Description

ARRANGEMENT STRUCTURE OF DIMPLES FOR GOLF BALL

Technical Field

[1] The present invention relates, in general, to dimple arrangement structures for golf balls and, more particularly, to a dimple arrangement structure for a golf ball which is constructed such that dimples arranged to have a symmetrical structure, so that the flow of air above and below and on opposite sides of the golf ball, which is driven by striking, can be maintained constant, and drag force can be reduced while lifting force is increased. Background Art

[2] Generally, resistance, occurring in a golf ball that is being driven at high speed, is classified into friction resistance, which occurs ahead of the golf ball, and form resistance, which occurs behind the golf ball. Friction resistance is resistance which occurs on the golf ball due to friction between the golf ball and air. Form resistance is resistance which occurs due to vortexes of air that are generated behind the golf ball when it is being driven in air.

[3] Form resistance acts as a major factor that deteriorates characteristics that determine the trajectory of the golf ball and the distance that the golf ball is driven. To reduce form resistance, concave depressions, called dimples, are formed in the outer surface of the golf ball.

[4] Compared to a golf ball having no dimples, in the case of a golf ball having dimples, because the flow air around the golf ball is slowed, the intensity of vortexes generated behind the golf ball is reduced, in other words, the region of a slipstream is reduced. Thereby, form resistance, which occurs due to the slipstream that pulls the golf ball in a direction opposite the direction in which the golf ball is driven, is reduced.

[5] Meanwhile, to arrange the dimples on the surface of the golf ball, the surface of the golf ball is sectioned into several areas, thus forming various polyhedra. The arrangement of the dimples is determined based on the polyhedron defined on the golf ball. For example, there are various methods of sectioning a sphere into spherical surfaces forming a polyhedron, such as a spherical tetrahedron having four spherical triangles, a spherical hexahedron having six spherical squares, a spherical octahedron having eight spherical triangles, a spherical dodecahedron having twelve spherical pentagons, a spherical icosahedron having twenty spherical triangles, etc.

[6] Furthermore, the above-mentioned polyhedra may be further subdivided into 12 to

20-hedron or 6 to 8-hedron on which dimples are arranged. However, in all designs for sectioning the surface of the golf ball, even though dimples are arranged along the

various spherical polyhedra, it is difficult to prevent the dimples from overlapping each other on a golf ball having a predetermined diameter.

[7] Nevertheless, efforts to develop golf balls having dimple arrangement structures defined by improved ball surface sectioning designs have continued. The reason for this is that, because the surface area of the spherical polyhedron varies depending on the ball surface sectioning design, the sizes, depths and shapes of dimples can be varied when the dimples are arranged on the entire surface of the golf ball.

[8] In other words, because the driving characteristics of a golf ball vary depending on the dimple arrangement, new ball surface sectioning designs are continuously studied. Furthermore, in the case where dimples are arranged on the surface of the golf ball in a method using a spherical polyhedron, when the dimples are symmetrically arranged in each surface of the polyhedron, rather than being asymmetrically arranged in the surface, the driving characteristics of the golf ball become superior.

[9] That is, in this case, when the golf ball is driven, in a low-speed range from the top point of the trajectory to the position at which the golf ball contacts the ground, the resistance of air is maintained more even, so that undesirable movement of the golf ball is reduced, thus forming a stable trajectory.

[10] Furthermore, in a flying range, called a high-speed range, from the position at which the golf ball is struck, to the top point of the trajectory, the pressure drag force of a large dimple is greater than that of a small dimple. In contrast, in the low-speed range, the pressure drag force of the large dimple is less than that of the small dimple.

[11] Therefore, to ensure stable landing characteristics and superior driving characteristics of the golf ball, an improved method of sectioning the surface of the golf ball is required, and various studies on an effective dimple arrangement on the sectioned surfaces of the golf ball are required.

[12] In the conventional dimple arrangement structures, to realize perfect symmetry of the dimple arrangement, several manufacturing companies have conducted many studies on the dimple arrangement structure. Furthermore, dimple arrangements have been developed through many kinds of arrangement methods for a number of dimples ranging from 430 to 560. However, when considering the predetermined diameter of the golf ball, it is very difficult to realize perfect symmetry of the dimple arrangement structure.

[13] Typically, golf balls having dimples are manufactured through injection molding using a mold including an upper mold and a lower mold, and lots of efforts for producing the golf balls such that the upper part and the lower part thereof are the same as each other have been conducted. However, in the conventional techniques, dimples are arranged without a prescribed rule. Even if there were a prescribed dimple arrangement rule, it is very difficult to satisfactorily arrange about five hundred dimples

on the surface of the golf ball having a diameter of 42.61 mm.

[14] The present invention was proposed based on the notion that the above problems can be solved by reducing the number of dimples and maintaining the distances between the dimples constant.

[15] Fig. 1 is a view showing a conventional dimple arrangement structure for a golf ball.

Fig. 2 is a view showing a hexagonal dimple face of the conventional dimple arrangement structure.

[16] The convention dimple arrangement structure for the golf ball shown in Figs. 1 and 2 was disclosed in Korean Patent Registration No. 0138895 (date: Feb. 23, 1998) and is constructed such that six tetragonal faces and eight hexagonal faces, each of which has a predetermined dimple arrangement structure, are defined on the surface of the golf ball.

