A golf ball of this nature is known from US-A-4,878,674.

The golf ball described in this document comprises a solid spherical body made from a translucent material in which a diametrically extending continuous hole is formed. A light stick containing chemiluminescent material can be arranged in the hole. The light stick has two chambers which are separated from one another by a partition and contain chemical components of the chemiluminescent material. The light stick has to be activated before it is fitted. It is activated by bending the light stick manually until the partition breaks, after which the components can mix with one another. This results in a chemical reaction during which light is emitted, which then shines out through the golf ball.

A drawback of this known light-emitting golf ball is that it is difficult to use. Positioning the light stick in the hole after activation causes problems. The light stick is small and flexible and, moreover, has to find a frictional fit in the recess. After the light stick has been fitted, it still has to be centred in the hole, for example with the aid of a golf tee. The light sticks are stored separately from the golf ball, and consequently there is a risk of the sticks breaking prematurely.

The properties of the golf ball are not ideal. The golf ball is unstable owing to the lack of symmetry and the fact that the outer casing is not closed. During use, the light stick can slide out of the hole if the golf ball is hit very hard.

The object of the present invention is to overcome the above drawbacks and, in particular, to provide a light-emitting golf ball which is simple to activate and has good properties when hit and during flight, which golf ball can be used even for official competitions.

According to the invention, this object is achieved by means of a light-emitting golf ball according to claim 1. The golf ball comprises a spherical body which is provided with a

cavity in the centre. The cavity is divided into compartments which are separated and sealed from one another by a partition element. The compartments contain chemical components of a chemiluminescent material. The partition element is of frangible design. According to the invention, the light-emitting agents are activated by an impact load which is exerted on the outer casing. The impact load causes the partition element which is arranged in the cavity of the body to break open. As a result, the components come into open communication with one another, and the components of the chemiluminescent material can mix and emit light. The result is a golf ball with light-emitting means which are accommodated in the core and are automatically activated by a first impact load exerted on the outer casing of the golf ball. This impact load is derived, for example, from the ball being hit with a golf club. After the chemical reaction has finished, the golf ball can continue to be used as a conventional golf ball. The golf ball may be of symmetrical design with a preferably closed outer casing. Consequently, it is possible to give the golf ball properties when hit and in flight which are desired of conventional golf balls. In particular, the golf ball is designed in such a manner that it complies with the requirements of the United States Golf Association.

Advantageously, the partition element is designed in such a manner that an impact load of at least 300 N, and more particularly of 1000 N, has to be exerted on the outer casing before the partition element breaks. An impact load of this nature occurs in particular when the golf ball is driven, and can also be achieved by throwing the golf ball forcibly onto hard ground. This lower limit for breaking the partition element ensures that the light means are not inadvertently activated prematurely, for example during transport.

Preferred embodiments of the invention are defined in the subclaims.

The invention will be explained in more detail with reference to the appended drawing, in which: Fig. 1 shows a perspective view, in exploded form, of a first embodiment of a golf ball according to the invention, without outer shell;

Fig. 2 shows a cross-sectional view of the golf ball from Fig. 1, with outer shell; Fig. 3 shows a view corresponding to Fig. 2, with the golf ball in a first state of deformation; Fig. 4 shows a view in accordance with Fig. 2, with the golf ball in a second state of deformation; Fig. 5 shows a diagrammatic, perspective view of a second embodiment of a golf ball according to the invention; Fig. 6 shows a perspective view, in exploded form, of the golf ball from Fig. 5; Fig. 7 shows a cross-sectional view of the golf ball from Fig. 6; Fig. 8 shows a view in accordance with Fig. 7, with the golf ball in a first state of deformation; Fig. 9 shows a view in accordance with Fig. 7, with the golf ball in a second state of deformation; Fig. 10 shows a diagrammatic, perspective view of a third embodiment of a golf ball according to the invention; Fig. 11 shows a perspective view, in exploded form of the golf ball from Fig. 10; and Fig. 12 shows a cross-sectional view of the golf ball from Fig. 10.

