JP4017740B2 - Three-piece thread wound golf ball - Google Patents

Description

【００１４】
今日通常市場で入手できるスリーピース固体コア糸巻きゴルフボールの場合に比べて、本ボールコアの直径はかなり大きく又コア比重はかなり低い。従ってボール固体コア直径又は体積のこのボールの比重に対する比率は他の公知のボールの場合に比べてかなり大きい。とくにインチで表したボール直径ではこの比率は、０．９／１ないし１．３０／１の広い範囲、なるべくは１．０／１ないし１．２５／１の範囲になければならない。大きい方の固体コア直径とその低い方の比重とは、糸巻き中間層の糸の種類及び外側固体カバーの材料及び厚さと協働して、ボール重量及び慣性モーメントの周辺部分に向かうかなり望ましい転移を生ずる。従って本ゴルフボールでは全慣性モーメントの望ましい増加が得られて、他の公知のゴルフボールに比べて種種のゴルフクラブで打った後、ゴルフボールの初期相対スピン速度が対応して増加するようになる。
【００１５】
本発明によれば１．３５ないし１．５０インチ（３４．３ないし３８．１ｍｍ）の直径を持つボール固体中央コア部分は、１．５４０ないし１．６００インチ（３９．１ないし４０．６ｍｍ）の直径に、なるべくは１．５６０ないし１．５８０インチ（３９．６ないし、４０．１ｍｍ）の直径に糸巻きする。巻付け糸は、糸巻き中間部分を形成するのに使う高速エラストマー質糸材料である。糸巻き材料は、約８００ないし１０００％の伸びと、約４０００ないし５０００ｐｓｉの引張強さと、０．０６２５（＋／−０．００２）インチ×０．０２４（＋／−０．００６）インチの長方形横断面寸法法とを持つ配合の天然ゴム及び合成ゴムから成る。ボールカバーの層又は部分は、１．００ないし１．０４ｇ／ｃｍ³ の密度と、５，０００ないし１０，０００ｐｓｉの曲げ係数と、５５ないし６５のシヨアＤデュロメータ硬さとを持つ固体熱可塑性材料から成る。カバー部分の表面はボール表面積の７０ないし８０％を占める多くの小さく浅いデインプルを持つ。これ等のデインプルは４００ないし５００ｍｍ³ の全容積を持つ。仕上がりのゴルフボールは、１．６８０ないし１．６８８インチ（４２．７ないし４２．９ｍｍ）の外径と、４４．５ないし４５．９ｇの重量と、１．０９０ないし１．１１３ｇ／ｃｍ³ の密度と、８５＋／−１５ポイントのアツテイ圧縮読みとを持つ。
【００１６】
ゴルフボールカバー部分に対する有用な材料配合物は、２５＋／−５重量％のナトリウムイオノマー［デュポンサーリン（Ｄｕｐｏｎｔ Ｓｕｒｌｙｎ）８１４０］と、６９＋／−５重量％の亜鉛イオノマー（デュポンサーリン９３２０）と、６重量％のナトリウムイオノマー（デュポンサーリン８６６０）とを５８重量％の二酸化チタンと共に含む。ボールカバーに対する他の有用な配合物は、５０＋／−５重量％のナトリウムイオノマー（デュポンサーリン８１４０）と、４４＋／−５重量％の亜鉛イオノマー（デュポンサーリン９３２０）と、６重量％のナトリウムイオノマー（デュポンサーリン８６６０）とを５８重量％の二酸化チタンと共に含む。
【００１７】
本発明によれば、増大したコア直径及び減少した比重を持つ固体中心コアとエラストマー質糸巻き中間部分とを備えることにより選定したゴルフクラブにより打った後飛翔中のボールに望ましい増大した慣性モーメント及びスピン特性の得られるスリーピース糸巻きゴルフボールが得られ有利である。このようにして本ボールは広い範囲のプレイ条件のもとで使う各特性の望ましい全組合わせを生ずる。
【００１８】
本発明の他の利点は、スリーピースゴルフボールが通常わずかに約１．０ないし１．０６インチの直径を持つ小さい直径の中心部を持つように作られることであり、本ボールは典型的には飛びの大きいゴムボール又は流体充てん中空球体である。ゴルフボールの製造中にこれらの中心部は凍結しなければならなくて設定した直径になるようにこの中心部にかなりの量の糸を巻付けなければならない。しかし本発明ではボール製造費は、中心部を凍結させるのに使う媒体の費用により低減される。さらに中心部は直径が比較的大きいから、中心コアに当てがう巻き糸の量及び費用とこの中心部を設定寸法に糸巻きするのに必要な時間とは、共に低減させることが望ましい。
【００１９】
以下本発明を添付図面について詳しく説明する。
【００２０】
【実施例】
図１に示すように従来のツーピースゴルフボール１０は、固体のコア１１及び外側成形カバー１２を備えるが中間の層又は部分は設けていない。従来のスリーピースゴルフボール１４は図２に示すように液体コア中心部１５，糸巻き中間層１６及び外側成形カバー１８を備えている。
【００２１】
本発明は図３に横断面で示すように改良されたスリーピース糸巻きゴルフボール２０にある。スリーピース糸巻きゴルフボール２０は、実質的にポリブタジエン材料から形成され１．３５ないし１．５０インチ（３４．３ないし３８．１ｍｍ）の増大した直径を持つ個体の中心コア部分２２を備えている。好適とするコア直径は１．４００ないし１．４５０インチ（３５．６ないし３６．８ｍｍ）である。コア部分２２は、ボールの外面を覆う多数の浅いデインプル２８を設けた外側の個体カバー２６により囲んだ中間の糸巻き部分２４により囲んである。
