NZ235783A - Golf ball with dimples in sets of differing diameter - Google Patents

Description

235783 # 4 Under -the provisions of Regulation 23 (1) the Specification has been ante-dated to 18 &L Priority Date(s): .. ^ 7?., Complete Specification Filed: Clas$» Bk-.s&znj. j.4..-.

Publication Date: . ?.?.

P.O. Journal, No: .* NEW ZEALAND PATENTS ACT, 1953 Initials No.: Date: COMPLETE SPECIFICATION MULTIPLE DIMPLE GOLF BALL Divided from 224374 26 April 1988 *3ocr»9o -+/We, ACUSHNET CCMPANY, a corporation of the State of Delaware, United States of America, of Belleville Avenue, New Bedford, Massachusetts 027457-United States of America hereby declare the invention for which -I- / we pray that a patent may be granted to «*e/us, and the method by which it is to be performed, to be particularly described in and by the following statement: - (followed by page la) —"""Tr vn*. w»»r «<-»wwtiiicio,ipat »-• -• 23 5 7 8 3 The present invention relates to golf balls and is particularly concerned with the production of golf balls that travel farther than golf balls now on the market without violating any of the rules promulgated by the United States Golf Association (USGA). This is made possible by covering more than 78% of the surface of the golf ball with dimples.

Since the dawn of golf, attempts have been made to improve the distance a golf ball will travel, and this is especially true over the last decade.

The USGA promulgates rules for the game of golf which include specifications for the golf ball itself. Compliance with USGA rules is not obligatory and indeed some companies actually allege that they sell "hot" balls that violate USGA rules. Any major manufacturer of golf balls could easily make a "hot" ball which violates the USGA rules; however, all respectable manufacturers adhere to the USGA rules religiously since violation of a rule can result in the ball being banned from all USGA play. There are three performance tests for golf balls imposed by the USGA, one being velocity, another relating to golf ball - la - "* ^ _ ,.. , , ... , _ 235 783 symmetry, and the third being an overall distance.

The velocity requirement, commonly referred to as the maximum initial velocity, specifies that the golf ball may not exceed a velocity of 250 feet per second when measured on apparatus approved by the USGA. There is a 2% tolerance on the velocity, i.e. the highest permissible velocity is 255 feet per second. Most manufacturers have a safety factor and make their average maximum velocity at some lesser value such as in the 250-253 range to minimize the risk of being declared "illegal".

The rule relating to golf ball symmetry simply states that the golf ball shall be designed and manufactured to perform in general as if it were spherically symmetrical. It is generally accepted that golf balls with substantially uniform dimple clusters will meet the USGA test but that golf balls with non-uniform dimple clusters will not. One example of a golf ball with substantially uniform dimple clusters is shown in British Patent No. 1,381,897 in which all dimples have substantially the same diameter and depth and are substantially uniformly spaced over the surface of the ball. Another example of a golf ball with substantially uniform dimple clusters is U.S. Patent No. 4,142,727.

While this patent teaches dimples of different dimensions and different spacings, there are 12 substantially uniform dimple clusters. An example of a golf ball with non-uniform 2- ^ 235783 dimple clusters is U.S. Patent No. 3,819,190 wherein the dimples at the poles are substantially different from those which cover the rest of the surface of the ball.

The total overall distance is measured by a test known as the Overall Distance Standard and is 280 yards plus a tolerance of 6% (for a total permissible distance of 296.8 yards). There is talk within the industry that the tolerance will be lowered to 4%, i.e. total permissible distance of 291.2 yards. The Overall Distance Standard is a measurement of carry and roll. Carry is the distance from the tee to the point where the golf ball first impacts with the ground while carry and roll is the total distance from the tee to the point where the ball finally comes to rest. The Overall Distance Standard is tested on apparatus approved by the USGA on the outdoor range at the USGA Headquarters. This apparatus is intended to simulate a club known as a driver. Whether the tolerance is 6% or 4%, to the best of the knowledge of the applicants no one has been able to even come close to approaching the total permissible distance of the Overall Distance Standard while still having a size, weight and initial velocity which fall within the USGA Standards.

While the Overall Distance Standard is the norm used by the USGA, the industry frequently uses a distance standard that takes into account the overall distance (carry and „ ■/«»• • ... # 235783 roll) of a ball hit successively with a driver and a #5 iron. It is still necessary that such a golf ball comply with the USGA standard; however, since the USGA apparatus simulates a hit with a driver, two balls that have essentially the same overall distance on the USGA machine can have substantially different values in the drive plus #5 iron test. It has been found that there is a trade-off in manufacturing golf balls between a ball that has a good overall distance when hit with a driver and a ball that has a good overall distance when hit with a #5 iron.

