TO ALL WHOM IT MY CONCERN:

Be it known that I, ROBERT P. M0LIT0R, a citizen of the United States of America, residing at South Hadley, in the County of Hampshire, and State of Massachusetts, have invented new and useful improvements in

GOLF BALL of which I declare the following to be a full, clear and exact description: This invention relates to golf balls and more especially to a golf ball of a larger diameter or size than the minimum size limit of 1.680 inches in diameter prescribed by the United States Golfers Association (USGA) specification and to structural characteristics of the ball, the ball of the invention having advantageous characteristics over the standard size ball of 1.680 inches in diameter- The USGA rules contain the following specifications: The size of the ball shall not be smaller than 1.680 inches in diameter. The weight of the ball shall not be greater than 1.620 ounces. The initial velocity shall not be greater than 250 feet per second with a + 2% allowance, making the maximum initial velocity limit of 255 feet per second. These properties established by the USGA rules effectively limit the flight distance of a golf ball. It is practically a universal opinion of those skilled in this art that the smallest ball, all other variables being equal, will go the farthest.

The manufacturers of golf balls, being of the opinion that increasing the size or diameter of a golf ball causes a loss of distance in flight, have not marketed a ball of increased size, that is, a ball greater than 1.680 inches in

diameter because they believed that such a ball would not be acceptable. For many years essentially all advertising per¬ taining to golf balls extolled the long flight distance which a particular make of ball will travel in any given set of circumstances.

The manufacturers of golf balls have believed that there is an overriding disadvantage to a larger ball, namely, that it will not travel in flight as far as a smaller ball of the same weight. Hence the trend in golf ball design of all manu- facturers of golf balls has been to construct a golf ball having a diameter or size as close to 1.680 inches as commer¬ cially feasible which will go the farthest without violating the USGA rules. The minimum size limit as specified by the United States Golfers Association (USGA) is 1.680 inches in diameter.

When the specified size of 1.680 inches is referred to herein, it is to be understood by one skilled in the art that commercially available golf balls may vary slightly relative to this size. It is recognized that commercially available golf balls may be in a size range of from 1.680 inches to 1.690 inches in diameter. It is usual for golf ball manu¬ facturers to adopt manufacturing specifications and tolerances slightly above the specified diameter of 1.680 inches to make sure that the golf balls do not fall below the specified mini- mum diameter of 1.680 inches.

This invention relates to a golf ball of a diameter appreciably greater than the diameter of the minimum standard size golf ball specified in the USGA rules.

The invention has for an object the provision of a golf ball having an outside diameter appreciably greater than 1.680 inches and which provides distinct advantages in play over the ball of standard size and which will attain distance

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in flight comparable to the flight distance of a high quality golf ball of the standard size.

Another object of the invention is the provision of a golf ball of a diameter appreciably greater than the diameter of the standard size golf ball having an increased amount of elastic or resilient material in a ball of either the molded solid center type of polymeric material or of the stretched rubber thread-wound center type and thereby attain a golf ball having increased resilience or elasticity. Another object of the invention is the provision of a golf ball of a diameter appreciably greater than the diameter of the standard size golf ball provided with a center or core structure of resilient or elastic material which may be of molded polymeric material or stretched rubber thread-would construction, the amount of resilient or elastic material being increased as compared with that in the core structure of the standard size golf ball of 1.680 inches in diameter whereby the ball on impact with a golf club has a greater distortion and surface area on the club face and which is readily capable of an initial velocity of 255 feet per second.

Another object of the invention is the provision of a golf ball of a size or diameter appreciably greater than the standard golf ball which has an increased radius of gyration promoting better control of the ball, the larger ball having significant advantages in that the ball contacted by a golf club has a superior feel, no loss of distance and improved trajectory and, by reason of its increased diameter, sets up better in the fairway, in the rough and in a sand trap than the standard size ball and putts better than the standard ball.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation

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and function of the related- elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which: In the drawings:

FIGURE 1 illustrates a comparison of the present standard size ball of 1.680 inches in diameter with the ball of in- creased size or diameter of the invention, the view being substantially twice actual size and illustrating the impact regions of each ball with a golf club face;

FIGURE 2 illustrates the golf ball of the invention with a portion of the cover broken away to show a wound center, and

FIGURE 3 is a view of the golf ball of the invention with a portion of the cover removed to show a solid elastic center structure.

