plan view and a front view of the head (H4) according to the second embodiment. [Figure 7]FIG. 7 is a plan view and a front view of a head (H5) according to the set of the second embodiment. [Figure 8] FIG. 8 is a plan view and a front view of a head (H6) according to the set of the second embodiment. [Figure 9] FIG. 9 is a plan view and a front view of a head (H4) according to the set of the comparative example. [Figure 10] FIG. 10 is a plan view and a front view of a head (H5) according to the set of the comparative example. [Figure 11] FIG. 11 is a plan view and a front view of a head (H6) according to the set of the comparative example. [Figure 12] FIG. 12 is a partially enlarged plan view in which upper heel lines of heads (H5) and (H6) of the same set are added to the head (H4) according to the set of the first embodiment. [Figure 13] FIG. 13 is a partially enlarged plan view in which upper heel lines of heads (H5) and (H6) of the same set are added to the head (H4) according to the set of the second embodiment. [Figure 14] FIG. 14 is a partially enlarged plan view in which upper heel lines of heads (H5) and (H6) of the same set are added to the head (H4) according to the set of the comparative example. [Figure 15] FIG. 15 is a diagram for explaining the reference state.

MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, embodiments will be described in detail while appropriately referring to the drawings.

[0011] In the present application, a reference state, a reference vertical plane, a toe-heel direction, a face-back direction, an up-down direction, and a face center are defined.

[0012] The reference state is defined as the state in which the club head is placed on the ground plane HP at a predetermined lie angle. As shown in Figure 15, in this reference state, the shaft axis Z is contained within the plane VP perpendicular to the ground plane HP. The shaft axis Z is the center line of the shaft. Typically, the shaft axis Z coincides with the center line of the hosel hole. The plane VP is defined as the reference vertical plane. The predetermined lie angle is listed, for example, in the product catalog.

[0013] It is known that the loft angle, lie angle, and face angle can be adjusted by the rotational position of a sleeve provided at the tip of the shaft. In this club, the sleeve can be detachably fixed to the head with a fixing means such as a screw. Therefore, the shaft can be attached to and detached from the head in this club. In a club having such a detachable mechanism, all adjustment items are set to neutral in the above-mentioned standard state. Neutral means the center of the adjustment range. The club of the present invention may have such a detachable mechanism.

[0014] In this standard state, the face angle is considered to be 0 degrees. That is, in a plan view from above, the normal to the face center of the striking face is considered to be perpendicular to the toe-heel direction. The definitions of the face center and the toe-heel direction are described below.

[0015] In this application, the toe-heel direction is the direction of the intersection line NL between the reference vertical plane VP and the ground plane HP (see Figure 15). The toe side in the toe-heel direction is also simply referred to as the "toe side." The heel side in the toe-heel direction is also simply referred to as the "heel side."

[0016] In this application, the face-back direction is the direction perpendicular to the toe-heel direction and parallel to the ground plane HP. The face side in the face-back direction is also simply referred to as the "face side." The back side in the face-back direction is also simply referred to as the "back side."

[0017] In this application, the vertical direction is the direction perpendicular to the toe-heel direction and perpendicular to the face-back direction. In other words, in this application, the vertical direction is the direction perpendicular to the ground plane HP.

[0018] In this application, the face center Fc is determined as follows: First, an arbitrary point Pr is selected near the approximate center of the striking face in the vertical and toe-heel directions. Next, a plane is determined that passes through this point Pr, extends along the normal direction of the striking face at point Pr, and is parallel to the toe-heel direction. A line is drawn between this plane and the striking face, and its midpoint Px is determined. Next, a plane is determined that passes through this midpoint Px, extends along the normal direction of the striking face at point Px, and is parallel to the vertical direction. A line is drawn between this plane and the striking face, and its midpoint Py is determined. Next, a plane is determined that passes through this midpoint Py, extends along the normal direction of the striking face at point Py, and is parallel to the toe-heel direction. A line is drawn between this plane and the striking face, and its midpoint Px is newly determined. Next, a plane is determined that passes through this new midpoint Px, extends along the normal direction of the striking face at point Px, and is parallel to the vertical direction. A line is drawn at the intersection of this plane and the hitting face, and its midpoint Py is newly determined. This process is repeated to sequentially determine Px and Py. In the repetition of this process, the new position Py (the last position Py) at which the distance between the new midpoint Py and the immediately preceding midpoint Py becomes 0.5 mm or less is the face center Fc.

[0019] Figure 1 shows a golf club set 2 according to one embodiment of the present invention. Set 2 includes a plurality of golf clubs. In this embodiment, set 2 has three golf clubs 4.

[0020] Each golf club 4 has a head 6, a shaft 8, and a grip 10. The length of each club 4 is different. The length of the shaft 8 is different for each club 4. The loft angle of the head 6 is different for each club 4. The grip 10 is common to all clubs 4.

[0021] In Set 2, the number of clubs in Set 4 is preferably 3 or more. Considering the restrictions on the number of clubs in the rules of golf, the number of clubs in Set 2 is preferably 6 or less, more preferably 5 or less, and most preferably 4 or less.

[0022] In Set 2, all heads 6 are hollow. Set 2 does not include a driver (1-wood). A set may include a driver.

[0023] In this embodiment, all heads 6 are of the hybrid type. Heads 6 may also be, for example, wood-type (fairway wood-type).

[0024] Set 2 has a first club 41, a second club 42, and a third club 43, in order of increasing loft angle. Club 41 has a head 61 and a shaft 81. Club 42 has a head 62 and a shaft 82. Club 43 has a head 63 and a shaft 83. Head 61 has a loft angle La1. Head 62 has a loft angle La2. Head 63 has a loft angle La3. Loft angle La1 is smaller than loft angle La2. Loft angle La2 is smaller than loft angle La3. As the loft angle increases, the club length decreases. As the loft angle increases, the shaft length decreases.

