In 1988 Spalding obtained a patent for a new dimple pattern with 332 dimples in two sizes¹. The new dimple pattern is shown below. The 162 dark colored dimples had a diameter of 0.154 inches and the 170 dimples labeled 2 had a diameter of 0.167 inches. Let’s call this the Spalding 4,880,241 Dimple Pattern.

Polar View

Equitorial view

In my golf ball collection there are three Spalding golf balls that appear on the USGA Conforming Golf Ball lists that have this dimple pattern.

#538, 2 TOP-FLITE XL, (logo) Spalding (appears June 13, 1987-91 on the USGA lists²)

#66, 4 TOP-FLITE XL Spalding (appears on the June 13, 1987 USGA list²

#560, 1 TOP-FLITE XL^II, Spalding (appears June 13, 1988-90 on the USGA lists²).

The Spalding patent 4,880,241 was filed in April 1988. To be valid, a patent must be filed within one year of the date of the invention. This means that this dimple technology was invented by about May 1987. A patent must be novel, useful, and not obvious. This dimple pattern on this golf ball had never been disclosed before, so it was novel. It was useful because this particular dimple pattern wouled travel farther than other golf balls. It was not obvious that this dimple pattern would do this.

The golf balls of this invention had 76% of the surface covered with dimples³. This increased the distance that the golf ball would travel. The three XL TOP-FLITE golf balls #245, 333, and 524 that appeared on earlier USGA lists had only 59% of the surface covered with dimples. They had 320 large dimples and 12 small dimples arranged in the Spalding icosahedron dimple pattern⁴.

This new Spalding dimple technology was important because Spalding and Acushnet Companies had spent considerable time in court from 1981 to 1990 hashing out patent issues⁵. Spalding had obtained a patent on a new cover material called Surlyn® in 1974 and had sued Acushnet for infringing and won. Acushnet filed an appeal and sued Spalding over patent violations regarding golf ball dimple patterns, fluorescent ball covering, and golf ball moldiing. Finally in 1990 the two companies settled their differences and agreed to cross license their patents.

References

1. Terrence Melvin and Dennis Nesbit, US 4,880,241, filed Apr. 22, 1988, allowed Nov. 14, 1989.
2. See Supplemental Information on my website for the USGA golf ball lists.
3. % coverage is equal to the total area of all the dimples divided by the surface area of the golf ball.
4. See my earlier post ‘Spalding Icosahedron Pattern’ in the Discussion tab on my website.
5. See Acushnet Company History at https://fundinguniverse.com>Company-histories.