US 4,650,193 · Granted 1987-03-17
The Two-Piece Golf Ball That Changed How Pros Play
A golf ball made of two layers: a hard springy center wrapped in a soft outer shell. By tweaking the chemistry of the core during manufacturing, engineers created a ball that plays as well as expensive hand-wound ones but is cheaper and easier to make.
The plain-English version
What it protects
The claim covers a golf ball design where the core has a hard, resilient center surrounded by a softer outer layer, plus the manufacturing method of treating and molding elastomer material to create that hardness gradient. What's protected here is the specific structure of how the two materials meet and transition, and the process of using cure-altering agents to control how hard or soft each layer becomes during manufacturing.
Why it matters
Two-piece golf balls became the industry standard because they combined durability, consistent performance, and lower production cost than the hand-wound balata balls that dominated before. This patent's innovation in core construction allowed manufacturers to engineer balls with predictable playability without labor-intensive winding, opening up mass production and making premium performance accessible to everyday golfers rather than just professionals.
Real-world use
Every golf ball you buy at a sporting goods store today likely uses this two-piece core design. When you hit a drive, the hard center gives it the spring-back energy while the soft outer layer controls spin and feel.
Original USPTO abstract
Disclosed is a two-piece golf ball and methods for its production. The ball comprises a core having a central portion of a cross-linked, hard, resilient material and having a soft, deformable outer layer. Balls comprising the novel cores and a conventional cover material having playability properties approaching or exceeding thread-wound balata covered balls. The core is preferably manufactured by surface treating a slug of a suitable, curable elastomer composition with a cure altering agent, and molding the slug under conditions to produce a spherical core having a hardness gradient in its surface layers.
Patent details
- Publication number
- US 4,650,193
- Filing date
- 1984-12-10
- Grant date
- 1987-03-17
- Assignee
- Spalding & Evenflo Companies, Inc.
- Inventor(s)
- MOLITOR; ROBERT P., MELVIN; TERRENCE
- CPC class
- A63B37/0003
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