【００２２】
内部のコア部分２２の重要な特性は、このコア部分が現在知られている、スリーピース糸巻きゴルフボールに対し設けたコア部分よりかなり大きい直径及びかなり小さい比重を持つことである。コア部分２２の比較的大きい直径及び比較的小さい比重は、中間部分２４に使われる巻き糸の直径及び種類と外側カバー２６の材料と共に、ゴルフボールの重量をその周辺に向かい外方にかなり比例的に転移させるようになる。その結果スリーピース糸巻きゴルフボール２０の慣性モーメントが増大し、従って特定のゴルフクラブで打った後スリーピース糸巻きゴルフボール２０の初期スピン速度が増大する。本発明スリーピース糸巻きゴルフボールの構造によりボールスピン及び軌道距離の制御が他の公知のゴルフボールにより得られるよりも一層高度にできる。本ボールの増大したコア直径及び減小した比重は、中間巻糸層及びカバーの寸法及び材料と共に使用するときに著しい重要性を持つ。
【００２３】
図３に示すように本発明のスリーピース糸巻きゴルフボールの外側部分は、配合した天然ゴム及び合成ゴムに対して高速形（ｈｉｇｈ ｖｅｌｏｃｉｔｙ ｔｙｐｅ）エラストマー糸材料を緊密に巻いた中間部分２４と、バラタ（Ｂａｌａｔａ）カバー材料の特性を示す外側カバー２６とを備える。使用巻き糸材料により、クラブで打った後の初期ボール速度が増大する。ボールカバーは、１．００ないし１．０４ｇ／ｃｍ³ の密度を持つ熱可塑性材料から形成され多くの浅いデインプルを持ち、従来のツーピース多層ボール及びバラタスリーピース糸巻きボールの場合と同様な軌道距離にわたり飛翔制御作用を加えることができる。
【００２４】
ボール中心コア部分の直径が増大し比重が低減しているので、本発明ゴルフボールは１番ウッドドライバー及び３番、６番及び９番アイアンのクラブを含む種種のゴルフクラブで打ったときに、向上したスピン特性が得られる。とくに比較的番数の高いクラブによりたとえば３番アイアン、６番アイアン及び９番アイアンのクラブにより打った後にｒｐｍで表わした初期ボールスピン速度は、１番ドライバークラブで打った後のボール初期スピン速度を次の表２に表記したような最低初期スピン速度比だけ越える。
【００２５】
【表２】

【００２６】
向上したボールスピン特性の結果として、本発明の中実のスリーピース固体コアゴルフボールは又、他の公知の同等のゴルフボールの距離に少なくとも等しいか又この距離を越える飛翔弾道距離を生ずる。
【００２７】
さらに本発明をその範囲を限定するわけではない次の例により説明する。
【００２８】
例１
次のような材料、寸法及び特性を持つスリーピース個体コア糸巻きゴルフボールを構成した。
コア材料 ポリブダジエン
コア直径インチ １．４００（３５．６ｍｍ）
コア比重 １．２３６
コア直径／比重比率 １．１３／１
中間巻き糸材料 天然及び合成ゴム
糸横断面寸法、インチ ０．０６２×０．０２４
中間層直径、インチ １．５５０（３９．４ｍｍ）
中間厚さ、インチ ０．０７５（１．９０ｍｍ）
カバー材料 イオノマー
カバー厚さ、インチ ０．６５（１．６５ｍｍ）
ボール直径、インチ １．６８０
【００２９】
公知のゴルフボールに比べた本発明ゴルフボールに対する比較ボールスピン試験成績がトルーテンパー（Ｔｒｕｅ Ｔｅｍｐｅｒ）製ロボットを使って得られたが下記の表３に表記され又図４の線図により示してある。
【００３０】
【表３】

【００３１】
表３及び図４のこのゴルフボール比較スピン速度データに基づいて、本発明により構成した２個のゴルフボールは公知のスリーピースバラタゴルフボールの場合に対し実質的に等しいか又は一層良好なスピン成績を生ずるのは明らかである。なおとくに表３及び図４に明らかなようにｒｐｍで表わしたボール初期スピン速度は、改良されたスリーピース糸巻きゴルフボールのボール構造がドライバー及びロングアイアンで打ったときのツーピースデイスタンスゴルフゴールに極めて類似して又ミッドアイアンクラブで打ったときはツーピースハイスピンゴルフボールに類似してそれぞれスピンを生じ、そしてショートアイアンクラブで打ったときはボールはバラタ糸巻きゴルフボールに極めて類似した性能を生ずる。
【００３２】
ドライバー、５番アイアンクラブ及び９番アイアンクラブにより打った後他の公知のボールに比べて本発明ゴルフボールの全飛翔距離に対する比較試験成績は次の表４に示してある。
【００３３】
【表４】

【００３４】
表４の前記の比較ボール飛翔距離成績から明らかなように、本発明ゴルフボールはバラタカバー付きボールの好ましい飛翔特性と又ツーピース多重層ゴルフボールの飛翔特性とを持つ。前記したような要素の組合せにより、バラタカバー付きボールの費用及び耐久性不足を解決してバラタカバー付きボールの望ましい性質に少なくとも類似しさらに向上もしているゴルフボールが得られる。