The golf ball in Figs. 1 and 2 comprises a spherical body made from a transparent plastic material. The spherical body is substantially composed of a flexible core body 1 which is surrounded by a relatively hard outer shell 2. The core body is made, for example, from a transparent polyurethane. The outer shell 2 is made, for example, from transparent ionomer resin, such as SurlynTM. As can be seen clearly from Fig. 1, the core body 1 is composed of two shell halves la, lb. The shell halves la, lb are provided with complementary projections and recesses for joining the shell halves la, lb securely together in combination with a suitable adhesive. The core body 1 is provided with a cavity 3 which is closed on the outside, each shell half la, lb comprising a cavity part 3a, 3b. The cavity preferably is shaped symmetrical around the mass centre of the golf ball, and is constructed for example spherical, tetrahedrical or ortahedronic. In the cavity 3, there is a partition 5 which divides the cavity 3 into two compartments 6a,

6b which are separated from one another. The two compartments 6a, 6b each contain one chemical component of a chemiluminescent material. The partition 5 is designed in the form of a disc and bears in a sealed manner against the wall of the cavity 3 all the way around. The partition 5 is of fragile design and breaks if a specific impact load is exerted on the relatively hard outer shell 2. For this purpose, the partition 5 consists, for example, of thin and/or weakened glass or plastic.

Fig. 3 diagrammatically depicts the situation in which the golf ball is being driven off a golf tee 10 by a golf club 11. The impact force which is exerted on the outer shell 2 by the golf club 11 deforms the outer shell 2, and consequently also the core body 1. Since the partition 5 is connected to the spherical body, and more particularly is accommodated in a manner sealed all the way around in a groove in the wall of the cavity 3, the deformation of the core body 1 subsequently ensures that the partition 5 is also deformed (Fig. 3) and is broken into small pieces (Fig. 4). The golf ball then returns to its original round shape. After the partition wall 5 has broken, the two compartments 6a, 6b are in open communication with one another and the two chemical components can mix. This mixing causes a chemical reaction during which light is emitted. The light emitted will shine through the transparent core body 1 and the transparent outer shell 2 and will illuminate the golf ball.

Consequently, the golf ball according to the invention is particularly suitable for completing a round on a golf course which has been begun once dusk begins to fall. This is particularly advantageous since a round on a golf course lasts about four hours. Therefore, there is a high risk, particularly in the autumn or the winter, that dusk will fall during a round.

By using the golf ball according to the invention, the ball remains visible and the round can be completed. The golf ball can also be used to play a round entirely in the dark, for example during a night tournament.

The partition 5 is preferably of fragile design in such a way that a minimum external impact load of 300 N, and more particularly of 1000 N, is required in order to break the partition 5. This can be achieved by suitably selecting the material, the thickness and whether or not to form weakened

sections in the partition. In addition to hitting the ball with a golf club 11, the minimum impact load required can also be achieved by throwing the golf ball forcibly against the hard ground or against a wall.

The thickness of the outer shell 2 is, for example, 1- 3 mm. The diameter of the core body 1 is, for example, 36-41 mm.

The diameter of the cavity 3 is, for example, 10-20 mm.

A possible method for producing the golf ball illustrated in Figs. 1-4 comprises the following steps: -the cavity part 3a in the first shell half la is filled with the first chemical component; -the filled cavity part 3a is covered with the partition 5; -the cavity part 3b in the second shell half lb is filled with the other chemical component; -the first shell half la together with partition 5 is turned over, positioned on the second shell half lb and glued securely thereto.

It is thus possible, in a simple manner to implement rapid and efficient series production of golf balls according to the invention without there being any risk of making a mess with the chemical components.

In a variant, the shell halves la, lb with the partition 5 arranged between them are glued together and the resultant compartments 6a, 6b are filled with the separate chemical components from the outside by means of injection.

The golf ball illustrated in Figs. 5-9 is composed of two shell halves 51a, 51b of a flexible core body 51 and a relatively hard outer shell 52 which has been moulded around them and has dimples. The shell halves 51a, 51b together delimit a cavity 53 in which a plurality of inwardly projecting, conical support points 54 are provided. A spherical partition element 55 rests on the support points 54. The partition element 55 divides the cavity 53 into two compartments 56a, 56b (cf. Fig. 7) which are separate from one another. The compartment 56a is in this instance located inside the spherical partition element 55. The second compartment 56b is formed by the space which is left clear between the wall of the cavity 53, the conical support points 54 and the outside of the partition element 55.

