GOLF CLUB HEAD

Abstract

This invention provides an iron golf club head comprising a face surface with a plurality of scorelines formed in it, and an indicating portion which indicates at least the cross-sectional shape of the scoreline.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an iron golf club head.

2. Description of the Related Art

In general, a plurality of parallel linear grooves are formed in the face surface of a golf club head to extend in the toe-to-heel direction. These grooves are called, for example, scorelines, marking lines, or face lines (in this specification they will be referred to as scorelines). These scorelines have an effect of increasing the back spin amount on a struck golf ball, or suppressing a significant decrease in back spin amount on a struck golf ball upon a shot in rainy weather or one taken from the rough. As for an athletic iron golf club head, owing to reform of a rule associated with scorelines, a golf club head having scorelines conforming to the reformed rule has been proposed (for example, Japanese Patent Laid-Open No. 2009-148538).

It is more difficult to ensure a given spin amount under the reformed rule than under the previous rule, so a wider variety of improvements regarding the shape of scorelines are in progress than before. However, because scorelines are elongated grooves, their features in terms of shape can hardly be perceived at first glance. This makes it hard for the user to recognize features of the scorelines on the golf club head.

SUMMARY OF THE INVENTION

It is an object of the present invention to allow the user to easily visually discern features of scorelines in terms of shape.

According to the present invention, there is provided an iron golf club head comprising: a face surface with a plurality of scorelines formed therein; and an indicating portion which indicates at least a cross-sectional shape of the scoreline.

Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are front and back views, respectively, of a golf club head according to an embodiment of the present invention;

FIG. 2 is a sectional view of a face surface;

FIG. 3A is a perspective view of an indicating portion;

FIG. 3B is a left side view of the golf club head shown in FIGS. 1A and 1B;

FIG. 4 is a view for explaining a method of forming scorelines and grooves;

FIGS. 5A and 5B are views for explaining another example of a method of forming an indicating portion;

FIG. 6A is a view for explaining another example of an indicating portion; and

FIG. 6B is a view for explaining a specification value indicating portion.

DESCRIPTION OF THE EMBODIMENTS

First Embodiment

FIG. 1A is a front view of a golf club head 1 according to an embodiment of the present invention, and FIG. 1B is a back view of the golf club head 1. Referring to FIGS. 1A and 1B, a double-headed arrow d1 indicates the toe-to-heel direction. The golf club head 1 has a face surface (striking surface) 10 which forms the front surface of the head 1, a sole portion 11 which forms the bottom portion of the head 1, a back portion 12 which forms the back surface of the head 1, and a hosel portion 13 which receives a shaft (not shown). The iron golf club head according to the present invention is applicable to a long iron golf club head and, more specifically, to all of middle iron, short iron, and wedge golf club heads, but is especially suitable for a wedge golf club head.

A plurality of scorelines 20 are formed in the face surface 10. The respective scorelines 20 are parallel linear grooves extending in the toe-to-heel direction (direction d1). FIG. 2 is a sectional view of the face surface 10 and, more specifically, a sectional view of the scorelines 20 taken along a cross-section perpendicular to the toe-to-heel direction (direction d1). In this embodiment, each scoreline 20 has the same cross-sectional shape throughout its entire longitudinal portion except for its two ends (toe- and heel-side ends). Also, the scorelines 20 have the same cross-sectional shape.

The scoreline 20 includes a pair of side walls 21 and a bottom wall 22, and has a trapezoidal cross-sectional shape bilaterally symmetric about a center line CL. Note that the cross-sectional shape of the scoreline 20 is not limited to a trapezoidal shape, and may be other shapes such as a V shape. Although rounded portions are formed on edges 23 of the scoreline 20, they may be omitted.

A depth D of the scoreline 20 is the distance between the bottom wall 22 and the face surface 10. A width W of the scoreline 20 is defined by the 30-degree measurement method. A pitch P between adjacent scorelines 20 is equal (constant pitch) but may vary. When the golf club head 1 is intended for athletes, the shape, size, and pitch P of the scorelines 20, for example, comply with a relevant rule.

Referring back to FIGS. 1A and 1B, the golf club head 1 includes an indicating portion 30. In this embodiment, the indicating portion 30 is disposed in the toe-side upper portion of the back portion 12. FIG. 3A is a perspective view of the indicating portion 30.