In other words, a golf ball manufactured to have a good overall distance when hit with a driver will generally have a poorer overall distance when hit with a #5 iron than a golf ball that is manufactured to have a good overall distance when hit with a #5 iron and vice versa.

There is a constant need within the golf ball industry to produce a golf ball with good overall distance when hit with both a #5 iron and a driver.

It has been found that distance is related to the aerodynamic characteristics of the golf ball and, more particularly, to the number of dimples, the dimple spacing, the dimple depth and the dimple diameter. It has also been found that dimple spacing is very important. To quantify dimple spacing, reference may be made to the percentage of the ball's surface area which is covered .. ' , v-.< ' • ••».,•> f.-->r -, ,.rt 235783 2:5783 by dimples. Prior art patents (see for example U.S. Patent No. 878,254) teach that golf balls have 25 to 75% of their surface area covered by dimples and at the present time, no balls have more than about 75.5% of their surface area covered by dimples. Another way to categorize the percentage of space taken up by the dimples on the surface of the golf balls is to refer to the land area between the dimples, which is often referred to as fret.

The applicants have now discovered that if the total surface area of the golf ball covered with dimples exceeds 78%, the golf ball will have substantially greater distance with a #5 iron and with a driver for both carry and carry plus roll.

One way to achieve covering more than 78% of the surface of the golf ball with dimples is to employ dimples of different diameters on the surface of the golf ball and specifically, it has been found that by employing five sets of dimple patterns, this goal is obtained. These five sets comprise four sets of a dual dimple pattern having a total of 324, 384, 414 or 484 dimples and a triple dimple pattern having a total of 48 4 dimples. In all cases, the dimples are substantially evenly spaced over the surface of the golf ball.

A golf ball with 324 dimples is prepared by laying out an icosahedron pattern on the surface of the golf 235 7 83 ball and making substantially equilateral spherical triangles sufficient to yield 332 vertices, each vertex being the center of a dimple. If this icosahedron/spherical triangle procedure is used to form 332 vertices, there will be 332 points at which dimples can be placed and these will be substantially equally spaced over the surface of the golf ball. Removal of four dimples at each pole, three for a trademark and the other for an identifying number, gives the preferred number of 324 dimples. Additionally, other minor changes can be made in the layout of the dimples as previously discussed. For the golf ball with 324 dimples there are 124 dimples with a diameter of about 0.157 inches ±0.002 inches and the remaining 200 dimples have a diameter of about 0.170 inches ±0.002 inches.

A golf ball with 3 84 dimples is prepared by laying out an icosahedron pattern on the surface of the golf ball and making substantially equilateral spherical triangles sufficient to yield 392 vertices, each vertex being the center of a dimple. Laying out of dimple centers on golf balls in this manner is disclosed, for example, in British Patent No. 1,381,897. If this icosahedron/spherical triangle procedure is used to form 392 vertices, there will be 39 2 points at which dimples can be placed and these will be substantially equally spaced over the surface of the golf ball. It is generally considered desirable in top grade golf balls to remove four dimples at each pole, 0 235 7 83 three for application of a trademark and the other for application of an identifying number. This gives the preferred number of dimples of 384 dimples. In addition to removal of dimples for the trademark if desired, other minor changes can be made in the layout of the dimples, e.g. separation of the dimples at the parting line of the golf ball mold to facilitate buffing of the parting line. For the golf ball with 384 dimples there are 144 dimples with a diameter of about 0.140 inches +0.002 inches and the remaining 240 dimples have a diameter of about 0.160 inches ±0.002 inches.

A ball with 414 dimples is prepared by laying out an icosahedron pattern on the surface of the golf ball and making substantially equilateral spherical triangles sufficient to yield 422 vertices, each vertex being the center of a dimple. If this icosahedron/spherical triangular procedure is used to form 422 vertices, there will be 422 points at which dimples can be placed and these will be substantially equally spaced over the surface of the golf ball. Removal of four dimples at each pole, three for a trademark and the other for an identifying number, gives the preferred number of 414 dimples. For this layout, 144 dimples have a diameter of about 0.140 inches i 0.002 inches and the remaining 270 dimples have a diameter of about 0.150 inches ± 0.002 inches.