[17] In the case where dimples are formed on the golf ball through the above-mentioned dimple arrangement structure, the effects of a reduction in drag force and an increase in lifting force can be achieved by the dimples. However, in the conventional technique, in the dimple arrangement structure of each tetragonal face, dimples are set along three horizontal lines and three vertical lines, and other dimples are set between the dimple lines. This structure hampers the increase in the area of the dimples to the surface are of the golf ball, which directly pertains to a reduction in drag force and to an increase in lifting force.

[18] Therefore, even though the golf ball has a symmetrical structure, because the dimples are arranged such that lines connecting the centers of four adjacent dimples define a square, the ratio of the area of the dimples to the surface area of the golf ball is reduced, so that effects of a reduction in drag force and an increase in lifting force are reduced.

[19] Furthermore, in each of the eight hexagonal faces of the dimple arrangement structure according to the conventional technique, dimples disposed along the perimeter of the hexagonal face are smaller than dimples disposed in the central portion thereof.

[20] Here, dimples disposed in a boundary area between adjacent hexagonal faces are tangent to a boundary line therebetween, unlike a boundary area between a hexagonal face and a tetragonal face, in which some dimples are included in both kinds of faces in common. Therefore, this also causes a problem in that the effects of the reduction in drag force and the increase in lifting force are reduced. Disclosure of Invention Technical Problem

[21] Accordingly, the present invention has been made keeping in mind the above

problems occurring in the prior art, and an object of the present invention is to provide a dimple arrangement structure for a golf ball which is constructed such that dimples are arranged to have a symmetrical structure, so that the flow of air above and below and opposite sides of the golf ball, which is driven by striking, can be maintained constant, and drag force can be reduced while lifting force is increased. Technical Solution

[22] In a first aspect, the present invention provides a dimple arrangement structure for a golf ball, wherein a surface of the golf ball is sectioned by imaginary dividing lines into six hexagonal areas and eight approximately triangular areas disposed between the hexagonal areas, and dimples are arranged in each of the areas.

[23] In a second aspect, the dimples, arranged in the hexagonal areas, and the hexagonal areas may form respective first through sixth hexagonal dimple faces (Pl, P2, P3, P4, P5 and P6), the first through fourth hexagonal dimple faces (Pl, P2, P3 and P4) may be consecutively arranged in a direction perpendicular to a center line, along which a diameter of the golf ball is defined, and the fifth and sixth hexagonal dimple faces (P5 and P6) may be disposed on opposite sides of the second hexagonal dimple face (P2).

[24] In a third aspect, the first through fourth hexagonal dimple faces (Pl, P2, P3 and P4) may have identical dimple arrangement structures, and the fifth and sixth hexagonal dimple faces (P5 and P6) may have identical dimple arrangement structures.

[25] In a fourth aspect, the first and third hexagonal dimple faces (Pl and P3) may have identical dimple arrangement structures and the second, fourth, fifth and sixth hexagonal dimple faces (P2, P4, P5 and P6) may have identical dimple arrangement structures.

[26] In a fifth aspect, the first through sixth hexagonal dimple faces (Pl, P2, P3, P4, P5 and P6) may have identical dimple arrangement structures.

[27] In a sixth aspect, in each of the first through sixth hexagonal dimple faces (Pl, P2,

P3, P4, P5 and P6), a maximum of eight dimples may be arranged along the center line.

[28] In a seventh aspect, in each of the hexagonal dimple faces, a maximum of seven dimples may be arranged along the center line of the hexagonal dimple face.

[29] In an eighth aspect, in the hexagonal dimple face, in the case where three adjacent circular dimples, having identical diameters, are arranged in a triangular shape, a triangle may be defined by lines connecting centers of the dimples, and the dimples may be arranged such that a sum of differences between lengths of sides of the triangle and a height of the triangle is equal to a common width (rl) of common dimples, which are disposed in a boundary line between the adjacent hexagonal dimple faces.

[30] In a ninth aspect, in rows of dimples oriented in a direction of the center line C in the

hexagonal dimple face, the dimples may be arranged such that a sum (dl+d2+d3) of widths of insertion portions of rows of dimples, having identical diameters, inserted into adjacent rows of dimples, having identical diameters, is equal to a common width (rl) of common dimples, which are disposed between the adjacent hexagonal dimple faces.

[31] In a tenth aspect, a plurality of dimples having identical diameters may be arranged in each of the hexagonal dimple faces.

[32] In a eleventh aspect, a maximum of nine dimples may be arranged in a direction perpendicular to the center line C of each of the hexagonal dimple faces, and the dimples may be arranged such that dimples that are disposed on respective opposite ends of the hexagonal dimple face are included in the adjacent hexagonal dimple faces in common.

[33] In a twelfth aspect, in each of boundary areas between the first and third hexagonal dimple faces (Pl and P3) and the fifth and sixth hexagonal dimple faces (P5 and P6), a diameter of a dimple of one hexagonal dimple face may be less than a half of a diameter of a dimple of an adjacent hexagonal dimple face.

[34] In a thirteenth aspect, the triangular dimple faces may have identical dimple arrangement structures and be arranged symmetrically with each other.

[35] In a fourteenth aspect, at least one dimple disposed in a boundary area between the adjacent hexagonal dimple faces may be included in the hexagonal dimple faces in common.