The indicating portion 30 has a first surface 32 which partially constitutes the back portion 12, and a second surface (end surface) 33 perpendicular to the first surface 32. A plurality of (two) grooves 31 are formed in the indicating portion 30 to indicate the scorelines 20. The grooves 31 are formed to have a depth direction perpendicular to the first surface 32, and extend in the toe-to-heel direction (direction d1). This means that the grooves 31 serve as scorelines 20 formed in the back portion 12 in place of the face surface 10.

The first surface 32 has the shape of the grooves 31 as viewed from the top (assuming the depth direction of the grooves 31 as the line of sight direction). In other words, each groove 31 in the first surface 32 indicates the same shapes as a portion of the scoreline 20 in the face surface 10 as viewed from the front.

The second surface 33 is perpendicular to the direction (direction d1) in which the grooves 31 extend, and has the cross-sectional shapes of the grooves 31. In other words, the grooves 31 indicate the cross-sectional shapes of the scorelines 20 in the second surface 33. The user can perceive the cross-sectional shapes of the scorelines 20 (the cross-sectional shapes of the grooves 31) as he or she observes the golf club head 1 from the toe side.

With this arrangement, in this embodiment, providing the indicating portion 30 indicating the cross-sectional shapes of the scorelines 20 allows the user to visually easily discern features of the scorelines 20 in terms of shape. As a result, the user can more easily recognize, for example, a given effect provided by features of the scorelines 20 in terms of shape. Also, the user can easily take into consideration the cross-sectional shapes of scorelines as one criterion for selection in purchasing a golf club.

The groove 31 may have the same shape (same size) as or a shape similar to that of the scoreline 20 except for its entire length (its longitudinal dimension). If the groove 31 has the same shape as that of the scoreline 20, it can provide an impression that it is reproduced more accurately, but its cross-sectional shape is often too small to see. On the other hand, if the size of the groove 31 increases, the visibility of its cross-sectional shape improves, but it becomes harder to ensure a space to place the indicating portion 30. Hence, the cross-sectional shape of the groove 31 is preferably larger than that of the scoreline 20 by a factor of 1 (inclusive) to 3 (inclusive).

Although only one groove 31 may be formed, a plurality of grooves 31 are preferably formed, as in this embodiment. Indicating the cross-sectional shapes of a plurality of scorelines 20 allows the user to easily recognize these cross-sectional shapes. In this case, by associating the pitch between the grooves 31 with the pitch P of the scorelines 20, the user can also easily perceive the pitch P of the scorelines 20 with visual and other senses. If, for example, the groove 31 has the same shape as that of the scoreline 20, the pitch between the grooves 31 is set equal to the pitch P of the scorelines 20. However, if, for example, the groove 31 has a shape similar to that of the scoreline 20 by a factor of two, the pitch between the grooves 31 is twice the pitch P of the scorelines 20.

In this embodiment, not only the cross-sectional shapes but also the shapes of the grooves 31 as viewed from the top are indicated in the first surface 32, so the user can easily sensuously perceive that the second surface 33 indicates cross-sections of the grooves 31. In addition, like the face surface 10, the grooves 31 are formed to extend in the toe-to-heel direction (direction d1), so the user can experience a sense that the grooves 31 indicate the face surface 10.

The indicating portion 30 can be formed in an arbitrary portion of the golf club head 1, but if it falls within the eyesight of the user upon address, he or she may feel distracted. To prevent this problem, the indicating portion 30 is preferably disposed in a portion that cannot be seen upon address. When, for example, the golf club head 1 is set on a horizontal plane at a specific lie angle while the face surface 10 is matched with the flight trajectory direction (to be also referred to as a specific position hereinafter), the indicating portion 30 is preferably in a portion that cannot be seen as the golf club head 1 is viewed from the top.

In this embodiment, the indicating portion 30 is disposed in the back portion 12, and therefore cannot be seen as the golf club head 1 is viewed from the top when the golf club head 1 is disposed at the specific position. FIG. 3B is a view for explaining this arrangement, and is a left side view of the golf club head 1. In an example shown in FIG. 3B, the golf club head 1 is assumed to be disposed at the specific position. When the golf club head 1 is viewed from the top (when the golf club head 1 is observed from above in FIG. 3B), the indicating portion 30 is positioned on the back surface of the face surface 10, and therefore cannot be visually perceived. With this arrangement, by disposing the indicating portion 30 in the back portion 12, the golf club head 1 can be oriented so as not to fall within the eyesight of the user in the commonly assumed case upon address.