[0025] Club 41 is a hybrid number 4 (H4). Club 42 is a hybrid number 5 (H5). Club 43 is a hybrid number 6 (H6). The club number for each club is not limited.

[0026] The loft angle La1 of the first club 41 (H4) may be between 20 and 24 degrees. The loft angle La2 of the second club 42 (H5) may be between 23 and 27 degrees. The loft angle La3 of the third club 43 (H6) may be between 26 and 30 degrees. The difference in loft angles (La2-La1) may be between 2 and 4 degrees. The difference in loft angles (La3-La2) may be between 2 and 4 degrees. The loft angles of each club are not limited.

[0027] In Set 2, the larger the loft angle, the heavier the head weight. In Set 2, the larger the loft angle, the smaller the head volume.

[0028] In this application, the matters described as head 6 are common to all heads 61 to 63.

[0029] Figure 2(a) is a front view of the head 6 as seen from the face side. The head 6 has a face portion 12, a crown portion 14, a sole portion 16, and a hosel portion 18. The face portion 12 has a striking face 12a. The striking face 12a is the outer surface of the face portion 12. The crown portion 14 has an outer crown surface 14a. The head 6 is hollow.

[0030] The striking face 12a has an outer edge 12b. The outer edge 12b includes the upper edge 12c of the striking face 12a. The upper edge 12c is the boundary between the striking face 12a and the outer surface 14a of the crown. The upper edge 12c is also referred to as the upper edge of the face.

[0031] The outer edge 12b is determined as follows: As shown in Figure 2(a), a number of cross-sections E1, E2, E3, etc. are defined, each containing a line segment connecting the head's center of gravity and the sweet spot SS. In these cross-sections, the point is determined where the radius of curvature of the head's outer surface first becomes 200 mm when moving from the sweet spot SS side towards the outside of the striking face 12a (see Figure 2(b)). The set of these points can be considered the outer edge 12b of the striking face 12a. The sweet spot SS is the intersection point of the striking face 12a and the normal to the striking face 12a that passes through the head's center of gravity.

[0032] [Head 61-1: H4] Figure 3 shows a plan view of head 61-1 of the golf club set 21 of the first embodiment, viewed from the crown side, and a front view of it viewed from the face side. Set 21 is an example of Set 2 described above. Head 61-1 is an example of head 61 described above. Head 61-1 is a hybrid 4-iron (H4).

[0033] Head 61-1 has an upper heel line 100 on the back side of the upper edge 12c of the striking face 12a. The upper heel line 100 is a visible line. The upper heel line 100 extends from the heel side toward the toe side. Head 61-1 also has an extension line 102 extending toward the toe side from the toe-side end F1 of the upper heel line 100. The extension line 102 is a visible line. The upper heel line 100 is a ridge line. The extension line 102 is a ridge line. In the front view, the upper heel line 100 overlaps with the contour line of head 61-1. This is also true in other front views of the present invention.

[0034] The heel upper line 100 is located in a region where the face-to-back distance from the face upper edge 12c is 10 mm or less. That is, at any toe-heel position, the face-to-back distance between the heel upper line 100 and the face upper edge 12c is 10 mm or less. Preferably, the face-to-back distance between the heel upper line 100 and the face upper edge 12c is 9 mm or less, and more preferably 8 mm or less. Preferably, the face-to-back distance between the heel upper line 100 and the face upper edge 12c is 2 mm or more, more preferably 3 mm or more, and more preferably 4 mm or more. The heel upper line 100 extends along the face upper edge 12c.

[0035] The points constituting the upper heel line 100 can be determined as follows: A reference point is set 10 mm back from the upper edge 12c of the face, and points are marked at 1 mm intervals along the face-back direction from this reference point to the upper edge 12c of the face. This "1 mm" is the distance in the face-back direction. The radius of curvature at each point is measured in order of proximity to the reference point. This radius of curvature is the radius of the circle passing through the measured point and the two points adjacent to it. The point where the radius of curvature is first 8 mm or less can be a point that constitutes the upper heel line 100. This point can be determined at each position in the toe-heel direction. The set of these points can be the upper heel line 100. This definition can also be applied to the extension line 102.

[0036] The lower front view in Figure 3 is a projection of the head 61-1 projected onto a plane perpendicular to the face-back direction. The heel upper line 100 in this front view is a projection line projected onto a plane perpendicular to the face-back direction. As this projection line shows, the heel upper line 100 has a lowest point F, a point F1 10 mm away from the lowest point F towards the toe, and a point F2 5 mm away from the lowest point F towards the heel. These "10 mm" and "5 mm" are distances in the toe-heel direction. Point F1 is the toe-side endpoint of the heel upper line 100. Point F2 is the heel-side endpoint of the heel upper line 100. The heel upper line 100 has a lowest position LP in the vertical direction (see the front view in Figure 3). The lowest point F is the point at this position LP.

[0037] The head 61-1 has a fillet portion 104. The fillet portion 104 includes the heel upper line 100 and the face upper edge 12c. The face upper edge 12c constitutes the front edge of the fillet portion 104. The heel upper line 100 constitutes the rear edge of the fillet portion 104. The head 61-1 also has an extended fillet portion 106. The extended fillet portion 106 includes an extension line 102 and the face upper edge 12c. The face upper edge 12c constitutes the front edge of the extended fillet portion 106. The extension line 102 constitutes the rear edge of the extended fillet portion 106. The fillet portion 104 is part of the crown outer surface 14a. The extended fillet portion 106 is part of the crown outer surface 14a. The fillet portion 104 and the extended fillet portion 106 are convex curved surfaces. There is no visible line between the heel upper line 100 and the face upper edge 12c. There is no visible line between the extension line 102 and the face upper edge 12c. The radius of curvature Rf of the fillet portion 104 in the face-back direction is preferably 2 mm or more and 15 mm or less, more preferably 3 mm or more and 12 mm or less, and more preferably 3 mm or more and 7 mm or less. The radius of curvature Rf is measured in a cross section along the face-back direction.