Commercially acceptable golf balls at the present time have center structures of two types, viz. a stretched rubber thread-wound construction wherein the center of the ball is created by winding rubber thread around a small sphere, or the ball may have a solid center or core of molded resilient polymeric material. Golf balls having centers of either type are enclosed by covers of which may be formed from any suitable tough material or synthetic polymeric material. The first type is termed a balata cover which is made of natural balata rubber. The cover of the ball of this invention can be formed from any suitable tough polymeric material. Synthetic transpoly- isoprene is similar to natural balata rubber and may likewise be used as a cover stock material in accordance with this

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invention. The second type may comprise synthetic polymeric material marketed under the trademark Surlyn, Surlyn being a trademark owned by E. I. du Pont de Nemours for ionic poly¬ ethylene or polymeric resins. These resins are described in U. S. Patent No. 3,264,272 issued August 2, 1966. The balata cover may be used with both the rubber thread-wound center ball and the solid polymeric material center ball, but the balata material is not usually used as a cover on a center of solid polymeric material. Covers of the above-described materials are adhered to the center structures in a conventional manner. The term "adhered" as used herein relative to the bonding of the cover to the center is understood by one skilled in the art that this term encompasses the bonding of the cover to the core by means of adhesives, mechanical bonding, and welding techniques wherein a molten cover stock is fused to the core.

The golf ball of the present invention is of larger size or outside diameter than the standard golf ball, the minimum size standard golf ball according to the USGA specification being 1.680 inches. Under the present USGA rules the ball cannot be smaller than 1.680 inches in diameter but there is no restriction in the rules that prohibits the use of a golf ball of larger diameter.

FIGURE 1 illustrates on an enlarged scale a size compari- son between the minimum size golf ball of a diameter of 1.680 inches and the ball of increased size or diameter of the invention. In FIGURE 1, the standard size ball of a diameter of 1.680 inches is illustrated at 10 and the ball of the invention of increased size or diameter is indicated at 12. For purposes of illustration, FIGURE 1 includes a metal golf club head 14 with a face or surface 15 for engagement with the golf ball. The club face 15 is illustrated in contact

with the surface of the larger ball 12 of the invention and the broken line 15' illustrates the club surface or face in its contact with the smaller standard size ball 10. The golf balls illustrated in FIGURE 1 are approximately twice actual size.

The size or outside diameter of the larger ball 12 of the invention is in a range of 1.695 inches and 1.735 inches. The larger ball 12 of the invention may have one form of center structure, or the larger ball designated 12' in FIGURE 3 may have a different type of center structure. As illus¬ trated in FIGURE 2 the golf ball 12 of increased size of the invention has a stretched rubber thread-wound center 20 and a cover construction 21. The golf ball of increased size of the invention shown at 12* in FIGURE 3 has a solid center 24 of resilient material enclosed in a cover 25.

Referring to FIGURE 1, the geometric center of the stand¬ ard golf ball 10 is indicated at 28 and the radius of the standard ball is indicated at 31. The geometric center of the larger ball 12 of the invention is indicated at 36 and the radius of the larger ball is indicated at 38. The radius 38 of the larger ball 12 is longer than the radius 31 of the smaller or standard ball. The larger ball 12 of the invention therefore has a greater radius of gyration.

It is understood by one skilled in the art that the density of a golf ball is not always uniform throughout its cross section and this may be true for either a ball having a wound center or one having a solid resilient center. Regard¬ less of this fact, by reason of the increase in radius of the larger ball of the invention, the radius of gyration of the ball will be greater, assuming all other variables are con¬ stant. The increase in the radius of gyration enhances the physical properties of the golf ball as will be hereinafter explained.

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The point of contact or moment of the standard ball 10 with respect to the golf head face shown in broken lines at

15' is indicated at 34. The point of contact or moment of the larger ball 12 of the invention with respect to the golf head face 15 is indicated at 40.

In FIGURE 1, the sole 17 of the club head 14 is shown in a horizontal plane tangent to the theoretical point of con¬ tact of both the standard and increased size balls with the ground or fairway. However, the position of either of the balls with respect to the face 15 of the club head 14 may vary because the ball 12 of increased size tends to be ele¬ vated higher by the grass on the terrain of a golf course than the small diameter standard ball.

In FIGURE 2 the cover 21 for the ball 12 having a stretched rubber thread-wound center 20 may be of balata gum or it may be fashioned of an ionomer or polymeric resin mar¬ keted under the trademark Surlyn by E. I. du Pont de Nemours.

The ball of the invention as illustrated at 12' in FIGURE 3 has a resilient solid center 24 of a polymeric resin and a cover 25 of another polymeric material. This ball con¬ struction is generally referred to as a two piece construction and is known in the art.

Balls 12 and 12', as illustrated in FIGURES 2 and 3, provide for centers of additional volume. Because of the increased size of the balls, the overall surface area of the balls is increased. The USGA specifications require that the ball weight must not exceed 1.620 ounces. Because of the increased surface area, it has been found by tests that the larger ball of the invention on impact with a golf club has greater distortion and, therefore, greater area of contact between the club face and the ball cover. As a result of this additional contact, it is possible for a golfer to better

control the flight characteristics of the golf ball. This improved control results because of the greater surface con¬ tact, and an experienced golfer can impart desirable flight characteristics to the golf ball, such as fade, draw, back- spin, etc.

