You can freely build on How the Wiffle Ball Design Works

What this patent covers

The patent describes a hollow, spherical ball made of a lightweight plastic material. The surface features a series of circular holes on one hemisphere, leaving the other hemisphere solid. This uneven weight and air resistance distribution allows the ball to be thrown in ways that cause it to curve or flutter significantly in flight, making it safer and easier to hit than a standard baseball.

What is now free to use

All 0 claims of US 2776139 are in the public domain. Specifically:

The 0 dependent claims add narrowing limitations and are also free.

What is NOT covered

Patent expiry frees this specific invention. Separately-patented improvements made after expiry may still be protected.

• Does not cover solid balls or balls made of dense materials like rubber or leather.

• Does not cover balls with holes distributed evenly across the entire surface.

• Does not cover balls that are not intended for use in games or recreational play.

Who is building on this today

The Wiffle Ball, Inc. remains the primary manufacturer of the original design. Various toy companies have since produced variations, but the core design remains a standard for plastic recreational balls.

Products built on expired version of this technology

How to cite this patent in your documentation

Individual. US Patent 2776139. Game ball. Granted 1957, expired 1974. Now in the public domain.

Note: This is a convenience citation. Consult a patent attorney for formal freedom-to-operate analysis.

PatentBrief is an educational resource and does not provide legal advice. Patent expiration information is derived from USPTO records and may not reflect continuation patents, divisional filings, or separately-patented improvements. For commercial use or production decisions, obtain a formal freedom-to-operate (FTO) opinion from a registered patent attorney.