You can freely build on How the Slinky Toy Works

What this patent covers

The patent describes a helical spring made of a specific gauge of wire that can store and release potential energy. When placed on an incline, such as a set of stairs, the spring moves by shifting its center of gravity. As one end of the spring moves forward, it stretches and then contracts, pulling the rest of the coil along with it in a rhythmic, walking motion.

What is now free to use

All 0 claims of US 2415012 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 springs made of materials other than metal, such as plastic coils.

• Does not cover non-helical spring designs or shapes.

• Does not cover the use of the spring for industrial or mechanical dampening purposes.

Who is building on this today

James Industries remains the primary manufacturer, though many generic toy companies now produce plastic and metal variations of the helical spring toy.

Products built on expired version of this technology

How to cite this patent in your documentation

James Industries Inc. US Patent 2415012. Toy and process of use. Granted 1947, expired 1966. 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.