' V'~v" ' .... ■ * ' . . .... 1®' 235783 For golf balls with a total of 484 dimples with either two different dimple diameters or three different dimple diameters, an icosahedron pattern is laid out on the surface of the golf ball making substantially equilateral spherical triangles sufficient to yield 492 vertices, each vertex being the center of a dimple. In this icosahedron/spherical triangle procedure there will be 49 2 points at which dimples can be placed and these will be substantially equally spaced over the surface of the golf ball. As with the 324, 384 and 414 patterns, removal of four dimples at each pole, three for a trademark and the other for an identification number gives the preferred number of 484 dimples. For a dual dimple pattern there are 174 dimples with a diameter of about 0.130 inches and 310 dimples with a diameter of about 0.140 inches ±0.002 inches.

For the three different diametered dimples, there are 170 dimples with a diameter of about 0.130 inches ±0.002 inches, 260 dimples with a diameter of about 0.140 inches ±0.002 inches and 50 dimples with a diameter of about 0.150 inches ±0.002 inches.

In the four dual dimple patterns the smaller diametered dimples are arranged along the edges and vertex centers of the icosahedron while the larger dimples are arranged inside the triangles formed by the smaller dimples. In the 484 pattern with three different dimple diameters. 235783 the medium sized dimples with diameters of about 0.140 inches ±0.002 inches are arranged such that they form a similar triangle just inside the individual triangles formed by the smaller dimples. The largest diametered dimples, of which there are three per individual triangle, form a triangle inside the medium sized dimples.

These dimple patterns produce a golf ball with very little land area between adjacent dimples, typically at least about 78% of the surface area of the ball is covered by dimples and preferably above about 79%.

A number of golf balls herein described are claimed in the present specification. Golf balls having at least 384 dimples and up to about 392 dimples are claimed in New Zealand Patent Specification No. 224374 from which the present specification has been divided.

Figure 1 A illustrates a hemisphere of a golf ball with a dual dimple configuration for a 324 pattern.

Figure 1 B illustrates a hemisphere of a golf ball with a dual dimple for a 384 pattern.

Figure 1 C illustrates a hemisphere for a golf ball with a dual dimple configuration for a 414 pattern.

Figure 1 D illustrates a hemisphere for a golf ball with a dual dimple configuration for a 484 pattern.

Figure 2 illustrates a hemisphere of a golf ball for a triple dimple pattern for 484 pattern. - 1 ""nnmiiMi idniHiMtoilirin W'l!ri1"" ,-iTifTf "ifflrtnf - iMttiW 235 7 83 Figure 3 illustrates a hemisphere of a golf ball with a dual dimple pattern as disclosed in Example 7 herein.

Figure 4 illustrates a hemisphere of a golf ball with a triangular dimple shape as taught by Example 8 herein.

In Fig. 1A, the dimples are laid out in an icosahedron/ spherical triangular pattern as described hereinbefore. The outer periphery is the equator 8 of the ball.

Area 10 at the pole of the ball is a smooth surface for application of a trademark. Area 12 is similarly smooth for application of an identifying number. Dimples 14 are the larger size dimples, i.e. about 0.170 inches, while dimples 18 are dimples of the smaller diameter, i.e. about 0.157 inches.

In Fig. 1 B, the dimples are laid out in an icosahedron/ spherical triangular pattern as described hereinbefore. The outer periphery is the equator 8 of the ball.

Area 10 at the pole of the ball is a smooth surface for application of a trademark. Area 12 is .similarly smooth for application of an identifying number. Dimples 14 are the larger size dimples, i.e. about 0.160 inches, while dimples 18 are dimples of the smaller diameter, i.e. about 0.14 0 inches.

In Fig. 1 C, the dimples are laid out in an icosahedron/ ,....^,3^., 245783 spherical triangular pattern as described hereinbefore. The outer periphery is the equator 8 of the ball.

Area 10 at the pole of the ball is a smooth surface for application of a trademark. Area 12 is similarly smooth for application of an identifying number. Dimples 14 are the larger size dimples, i.e. about 0.15 inches while dimples 18 are of smaller diameter, i.e. about 0.140 inches © In Fig. 1 D, the dimples are laid out in an icosahedron/ spherical triangular pattern as described hereinbefore. The outer periphery is the equator 8 of the ball.