【００３５】
以上本発明のスリーピース糸巻きゴルフボールを一般的に又その好適な実施例について説明したが本ボールの各部分についてなお種種の変化変型を行うことができるのはもちろんである。
【図面の簡単な説明】
【図１】従来のツーピースハイスピンゴルフボールの横断面である。
【図２】液体心を持つ従来のスリーピースゴルフボールの横断面図である。
【図３】それぞれ本発明により構成した比較的大きい固体中心コアと糸巻き中間層とを持つ改良されたスリーピースゴルフボールの横断面図である。
【図４】種種の番数の標準ゴルフクラブにより打った後のゴルフボール比較初期スピン速度を示す線図である。
【符号の説明】
２０ ゴルフボール
２２ コア部分
２４ 中間糸巻き部分
２６ カバー部分
２８ デインプル[0001]
[Industrial application fields]
The present invention relates to an improved three-piece wound golf ball structure comprising a solid central core, an intermediate wound layer and an outer cover piece. In particular, the present invention provides a relatively large core diameter and reduced specific gravity to provide increased moment of inertia and spin rate and improved trajectory distance after hitting by any of a variety of golf clubs. The present invention relates to a thread wound golf ball as described above.
[0002]
[Prior art]
Conventionally known golf balls have a two-piece structure consisting of a central core and an outer cover having a number of dimples formed on the outer surface, or a cover with a central core and a solid or elastomeric wound intermediate portion and a solid dimple. And a three-piece structure. The core is usually made from natural or synthetic rubber and has a solid or liquid / paste form. The cover material is usually a balata or ionomer that cooperates with a suitable filler material. Due to changes in the chemical or physical properties of the ball material or the physical orientation of these materials, the feel, flight distance, rebound, as described in various prior patent specifications. Changes are made in golf ball properties such as bound coefficient, durability, moment of inertia, spin, and the like.
[0003]
For example, U.S. Pat. No. 4,076,255, invented by Moore et al., Describes polybutadiene having a high cis content and an elastomer graphed, crosslinked or chain extended (chain). A three-piece golf ball having a solid core formed of a cured composition comprising a monomer capable of being extended. A core having a Shore C hardness of 60 to 80 covers a normal elastic yarn with a wrapping cover, but the core diameter is not shown.