[0038] [Head 62-1: H5] Figure 4 shows a plan view of head 62-1 of the golf club set 21, viewed from the crown side, and a front view of it, viewed from the face side. Head 62-1 is an example of the head 62 mentioned above. Head 62-1 is a hybrid 5-iron (H5).

[0039] Head 62-1 has an upper heel line 200 on the back side of the upper edge 12c of the striking face 12a. The upper heel line 200 is a visible line. Head 62-1 also has an extension line 202 extending toward the toe from the toe end F1 of the upper heel line 200. The extension line 202 is a visible line. The upper heel line 200 is a ridge line. The extension line 202 is a ridge line.

[0040] The upper heel line 200 is located within 10 mm of the face-to-back distance from the upper face edge 12 c. The upper heel line 200 extends along the upper face edge 12 c.

[0041] The lower front view in Figure 4 is a projection of the head 62-1 projected onto a plane perpendicular to the face-back direction. The heel upper line 200 in this front view is a projection line projected onto a plane perpendicular to the face-back direction. As this projection line shows, the heel upper line 200 has a lowest point F, a point F1 10 mm away from the lowest point F towards the toe, and a point F2 5 mm away from the lowest point F towards the heel. Point F1 is the toe-side endpoint of the heel upper line 200. Point F2 is the heel-side endpoint of the heel upper line 200.

[0042] The head 62-1 has a fillet portion 204. The fillet portion 204 includes the heel upper line 200 and the face upper edge 12c. The face upper edge 12c constitutes the front edge of the fillet portion 204. The heel upper line 200 constitutes the rear edge of the fillet portion 204. The head 62-1 also has an extended fillet portion 206. The extended fillet portion 206 includes the extension line 202 and the face upper edge 12c. The face upper edge 12c constitutes the front edge of the extended fillet portion 206. The extension line 202 constitutes the rear edge of the extended fillet portion 206. The fillet portion 204 is part of the crown outer surface 14a. The extended fillet portion 206 is part of the crown outer surface 14a. The fillet portion 204 and the extended fillet portion 206 are convex curved surfaces. There is no visible line between the upper heel line 200 and the upper face edge 12c. There is no visible line between the extension line 202 and the upper face edge 12c.

[0043] [Head 63-1: H6] Figure 5 shows a plan view of head 63-1 of the golf club set 21, viewed from the crown side, and a front view of it viewed from the face side. Head 63-1 is an example of the head 63 mentioned above. Head 63-1 is a hybrid 6-iron (H6).

[0044] Head 63-1 has an upper heel line 300 on the back side of the upper edge 12c of the striking face 12a. The upper heel line 300 is a visible line. Head 63-1 also has an extension line 302 extending toward the toe from the toe end F1 of the upper heel line 300. The extension line 302 is a visible line. The upper heel line 300 is a ridge line. The extension line 302 is a ridge line.

[0045] The upper heel line 300 is located within 10 mm of the face-to-back distance from the upper face edge 12 c. The upper heel line 300 extends along the upper face edge 12 c.

[0046] The lower front view in Figure 5 is a projection of the head 63-1 projected onto a plane perpendicular to the face-back direction. The heel upper line 300 in this front view is a projection line projected onto a plane perpendicular to the face-back direction. As this projection line shows, the heel upper line 300 has a lowest point F, a point F1 10 mm away from the lowest point F towards the toe, and a point F2 5 mm away from the lowest point F towards the heel. Point F1 is the toe-side endpoint of the heel upper line 300. Point F2 is the heel-side endpoint of the heel upper line 300.

[0047] The head 63-1 has a fillet portion 304. The fillet portion 304 includes the heel upper line 300 and the face upper edge 12c. The face upper edge 12c constitutes the front edge of the fillet portion 304. The heel upper line 300 constitutes the rear edge of the fillet portion 304. The head 63-1 also has an extended fillet portion 306. The extended fillet portion 306 includes an extension line 302 and the face upper edge 12c. The face upper edge 12c constitutes the front edge of the extended fillet portion 306. The extension line 302 constitutes the rear edge of the extended fillet portion 306. The fillet portion 304 is part of the crown outer surface 14a. The extended fillet portion 306 is part of the crown outer surface 14a. The fillet portion 304 and the extended fillet portion 306 are convex curved surfaces. There is no visible line between the upper heel line 300 and the upper face edge 12c. There is no visible line between the extension line 302 and the upper face edge 12c.

[0048] In Figure 3, the double arrow H indicates the height of the lowest point F. Height H is the height from the ground plane HP in the reference state. Height H is measured along the vertical direction. In set 21, as the loft angle increases, height H decreases.

[0049] [Head 61-2: H4] Figure 6 shows a plan view of head 61-2 of the golf club set 22 of the second embodiment, viewed from the crown side, and a front view of it viewed from the face side. Set 22 is an example of Set 2 described above. Head 61-2 is an example of head 61 described above. Head 61-2 is a hybrid #4 (H4). Head 61-2 is the same as head 61-1.