Area 10 at the pole of the ball is a smooth surface for application of a trademark. Area 12 is similarly smooth for application of an identifying number. Dimples 14 are the larger size dimples, i.e. about 0.14 0 inches, while dimples 18 are dimples of the smaller diameter, i.e. about 0.130 inches. In Fig. 2, the dimples are laid out in an e icosahedron/spherical triangular pattern as described hereinbefore for a 484 triple dimple pattern. The outer periphery is the equator 28 of the ball.

Dimples 30 at the pole of the ball can be absent to make a smooth surface for a trademark. Dimples 32 can similarly be absent for an identifying number. Dimples 34 and 36 are the larger —. sorter. r. '/"-'V J" 235783 sized dimples. In the triple dimple configuration of the 484 pattern, dimples 34 are about 0.140 inches in diameter and dimples 36 are about 0.150 inches in diameter and dimples 38 are the smallest sized dimple, i.e. about 0.130 inches in diameter.

These and other aspects of the present invention may be more fully understood with respect to the following examples.

EXAMPLE 1 A golf ball made with a total of 384 dimples having 144 smaller dimples of about 0.140 inches in diameter and a depth of 0.0110 inches and having 240 larger dimples of about 0.160 inches in diameter and a depth of 0.0110 inches was tested against a conventional golf ball with 384 dimples, all being about 0.150 inches in diameter and a depth of 0.0115 inches.

Both balls were two piece balls with a core and a cover. The core was made from polybutadiene crosslinked by zinc diacrylate.

Carry distance and total distance (carry and roll) were determined in a field test using an apparatus commonly referred to in the golf ball industry as a dual pendulum machine. The dual pendulum machine has a pendulum on each side of a motor which swings the pendulums so that - ,. . f?». r..^J...".frrj__x. -. , , © © 235783 they hit two golf balls simultaneously, one with each pendulum. The balls are tested at a temperature of about 70°F. Two balls at a time are then hit by the pendulums into an open field where carry distance and total distance are individually sighted and recorded by workers. A series of eight balls is hit on each side of the machine. At the end of the run, the balls were collected and returned to the machine. They were sorted and then reversed as to the pendulum by which they were hit. Measurements were again made, the balls collected and this procedure was repeated. There was a total of 32 hits for each type of ball, i.e. each of the eight individual balls was hit four times, twice on each side of the dual pendulum machine.

The procedure just described was used for distance testing of both the driver and the #5 iron. The dual pendulum has an adjustable striking face. In order to duplicate a driver, a 13.9° launch angle was used. A 13.9° launch angle is achieved by using a striking face having an angle of 15° with respect to the vertical. In order to duplicate a #5 iron, a 22° launch angle was used. A 22° launch angle is achieved by using a striking face having an angle of 26° with respect to the vertical. The results of the distance tests are as follows: t/Wpk'p-- . 235 783 o Diameter (in.) Weight (02.) PGA Compression Initial Velocity (ft/sec) TABLE I Ball of Invention 1.68 1.605 94 253.08 Prior Art 1.68 1.605 95 252.71 Dimple Dimensions (in. ) Theoretical Diameter Actual Diameter Actual Depth Large 0.160 0.1597 0.0108 Small 0.140 0.1367 0.0110 0.150 0.1474 0.0115 © % of Ball Surface covered by dimples Theoretical Actual Distance (yds.) Driver 5-iron Total Carry 198.4 168.9 367.3 79.4 78.1 Carry + Roll 209 .0 171.3 380 .3 Carry 195.2 166.8 362.0 76.5 73.9 Carry + Roll 204.8 169.4 374.2 \ \ 'Mi- ii i I mil III | i ii lllllliriiimn,.ii - —, .jri—f*' 235 7 83 It is readily apparent that the dual dimple golf ball has a better overall distance with both a #5 iron and with a driver than a conventional golf ball. This is truly surprising and unexpected because, in general, a ball which exhibits improved overall distance with a driver does not show an improved overall distance with a #5 iron, and vice versa, as previously disclosed hereinabove.

EXAMPLE 2 • In this example, golf balls with a dual dimple diameter pattern were live tested against conventional golf balls in which all of the dimples had the same diameter. Twelve live golfers instead of the apparatus referred to in Example 1 as a dual pendulum machine were used to hit the balls.

Both sets of balls were two piece balls with solid cores made from polybutadiene crosslinked with zinc diacrylate.

Each one of the balls had 38 4 dimples. Physical data on each of the balls are listed in Table II below as well as the results of two days of distance testing. 6 \ , .'" ■■■« 235783 Diameter (in.) Weight (oz.) PGA Compression Initial Velocity (ft/sec) TABLE II Ball of Invention 1.68 1.60 100.2 253.12 Prior Art 1.68 1.60 97.8 253.17 Dimple Dimensions . (in. ) .