An example of a method of forming scorelines 20 and grooves 31 will be described next with reference to FIG. 4. Scorelines 20 and grooves 31 can be formed by forging, casting, cutting, or laser machining. The case wherein both scorelines 20 and grooves 31 are formed by cutting will be described herein. Both scorelines 20 and grooves 31 can be formed with relatively high accuracy by cutting.

FIG. 4 is a view for explaining cutting by an NC milling machine. First, a golf club head 1A in which scorelines 20 and grooves 31 are to be formed is fixed to an NC milling machine via a jig 101, as shown in a state ST1. The NC milling machine has a spindle 102 rotated about the Z-axis, and a cutting tool (end mill) 103 is attached to the lower end of the spindle 102. As the cutting tool 103, a cutting tool suitable for forming scorelines 20 is used.

First, in the NC milling machine, the plane coordinates of the golf club head 1A are set, and the spindle 102 is then rotated. The face surface 10 is cut while relatively moving the golf club head 1A or the cutting tool 103 in the toe-to-heel direction (direction d1). With this operation, scorelines 20 are formed. When one scoreline 20 is formed, the cutting tool 103 is separated from the face surface 10, and the next scoreline 20 is formed upon relatively moving the cutting tool 103 in the direction in which the scorelines 20 are aligned. All scorelines 20 are thus formed.

A golf club head 1B in which grooves 31 are to be formed is fixed to an NC milling machine via a jig 101′, as shown in a state ST2. In this embodiment, the grooves 31 are formed in the back portion 12, so the direction of the golf club head 1B in the state ST2 is opposite to that in the state ST1.

If the groove 31 has the same shape as that of the scoreline 20, the same cutting tool 103 may be used without replacement. With this arrangement, highly reproducible grooves 31 can be formed. If the groove 31 has a shape similar to that of the scoreline 20, the cutting tool 103 is replaced as needed.

Next, in the NC milling machine, the plane coordinates of the golf club head 1B are set, and the spindle 102 is then rotated. A back portion 12 is cut while relatively moving the golf club head 1B or the cutting tool 103 in the toe-to-heel direction (direction d1). With this operation, grooves 31 are formed. When one groove 31 is formed, the cutting tool 103 is separated from the back portion 12, and the next groove 31 is formed upon relatively moving the cutting tool 103 in the direction in which the grooves 31 are aligned. All grooves 31 are thus formed.

In this embodiment, since scorelines 20 and grooves 31 are formed using a common processing machine (NC milling machine), this can be done relatively easily. Also, a series of operations of forming scorelines 20 and grooves 31 can be continuously performed, thus enhancing the operation efficiency.

Second Embodiment

Another example of the formation of an indicating portion 30 will be described. A golf club head 1 can be constituted by a plurality of members. At this time, the indicating portion 30 is used as a separate member. FIGS. 5A and 5B are views for explaining another example of a method of forming an indicating portion 30. The same reference numerals as in FIGS. 5A and 5B denote the same constituent components as in the above-mentioned first embodiment, and a description thereof will not be given.

The golf club head 1′ shown in FIGS. 5A and 5B includes a main body portion 2 and indicating member 3. The indicating member 3 is a block-like member including the indicating portion 30. The main body portion 2 has a configuration other than that of the indicating portion 30, and a recess 121 which receives the indicating member 3 is formed in a back portion 12. By fixing the indicating member 3 to the recess 121 using, for example, an adhesive material, the same indicating portion 30 as in the above-mentioned first embodiment can be formed.

The use of the indicating portion 30 as a separate member makes it possible to form an indicating portion 30 even if it is difficult to, for example, directly form grooves 31 in the back portion 12. As a method of forming grooves 31 in the indicating member 3, various processing methods including forging, casting, cutting, and laser machining can be used, as in the above-mentioned embodiment.