[36] In a fifteenth aspect, dimples, each having a relatively small diameter, may be disposed on opposite sides of a boundary line between the adjacent hexagonal dimple faces, thus preventing the dimples from overlapping each other.

[37] In a sixteenth aspect, in each of the hexagonal dimple faces, a maximum of six dimples may be arranged in a direction perpendicular to the center line of the hexagonal dimple face, and dimples, disposed on opposite ends of the hexagonal dimple face, may be included in or be disposed adjacent to the adjacent hexagonal dimple faces.

[38] In a seventeenth aspect, the hexagonal dimple faces may be formed in respective squares, which are defined by connecting points, by which a circumference of the golf ball is sectioned into four parts.

[39] In an eighteenth aspect, the dimples may be arranged in each of the hexagonal dimple faces such that dimples, disposed on opposite ends of the hexagonal dimple face with respect to the center line, are included in the adjacent hexagonal dimple faces in common.

[40] In a nineteenth aspect, a bonding line of the golf ball may be linear along the center lines of the associated hexagonal dimple faces.

[41] In a twentieth aspect, a bonding line of the golf ball may be formed in a zigzag manner in a direction perpendicular to the center lines of the associated hexagonal dimple faces.

Advantageous Effects

[42] As described above, the present invention realizes a symmetrical dimple arrangement structure of a golf ball in which dimples are arranged in a symmetrical manner on the upper, lower, left and right portions of the golf ball and the left and right of the golf ball are balanced, so that the flow of air above and below and on opposite sides of the golf ball, which is driven by striking, can be maintained constant.

[43] Furthermore, to arrange dimples on the golf ball in a shape in which faces each having a predetermined shape are defined on the golf ball, the surface of the golf ball is sectioned by imaginary dividing lines forming a spherical hexahedron, and the areas defined by sectioning the surface of the golf ball into six parts have identical dimple arrangement structures. Thus, the present invention is advantageous in that the golf ball has a symmetrical structure in every direction.

[44] In addition, hexagonal dimple faces are defined in the areas, defined by sectioning the surface of the golf ball into six parts, and the hexagonal dimple faces have a symmetrical structure with respect to the arrangement and size of dimples. Therefore, there is an advantage in that drag force is reduced and lifting force is increased.

[45] As well, in response to the dimple arrangement structure, the bonding line of the golf ball can be formed into various shapes, so that the cost of molding the golf ball can be reduced. Brief Description of the Drawings

[46] Fig. 1 is a view showing a conventional dimple arrangement structure for a golf ball;

[47] Fig. 2 is a view showing a hexagonal dimple face of the conventional dimple arrangement structure;

[48] Fig. 3 is a schematic view illustrating an arrangement structure of dimples for a golf ball, according to a first embodiment of the present invention;

[49] Fig. 4 is a schematic view illustrating a hexagonal dimple face of the dimple arrangement structure according to the first embodiment of the present invention;

[50] Fig. 5 is a schematic view illustrating sectioned faces of the dimple arrangement structure according to the first embodiment of the present invention;

[51] Fig. 6 is a development view illustrating the dimple arrangement structure according to the first embodiment of the present invention;

[52] Fig. 7 is a plan view illustrating the hexagonal dimple face of the dimple arrangement structure according to the first embodiment of the present invention;

[53] Fig. 8 is an enlarged view showing part of the hexagonal dimple face of the dimple

arrangement structure according to the first embodiment of the present invention; [54] Fig. 9 is an enlarged view illustrating the arrangement of dimples in the hexagonal dimple face of the dimple arrangement structure according to the first embodiment of the present invention; [55] Fig. 10 is another enlarged view illustrating the arrangement of the dimples in the hexagonal dimple face of the dimple arrangement structure according to the first embodiment of the present invention; [56] Fig. 11 is a plan view illustrating the dimple arrangement in the hexagonal dimple face of the dimple arrangement structure according to the first embodiment of the present invention; [57] Fig. 12 is a plan view showing a boundary area between the hexagonal dimple faces of the dimple arrangement structure according to the first embodiment of the present invention; [58] Fig. 13 is a plan view showing another boundary area between the hexagonal dimple faces of the dimple arrangement structure according to the first embodiment of the present invention; [59] Fig. 14 illustrates the golf ball having the dimple arrangement structure according to the first embodiment of the present invention; [60] Fig. 15 is structural views illustrating the golf ball having the dimple arrangement structure according to the first embodiment of the present invention; [61] Fig. 16 is a development view illustrating dimple arrangement in the hexagonal dimple faces of the dimple arrangement structure according to the first embodiment of the present invention; [62] Fig. 17 is a development view illustrating dimple arrangement in hexagonal dimple faces of a dimple arrangement structure for a golf ball, according to a second embodiment of the present invention; [63] Fig. 18 is a perspective view of the golf ball to illustrate dimple arrangement in the hexagonal dimple faces disposed adjacent to an approximately triangular dimple face, according to the second embodiment of the present invention; [64] Fig. 19 is a development view illustrating dimple arrangement in hexagonal dimple faces of a dimple arrangement structure for a golf ball, according to a third embodiment of the present invention; [65] Fig. 20 is views showing several examples of dimple arrangement in the hexagonal dimple face of the dimple arrangement structure according to the present invention; [66] Fig. 21 is a development view illustrating arrangement in hexagonal dimple faces of a dimple arrangement structure for a golf ball, according to a fourth embodiment of the present invention; [67] Fig. 22 is views showing several other examples of dimple arrangement in the

hexagonal dimple face of the dimple arrangement structure according to the present invention;