It was found that the greater moment or radius of gyra¬ tion developed improved play of the ball. It was also found in player tests that the larger ball had a superior feel, had no loss of distance as compared with a high grade standard ball of a diameter of 1.680 inches, that the ball had an improved trajectory and that the ball by reason of its larger diameter was elevated higher in the fairway, in the rough and in the sand trap far better than the smaller 1.680 inch size ball. Furthermore, the larger ball tends to be more accurate in play by professionals and average golfers and particularly in putting probably due to the resultant greater radius of gyration. Tests have shown that a player can exercise better control of the larger ball than with the smaller standard size ball of 1.680 inches in diameter. The ball of the inven¬ tion of a size in a range of 1.695 inches and 1.735 inches in diameter is found to have improved characteristics in play as compared with the standard ball of 1.680 inches in dia¬ meter. It is found by tests that a preferred range in size of the larger ball of the invention is between 1.700 and 1.730 inches to attain optimum characteristics of the larger ball in play. The larger ball of the invention ^' having a larger center of resilient material is capable of storing added energy and this factor increases the coefficient of restitu¬ tion and hence the velocity of the ball as well as promoting improved control of the ball in play. The best size range of

the larger ball of the invention is between 1.700 inches and 1.720 inches in diameter, a ball in this size range having been preferred by golfers in tests.

The improved characteristics and results attained by the ball of increased size were wholly unexpected and un- obvious because of the universal opinion that a larger ball produced increased air drag and would not attain the driving distance of a standard smaller size ball. It seems signifi¬ cant that manufacturers of golf balls for years have adver- tised that the main attribute for a golf ball is that it will attain the greatest driving distance in play.

While the reasons why the larger size ball has advanta¬ geous characteristics may not be fully understood, tests have proven that the larger ball attains all of the advantages hereinabove set forth and that the larger ball travels a dis¬ tance at least equal to the distance attained by the smaller size standard golf ball. All other factors being constant, it is believed that the additional elasticity provided by the larger center or core of elastic material may compensate for the possible increase in air drag which might be attributed to the larger ball in flight.

As the ball of the invention is larger than a conventional ball, it has a greater volume than a conventional ball. Since the ball of this invention is manufactured from conventional materials which are used in the manufacture of standard size balls, if all other variables are constant, the ball of this invention will inherently weigh more than a conventional standard size ball. As has been pointed out hereinabove, the weight of a golf ball is regulated by USGA specifications, such that the weight shall not be greater than 1.620 ounces.

Further, if the ball of the subject invention incorpor¬ ated a cover having a thickness identical to that of the

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conventional standard size ball, the ball of this invention would incorporate significantly greater mass on its circum¬ ference as compared to the standard size ball. It is generally felt that it is undesirable to incorporate this additional mass on the outer parameter of a golf ball. In order to alle¬ viate this problem, it has been found that the cover of the golf ball of this invention should be of a reduced thickness when compared to the cover thickness of conventional standard size balls. The cover thickness of the ball of this invention can be from .030 inches to .110 inches. A more preferred range for the cover thickness is .050 inches to .090 inches with the most preferred cover thickness being .060 inches. Further, it is recognized that minimum cover thickness is governed by not only gravity of cover material and its physical properties, but also by durability requirements.

In the manufacture of standard size golf balls of a dia¬ meter of 1.680 inches having solid centers of resilient mate¬ rial, it has been conventional practice to include an amount of inert filler in the center to bring the ball weight up to the maximum permissible weight of 1.620 ounces.

The larger size ball of this invention makes it possible to eliminate an inert filler so that the elasticity or resil¬ iency of the center can be maximized. An inert filler neces- sarily is of a dense material and has no ability to store kinetic energy when struck by a golf club. As the center of the larger golf ball of the invention has additional resilient material, the ball weight of 1.620 ounces may be attained without an inert filler. The center having the added resilient material has the ability to store more kinetic energy and the center fashioned solely of resilient material can be used in a ball of a size

or outside diameter up to about 1.740 inches without exceeding the permissible USGA weight limit of 1.620 ounces.

Another advantage of the larger ball is that the ball can be better controlled in its back spin characteristic so that the ball can be made to stop when it strikes the green instead of bounding forward. It is believed that the ability to effect back spin onto a golf ball is related to the extent to which a golf ball deforms when it is struck with a golf club and how it travels off of the club face. The larger ball of the invention has greater resiliency in the center structure by reason of the increased amount of resilient material. This improved resilient characteristic of the ball results in greater deformation of the ball when struck with a golf club providing increased area of contact of the ball with the club head surface thereby providing better control of the back spin of the ball.

It was discovered that there was less tendency for the ball to be tight or severely constricted after the cover was applied due to its larger diameter. Also the larger diameter center of resilient material apparently yields less reinforce¬ ment of the cover to the center under high speed impact with the golf club so that the distortion properties of the larger ball are greater than they are with the smaller standard size ball without any sacrifice of compression or initial velocity. It is apparent that, within the scope of the invention, modifications and different arrangements may be made other than as herein disclosed, and the present disclosure is il¬ lustrative merely, the invention comprehending all variations thereof.