[0050] Head 61-2 has an upper heel line 400 on the back side of the upper edge 12c of the striking face 12a. The upper heel line 400 is a visible line. Head 61-2 also has an extension line 402 extending toward the toe from the toe end F1 of the upper heel line 400. The extension line 402 is a visible line. The upper heel line 400 is a ridge line. The extension line 402 is a ridge line.

[0051] The upper heel line 400 is located within 10 mm of the face-to-back distance from the upper face edge 12 c. The upper heel line 400 extends along the upper face edge 12 c.

[0052] The lower front view in Figure 6 is a projection of the head 61-2 projected onto a plane perpendicular to the face-back direction. The heel upper line 400 in this front view is a projection line projected onto a plane perpendicular to the face-back direction. As this projection line shows, the heel upper line 400 has a lowest point F, a point F1 10 mm away from the lowest point F towards the toe, and a point F2 5 mm away from the lowest point F towards the heel. Point F1 is the toe-side endpoint of the heel upper line 400. Point F2 is the heel-side endpoint of the heel upper line 400.

[0053] The head 61-2 has a fillet portion 404. The fillet portion 404 includes the heel upper line 400 and the face upper edge 12c. The face upper edge 12c constitutes the front edge of the fillet portion 404. The heel upper line 400 constitutes the rear edge of the fillet portion 404. The head 61-2 also has an extended fillet portion 406. The extended fillet portion 406 includes an extension line 402 and the face upper edge 12c. The face upper edge 12c constitutes the front edge of the extended fillet portion 406. The extension line 402 constitutes the rear edge of the extended fillet portion 406. The fillet portion 404 is part of the crown outer surface 14a. The extended fillet portion 406 is part of the crown outer surface 14a. The fillet portion 404 and the extended fillet portion 406 are convex curved surfaces. There is no visible line between the upper heel line 400 and the upper face edge 12c. There is no visible line between the extension line 402 and the upper face edge 12c.

[0054] [Head 62-2: H5] Figure 7 shows a plan view of head 62-2 of the golf club set 22, viewed from the crown side, and a front view of it, viewed from the face side. Head 62-2 is an example of head 62 as described above. Head 62-2 is a hybrid 5-iron (H5). Head 62-2 is the same as head 62-1.

[0055] Head 62-2 has an upper heel line 500 on the back side of the upper edge 12c of the striking face 12a. The upper heel line 500 is a visible line. Head 62-2 also has an extension line 502 extending toward the toe from the toe end F1 of the upper heel line 500. The extension line 502 is a visible line. The upper heel line 500 is a ridge line. The extension line 502 is a ridge line.

[0056] The upper heel line 500 is located within 10 mm of the face-to-back distance from the upper face edge 12 c. The upper heel line 500 extends along the upper face edge 12 c.

[0057] The lower front view in Figure 7 is a projection of the head 62-2 projected onto a plane perpendicular to the face-back direction. The heel upper line 500 in this front view is a projection line projected onto a plane perpendicular to the face-back direction. As this projection line shows, the heel upper line 500 has a lowest point F, a point F1 10 mm away from the lowest point F towards the toe, and a point F2 5 mm away from the lowest point F towards the heel. Point F1 is the toe-side endpoint of the heel upper line 500. Point F2 is the heel-side endpoint of the heel upper line 500.

[0058] The head 62-2 has a fillet portion 504. The fillet portion 504 includes the heel upper line 500 and the face upper edge 12c. The face upper edge 12c constitutes the front edge of the fillet portion 504. The heel upper line 500 constitutes the rear edge of the fillet portion 504. The head 62-2 also has an extended fillet portion 506. The extended fillet portion 506 includes the extension line 502 and the face upper edge 12c. The face upper edge 12c constitutes the front edge of the extended fillet portion 506. The extension line 502 constitutes the rear edge of the extended fillet portion 506. The fillet portion 504 is part of the crown outer surface 14a. The extended fillet portion 506 is part of the crown outer surface 14a. The fillet portion 504 and the extended fillet portion 506 are convex curved surfaces. There is no visible line between the upper heel line 500 and the upper face edge 12c. There is no visible line between the extension line 502 and the upper face edge 12c.

[0059] [Head 63-2: H6] Figure 8 shows a plan view of head 63-2 of the golf club set 22, viewed from the crown side, and a front view of it, viewed from the face side. Head 63-2 is an example of head 63 as described above. Head 63-2 is a hybrid 6-iron (H6).

[0060] Head 63-2 has an upper heel line 600 on the back side of the upper edge 12c of the striking face 12a. The upper heel line 600 is a visible line. Head 63-2 also has an extension line 602 extending toward the toe from the toe end F1 of the upper heel line 600. The extension line 602 is a visible line. The upper heel line 600 is a ridge line. The extension line 602 is a ridge line.

[0061] The upper heel line 600 is located within 10 mm of the face-to-back distance from the upper face edge 12 c. The upper heel line 600 extends along the upper face edge 12 c.

[0062] The lower front view in Figure 8 is a projection of the head 63-2 projected onto a plane perpendicular to the face-back direction. The heel upper line 600 in this front view is a projection line projected onto a plane perpendicular to the face-back direction. As this projection line shows, the heel upper line 600 has a lowest point F, a point F1 10 mm away from the lowest point F towards the toe, and a point F2 5 mm away from the lowest point F towards the heel. Point F1 is the toe-side endpoint of the heel upper line 600. Point F2 is the heel-side endpoint of the heel upper line 600.