[68] Fig. 23 is a view showing another boundary area between the hexagonal dimple faces of the dimple arrangement structure according to the present invention;

[69] Fig. 24 is a view showing another boundary area between the hexagonal dimple faces of the dimple arrangement structure according to the present invention;

[70] Fig. 25 is a perspective view illustrating an example of a bonding line of the golf ball according to the present invention;

[71] Fig. 26 is a development view illustrating another example of the bonding line of the golf ball according to the present invention; and

[72] Fig. 27 is a perspective view illustrating another example of the bonding line of the golf ball according to the present invention. Best Mode for Carrying Out the Invention

[73] Hereinafter, a first embodiment of the present invention will be described in detail with reference to the attached drawings.

[74] Fig. 3 is a schematic view illustrating an arrangement structure of dimples for a golf ball, according to a first embodiment of the present invention. Fig. 4 is a schematic view illustrating a hexagonal dimple face of the dimple arrangement structure according to the first embodiment of the present invention. Fig. 5 is a schematic view illustrating sectioned faces of the dimple arrangement structure according to the first embodiment of the present invention. Fig. 6 is a development view illustrating the dimple arrangement structure according to the first embodiment of the present invention. Fig. 7 is a plan view illustrating the hexagonal dimple face of the dimple arrangement structure according to the first embodiment of the present invention. Fig. 8 is an enlarged view showing part of the hexagonal dimple face of the dimple arrangement structure according to the first embodiment of the present invention. Fig. 9 is an enlarged view illustrating the arrangement of dimples in the hexagonal dimple face of the dimple arrangement structure according to the first embodiment of the present invention. Fig. 10 is another enlarged view illustrating the arrangement of the dimples in the hexagonal dimple face of the dimple arrangement structure according to the first embodiment of the present invention. Fig. 11 is a plan view illustrating the dimple arrangement in the hexagonal dimple face of the dimple arrangement structure according to the first embodiment of the present invention. Fig. 12 is a plan view showing a boundary area between the hexagonal dimple faces of the dimple arrangement structure according to the first embodiment of the present invention. Fig. 13 is a plan view showing another boundary area between the hexagonal dimple faces of the dimple arrangement structure according to the first embodiment of the present

invention. Fig. 14 illustrates the golf ball having the dimple arrangement structure according to the first embodiment of the present invention. Fig. 15 is structural views illustrating the golf ball having the dimple arrangement structure according to the first embodiment of the present invention. Fig. 16 is a development view illustrating dimple arrangement in the hexagonal dimple faces of the dimple arrangement structure according to the first embodiment of the present invention.

[75] As shown in Fig. 6, the dimple arrangement structure for the golf ball according to the first embodiment of the present invention includes first through sixth hexagonal dimple faces Pl, P2, P3, P4, P5 and P6, which are formed by sectioning the surface of the golf ball having the dimples using imaginary dividing lines S.

[76] The first through fourth hexagonal dimple faces Pl, P2, P3 and P4 are consecutively arranged in a direction perpendicular to a center line C, which is equal to the diameter of the golf ball. The fifth and sixth hexagonal dimple faces P5 and P6 are disposed on opposite sides of the second hexagonal dimple face P2.

[77] As such, the surface of the golf ball according to this embodiment is sectioned into six hexagonal areas and eight approximately triangular areas, which are defined between the hexagonal areas. Dimples, each having a predetermined shape, are arranged in each area.

[78] As shown in Fig. 3, when the diameter of a maximum circumferential circle Cl of the golf ball is 42.67mm, the length of the circumferential circle Cl is 134.0518mm. When the circumferential circle is sectioned into four parts, a square L, each side of which has a length of 33.5130mm, is defined in the circumferential circle. A circle C2, which has a predetermined diameter such that it is inscribed in the square L, is defined in the square L. When the above process is repeatedly conducted, the surface of the golf ball is sectioned into six parts, thus defining a spherical hexahedral structure.

[79] Fig. 4 shows the inscribed circle C2 of Fig. 3. From the inscribed circle C2, a hexagon is drawn using an imaginary dividing line S, thus defining a hexagonal dimple face. If this hexagonal dimple face is applied to the surface of the golf ball of Fig. 3, the shape of Fig. 5 results.

[80] Dimples are formed on the surface of the golf ball, which is defined as a spherical hexahedron that has six faces, each edge of which has a length of 33.5130mm, which is obtained by dividing 134.0518mm, which is the circumference of a golf ball having a diameter of 42.676mm, by 4. Here, as shown in the development view of the hexahedron of Fig. 6, first through sixth boundary lines Bl through B6 between the dimple faces of the hexahedron must precisely intersect at right angles to realize the symmetrical dimple arrangement structure.

[81] As shown in Fig. 7, in the arrangement of the dimples, although a desired number of dimples is easily arranged in each hexagonal dimple face along the center line C, that

is, in a vertical direction when seen in the drawing, there is a problem in that it is difficult to efficiently arrange the number of dimples in a horizontal direction.