[0004]
U.S. Pat. No. 4,625,964, invented by Yamada, has a core made of polybutadiene having a specific gravity of at least 1.50 and a diameter not exceeding 32 mm (1.26 inches). Three-piece solid golf balls are described. The ball intermediate layer has a specific gravity less than the specific gravity of the core and a thickness of 3.2 to 5.4 mm, and the cover has a thickness of 1 to 3 mm and a Shore D hardness not exceeding 64.
[0005]
U.S. Pat. No. 4,696,475, invented by Tomita et al., Describes a three-piece wound golf ball with improved resilience and increased flight distance. The core rubber and / or wound yarn has a core diameter of 28-30 mm (1.10 to 1.18 inches), including 30% by weight or more of an isoprene-butadiene copolymer.
[0006]
U.S. Pat. No. 4,714,253, invented by Nakahara et al., Describes a three-piece solid golf ball in which the diameter, specific gravity and hardness of the central core and intermediate solid layer are controlled. is there. The central core has a diameter of 20 to 32 mm (0.79 to 1.26 inches), a specific gravity of 1.03 to 1.25, and a Shore C hardness of 57 to 80. The solid intermediate layer has a diameter of 36 to 40 mm, a specific gravity of 1.30 to 2.50 and a Shore C hardness of 70 to 83, but this intermediate layer is not wound with a thread.
[0007]
US Pat. No. 5,397,129, invented by Kato et al., Describes a three-piece with a solid rubber core having a diameter of 23 to 34 mm (0.91 to 1.34 inches). A thread wound golf ball is described. Various types of rubber are used for the core, intermediate winding and molded cover. This material includes butadiene rubber and natural rubber.
[0008]
U.S. Pat. No. 5,445,387, whose inventor is Maruko et al., Discloses a three-piece wound golf ball having a solid core made of high cis polybutadiene, an ordinary wound intermediate rubber layer and a cover. Is described. The core hardness increases continuously from the center to the outer surface. The solid core diameter is 26 to 31 mm (1.02 to 1.22 inches), the intermediate layer diameter is 39 to 41 mm, and the ball diameter is 42.5 to 45 mm (1.67 to 1.77 inches). It is.
[0009]
U.S. Pat. No. 5,553,852, invented by Higuchi et al., Has a diameter of 29 to 37 mm (1.14 to 1.46 inches) and a JISC hardness of 45 to 80. A solid core with a specific core of 1.05 to 1.4 but a thickness of 1 to 3.5 mm (0.039 to 0.138 inches) and a specific gravity of 0.9 to 1.2 Three-piece solid golf balls larger than the intermediate layer are described. The cover is 1 to 3 mm (0.039 to 0.118 inches) thick and softer than the intermediate layer.
[0010]
Although golf balls with various structures and properties are known, it has been recognized by players that there are significant drawbacks to the structure and flight properties of known golf balls. In particular, the two-piece golf ball has a much inferior control system required when a shot is made with a middle iron or short iron club. Furthermore, the two-piece golf ball has a much lower shot feel to the player. Known three-piece balata golf balls exhibit a spin rate that is too high for good flight distances when hit with a driver and long iron club. That is, there is a need for desirable improvements in golf ball structure and spin characteristics, all obtained at reduced ball manufacturing costs.
[0011]
DISCLOSURE OF THE INVENTION
The present invention provides an improved solid three-piece golf ball structure having a desired combination of properties and exhibiting various desirable advantageous flight characteristics according to the type of golf club that hits the golf ball. Particularly when the golf ball of the present invention is hit with a driver, other wood clubs or relatively long iron clubs, it is desirable that the ball has a performance very similar to that of a distance two-piece golf ball. The ball is very similar to two-piece high-spin golf balls and multi-layer balls with a soft cover, and when hit with a short iron or putter, the ball is very similar to a three-piece liquid core balata wound golf ball.
[0012]
These desired flight characteristics of the spherical three-piece wound golf ball of the present invention are obtained by providing a ball with a central solid homogeneous core. The core is substantially spherical and has a significantly increased diameter of 1.350 to 1.500 inches (34.3 to 38.1 mm), preferably 1.400 to 1.450 inches (35.6 to 36). .8 mm) core diameter. This solid core consists mainly of polybutadiene with some desirable additives, a specific gravity of 1.20 to 1.25, a Shore D durometer hardness of 55 to 75, and a 59 to 75 on an Atitia compression tester. Compression state (compression). A wide suitable range suitable for the chemical composition of this golf ball core is shown in Table 1 below.