Theoretical Diameter Actual Diameter Actual Depth Large 0.160 0.1597 0.0108 Small 0.140 0.1367 0.0110 0.150 0.1468 0.0110 © % of Ball Surface covered by dimples Theoretical Actual Distance (yds..) Driver 5-iron Total Carry 190.2 156.5 346.7 79.4 78.1 Carry + Roll 204.6 164.9 369.5 Carry 188.4 154.6 343.0 76.5 73.3 Carry 4- Roll 203.7 162.8 366.5 It is readily apparent that the dual dimple golf ball outperformed the conventional golf balls by about 3.0 yards. -16-" 235783 EXAMPLE 3 A dual dimple golf ball was tested against two conventional golf balls using live golfers to hit the O balls instead of a dual pendulum machine. All balls were two piece golf balls with solid rubber cores made from polybutadiene crosslinked with zinc diacrylate. All balls had 384 dimples. Table III below lists both the physical characteristics of the golf balls as well as the results of two days worth of distance testing.

Q ■ \ o o Ball of. Invention 00 1 Diameter (in.) Weight (02.) PGA Compression Initial Velocity (ft/sec) Dimple Dimensions (in.) Theoretical Diameter Actual Diameter Actual Depth % of Ball Surface covered by dimples Theoretical Actual 1.68 1.60 94 253.52 Large Small 0.160 0.1590 0.0108 0.140 0.1371 0.0109 Distance <v3s-> Driver 5-iron Total Carry 191.3 163.4 354.7 79.4 77.7 Carry +. Roll 207 .0 172.1 379.1 Igpggpri nil 11 ill i Ii 11 I ii Mil I III I I I« I TABLE III o o Prior Art ILL iJLL ' 1.68 1.68 1.60 1.60 95 95 253.08 253.08 % 0.150 0.1479 0.0118 0.150 0.1480 0.0108 76.5 76 .5 74.4 74 .5 ro Carry Carry 01 Carry + Roll Carry + Roll CJI 186.3 203.0 188.6 206.9 159.9 167.9 157.7 165.3 CO 346.2 370.9 346.3 372.2 CM 235783 It is apparent that the dual dimple golf ball travelled farther than any of the conventional single dimple golf balls.

EXAMPLE 4 • A dual dimple golf ball was tested against a conventional golf ball using live golfers. All golf balls were manufactured from a two piece golf ball with a solid rubber core made from polybutadiene crosslinked with zinc diacrylate. All balls had 384 dimples. Table IV lists both the physical characteristics of the golf balls and the distance results after two days of testing.

Chf^VV. 7^7 --r..,, 235783 o o Diameter (in.) Weight (oz.) PGA Compression Initial Velocity (ft/sec) Dimple Dimensions (in. ) Theoretical Diameter Actual Diameter Actual Depth TABLE IV Ball of Invention 1.68 1.60 94.9 253.78 Large Small 0.160 0.1590 0.0108 0.140 0.1371 0.010 9 % of Ball Surface covered by dimples Theoretical Actual 79.4 77.7 Distance (yds.) Driver 5-iron Total Carry 198.0 158.1 356.1 Carry + Roll Prior Art 1.68 1.60 95.6 252.53 0.15 0.1490 0.0116 76.5 75.5 Carry 194.6 157.1 351.7 Carry + Roll 207 .2 162.3 369.5 It is apparent from the foregoing that a ball with superior distance is produced when a dual dimple pattern as disclosed herein is used. 205.8 161.1 366.9 ' ' —--aw****" " --—"wwaa \ \ -"/Mu.M^, ... 235783 EXAMPLE 5 o In this example, different dimple patterns are compared for percent of'surface coverage.