[82] In other words, because the dimple effect of the golf ball, that is, the dynamic lift effect and the spin effect, is increased as the ratio of the area of dimples to the surface area of the golf ball is increased, if the dimples are arranged in a row in vertical and horizontal directions, as shown in Fig. 8a, the dimple effect is reduced due to the reduction in the area of the dimples.

[83] Meanwhile, in the case where the dimples are arranged in a zigzag manner, as shown in Fig. 8b, the horizontal or vertical length D of the hexagonal dimple face of Fig. 7 is obtained by adding the diameters of the associated dimples. However, in the case of Fig. 8b, because insertion portions d exist between the dimples arranged in the horizontal direction, in the calculation of the horizontal length D of the hexagonal dimple face, the length of the insertion portions d must be subtracted.

[84] Furthermore, the dimples of the vertical lines and the horizontal lines are precisely disposed in the hexagonal dimple face of Fig. 7, and the dimples other than dimples, which are included in the hexagonal dimple face and the adjacent left, right, upper and lower hexagonal dimple faces in common, must be arranged in the manner of Fig. 8b.

[85] In the dimple arrangement shown in Fig. 9, when the centers A, B, C and D of four adjacent dimples 10 are connected by lines, line segments Ll, L2, L3 and L4 are defined. The line segments, which connect the centers of four adjacent dimples, have identical lengths and thus define two equilateral triangles.

[86] Here, it is easily understood that a line segment L6 is the height of each equilateral triangle. Furthermore, from the length of the line segment L6, which is the height of the equilateral triangle, the insertion portion d, which exists in the dimple arrangement of Fig. 8b, can be determined.

[87] That is, as shown in Fig. 10, the difference between the height (L6) of the equilateral triangle and each side (Ll, L2, L5) of the equilateral triangle becomes the length of the insertion portion d. Therefore, from this, in consideration of the horizontal length D and the vertical length D shown in Fig. 7, that is, 33.5130mm, and the insertion portions d, the number of dimples in the vertical direction and the horizontal direction can be determined.

[88] The ideal number of dimples in the vertical direction is seven. When dimples are arranged in the horizontal direction based on the seven center dimples in the manner of Fig. 8b, the shape of Fig. 11 is obtained.

[89] In detail, in the hexagonal dimple face, in the case where three adjacent circular dimples, having identical diameters, are arranged to form a triangular shape, a triangle is defined by lines connecting the centers of the dimples. Here, the dimples are arranged such that the sum {(L1-L6)+(L2-L6)+(L5-L6)} of differences between the

lengths Ll, L2 and L5 of the sides of the triangle and the height L6 of the triangle is equal to the common width rl of common dimples, which are disposed in the boundary line between the hexagonal dimple face and the adjacent hexagonal dimple face.

[90] Therefore, in the case where the dimples are arranged in a zigzag arrangement in the hexagonal dimple face, the common width of the common dimples between the adjacent hexagonal dimple face can be determined from the distance between the dimples.

[91] As shown in FIG. 11, among three dimples disposed along each of left and right boundary lines of the hexagonal dimple face, in the case of upper and lower dimples, because the circumferences of the corresponding lines are equal to each other, dimples equal to the dimples disposed in the central portions of the hexagonal face can be used as the upper and lower dimples. Furthermore, among the three dimples, in the case of a medial dimple, although it may be increased in size due to the difference between circumferences, this problem can be solved by fine adjustment of the dimple arrangement.

[92] In rows of dimples oriented in the direction of the center line in the hexagonal dimple face, the dimples are arranged such that the sum (dl+d2+d3) of widths of insertion portions d of rows of dimples having identical diameters, inserted into the adjacent rows of dimples having identical diameters, is equal to the common width rl of the common dimples disposed between the adjacent hexagonal dimple faces.

[93] In other words, in the case where several rows of dimples are arranged based on either side of the center line C, when the rows of dimples are arranged such that the sum (dl+d2+d3) of the widths of the insertion portions d of the rows of dimples is equal to the common width rl of the common dimples, the symmetry of the dimples and the dimple proportions are satisfactory.

[94] As describe above, in the dimple arrangement of the spherical hexahedral structure of the golf ball sectioned into six faces, numbers of vertically and horizontally arranged dimples such that the adjacent hexagonal dimple faces can be effectively connected to each other can be obtained. This also makes it possible to realize the symmetrical structure of the dimples of the golf ball.

[95] As shown in Fig. 11, in the golf ball according to this embodiment, thirty-seven dimples are in each hexagonal dimple face, and six dimples are in the boundary lines thereof. When one spherical hexahedron is defined in the golf ball by sectioning the surface of the golf ball into six surfaces, as shown in the development view of Fig. 6, in boundary portions between the first and third hexagonal dimple faces Pl and P3 and the fifth and sixth hexagonal dimple faces P5 and P6, there is a problem in that the dimple disposed at the uppermost and lowermost positions in each hexagonal dimple face overlaps a corresponding dimple of the adjacent hexagonal dimple faces.

[96] Fig. 12 shows an example of such a problem, in which dimples overlap each other between the first and third hexagonal dimple faces Pl and P3 and the fifth hexagonal dimple face P5. To solve this problem, there are two methods, as shown in Fig. 13.