[0013]
[Table 1]

[0014]
Compared to the three-piece solid core wound golf balls currently available on the market today, the ball core has a much larger diameter and a lower core specific gravity. Therefore, the ratio of the ball solid core diameter or volume to the specific gravity of this ball is much greater than that of other known balls. Especially for ball diameters expressed in inches, this ratio must be in a wide range of 0.9 / 1 to 1.30 / 1, preferably in the range of 1.0 / 1 to 1.25 / 1. The larger solid core diameter and its lower specific gravity, in combination with the thread type of the wound intermediate layer and the material and thickness of the outer solid cover, provide a fairly desirable transition toward the ball weight and moment of inertia toward the periphery. Arise. Thus, the present golf ball provides a desirable increase in total moment of inertia, and after hitting with various golf clubs, the initial relative spin speed of the golf ball is correspondingly increased compared to other known golf balls. .
[0015]
According to the present invention, a ball solid central core portion having a diameter of 1.35 to 1.50 inches (34.3 to 38.1 mm) is 1.540 to 1.600 inches (39.1 to 40.6 mm). Is preferably wound to a diameter of 1.560 to 1.580 inches (39.6 to 40.1 mm). Winding yarn is a high speed elastomeric yarn material used to form a spool intermediate portion. The spool material has an elongation of about 800 to 1000%, a tensile strength of about 4000 to 5000 psi, and a rectangular crossing of 0.0625 (+/− 0.002) inches × 0.024 (+/− 0.006) inches. It consists of natural rubber and synthetic rubber compounded with the surface dimension method. The layer or portion of the ball cover is made of a solid thermoplastic material having a density of 1.00 to 1.04 g / cm ³ , a flexural modulus of 5,000 to 10,000 psi, and a Shore D durometer hardness of 55 to 65. Become. The surface of the cover portion has many small shallow dimples that occupy 70-80% of the ball surface area. These dimples have a total volume of 400 to 500 mm ³ . The finished golf ball has an outer diameter of 1.680 to 1.688 inches (42.7 to 42.9 mm), a weight of 44.5 to 45.9 g, and 1.090 to 1.113 g / cm ³ . It has a density and an 85 +/- 15 point hot compression reading.
[0016]
Useful material formulations for golf ball cover parts include 25 +/- 5 wt% sodium ionomer [Dupont Surlyn 8140], 69 +/- 5 wt% zinc ionomer (DuPont Surrin 9320), 6 wt%. % Sodium ionomer (DuPont Surin 8660) with 58% by weight titanium dioxide. Other useful formulations for ball covers include 50 +/− 5 wt% sodium ionomer (DuPont Surin 8140), 44 +/− 5 wt% zinc ionomer (DuPont Surrin 9320), and 6 wt% sodium ionomer ( Dupont Surlyn 8660) with 58% by weight titanium dioxide.
[0017]
In accordance with the present invention, an increased moment of inertia and spin desired for a ball in flight after being hit by a golf club selected by providing a solid central core with increased core diameter and reduced specific gravity and an elastomeric spool intermediate portion. A three-piece thread-wound golf ball having characteristics can be advantageously obtained. In this way, the ball produces the desired total combination of properties for use under a wide range of play conditions.
[0018]
Another advantage of the present invention is that three-piece golf balls are typically made to have a small diameter center with a diameter of only about 1.0 to 1.06 inches, It is a rubber ball or a fluid-filled hollow sphere with large flying. During golf ball manufacture, these centers must be frozen and a significant amount of yarn must be wrapped around them to achieve a set diameter. However, in the present invention, ball manufacturing costs are reduced by the cost of the media used to freeze the center. In addition, since the central portion is relatively large in diameter, it is desirable to reduce both the amount and cost of winding thread applied to the central core and the time required to wind the central portion to a set size.
[0019]
The present invention will now be described in detail with reference to the accompanying drawings.
[0020]
【Example】
As shown in FIG. 1, a conventional two-piece golf ball 10 includes a solid core 11 and an outer molded cover 12, but no intermediate layer or portion. As shown in FIG. 2, the conventional three-piece golf ball 14 includes a liquid core central portion 15, a thread winding intermediate layer 16, and an outer molded cover 18.
