A golf ball having improved driving characteristics includes a hard, hollow sphere surrounded by an outer. A second layer may be disposed between the sphere and the outer cover. The hollow sphere is made from a hard material such as a metal, metal alloy, or intermetallic material and may be solid, perforated or porous. The second layer surrounding the sphere is generally made of a natural rubber or synthetic polymer or a combination of each which is surrounded by an outer cover made of an ionomer, urethane or balata. The hard sphere preferably contains a gas. A golf ball of this construction has improved performance characteristics such as low spin rate and further distance.
1. A modem golf ball comprising:
a cover material defining an inner surface and an outer surface, said outer surface having a dimpled pattern;
a single, one-piece metal sphere having an outer surface which is surrounded by the inner surface of the cover, said single sphere further defining an inner surface surrounding a material of lower density than the density of said cover material; and
said single sphere further defining a wall formed of a metal having a thickness between said inner and outer surfaces of said sphere of at least 0.020 inches.
2. A modem golf ball as defined in claim 1 , wherein the metal is selected from the group consisting of titanium and titanium alloys.
3. A modern golf ball as defined in claim 1 , wherein said single sphere is comprised of two or more spherical portions each formed by stamping, said portions of said sphere being fixedly secured together to form said single sphere.
4. A modem golf ball as defined in claim 1 , wherein said single sphere is comprised of two or more spherical portions each formed by hydroforming, said portions of said sphere being fixedly secured together to form said single sphere.
5. A modem golf ball as defined in claim 1 , wherein said single sphere is comprised of two or more spherical portions each formed by superplastic forming, said portions of said sphere being fixedly secured together to form said single sphere.
6. A modem golf ball as defined in claim 1 , wherein said single sphere is comprised of two or more spherical portions each formed by metal spinning, said portions of said sphere being fixedly secured together to form said single sphere.
7. A modem golf ball as defined in claim 3 , wherein said portions of said sphere are fixedly secured together by welding.
8. A modern golf ball as defined in claim 7 , wherein said welding is electron beam welding.
9. A modern golf ball as defined in claim 7 , wherein said welding is laser welding.
10. A modem golf ball as defined in claim 7 , wherein said welding is electrical resistance welding.
11. A modern golf ball as defined in claim 3 , wherein said portions of said sphere are fixedly secured together by gluing.
12. A modern golf ball as defined in claim 1 , wherein said wall has a thickness of about 0.02 inches to about 0.08 inches.
13. A modem golf ball as defined in claim 1 , wherein said single sphere has an outer diameter of between about 0.39 inches and about 1.5 inches.
14. A modem golf ball as defined in claim 1 , wherein the material of lower density in said sphere comprises a gas.
15. A modem golf ball as defined in claim 14 , wherein said gas is under pressure.
16. A modem golf ball as defined in claim 14 , wherein said gas is air.