TABLE V Pattern Number Total Number of Pimples Number -Dimples at Different Diameter Percent Dimple Dimple Diameter Coverage 1 324 324 0.157 70.7 2 324 124 200 0.157 0.170 78.3 3 384 384 0.146 72.5 4 384 144 240 0.140 0.160 79.4 414 414 0.140 71.9 6 414 270 144 0.150 0.140 78.8 7 484 484 0.130 72.5 8 484 174 310 0.130 0.140 79.9 9 484 174 260 50 0.130 0.140 0.150 81.2 It is readily apparent that a pattern of dual dimples provides at least 5% more dimple coverage than a single dimple pattern and that the three size dimple pattern provides at least a 1.3% increase in dimple coverage as compared to the dual dimple pattern. 235783 EXAMPLE 6 Three piece golf balls were made with liquid filled centers having an exterior diameter of 1-1/8 inch. This center was covered with elastic thread of dimensions of 0.022 inch x 1/16 inch to a wound ball size of 1.610 inches in diameter. A cover was molded on top of the wound core. The cover composition comprised: Resin (Transpolyisoprene) 76.7% Filler 22.0% Other 1.3% The molded balls were treated and painted in a standard manner. The diameter of the finished ball was 1.680 inches ± 0.003 inches.

The golf ball had 384 dimples with two different size dimples. The smaller dimples were 0.14 0 inches ± 0.002 inches while the larger dimples were 0.16 0 inches ± 0.002 inches.

In distance testing, these balls were statistically superior to identically made golf balls bearing 384 dimples each with a diameter of 0.146 inches ± 0.002 inches and a depth of 0.0115 inches ± 0.0003 inches which were substantially evenly spaced over the surface of the golf ball utilizing an icosahedron/spherical triangle pattern as described in British Patent No. 1,381,897 except that four vertices at each pole do not have dimples in D til 235/aa order to provide a smooth surface for the trademark and identifying number and the vertices have been slightly rearranged to separate the dimples for the mold parting line.

It was noted that both the prior art golf ball and the present invention golf ball of this example had the same spin.

This example corresponds to Example 10 of U.S. application Serial No. 544,780 filed October 24, 1983 which is incorporated herein by reference.

Golf balls are made according to Example 2 of U.S. patent application Serial No. 544,780 filed October 24, 1983, except that multiple dimples marked 18 which are identical to the dimples marked 18 in Fig. 1 of the present application, had a diameter of 0.140 inches ± 0.002 inches while the balance of the dimples had a diameter of 0.160 inches ± 0.002 inches. The average diameter of all the dimples was 0.151 inches ± 0.002 inches. The spin rate of the golf balls as measured pursuant to the U.S. patent application Serial No. 544,780 is the same as that of Example 2 of the parent. In distance testing the balls of the present Example are statistically superior to the golf balls of Example 2. 235 783 EXAMPLE 7 This example illustrates a second configuration for a golf ball made with 384 dimples with dimples of two different sizes.

This second configuration of 384 dual dimples has 66 dimples having a diameter of about 0.13 inches ± 0.002 inches and 318 dimples having a diameter of about 0.160 inches ± 0.002 inches.

The dimple pattern for this second configuration of 384 dimples is prepared by laying out an icosahedron pattern on the surface of the golf ball and making substantially equilateral spherical triangles sufficient to yield 39 2 vertices, each vertex being the center of a dimple. The process is similar to that used to lay out the 384 dual dimple ball having 144 dimples with a diameter of about 0.140 inches and 240 dimples with a diameter of about 0.160 inches. As with the 384 ball, preferably 4 dimples are removed at each pole, 3 for a trademark and 1 for an identification number.

In the second configuration for the 38 4 ball, the smaller dimples, about 0.13 inches, are positioned in groups of six at each vertex of the icosahedron. Specifically, one of the small dimples is placed directly at the vertex. Clustered around the small dimples at the vertex are five additional small dimples which are the immediate neighbors o G © 235783 to the small dimple at the vertex. These six small dimples form a pentagonal arrangement.

In Fig. 3 the dimples are laid out in accordance with this example. Outer periphery is the equator 4 0 of the ball. In accordance with this example, cleared area 42 exists which had three dimples removed therefrom for the purpose of affixing a trademark and area 44 had a dimple removed for the purpose of affixing an identification number. Dimples 46 are small dimples, i.e. about 0.13 inches ± 0.002 inches and dimples 48 are larger dimples, i.e. about 0.16 inches ± 0.002 inches.

It has been found that a golf ball having the second configuration of 384 dimples produces a ball having about 82% of its surface covered with dimples.

EXAMPLE 8 Yet another way to achieve covering more than 78% of the surface of a golf ball with dimples is to employ a pattern of triangularly shaped dimples with a total of 320 triangular dimples covering the ball. In fact, such an arrangement has been found to cover between about 81% to about 87% of the surface of the ball with dimples.