Figs. 7-9 illustrate the successive steps involved in activating the light-emitting means in the golf ball, and it can again be seen clearly that deformation of the outer shell 52 leads to deformation of the core body 51, with the result that the inwardly projecting support points 54 break open the partition element 55. After this, the two chemical components can mix with one another and emit light.

A possible method for producing this embodiment is for the spherical partition element 55 containing the first chemical component to be placed onto the support points 54 in the first shell half 51a. The first shell half 51a can then be covered and joined to the second shell half 51b, and the second compartment 56b can be filled with the second chemical component by injection.

In both embodiments shown, the wall of the cavity can be provided with a chemically resistant coating, so that the chemical compounds cannot affect the material of the flexible core body from the inside, which is advantageous. In a variant the core body itself is made from a chemically resistant material.

A coloured or reflective coating layer may be applied to the outer wall of the core body, having a diffusing effect, leading to an attractive scattering of light.

In addition to the arrangement shown in which the spherical body is split into a core body and an outer shell, it may also be made from a single transparent material.

Figs. 10-12 show a variant of a golf ball which is composed of a plurality of shell parts 101 and in which there is a cavity 103. Two hemispherical housing parts 106 are accommodated in the cavity 103, inside which housing parts there is a breakable capsule 107. In the assembled form, the housing parts 106 bear substantially against the walls of the cavity 103. The housing parts 106 comprise inwardly projecting support rings 108, between which ends of the capsule 107 are enclosed. A first chemiluminescent component is accommodated in the capsule 107, while a second chemiluminescent component is accommodated in the space between the capsule 107 and the housing parts 106.

An impact load exerted on the outside of the golf ball will

break the capsule 107, after which the chemiluminescent components can react with one another and emit light.

The advantages of this variant reside partially in the production process. The assembly of housing parts 106 and capsule 107 and chemiluminescent components already accommodated therein can easily be enclosed by the shell parts 101. In particular, inner shell parts lOla are positioned around the assembly of housing parts 106 and capsule 107, after which a further outer shell part lOlb can be injection-moulded around the inner shell parts 101a, and a relatively hard outer shell 102 can be injection-moulded around the outer shell part lOlb.

In particular, the outer shell part lOlb can advantageously be moulded on without the assembly of housing parts 106 and capsule 107 being undesirably deformed.

In addition to the embodiments shown, numerous variants are conceivable. For example, it is also possible for a closed capsule with two compartments which are separated from one another by a partition to be arranged in the cavity. A capsule of this nature can completely or partially fill the cavity.

Preferably, the capsule is connected to the spherical body at one or more points. It is also possible for two capsules, each with their own compartment, to be arranged in the cavity. In this case, it is important that both capsules are made frangible and/or are connected to the spherical body in such a manner that they both break if an impact load is exerted on the outer casing of the golf ball.

In a variant which is not shown, breaker bodies, such as small steel balls, are accommodated in the first and/or second compartment, which balls are able to contribute to the action of breaking a partition element between the two compartments.

The partition element is preferably designed in such a manner that, when activated, it breaks into a large number of small pieces which will have little or no further effect on the in-flight properties of the golf ball.

Therefore, the invention provides a light-emitting golf ball which begins to emit light after an impact load has been exerted on the outside of the golf ball. The impact load preferably comprises a force which is exerted on the golf ball by a golf club when driving off the tee. While the golf ball is

flying through the air, the two chemical components have the time and opportunity to mix with one another, and the golf ball will begin to emit light. By varying the wall thicknesses, types of material, and positioning, size and number of dimples on the outer shell, the golf ball can be designed in such a manner that it satisfies the requirements imposed on professional golf balls, such as the weight, size, hardness and resilience. After the light-emitting means have been exhausted, the golf ball can advantageously continue to be used for a long time by day. The chemical components enclosed in the core of the golf ball cannot leak out of the golf ball even after the light-emitting means have been exhausted.