The present invention is directed to a golf ball having a non-planar parting line about non-circular dimples on its spherical surface. The parting line comprises non-concentric arcs having straight connecting line segments between the arcs. Each arc maintains a tangency with its connecting lines and a relief distance greater than or equal to 0.003 inches when measured from an average non-circular dimple diameter to one of the non-concentric arcs and an absolute relief distance of at least 0.001 inches when measured from all points on the non-circular dimple perimeter to one of the non-concentric arcs. The sum of the lengths of the non-concentric arcs relates to the sum of the straight connecting line segments according to the equation:
(0.15)L.sub.ARCSL.sub.LINES(0.50)L.sub.ARCS.

Golf balls including at least one modified dimple group are disclosed. The modified dimple group comprises one or more modified dimples forming an axially symmetric pattern about a Correction Area Centroid located on an axis of symmetry at a latitude greater than 0, where 0 represents the hemispherical pole and 90 represents the equator. The modified dimples can be altered, for example, by changing dimple coverage, dimple diameter, dimple depth, dimple edge angle, dimple volume, dimple cross-sectional shape, and/or dimple plan shape. Optionally, the dimples have a catenary cross-sectional shape and the modified dimples are altered by changing the shape factor and/or chord depth. Such modifications preferably produce a golf ball that flies more consistently regardless of orientation when struck than a corresponding golf ball without such modifications.

The present invention is directed to golf balls having improved aerodynamic performance due, at least in part, to the alteration of the dimple surfaces. In particular, the present invention relates to a golf ball that includes at least a portion of its dimples having circular perimeters and dimple profiles having a concentric groove or a non-concentric groove on the surface of the dimple. The golf ball dimples of the present invention provide golf ball surfaces having unique appearances, while maintaining ideal aerodynamic characteristics.

In a golf ball, dimples are arranged on a spherical polyhedron formed by dividing a surface of a sphere using small circles and great circles only on the equator, without arranging the dimples on a spherical polyhedron formed by dividing a surface of a sphere using great circles. The formed spherical polyhedron includes two spherical regular hexagons centered on a pole, twelve near-pole spherical isosceles triangles, twelve near-equator spherical pentagons, and twelve near-equator spherical isosceles triangles, in which the dimples are arranged. Thus, a dimple area ratio may be improved by 2 to 4%, compared to the prior art in which dimples are arranged in spherical polygons of a cubeoctahedron (or an octahedron) divided by great circles.

The present invention concerns golf balls having a modified aerodynamic configuration and a method for creating a modified aerodynamic configuration that improves dimple coverage, interdigitation, and non-alignment in golf ball dimple patterns by rotating the repeating area elements about pre-determined center points, with further optional steps of expanding or contracting the elemental arrangements about pre-determined center points, enlarging or reducing the sizes of dimples, and adding extra dimples to occupy land areas created by the previous steps. The resulting modified aerodynamic configuration with a rotated element has increased dimple coverage, greater interdigitation and improved non-alignment.

The present invention is a golf ball dividing method for symmetrically arranging dimples on a surface of a golf ball and a dimple arrangement method of arranging dimples along dividing lines based on sizes of dimples. The dimples having large diameters are effectively arranged on the deformed spherical triangle symmetrically over the entire surface of a sphere, so that it is possible to an effect of improving the flying stability and flight distance of the golf ball. Accordingly, it is possible to solve the problem of flying stability due to the lack of symmetry in the dimple arrangement method of the prior art for increasing an dimple area ratio by dividing the surface of the golf ball as a spherical octahedron and arranging dimples having large diameters, so that it is possible to improve a lift force to increase a flight distance and the flying stability of the golf ball.

A surface of a sphere is divided by using not only great circles but also small circles, forming a spherical polyhedron. The spherical polyhedron includes two spherical regular pentagons, each having a center at the pole, ten spherical isosceles triangles near the pole, ten spherical pentagons near the equator, and ten other spherical isosceles triangles near the equator. Compared to a related art, dimples are accurately arranged in spherical polygons. Thus, a dimple area ratio is improved and the number of dimples is appropriately maintained.

The present invention is directed to golf balls having improved aerodynamic performance due, at least in part, to the alteration of the dimple surfaces. In particular, the present invention relates to a golf ball that includes at least a portion of its dimples having circular perimeters and dimple profiles having a concentric groove or a non-concentric groove on the surface of the dimple. The golf ball dimples of the present invention provide golf ball surfaces having unique appearances, while maintaining ideal aerodynamic characteristics.

A golf ball dimple pattern based on a hexagonal dipyramid is disclosed. The dimples are arranged based on six substantially similar dimple sections on each of the two hemispheres of the ball.

A golf ball 2 has a large number of dimples 10 on a surface thereof. A dimple pattern of each hemisphere of the golf ball 2 includes three units (T1, T2, and T3) that are rotationally symmetrical to each other. A dimple pattern of each unit includes two small units (T1a, T1b) that are mirror-symmetrical to each other. A standard deviation Su of areas of all the dimples 10 is not greater than 1.7 mm.sup.2. A standard deviation Pd of distances L between dimples 10 of all neighboring dimple pairs is less than 0.500 mm. A ratio So of a sum of areas of the dimples 10 relative to a surface area of a phantom sphere of the golf ball 2 is not less than 78.0%.