A ball with an icosahedron dimple pattern having 320 triangular dimples is prepared by laying out an icosahedron pattern on the surface of the ball by dividing its surface into twenty equal main triangles. Each main triangle 235783 is broken into sixteen smaller triangles by dividing the sides of the main triangle into four equal parts and joining the three points on each side with the arcs of great circles with neighboring sides. This process applied to all the 20 main triangles will produce three hundred and twenty small triangular areas and one hundred and sixty-two vertices. As with the other patterns, dimples can be removed for application of trademark and identification number.

The triangular dimples are arranged on the surface of the golf ball in such a manner that the fret line between adjacent dimples is maintained between about 0.015 inches and about 0.010 inches. The individual triangular dimples that are used to make up the dimples in this pattern are a combination of isosceles triangles, equilateral triangles, and triangles with no equal sides.

In Fig. 4, triangular dimples are laid out in an icosahedron/spherical pattern as described hereinbefore for a triangular 320 dimple pattern. The outer periphery is the equator 50 of the ball.

Dimples 52 are equilateral triangles, dimples 54 are isosceles triangles and dimples 56 are triangles of all unequal sides. " ' _ , .r ; 235783 Fret 58 measures between about 0.015 inches and about 0.010 inches. When the fret between each dimple measures about 0.015 inches, about 81% of the golf ball's surface is covered with triangular dimples. When the fret between the triangular dimples is decreased to about 0.010 inches, then the percentage of coverage of the surface of the golf balls increases to about 87%. It is preferred in this embodiment that the fret, whether it be about 0.015 inches or about 0.010 inches, be uniform across the surface of the ball. " It will be clear to those of skill in the art that the fret area can be greater than about 0.015 inches and yet still obtain a coverage less than about 81% and greater than about 78%.

A dimple, as used in the specification and claims and as used in the golf industry, is a standard term well-known to those of skill in the art.

When referring to a dimple diameter, the term "diameter" as used herein means the diameter of a circle defined by the edges of the dimple. When the edges of a dimple, are non-circular, the diameter means the diameter of a 235783 circle which has the same area as the area defined by the edges of the dimple. When the term "depth" is used herein, it is defined as the distance from the continuation of the periphery line of the surface of the golf ball to the deepest part of a dimple which is a section of a sphere. When the dimple is not a section of a sphere, the depth is computed by taking a cross section of the dimple at its widest point. The area of the cross section is computed and then a section of a circle of equal area is substituted for the cross section. The depth is the distance from the continuation of the periphery line to the deepest part of the section of the circle.

Fret, or surface area of a golf ball not covered by dimples is calculated by the following formula. d2 - (N)(d2) 4 where: D = diameter of ball N = number of dimples d = diameter of dimple The above formula is an excellent approximation to the exact formula: D2 - N^Dh where: h = D - yj |Dj2 - |c[ j ^ >^ltlr"WlB" 111 |U.._ 23573,-J

Claims (21)

WHAT WE CLAIM IS:

1 . A golf ball having dimples on the surface thereof, said dimples being divided into at least two sets of dimples, each said set of dimples differing from another set of dimples by having a dimple diameter which is different from the dimple diameter of said another set of dimples.

2. The golf ball of claim 1 wherein said dimples cover at least 78% of the surface area of the golf ball.

3. The golf ball of claim 2 wherein the total number of dimples is about 324.

4. A golf ball with dimples of two different dimple diameters comprising one of the dimple diameters of about 0.140 inches and the second dimple diameter of about 0.150 inches. •—— .■ynr-'— ***•—J^-"a*aignfir]iH| affrii" r■ ■ <mw»»« ■"* """"""WMHSs 235783 O o

5. The golf ball of claim 4 wherein the total number of dimples is about 414.

6. A golf ball with dimples of two different dimple diameters comprising one of the dimple diameters of about 0.130 inches•and the second dimple diameter of - about 0.140 inches.

7. The golf ball of claim 6 wherein the total-number of dimples is about 484.

8. A golf ball with dimples of three different dimple diameters comprising one of the dimple diameters of about 0.130 inches, a second dimple diameter of about 0.14 0 inches and a third dimple diameter of about 0.150 inches.

9. The golf ball of claim 8 wherein the total number of dimples is about 48 4. - 30 - < 235783

10. The golf ball of claim 1 comprising 320 ddirples wherein the fret between each dimple is between about 0.015 to about 0.010 inches.