[0021]
The present invention resides in an improved three-piece wound golf ball 20 as shown in cross section in FIG. The three-piece wound golf ball 20 includes a solid central core portion 22 formed substantially of a polybutadiene material and having an increased diameter of 1.35 to 1.50 inches (34.3 to 38.1 mm). The preferred core diameter is 1.400 to 1.450 inches (35.6 to 36.8 mm). The core portion 22 is surrounded by an intermediate bobbin portion 24 surrounded by an outer solid cover 26 provided with a number of shallow dimples 28 covering the outer surface of the ball.
[0022]
An important characteristic of the inner core portion 22 is that it has a much larger diameter and a much lower specific gravity than the core portion provided for the three-piece wound golf balls currently known. The relatively large diameter and relatively small specific gravity of the core portion 22, along with the diameter and type of thread used for the intermediate portion 24 and the material of the outer cover 26, are fairly proportional to the weight of the golf ball toward its periphery and outward. To be transferred to. As a result, the moment of inertia of the three-piece thread-wound golf ball 20 increases, and therefore the initial spin speed of the three-piece thread-wound golf ball 20 increases after hitting with a specific golf club. The structure of the three-piece thread-wound golf ball of the present invention makes it possible to control the ball spin and the orbital distance to a higher degree than that obtained by other known golf balls. The increased core diameter and reduced specific gravity of the ball are of significant importance when used with the intermediate wound layer and cover dimensions and materials.
[0023]
As shown in FIG. 3, the outer portion of the three-piece thread-wound golf ball of the present invention includes an intermediate portion 24 in which high-velocity type elastomer yarn material is tightly wound on the blended natural rubber and synthetic rubber, Balata) and an outer cover 26 that exhibits the properties of the cover material. The wound material used increases the initial ball speed after hitting with a club. The ball cover is formed from a thermoplastic material with a density of 1.00 to 1.04 g / cm ³ and has many shallow dimples, flying over the same orbital distance as conventional two-piece multilayer balls and ballast three-piece wound balls. Control action can be added.
[0024]
Since the diameter of the ball core portion is increased and the specific gravity is reduced, the golf ball of the present invention is hit with various golf clubs including No. 1 wood driver and No. 3, 6 and 9 iron clubs. Improved spin characteristics can be obtained. In particular, the initial ball spin speed expressed in rpm after hitting with a club of relatively high number, for example, a club of 3 iron, 6 iron and 9 iron, is the initial spin speed of the ball after hitting with the 1st driver club. Exceeds the minimum initial spin rate ratio as shown in Table 2 below.
[0025]
[Table 2]

[0026]
As a result of the improved ball spin characteristics, the solid three-piece solid core golf ball of the present invention also produces a flight ballistic distance that is at least equal to or greater than the distance of other known equivalent golf balls.
[0027]
The invention is further illustrated by the following examples which are not intended to limit the scope thereof.
[0028]
Example 1
A three-piece individual core wound golf ball having the following materials, dimensions, and characteristics was constructed.
Core material Polybudadiene core diameter inch 1.400 (35.6mm)
Core specific gravity 1.236
Core diameter / specific gravity ratio 1.13 / 1
Intermediate Winding Material Natural and Synthetic Rubber Yarn Cross Section Dimensions, Inches 0.062 x 0.024
Intermediate layer diameter, inch 1.550 (39.4 mm)
Intermediate thickness, inch 0.075 (1.90 mm)
Cover material Ionomer cover thickness, inch 0.65 (1.65 mm)
Ball diameter, inches 1.680
[0029]
Comparative ball spin test results for the golf balls of the present invention compared to known golf balls were obtained using a True Temper robot and are listed in Table 3 below and also shown in the diagram of FIG. .
[0030]
[Table 3]

[0031]
Based on this golf ball comparative spin speed data in Table 3 and FIG. 4, the two golf balls constructed in accordance with the present invention have substantially the same or better spin performance than the known three-piece balata golf balls. It is clear that this will occur. In particular, as shown in Table 3 and FIG. 4, the initial spin speed expressed in rpm is very similar to the two-piece distance golf goal when the ball structure of the improved three-piece wound golf ball is hit with a driver and a long iron. Also, when hit with a mid-iron club, each spins similar to a two-piece high spin golf ball, and when hit with a short iron club, the ball performs very similar to a balata wound golf ball.