[0063] The head 63-2 has a fillet portion 604. The fillet portion 604 includes the heel upper line 600 and the face upper edge 12c. The face upper edge 12c constitutes the front edge of the fillet portion 604. The heel upper line 600 constitutes the rear edge of the fillet portion 604. The head 63-2 also has an extended fillet portion 606. The extended fillet portion 606 includes the extension line 602 and the face upper edge 12c. The face upper edge 12c constitutes the front edge of the extended fillet portion 606. The extension line 602 constitutes the rear edge of the extended fillet portion 606. The fillet portion 604 is part of the crown outer surface 14a. The extended fillet portion 606 is part of the crown outer surface 14a. The fillet portion 604 and the extended fillet portion 606 are convex curved surfaces. There is no visible line between the upper heel line 600 and the upper face edge 12c. There is no visible line between the extension line 602 and the upper face edge 12c.

[0064] [Head 61-3: H4] Figure 9 shows a plan view of head 61-3 from the crown side and a front view of head 61-3 from the face side, relating to comparative example golf club set 23. Set 23 is an example of set 2 mentioned above. Head 61-3 is an example of head 61 mentioned above. Head 61-3 is a hybrid #4 (H4).

[0065] Head 61-3 has an upper heel line 700 on the back side of the upper edge 12c of the striking face 12a. The upper heel line 700 is a visible line. Head 61-3 also has an extension line 702 extending toward the toe from the toe end F1 of the upper heel line 700. The extension line 702 is a visible line. The upper heel line 700 is a ridge line. The extension line 702 is a ridge line.

[0066] The upper heel line 700 is located within 10 mm of the face-to-back distance from the upper face edge 12 c. The upper heel line 700 extends along the upper face edge 12 c.

[0067] The lower front view in Figure 9 is a projection of the head 61-3 projected onto a plane perpendicular to the face-back direction. The heel upper line 700 in this front view is a projection line projected onto a plane perpendicular to the face-back direction. As this projection line shows, the heel upper line 700 has a lowest point F, a point F1 10 mm away from the lowest point F towards the toe, and a point F2 5 mm away from the lowest point F towards the heel. Point F1 is the toe-side endpoint of the heel upper line 700. Point F2 is the heel-side endpoint of the heel upper line 700.

[0068] The head 61-3 has a fillet portion 704. The fillet portion 704 includes the heel upper line 700 and the face upper edge 12c. The face upper edge 12c constitutes the leading edge of the fillet portion 704. The heel upper line 700 constitutes the trailing edge of the fillet portion 704. The head 61-3 also has an extended fillet portion 706. The extended fillet portion 706 includes the extension line 702 and the face upper edge 12c. The face upper edge 12c constitutes the leading edge of the extended fillet portion 706. The extension line 702 constitutes the trailing edge of the extended fillet portion 706. The fillet portion 704 is part of the crown outer surface 14a. The extended fillet portion 706 is part of the crown outer surface 14a. The fillet portion 704 and the extended fillet portion 706 are convex curved surfaces. There is no visible line between the upper heel line 700 and the upper face edge 12c. There is no visible line between the extension line 702 and the upper face edge 12c.

[0069] [Head 62-3: H5] Figure 10 shows a plan view of head 62-3 of the golf club set 23, viewed from the crown side, and a front view of it, viewed from the face side. Head 62-3 is an example of head 62 as described above. Head 62-3 is a hybrid 5-iron (H5). Head 62-3 is the same as head 62-1.

[0070] Head 62-3 has an upper heel line 800 on the back side of the upper edge 12c of the striking face 12a. The upper heel line 800 is a visible line. Head 62-3 also has an extension line 802 extending toward the toe from the toe end F1 of the upper heel line 800. The extension line 802 is a visible line. The upper heel line 800 is a ridge line. The extension line 802 is a ridge line.

[0071] The heel upper line 800 is located within 10 mm of the face-to-back distance from the face upper edge 12 c. The heel upper line 800 extends along the face upper edge 12 c.

[0072] The lower front view in Figure 10 is a projection of the head 62-3 projected onto a plane perpendicular to the face-back direction. The heel upper line 800 in this front view is a projection line projected onto a plane perpendicular to the face-back direction. As this projection line shows, the heel upper line 800 has a lowest point F, a point F1 10 mm away from the lowest point F towards the toe, and a point F2 5 mm away from the lowest point F towards the heel. Point F1 is the toe-side endpoint of the heel upper line 800. Point F2 is the heel-side endpoint of the heel upper line 800.

[0073] The head 62-3 has a fillet portion 804. The fillet portion 804 includes the heel upper line 800 and the face upper edge 12c. The face upper edge 12c constitutes the front edge of the fillet portion 804. The heel upper line 800 constitutes the rear edge of the fillet portion 804. The head 62-3 also has an extended fillet portion 806. The extended fillet portion 806 includes the extension line 802 and the face upper edge 12c. The face upper edge 12c constitutes the front edge of the extended fillet portion 806. The extension line 802 constitutes the rear edge of the extended fillet portion 806. The fillet portion 804 is part of the crown outer surface 14a. The extended fillet portion 806 is part of the crown outer surface 14a. The fillet portion 804 and the extended fillet portion 806 are convex curved surfaces. There is no visible line between the upper heel line 800 and the upper face edge 12c. There is no visible line between the extension line 802 and the upper face edge 12c.

[0074] Figure 11 shows a plan view of head 63-3 of the golf club set 23, viewed from the crown side, and a front view of it, viewed from the face side. Head 63-3 is an example of the head 63 mentioned above. Head 63-3 is a hybrid 6-iron (H6).

[0075] Head 63-3 has an upper heel line 900 on the back side of the upper edge 12c of the striking face 12a. The upper heel line 900 is a visible line. Head 63-3 also has an extension line 902 extending toward the toe from the toe end F1 of the upper heel line 900. The extension line 902 is a visible line. The upper heel line 900 is a ridge line. The extension line 902 is a ridge line.