11. A golf ball having a surface with dimples arranged in a substantially icosahedron pattern thereon, said icosahedron pattern having a plurality of substantially equilateral triangles, each of said equilateral triangles having three side lines and a center area', said dimples being divided into two sets, each set of dimples having a different diameter, said dimples being arranged on said surface such that dimples selected from the first set of dimples are positioned on said three side lines of a plurality of said equilateral triangles and dimples selected from the second set of dimples are positioned in said center area of a plurality of said equilateral triangles.

12. The golf ball of claim 11 wherein the dimple diameter of one set of dimples is 0.140 inch i 0.002 inch and the dimple diameter of the other set of dimples is 0.160 inch + 0.002 inch.

13. A golf ball having a surface with dimples arranged thereon, said surface divided into two hemispherical surfaces, one said hemispherical surface having dimples arranged thereon substantially similar to the other hemispherical surface, each said hemispherical surface having dimples - 31 --.. - /■"■v.., "r- ~» ',;'r'T"ilrw-"^ - " ^vi,"L 235783 arranged in a hemi-icosahedron pattern thereon, said hemi-icosahedron pattern having a plurality of substantially equilateral triangles, each of said equilateral triangles having three sides and a center area, said dimples consisting O essentially of two sets of dimples, a first set of dimples having a small dimple diameter and a second set of dimples having a large dimple diameter as compared to said small dimple diameter, said dimples being arranged on the surface W of said golf ball such that dimples selected from said first set are positioned on each of said three sides of each of said equilateral triangles and dimples selected from said second set are positioned in each of said center areas of each of said equilateral triangles.

14. The golf ball of claim 13 wherein the small dimple diameter is 0.140 inch ± 0.002 inch and the large dimple diameter is 0.160 inch ± 0.002 inch.

O 15- * golf ball having a surface with a plurality of dimples arranged thereon, said dimples consisting essentially of two sets of dimples, a first set of dimples having a small dimple diameter and a second set of dimples having O a large dimple diameter as compared to said small dimple diameter, said dimples being arranged on said surface of said golf ball in a substantially icosahedron patte: composed of a plurality of equilateral triangles, each equilateral triangle of said icosahedron having three i. sides and a center area, said dimples being arrangiecb'o.i said surface such that dimples selected from said first - 32 - „ .... nf' *>• ... , _ +*#!** 23 5783 set are arranged on each of said three sides of each of said equilateral triangles and dimples selected from said second set are arranged in said center area of each of said equilateral triangles.

16. The golf ball of claim 15 wherein the small dimple diameter is 0.140 inch ± 0.002 inch and the large dimple diameter is 0.160 inch ± 0..002 inch.

17. A golf ball having dimples on the surface thereof, said dimples being arranged on the two hemispherical surfaces of the ball, the dimples on one of said hemispherical surfaces being arranged substantially the same as the dimples on the other of said hemispherical surfaces, the dimples on each said hemispherical surface being of at least two sets, one of said sets of dimples having a larger dimple diameter than another of said sets of dimples, imaginary lines drawn through adjacent dimples of one said set of dimples forming a plurality of substantially spherical triangles on the surface of the ball, the spherical triangles being arranged substantially in the form of a part of an icosahedron on each hemispherical surface of the ball, the dimples of a second said set of dimples^ lying wholly within the said spherical triangles foi^ by the said imaginary lines.

18. The golf ball of claim 17 wherein tjie dimpl of said second said set of dimples have a larger d'± diameter than the dimple diameter of the dimples of said one said set of dimples. - 33 - 235783

19. The golf ball of claim 17 wherein the dimple diameter of said second set of dimples is 0.160 inch ± 0.002 inch and the dimple diameter of said one set of dimples is 0.140 inch ± 0.002 inch.

20. A golf ball substantially as herein described with reference to any embodiment disclosed in the drawings and/or the examples.

21. A golf ball having dimples on the surface thereof, said dimples being arranged on the two hemispherical surfaces of the ball, the dimples on one of said hemispherical surfaces being arranged substantially the same as the dimples on the other of said hemispherical surfaces, the dimples on each said hemispherical surface being of at least two sets, one of said sets of dimples having a larger dimple diameter than another of said sets of dimples, imaginary lines drawn through adjacent dimples of one said set of dimples forming a plurality of substantially spherical triangles on the surface of the ball, the spherical triangles being arranged substantially in the form of at least a part of an icosahedron on each v hemispherical surface of the ball, the dimples of a second said set of dimples lying wholly within the said spherical triangles formed by the said imaginary lines. Jr.uM Conynntj fy foteftk# ©Hth®rlsa3 Agauto, A. I. & SOM.