[0032]
Table 4 below shows the comparative test results for the total flight distance of the golf ball of the present invention compared to other known balls after being hit by a driver, No. 5 iron club and No. 9 iron club.
[0033]
[Table 4]

[0034]
As is apparent from the comparative ball flight distance results in Table 4, the golf ball of the present invention has the preferable flight characteristics of the ball with a balata cover and the flight characteristics of a two-piece multilayer golf ball. The combination of the elements described above provides a golf ball that solves the cost and durability deficiencies of a ball with a balata cover and is at least similar to and further improved with the desirable properties of a ball with a balata cover.
[0035]
Although the three-piece thread-wound golf ball of the present invention has been described in general and preferred embodiments thereof, it is a matter of course that various changes and modifications can be made to each part of the ball.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a conventional two-piece high-spin golf ball.
FIG. 2 is a cross-sectional view of a conventional three-piece golf ball having a liquid core.
FIG. 3 is a cross-sectional view of an improved three-piece golf ball, each having a relatively large solid central core and a wound intermediate layer constructed in accordance with the present invention.
FIG. 4 is a diagram showing a golf ball comparative initial spin rate after hitting with a standard golf club of various numbers.
[Explanation of symbols]
20 golf ball 22 core portion 24 intermediate thread winding portion 26 cover portion 28 dimple

Claims (2)

1.35 to 1.50 inches (34.3 to 38.1 mm) core diameter, 1.23 to 1.24 specific gravity, 55 to 75 Shore D durometer hardness, 59 to 59 on an Atte compression tester A substantially spherical solid central core portion predominantly composed of polybutadiene having a compressed state of 75;
800 to 1000% elongation, 4000 to 5000 psi ( 27.5 MPa to 34.4 MPa ) tensile strength, 0.0625 (+/− 0.002) inches ( 1.58 mm +/− 0.5 mm) × 0. An elastomeric yarn material having a rectangular cross-sectional shape of 024 (+/− 0.006) inches (0.60 mm +/− 0.15 mm) is placed on the solid central core portion from 1.540 to 1.600 inches ( 39.1 to 40.6 mm) an intermediate bobbin portion wound around a diameter;
Thermoplastic material having a density of 1.00 to 1.04 g / cm ³ , a bending modulus of 5,000 to 10,000 psi (27.5 MPa to 68.9 MPa) , and a Shore D durometer hardness of 55 to 65 And a cover portion provided with a number of dimples having a total volume of 400 to 500 mm ³ occupying 70 to 80% of the ball surface area,
The golf ball has an outer diameter of 1.680 to 1.688 inches (42.7 to 42.9 mm), a weight of 44.5 to 45.9 grams, and a density of 1.090 to 1.118 g / cm ³ . And a three-piece wound golf ball comprising an 85 +/− 15 point compressed compression reading. 1.40 to 1.45 inches (35.6 to 36.8 mm) core diameter, 1.23 to 1.24 specific gravity, 55 to 75 Shore D durometer hardness, 59 to 59 on an Atte compression tester A substantially spherical solid central core portion predominantly made of polybutadiene having a compression state of 75, wherein the ratio of core diameter expressed in inches ( centimeters) to core specific gravity is 0.9 / 1 (2.29 / 1) to 1.3 / 1 (3.30 / 1) solid central core portion;
800 to 1000% elongation, 4000 to 5000 psi ( 27.5 MPa to 34.4 MPa ) tensile strength, 0.0625 (+/− 0.002) inches ( 1.58 mm +/− 0.5 mm) × 0. An elastomeric yarn having a rectangular cross-sectional shape of 024 (+/− 0.006) inches (0.60 mm +/− 0.15 mm) is 1.560 to 1.580 inches (39) on the solid central core portion. Intermediate thread wound around a diameter of .6 to 40.1 mm),
Formed from a thermoplastic material having a density of 1.00 to 1.04 g / cm ³ , a flexural modulus of 5,000 to 10,000 psi (27.5 MPa to 68.9 MPa) and a Shore D durometer hardness of 55 to 65 A cover portion provided with a number of dimples, which occupies 70 to 80% of the ball surface area and has a total volume of 400 to 500 mm ³ ;
The golf ball has an outer diameter of 1.680 to 1.688 inches (42.7 to 42.9 mm), a weight of 44.5 to 45.9 grams, and a density of 1.090 to 1.118 g / cm ³ . , 85 +/− 1.5 point hot compressed golf ball.

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