[97] Referring to Fig. 13, as a first method of avoiding the problem of the overlapping dimple, the associated dimples 10 of the fifth hexagonal dimple face P5 are replaced with small dimples 11 having diameters of approximately 2mm, while the dimples 10 of the first and third hexagonal dimple faces Pl and P5 maintain the original size thereof.

[98] As another method of avoiding the problem of Fig. 12, the associated dimples 10a of the first and third hexagonal dimple faces Pl and P3 are replaced with small dimples 11a having diameters of approximately 2mm while the dimples 10 of the fifth hexagonal dimple face P5 maintain the original size thereof, thus preventing the dimples from overlapping.

[99] Furthermore, the dimple arrangement of each of the six hexagonal dimple faces of the golf ball, which is formed through the above-mentioned process, can be symmetrical in all directions. This enhances the straightness and the distance that the golf ball is driven.

[100] Meanwhile, as shown in Fig. 14, in the spherical hexahedral structure of the golf ball, eight approximately triangular dimple faces are defined in areas other than the six hexagonal dimple faces. Dimples are arranged in the eight triangular dimple faces through one of several dimple arrangement methods.

[101] The eight approximately triangular dimple faces have an area of 25% or less of the entire surface area of the golf ball. The triangular dimple faces are regularly dispersed between the six hexagonal dimple faces, so that the triangular dimple faces influence the six hexagonal dimple faces to a degree of approximately 4%.

[102] Here, exceptionally, unlike the above description of the dimple arrangement structure of the golf ball according to this embodiment, depending on the manufacturing company, various sizes of dimples 21 through 25 may be arbitrarily arranged in each triangular dimple face, as long as this does not affect the symmetrical dimple arrangement structure of the golf ball.

[103] As shown in the perspective view of Fig. 14, the dimple arrangement structure of the golf ball according to this embodiment can have a predetermined rule. Thereby, a satisfactorily symmetrical structure of the dimple arrangement of the golf ball can be achieved. That is, the golf ball is sectioned into six faces which account for 75% of the entire surface area of the golf ball, and dimples are regularly arranged in each of the faces. In addition, dimples are regularly arranged in each of eight triangular dimple faces of Fig. 14. Thereby, a golf ball having a satisfactorily symmetrical dimple arrangement structure can be provided.

[104] Here, it is preferable that the triangular dimple faces have identical dimple arrangement shapes and that they be symmetrical with each other.

[105] In particular, as shown in a front view (a), a side view (b) and a plan view (c) of Fig. 15, the golf ball having the dimple arrangement structure according to this embodiment is sectioned by imaginary dividing lines S into the six hexagonal dimple faces, in each of which seven dimples are arranged in a row along the center line C thereof, and into the eight approximately triangular dimple faces, which are disposed between the six hexagonal dimple faces.

[106] Fig. 16 shows a development view of the first through six hexagonal dimple faces Pl through P6. As shown in the drawings, in the case of the fifth and sixth hexagonal dimple faces P5 and P6, the dimples are arranged such that some of the dimples, which are disposed on opposite ends of the hexagonal dimple faces with respect to the direction perpendicular to the center line C, also belong to the eight triangular dimple faces.

[107] Hereinafter, other embodiments of the present invention will be described in detail with reference to the attached drawings.

[108] Fig. 17 is a development view illustrating dimple arrangement in hexagonal dimple faces of a dimple arrangement structure for a golf ball, according to a second embodiment of the present invention. Fig. 18 is a perspective view of the golf ball to illustrate dimple arrangement in the hexagonal dimple faces disposed adjacent to an approximately triangular dimple face, according to the second embodiment of the present invention. Fig. 19 is a development view illustrating dimple arrangement in hexagonal dimple faces of a dimple arrangement structure for a golf ball, according to a third embodiment of the present invention. Fig. 20 is views showing several examples of dimple arrangement in the hexagonal dimple face of the dimple arrangement structure according to the present invention. Fig. 21 is a development view illustrating dimple arrangement in hexagonal dimple faces of a dimple arrangement structure for a golf ball, according to a fourth embodiment of the present invention. Fig. 22 is views showing several other examples of dimple arrangement in the hexagonal dimple face of the dimple arrangement structure according to the present invention. Figs. 23 and 24 are views showing several examples of the boundary area between the hexagonal dimple faces of the dimple arrangement structure according to the present invention.

[109] As shown in Figs. 17 and 18, in the dimple arrangement structure of the golf ball according to the second embodiment, the first and third hexagonal dimple faces Pl and P3 have identical dimple arrangement structures, and the second, fourth, fifth and sixth hexagonal dimple faces P2, P4, P5 and P6 have identical dimple arrangement structures.

[110] Particularly, in each of the first and third hexagonal dimple faces Pl and P3, small dimples are disposed on opposite ends of the hexagonal dimple face with respect to the center line C. In the case of the second, fourth, fifth and sixth hexagonal dimple faces P2, P4, P5 and P6, seven dimples are arranged in a row along the center line C.

[I l l] Furthermore, eight approximately triangular dimple faces are arranged between the hexagonal dimple faces Pl, P2, P3, P4, P5 and P6. Dimples 31 through 33 having various sizes may be arbitrarily formed in each triangular dimple face.

[112] Preferably, in the triangular dimple faces, dimples are defined in identical arrangement manners and are arranged so as to be symmetrical with each other.