[0076] The upper heel line 900 is located within 10 mm of the face-to-back distance from the upper face edge 12 c. The upper heel line 900 extends along the upper face edge 12 c.

[0077] The lower front view in Figure 11 is a projection of the head 63-3 projected onto a plane perpendicular to the face-back direction. The heel upper line 900 in this front view is a projection line projected onto a plane perpendicular to the face-back direction. As this projection line shows, the heel upper line 900 has a lowest point F, a point F1 10 mm away from the lowest point F towards the toe, and a point F2 5 mm away from the lowest point F towards the heel. Point F1 is the toe-side endpoint of the heel upper line 900. Point F2 is the heel-side endpoint of the heel upper line 900.

[0078] The head 63-3 has a fillet portion 904. The fillet portion 904 includes the heel upper line 900 and the face upper edge 12c. The face upper edge 12c constitutes the front edge of the fillet portion 904. The heel upper line 900 constitutes the rear edge of the fillet portion 904. The head 63-3 also has an extended fillet portion 906. The extended fillet portion 906 includes the extension line 902 and the face upper edge 12c. The face upper edge 12c constitutes the front edge of the extended fillet portion 906. The extension line 902 constitutes the rear edge of the extended fillet portion 906. The fillet portion 904 is part of the crown outer surface 14a. The extended fillet portion 906 is part of the crown outer surface 14a. The fillet portion 904 and the extended fillet portion 906 are convex curved surfaces. There is no visible line between the upper heel line 900 and the upper face edge 12c. There is no visible line between the extension line 902 and the upper face edge 12c.

[0079] [Curvature radius R1] In the projection line obtained by projecting the upper heel line onto a plane perpendicular to the face-back direction, the radius of the circle C1 passing through the lowest point F, points F1 and F2 is the radius of curvature R1 (see Figure 4).

[0080] In the golf club set 21 of the first embodiment, the radius of curvature R1 of head 62-1(H5) is larger than the radius of curvature R1 of head 61-1(H4). Also, the radius of curvature R1 of head 63-1(H6) is larger than the radius of curvature R1 of head 62-1(H5). In set 21, the radius of curvature R1 increases as the loft angle increases for all golf clubs. Specifically, in this set 21, the radius of curvature R1 was defined as follows. • Radius of curvature R1 of head 61-1 (H4): 16.5 mm • Radius of curvature R1 of head 62-1 (H5): 18.2 mm • Radius of curvature R1 of head 63-1 (H6): 21.1 mm

[0081] In the golf club set 22 of the second embodiment, the radius of curvature R1 of head 62-2(H5) is larger than the radius of curvature R1 of head 61-2(H4). Also, the radius of curvature R1 of head 63-2(H6) is larger than the radius of curvature R1 of head 62-2(H5). In set 22, the radius of curvature R1 increases as the loft angle increases for all golf clubs. Specifically, in set 22, the radius of curvature R1 was defined as follows. • Radius of curvature R1 of head 61-2 (H4): 16.5 mm • Radius of curvature R1 of head 62-2 (H5): 18.2 mm • Radius of curvature R1 of head 63-2 (H6): 18.5 mm

[0082] In the comparative example golf club set 23, the radius of curvature R1 of head 62-3 (H5) is smaller than that of head 61-3 (H4). Furthermore, the radius of curvature R1 of head 63-3 (H6) is smaller than that of head 62-3 (H5). In set 23, the radius of curvature R1 decreases as the loft angle increases for all golf clubs. Specifically, the radius of curvature R1 in set 23 was defined as follows: • Radius of curvature R1 of head 61-3 (H4): 20.6 mm • Radius of curvature R1 of head 62-3 (H5): 18.2 mm • Radius of curvature R1 of head 63-3 (H6): 17.4 mm

[0083] Figure 12 is an enlarged view of the area within the rectangle in Figure 3 (head 61-1). In Figure 12, the heel upper line 200 of head 62-1 (H5) and the heel upper line 300 of head 63-1 (H6) are shown side by side near the heel upper line 100 of head 61-1 (H4). Therefore, Figure 12 shows the heel upper lines of the three heads belonging to the golf club set 21 of the first embodiment. The lines are slightly offset from each other to make it easier to compare the shapes of the three heel upper lines.

[0084] Figure 13 is an enlarged view of the area within the rectangle in Figure 6 (head 61-2). In Figure 13, the heel upper line 500 of head 62-2 (H5) and the heel upper line 600 of head 63-2 (H6) are shown side by side near the heel upper line 400 of head 61-2 (H4). Therefore, Figure 13 shows the heel upper lines of the three heads belonging to the golf club set 22 of the second embodiment. The lines are slightly offset from each other to make it easier to compare the shapes of the three heel upper lines.

[0085] Figure 14 is an enlarged view of the area within the rectangle in Figure 9 (head 61-3). In Figure 14, the heel upper line 800 of head 62-3 (H5) and the heel upper line 900 of head 63-3 (H6) are shown side by side near the heel upper line 700 of head 61-3 (H4). Therefore, Figure 14 shows the heel upper lines of three heads belonging to the comparative example golf club set 23. The lines are slightly offset from each other to facilitate comparison of the shapes of the three heel upper lines.

[0086] The inventors have discovered that the shape of the line on the heel side of the club head in a golf club set can cause discomfort when addressing the ball. Ideally, a golf club set should allow for a consistent address position across all clubs. However, it was found that differences in the shape of the upper heel line within the set can cause discomfort between clubs. This discomfort can be reduced by increasing the radius of curvature R1 as the loft angle increases.

