How the Slinky Toy Works
The original 1947 patent for the Slinky, a helical spring toy designed to walk down stairs through the transfer of energy.
Original patent title: “Toy and process of use”
The original 1947 patent for the Slinky, a helical spring toy designed to walk down stairs through the transfer of energy. Granted to James Industries Inc in 1947 with 29 forward citations, and it is now in the public domain.
Key facts
Coverage
What does this patent actually cover?
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.
The gap
What does this patent NOT cover?
- 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.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The innovation lies in the specific ratio of wire diameter to coil diameter, which allows gravity to overcome the friction of the coils, creating a self-sustaining walking motion.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Original metal Slinky
Physics classroom demonstrations of wave motion
Why it matters
The bigger picture
This patent protected the Slinky, which became one of the most iconic toys in American history. It established a new category of kinetic toys that rely on physics rather than batteries or complex gears to function.
Filed
August 21, 1946
Granted
January 28, 1947
Market context
Who's building on this
Companies in this space
James Industries remains the primary manufacturer, though many generic toy companies now produce plastic and metal variations of the helical spring toy.
Market impact
The patent enabled the creation of a massive, long-lasting toy brand that has sold hundreds of millions of units. It proved that simple, physics-based toys could achieve immense commercial success.
Claim 1 — Plain English
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.
The clever bit
The innovation lies in the specific ratio of wire diameter to coil diameter, which allows gravity to overcome the friction of the coils, creating a self-sustaining walking motion.
What it does not cover
- 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.
Patent Journey
From filing to expiry
PatentBrief Score
Impact Score
Early stage
Citation count
29/40
Moderately cited
Claim breadth
0/20
Narrow claimsclaimsThe numbered statements at the end of a patent that legally define what the inventor owns.Read more →
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$20K – $63K
Midpoint $40K · expired or expiring · industry ×2.2
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
Concepts involved
Citations
Patent lineage
Cite this patent
James, R. T. (1947). How the Slinky Toy Works (U.S. Patent No. 2,415,012). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/2415012/slinky-toy
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How the Slinky Toy Works cover?
The original 1947 patent for the Slinky, a helical spring toy designed to walk down stairs through the transfer of energy.
Who owns patent US 2415012?
James Industries Inc owns this patent, granted in 1947.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 2415012 cited by?
This patent has been cited by 29 later patents that build on its ideas.
What problem does this patent solve?
This patent protected the Slinky, which became one of the most iconic toys in American history. It established a new category of kinetic toys that rely on physics rather than batteries or complex gears to function.
What does this patent NOT cover?
Does not cover springs made of materials other than metal, such as plastic coils.
Patent monitoring