[113] As shown in Fig. 19, in a dimple arrangement structure according to a third embodiment of the present invention, first through sixth hexagonal dimple faces Pl, P2, P3, P4, P5 and P6 have identical dimple arrangement structures.

[114] In detail, in each of the first through sixth hexagonal dimple faces Pl, P2, P3, P4, P5 and P6, eight dimples are arranged in a row along the center line C of the dimple face. A maximum of nine dimples is arranged in a direction perpendicular to the center line C of the dimple face.

[115] Furthermore, eight approximately triangular dimple faces are arranged between the hexagonal dimple faces Pl, P2, P3, P4, P5 and P6. Of course, dimples having various sizes may be arbitrarily formed in each triangular dimple face.

[116] Preferably, these triangular dimple faces have identical dimple arrangement structures and are arranged symmetrically with each other.

[117] This embodiment may have several kinds of hexagonal dimple faces, which are defined in each of squares that are defined by sectioning the maximum circumferential circle, having a length of 134.0518mm, into four parts such that each side of the square has a length of 33.5130mm. In detail, as shown in FIG. 20, five kinds of hexagonal dimple faces may be defined. When such hexagonal dimple faces are connected to each other, a spherical hexahedron structure, which surrounds the outer surface of the golf ball, is formed.

[118] In A type, B type and C type of Fig. 20, dimples, which have half circle portions protruding outside the contour of the hexagonal dimple faces, are disposed in common areas between the adjacent hexagonal dimple faces, so that these dimples are not tangent to the contour of the hexagonal dimple faces.

[119] Furthermore, approximately 234 to 242 main dimples are formed in the six hexagonal dimple faces. 7 to 9 main dimples are formed in each triangular dimple face, so that 56 to 72 main dimples are arranged in the eight triangular dimple faces.

[120] Therefore, 290 to 314 main dimples, having identical sizes, are arranged in the outer surface of the golf ball.

[121] As well, 16 to 32 small dimples are formed in the golf ball. Hence, preferably, the

total number of dimples formed in the golf ball is 320 to 350, but this may be varied as necessary.

[122] Meanwhile, in the C type of FIG. 20, dimples having identical sizes are formed in each hexagonal dimple face, and common areas, in which dimples are included in the adjacent faces in common, are defined at predetermined positions with respect to the horizontal direction.

[123] Furthermore, 36 dimples are arranged in each hexagonal dimple face such that the total number of dimples of the six hexagonal dimple faces is 216. In addition, three small dimples are defined in each of junction areas between the hexagonal dimple faces, which are adjacent to each other with respect to the vertical direction, in order to reduce drag force applied to the junction areas. Then, eight approximately triangular dimple faces, each of which has seven dimples, are defined.

[124] Among all of the dimples of the golf ball, if approximately 272 to 280 main dimples can be formed, the golf ball can be manufactured such that it is advantageously used in low or middle trajectory shots.

[125] Furthermore, in the common area in which the adjacent faces have dimples in common, only in the case where dimples each having a diameter of 4.7875mm are formed in the common area can the dimples be included in the adjacent hexagonal dimple faces in common, such that the symmetrical arrangement effect of the present invention can be exhibited.

[126] Meanwhile, in FIG. 21, first through sixth hexagonal dimple faces Pl, P2, P3, P4, P5 and P6 have identical dimple arrangement structures, but the first, third, fifth and sixth hexagonal dimple faces Pl, P3, P5 and P6 are oriented perpendicular to the second and fourth hexagonal dimple faces P2 and P4.

[127] This case shows a complex arrangement structure of the hexagonal dimple faces and a dimple arrangement structure for formation of the most complex dimple pattern.

[128] As shown in Figs. 22a, 22b and 22c, small dimples are formed in the upper, lower, left or right end of each hexagonal dimple face to prevent dimples from overlapping between the adjacent hexagonal dimple faces. Furthermore, dimples may be arranged in various arrangement manners such that the dimples are included in adjacent hexagonal dimple faces in common.

[129] Meanwhile, as shown in Fig. 23, in the present invention, dimples 10, each having a diameter of 4.7875mm, may be continuously arranged between hexagonal dimple faces, each of which is formed in each of squares that are defined by sectioning the maximum circumferential circle into four parts such that each side of the square has a length of 33.5130mm.

[130] Furthermore, small dimples 11, each having a diameter less than 1/2 of 4.7875mm, are arranged in the boundary area, that is, the common area between the adjacent

hexagonal dimple faces, such that the dimples 11 are included in the adjacent hexagonal dimple faces in common. Therefore, the symmetrical dimple arrangement structure of the golf ball can be realized.

[131] As shown in Figs. 22a, 22b and 22c showing examples of dimple arrangement of the hexagonal dimple face, various dimple arrangement structures can be realized. The hexagonal dimple faces, having various dimple arrangement structures, can be selectively used.

[132] Meanwhile, as shown in Fig. 24, the present invention may be constructed such that dimples, which are disposed on opposite ends of the center line C of each hexagonal dimple face, are included in adjacent hexagonal dimple faces in common.

[133] In this embodiment, the hexagonal dimple faces are inscribed in respective squares, which are defined by sectioning the circumferential circle of the golf ball into four parts, and sides of which have identical lengths. Furthermore, horizontal lines and vert ical lines parallel to the sides of the corresponding square are defined in each hexagonal dimple face.