[0087] As shown in Figure 12, in set 21 of the first embodiment, the differences in shape between the three upper heel lines are small. Also, the three upper heel lines are relatively close to straight. As shown in Figure 13, in set 22 of the second embodiment, the differences in shape between the three upper heel lines are also small. Also, the three upper heel lines are relatively close to straight. In contrast, in set 23 of the comparative example (Figure 14), the differences in shape between the three upper heel lines are large. Also, the curvature of the three upper heel lines is particularly large for clubs with a large loft angle (upper heel line 900).

[0088] In the comparative example set 23 (Figure 14), differences in the shape of the heel upper line between clubs can easily cause discomfort at address. As shown in Figure 14, when the heel upper line 900 is curved convexly toward the back, the hitting face 12a may feel as if it is pointing to the right. This is thought to be because the normal to the heel end of the heel upper line 900 points relatively to the right. When this feeling occurs, it becomes difficult to point the hitting face 12a toward the target, or uncertainty about whether the hitting face 12a is pointing toward the target can cause hesitation in the swing, leading to mis-shots. In addition, this curvature reduces the parallelism between the line of the face upper edge 12c and the heel upper line. Therefore, it is difficult to determine the direction in which the hitting face 12a is pointing. Thus, even from the perspective of curvature, differences occur between clubs, making it easy to feel discomfort at address between clubs.

[0089] In the first embodiment's set 21 (Figure 12) and the second embodiment's set 22 (Figure 13), there is little difference in the shape of the upper heel line between clubs, thus reducing discomfort when addressing the ball between clubs. Furthermore, even with clubs that have a large loft angle, the upper heel line is relatively close to a straight line, making it easier to point the hitting face 12a towards the target. From this point of view as well, discomfort when addressing the ball between clubs is reduced.

[0090] The difference S1 between the maximum and minimum values ​​of the radius of curvature R1 within the set is not limited. From the viewpoint of suppressing the curvature of the upper heel line that tends to occur as the loft angle increases and reducing the feeling of discomfort between clubs, this difference S1 is preferably 1 mm or more, more preferably 1.5 mm or more, and even more preferably 2 mm or more. If this difference S1 is too large, a feeling of discomfort between clubs may also occur. From this viewpoint, the difference S1 is preferably 7 mm or less, more preferably 6 mm or less, and even more preferably 5 mm or less.

[0091] The value of the radius of curvature R1 is not limited. If the radius of curvature R1 is too small, the upper heel line tends to curve in a plan view from above. From this viewpoint, the radius of curvature R1 is preferably 15 mm or more, more preferably 15.5 mm or more, and more preferably 16 mm or more. From the viewpoint of constraints on the head shape, the radius of curvature R1 is preferably 22 mm or less, more preferably 21 mm or less, and more preferably 20 mm or less.

[0092] A fillet is formed on the back side of the upper edge 12c of the face, and the back edge of the fillet is the upper heel line. When the fillet is present, the upper edge 12c of the face becomes less noticeable, and the upper heel line becomes relatively more noticeable. Therefore, the above effect caused by the shape of the upper heel line is enhanced.

[0093] At the lowest point F, the radius of curvature Rf of the fillet portion is defined as Rf1. It is preferable that the absolute value of the difference in the radius of curvature Rf1 between clubs is 1.5 mm or less for all combinations of adjacent clubs with the same loft angle. In this case, the difference in shape of the upper heel line between clubs is easily suppressed.

[0094] In the first and second embodiments described above, the Rf1 of H4 was 3.69 mm, the Rf1 of H5 was 4.59 mm, and the Rf1 of H6 was 6.05 mm.

[0095] As shown in Figure 3, the extension line 102 has a point Pc that is in the same toe-heel direction position as the face center Fc. In Figure 2, the double arrow D1 indicates the face-back distance between the shaft axis Z (the plane VP) and point Pc. When the distance D1 is large, differences in the upper heel line between clubs are more likely to occur, and the effects of the present invention are enhanced. From this viewpoint, the distance D1 is preferably 5.5 mm or more, more preferably 5.6 mm or more, and even more preferably 5.7 mm or more. In a typical head, the distance D1 is 13 mm or less, more preferably 12 mm or less, and even more preferably 11 mm or less.

[0096] In the first and second embodiments described above, the distance D1 was 6 mm at H4, 7 mm at H5, and 8 mm at H6.

[0097] The loft angle of the head (real loft angle) is not limited. When the loft angle is small, the line above the heel tends to be closer to a straight line, and the problem of discomfort is less likely to occur. From this viewpoint, a loft angle of 15° or more is preferred, 16° or more is more preferred, and 17° or more is even more preferred. Considering the range of loft angles for wood-type and hybrid-type heads, a loft angle of 30° or less is preferred, 29° or less is more preferred, and 28° or less is even more preferred.

[0098] In Figure 1, the double-headed arrow FP indicates face progression. Face progression is the face-to-back distance between the shaft axis Z (plane VP) and the foremost point of the leading edge. When comparing heads with the same loft angle and face height, a smaller face progression tends to result in a more pronounced curvature of the upper heel line. Therefore, the effects of the present invention are greater in heads with a small face progression. From this viewpoint, a face progression of 16 mm or less is preferable, 15.5 mm or less is more preferable, and 15 mm or less is even more preferable. If the face progression is too small, it may restrict the neck shape. From this viewpoint, a face progression of 10 mm or more is preferable, 10.5 mm or more is more preferable, and 11 mm or more is even more preferable.

[0099] This invention is particularly effective for hybrid-type heads. From this perspective, the head volume is 90 cm³. 3 The above is preferable, 95cm 3 The above is more preferable, 100cm 3 The above is more preferable. From this viewpoint, the head volume is 140 cm³. 3 The following is preferable: 135cm 3 The following is more preferable: 130cm 3 The following are preferable.