Third Embodiment

Although the indicating portion 30 in the above-mentioned first embodiment has a portion (first surface 32) indicating the shapes of the scorelines 20 as viewed from the top, and a portion (second surface 33) indicating the cross-sectional shapes of the scorelines 20, it may indicate the cross-sectional shapes of only the scorelines 20.

FIG. 6A illustrates an example of the latter arrangement. The same reference numerals as in FIG. 6A denote the same constituent components as in the above-mentioned first embodiment, and a description thereof will not be given.

FIG. 6A illustrates an example in which an indicating portion 30A is disposed in a back portion 12. The indicating portion 30A includes projections 35 indicating the cross-sectional shape of a scoreline 20, and a recess 34 surrounding it, and indicates the cross-sectional shape of only the scoreline 20. The indicating portion 30A can be formed as, for example, a back portion 12 in which the indicating portion 30A is to be formed is cut to form a recess 34 and thereby form projections 35. In this manner, the indicating portion need only be able to indicate at least the cross-sectional shape of the scoreline 20.

Note that in this embodiment, as in the above-mentioned second embodiment, the indicating portion 30A can be used as a separate member.

Fourth Embodiment

A specification value indicating portion indicating the specification values of a scoreline 20 may further be provided. FIG. 6B illustrates an example of this arrangement. The same reference numerals as in FIG. 6B denote the same constituent components as in the above-mentioned first embodiment, and a description thereof will not be given.

A specification value indicating portion 40 shown in FIG. 6B is disposed in a back portion 12, and indicates a width W and a depth D as the specification values of the scoreline 20. As other specification values, various kinds of values such as the radius of curvature of an edge 23, a pitch P, a cross-sectional area A of the scoreline 20, and (Cross-Sectional Area A)/(Pitch P) are available. Features of the scoreline 20 can further be provided to the user by indicating such specification values.

The specification values may be the design value or actual measurement value of the scoreline 20. The use of the actual measurement value allows the user to feel a sense of satisfaction in possessing her or her own unique golf club head in the world, thus enhancing the added value. In this case, the actual measurement value of one arbitrary scoreline 20 or the average of the actual measurement values of a plurality of scorelines 20 may be used.

Although the specification value indicating portion 40 can be disposed in an arbitrary portion of a golf club head 1 in place of the back portion 12, it is preferably in a portion that cannot be seen upon address, as in the indicating portion 30. The specification value indicating portion 40 can be prevented from falling within the eyesight of the user upon address by disposing it in the back portion 12, as in this embodiment.

The numerical values and texts of the specification value indicating portion 40 may be formed in the surface of the golf club head 1 by cutting, or the specification value indicating portion 40 may be, for example, a seal, which is pasted on the golf club head 1.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

This application claims the benefit of Japanese Patent Application No. 2012-134193, filed Jun. 13, 2012, which is hereby incorporated by reference herein in its entirety.

Claims

1. An iron golf club head comprising:

a face surface with a plurality of scorelines formed therein; and

an indicating portion which indicates at least a cross-sectional shape of the scoreline.

2. The head according to claim 1, wherein

said indicating portion is provided with a groove which indicates the scoreline, and

said indicating portion includes

a first surface indicating a shape of said groove as viewed from a front, and

a second surface which is perpendicular to said first surface, and a direction in which said groove extends, and indicates a cross-sectional shape of said groove as the cross-sectional shape of the scoreline.

3. The head according to claim 1, wherein said indicating portion is disposed in a portion, that cannot be seen as the golf club head is viewed from a top, when the face surface is set on a horizontal plane at a specific lie angle while the face surface is matched with a flight trajectory direction.

4. The head according to claim 3, wherein

the golf club head includes a back portion which forms a back surface thereof, and

said indicating portion is disposed in said back portion.

5. The head according to claim 1, wherein said indicating portion indicates cross-sectional shapes of the plurality of scorelines.

6. The head according to claim 1, wherein said indicating portion indicates a cross-sectional shape larger than the cross-sectional shape of the scoreline by a factor of 1 (inclusive) to 3 (inclusive).

7. The head according to claim 1, further comprising:

an indicating member including said indicating portion; and

a main body portion provided with a recess which receives said indicating member.

8. The head according to claim 2, wherein both the scorelines and said grooves are formed by cutting.

9. The head according to claim 1, further comprising a specification value indicating portion which indicates a specification value of the scoreline.