[134] In such hexagonal dimple faces, common areas may be formed on the horizontal lines between the adjacent hexagonal dimple faces or, alternatively, may be formed on the vertical lines between the adjacent hexagonal dimple faces.

[135] In the case of the hexagonal dimple faces having the common areas on the vertical lines, seven dimples 10 are arranged along the center line C of the hexagonal dimple face, that is, along the vertical center line of the corresponding square, and dimples, which are disposed on the opposite ends of the center line C of the hexagonal dimple face, are included in the adjacent hexagonal dimple faces in common.

[136] In such a hexagonal dimple face, the dividing line S is formed into a shape in which the opposite ends of the hexagonal dimple face with respect to the center line C are cut off.

[137] Therefore, it is preferable that the positions of the common areas of the hexagonal dimple faces be determined whether they are formed on the vertical lines or the horizontal lines, depending on the number of dimples formed in each hexagonal dimple face.

[138] Hereinafter, a bonding line of the golf ball according to the preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[139] Fig. 25 is a perspective view illustrating an example of the bonding line of the golf ball according to the present invention. Fig. 26 is a development view illustrating another example of the bonding line of the golf ball according to the present invention. Fig. 27 is a perspective view illustrating another example of the bonding line of the golf ball according to the present invention.

[140] As shown in Fig. 25, the bonding line BL of the golf ball means a boundary line between an upper mold and a lower mold for forming the golf ball through an injection molding process. In the embodiment of the present invention, the bonding line of the golf ball is formed into a zigzag-curved shape in a direction perpendicular to the center lines C of the associated hexagonal dimple faces.

[141] As such, the bonding line BL is formed in a zigzag manner between the dimples in the associated hexagonal dimple faces, so that the outer surface of the golf ball can be smooth enough that no signs of the bonding line are evident.

[142] However, in a mold for forming the golf ball through the injection molding process, because it is complex to machine the boundary areas of the mold between the upper mold and the lower mold, it is difficult to manufacture the mold, and the cost of manufacturing the mold is increased.

[143] Meanwhile, in an embodiment of Figs. 26 and 27, a bonding line BL of the golf ball is formed into a linear shape along the center line C of the associated hexagonal dimple faces.

[144] This bonding line BL is formed by injection molding using a mold having a structure such that a junction between upper and lower molds is defined to have a linear shape along the center line C of the associated hexagonal dimple faces.

[145] In other words, dimples are arranged on opposite sides based on the center line C of the associated hexagonal dimple faces, that is, based on the bonding line BL, so that a dimple arrangement structure in which the bonding line is formed into a linear shape on the central portion of the hexagonal dimple faces can be realized.

[146] Furthermore, imaginary dividing lines S of the hexagonal dimple faces are defined such that the centers of the common areas of the hexagonal dimple faces form the boundary lines, by which the circumferential circle is sectioned into four parts.

[147] In particular, as shown in Fig. 26, in the golf ball according to the this embodiment having the linear bonding line BL, first through fourth hexagonal dimple faces Pl, P2, P3 and P4 have identical dimple arrangement structures, and the fifth and sixth hexagonal dimple faces P5 and P6 have identical dimple arrangement structures. In addition, approximately triangular dimple faces, having dimples 41 through 47 having various sizes, are formed between the hexagonal dimple faces.

[148] In each of the first through fourth hexagonal dimple faces Pl, P2, P3 and P4, four lines of dimples are formed on each of opposite sides of the bonding line BL, that is, eight lines of dimples are formed in each hexagonal dimple face. Three dimples are arranged in the uppermost dimple line, and four dimples are arranged in the lowermost dimple line.

[149] In other words, it is preferable that the dimples be arranged such that there is a difference of one in the number of dimples between the uppermost dimple line and the

lowermost dimple line.

[150] Therefore, in a mold for forming the golf ball through the injection molding process, a process of machining the boundary areas of the mold between the upper mold and the lower mold can be easily conducted, and the cost of manufacturing the mold can be reduced.

[151] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention. Therefore, the above-mentioned embodiments must be regarded only as examples for description of the present invention, rather than as limiting the present invention. Industrial Applicability

[152] As described above, the present invention realizes a symmetrical dimple arrangement structure of a golf ball such that dimples are arranged in a symmetrical manner on the upper, lower, left and right portions of the golf ball and the left and right of the golf ball are balanced, so that the flow of air above and below and on opposite sides of the golf ball, which is driven by striking, can be maintained constant.

[153] Furthermore, to arrange dimples on the golf ball in a shape in which faces each having a predetermined shape are defined on the golf ball, the surface of the golf ball is sectioned by imaginary dividing lines forming a spherical hexahedron, and the areas, defined by sectioning the surface of the golf ball into six parts, have identical dimple arrangement structures. Thus, the present invention is advantageous in that the golf ball has a symmetrical structure in all directions.

[154] In addition, hexagonal dimple faces are defined in areas defined by sectioning the surface of the golf ball into six parts, and the hexagonal dimple faces have a symmetrical structure with respect to the arrangement and size of dimples. Therefore, there is an advantage in that drag force is reduced and lifting force is increased.

[155] As well, in response to the dimple arrangement structure, a bonding line of the golf ball can be formed into various shapes, so that the cost of molding the golf ball can be reduced.