[0100] The present invention is applied to a head having a crown. Preferably, the head has a hollow structure. Preferred heads are wood-type or hybrid-type, and more preferably hybrid-type.

[0101] Examples of fairway wood-type heads include the 3-wood (W#3), 4-wood (W#4), 5-wood (W#5), 7-wood (W#7), 9-wood (W#9), 11-wood (W#11), and 13-wood (W#13). The following (1a) to (1d) are typical configurations of fairway wood-type heads. (1a) Curved striking face (1b) Hollow structure (1c) 100cm3 Above 200 cm 3 The following volume (1d) Loft angle of 14 degrees or more and 33 degrees or less

[0102] As the gauge number of the hybrid head, hybrid 3 (H3), hybrid 4 (H4), hybrid 5 (H5), and hybrid 6 (H6) are exemplified. As the configuration of a general hybrid head, the following (2a) to (2d) can be mentioned. (2a) Curved striking face (2b) Hollow structure (2c) 90 cm 3 Above 140 cm 3 The following volume (2d) Loft angle of 15 degrees or more and 30 degrees or less

[0103] In the "golf club set" of the present invention, a plurality of golf clubs do not necessarily have to be sold at the same time. A plurality of golf clubs having different loft angles within the same series are applicable to the golf club set of the present invention even if each club is sold individually.

[0104] The following supplementary notes are part of the inventions included in the present invention. [Supplementary Note 1] A golf club set including at least three golf clubs having different loft angles, each of the golf clubs having a golf club head provided with a striking face and a crown portion, the crown portion of each head having a heel upper line extending from the upper edge of the striking face toward the back side within a region of 10 mm or less and from the heel side toward the toe side, each of the heel upper lines having a lowest point F, a point F1 that is 10 mm away from the lowest point F toward the toe side and is the toe-side end of the heel upper line, and a point F2 that is 5 mm away from the lowest point F toward the heel side and is the heel-side end of the heel upper line, When the radius of curvature R1 of a circle passing through the lowest point F, point F1, and point F2 is defined in the projection line obtained by projecting the upper heel line onto a plane perpendicular to the face-back direction, A set of golf clubs in which the radius of curvature R1 increases as the loft angle increases. [Note 2] The golf club set according to Appendix 1, wherein each of the heads has a fillet portion formed such that the upper edge of the striking face is the front edge, the upper heel line is the rear edge, and there is no visible line between the upper edge of the striking face and the upper heel line. [Note 3] The golf club set as described in Appendix 2, wherein in each of the heads, the radius of curvature Rf of the fillet portion in the face-back direction is 2 mm or more and 15 mm or less. [Note 4] When the radius of curvature Rf of the fillet portion at the lowest point F is Rf1, A golf club set according to any one of the appendices 1 to 3, wherein in all combinations of adjacent loft angles, the absolute value of the difference in the radius of curvature Rf1 between the clubs is 1.5 mm or less. [Note 5] In each of the aforementioned heads, The loft angle is between 15° and 30°. The face progression is 16mm or less. Head volume is 90cm³ 3 More than 140cm 3 A golf club set described in any one of the following appendices 1 to 4. [Explanation of Symbols]

[0105] 2, 21, 22, 23... Golf club set 4, 41, 42, 43... Golf clubs 6, 61, 62, 63, 61-1, 62-1, 63-1, 61-2, 62-2, 63-2, 61-3, 62-3, 63-3... Golf club heads 12. Face section 12a...Hitting face 12b...Outer edge of the striking face 12c... Upper edge of the striking face 14. Crown section 14a... Crown exterior 16. Sole 18. Hosel section 100, 200, 300, 400, 500, 600, 700, 800, 900... Upper heel line 104, 204, 304, 404, 504, 604, 704, 804, 904... Fillet section Fc... Face Center

Claims

1. A golf club set comprising at least three golf clubs with different loft angles, The aforementioned three golf clubs include a first hybrid club with a loft angle of 20 degrees or more and 24 degrees or less, a second hybrid club with a loft angle of 23 degrees or more and 27 degrees or less, and a third hybrid club with a loft angle of 26 degrees or more and 30 degrees or less. Each of the aforementioned golf clubs has a golf club head that includes a striking face and a crown. The crown portion of each of the heads has an upper heel line extending from the heel side toward the toe side in an area within 10 mm from the upper edge of the striking face toward the back side, Each of the aforementioned upper heel lines has a lowest point F, a point F1 located 10 mm away from the lowest point F towards the toe and which is the toe-side end of the upper heel line, and a point F2 located 5 mm away from the lowest point F towards the heel and which is the heel-side end of the upper heel line. When the radius of curvature R1 of a circle passing through the lowest point F, point F1, and point F2 is defined in the projection line obtained by projecting the upper heel line onto a plane perpendicular to the face-back direction, A set of golf clubs in which the radius of curvature R1 increases as the loft angle increases.

2. The golf club set according to claim 1, wherein each of the heads is provided with a fillet portion formed such that the upper edge of the striking face is the front edge, the upper heel line is the rear edge, and there is no visible line between the upper edge of the striking face and the upper heel line.

3. The golf club set according to claim 2, wherein in each of the heads, the radius of curvature Rf of the fillet portion in the face-back direction is 2 mm or more and 15 mm or less.

4. When the radius of curvature Rf of the fillet portion at the lowest point F is Rf1, The golf club set according to claim 2 or 3, wherein in all adjacent combinations of loft angles, the absolute value of the difference in the radius of curvature Rf1 between the clubs is 1.5 mm or less.

5. In each of the aforementioned heads, The face progression is 16 mm or less. Head volume is 90 cm³ ３ 140cm or more ３ A golf club set according to any one of claims 1 to 3 below.

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