Sumitomo Rubber Industries Limited

Kengo Oka

Tadahiro Ebisuno

Yoshikazu Yabuki

Mikio Yamada

Kaname Yamada

Keiji Moriyama

Kiyoto Maruoka

Takashi Sasaki

Akihiro Nakahara

Kazushige Sugimoto

Shinji Ohshima

Yoshiyuki Mimoto

Shinji Oshima

Susumu Yoshida

Golf ball

A pair of semispherical molds, each having dimple-forming projections on a connecting portion is used to shape a resinous material into a golf ball having dimples on a seam corresponding to the connecting portion. A ball fixing means is utilized to hold the golf ball thereto with the seam uncovered. A cutting member disposed at an end of a rotary shaft, and having a radius of curvature smaller than a sectional radius of curvature of the dimple is utilized to remove a burr from the seam of the golf ball. The rotary shaft rotates on its axis and moves forward when the cutting member is brought into contact with the dimple on the seam and backward when the cutting member is brought into contact with a convex land portion. The cutting member is then pressed against the seam successively in alternate contact with the dimples and the land portions.

Apparatus and method for manufacturing golf ball

An apparatus for removing the burr from the seam of a golf ball made using a pair of semispherical molds each having dimple-forming projections on a connecting portion to shape resin into a golf ball having dimples on a seam corresponding to the connecting portion. A ball fixing mechanism holds the golf ball thereto with the seam uncovered. A cutting member having a cutting member, disposed at an end of a rotary shaft, having a radius of curvature smaller than a sectional radius of curvature of each of the dimples. The rotary shaft rotates on its axis and moves forward when the cutting member is brought into contact with each of the dimples on the seam and backward when the cutting member is brought into contact with a convex land thereon. Thereafter, the cutting member is pressed against the seam successively removing the burr while maintaining the integrity of each of the dimples.

Apparatus for manufacturing a golf ball

A golf ball having a plurality of dimples on a surface thereof characterized in that more than 40% of all dimples are polygonal in shape and have a double slope in section having a straight first slope and a straight second slope continued radially inwardly from the first slope, and the gradient of the first slope of said double slope disposed in the vicinity of a dimple edge is greater than that of the second slope disposed in the vicinity of the bottom thereof.

In a golf ball having dimples and lands other than the dimples formed on the surface thereof, dimples are arranged so that less than 40 lands are provided which contain a rectangle having a short side greater than 0.4 mm and an area greater than 0.8 mm.sup.2 and not including a part of the dimple or the whole thereof. A land having the greatest area of all lands is so small that a dimple having an area greater than the average area of all dimples cannot be formed therein.

A golf ball has no great circles intersecting dimples. A method for manufacturing the golf ball uses the steps of molding the golf ball with a pair of semispherical molds having many dimple patterns formed on the inner surface thereof so as to form first dimples on the surface of the golf ball. Then a burr formed on the connecting portion between upper and lower molds is removed and dimples are subsequently formed and/or corrected on the connecting portion.

A golf ball having 280 to 540 dimples including plural types of dimples of different surface configurations such as circular dimples or regular polygonal dimples formed thereon. The percentage of dimples unadjacent to dimples of different surface configurations is less than 30 of the total number of dimples so that one dimple is adjacent to many dimples of different configurations.

A golf ball has one great circle and four one-half great circles which all intersect no dimples. Eight end points which include two end points of each one-half great circle are formed at the one great circle. These end points do not coincide with each other on the great circle. One of the one-half great circles intersects the other one-half great circle at a right angle at the middle point thereof on each of the great circle. In other words, an upper semispherical mold for an octahedral dimple golf ball arrangement is rotated a certain angle relative to the lower mold such that two of the three great circles are divided into four one-half great circles. The parting line of the mold becomes the one remaining great circle. In this manner, a more uniform flight of the golf ball canbe obtained regardless of whether the ball is hit on a seam, semi-seam of non-seam area.

A golf ball has dimples arranged in eight spherical equilateral triangles obtained by projecting, on the imaginary spherical surface of the golf ball, the ridge lines of a regular octahedron inscribing the imaginary spherical surface. Three great circles corresponding to the ridge lines being projected on the spherical surface. One great circle coinciding with a mold seam is formed as the sole great circle unintersecting dimples and the other two great circles intersect dimples. Between 300 to 550 dimples are formed in the golf ball with the dimples being equivalently arranged in each of the eight spherical equilateral triangles.

A golf ball having circular dimples and noncircular dimples arranged in different percentages depending on the spherical zones, whereby a favorable aerodynamic property is obtained by eliminating the difference in trajectories between line hitting and face hitting.

A golf ball with dimples disposed in a regular octahedral arrangement having a superior symmetrical property so as to arrange dimples symmetrically in each of numerously divided regions without deteriorating the symmetrical property of the golf ball and by varying volumes of dimples adjacent to each other at a specified ratio with diameters thereof equal to each other, thereby to provide a symmetrical property and uniformity for flying a long distance.

The present invention relates to a golf ball having dimples and a plurality of great circles unintersecting the dimples in which the specification of the dimples is set 1.02.ltoreq.VL/VF.ltoreq.1.20 where L is a zone ranging from each of the great circles to each of the circumferences corresponding to a central angle of less than approximately 10.degree.; F is a zone other than the L zone; the volume of each dimple arranged in the L zone is VL; and the volume of each dimple arranged in the F zone and having approximately the same diameter as that of said dimple arranged in the L zone is VF.

Growing community of inventors

Kobe, Japan

Kengo Oka