The Invention of Lincoln Logs
A 1920 patent for a toy construction system using notched wooden logs to build miniature cabins and structures.
Original patent title: “Toy-cabin construction”
A 1920 patent for a toy construction system using notched wooden logs to build miniature cabins and structures. Granted to Individual in 1920 with 24 forward citations, and it is now in the public domain.
Coverage
What does this patent actually cover?
The patent describes a system of wooden logs with notches cut into them at specific intervals. These notches allow the logs to be stacked perpendicularly to create interlocking walls for toy structures like cabins or forts. The design relies on the gravity-fed friction of the notches to keep the walls stable without needing glue or nails. It provides a modular method for children to build three-dimensional structures that look like miniature log cabins.
The gap
What does this patent NOT cover?
- Does not cover building systems that use plastic bricks or studs like LEGO.
- Does not cover non-notched construction sets or blocks that rely solely on stacking without interlocking joints.
- Does not cover structural designs for full-sized, habitable buildings.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
Key facts
What made this novel
The innovation was the specific placement of notches that allowed for a consistent, repeatable interlocking pattern, turning simple sticks into a versatile construction kit.
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
Lincoln Logs construction sets
Why it matters
The bigger picture
This patent marks the origin of Lincoln Logs, one of the most iconic toys in American history. It established a modular construction play pattern that influenced generations of educational toys focused on spatial reasoning and architecture.
Filed
January 8, 1920
Granted
August 31, 1920
Market context
Who's building on this
Companies in this space
The Lincoln Logs brand is currently owned by Basic Fun!, which continues to produce sets based on the original interlocking log concept. The modular construction principle remains a staple in the educational toy market.
Market impact
This patent helped define the construction toy category, proving that simple, tactile building systems could achieve long-term commercial success. It created a lasting brand that has remained a staple in toy boxes for over a century.
Claim 1 — Plain English
What this patent covers
The patent describes a system of wooden logs with notches cut into them at specific intervals. These notches allow the logs to be stacked perpendicularly to create interlocking walls for toy structures like cabins or forts. The design relies on the gravity-fed friction of the notches to keep the walls stable without needing glue or nails. It provides a modular method for children to build three-dimensional structures that look like miniature log cabins.
The clever bit
The innovation was the specific placement of notches that allowed for a consistent, repeatable interlocking pattern, turning simple sticks into a versatile construction kit.
What it does not cover
- Does not cover building systems that use plastic bricks or studs like LEGO.
- Does not cover non-notched construction sets or blocks that rely solely on stacking without interlocking joints.
- Does not cover structural designs for full-sized, habitable buildings.
Patent timeline
Application submitted to the patent office
Application published, typically 18 months after filing
Patent officially issued
Patent enters public domain
This patent is in the public domain
See the Freedom to Build guide — what is free to use, what is not, and how to cite this patent.
PatentBrief Score
Impact Score
Early stage
Citation count
28/40
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.
Claim text not yet imported for this patent
Concepts involved
Citations
Patent lineage
Cite this patent
Lloyd, W. J. (1920). The Invention of Lincoln Logs (U.S. Patent No. 1,351,086). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/1351086/lincoln-logs-wright
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 The Invention of Lincoln Logs cover?
A 1920 patent for a toy construction system using notched wooden logs to build miniature cabins and structures.
Who owns patent US 1351086?
Individual owns this patent, granted in 1920.
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 1351086 cited by?
This patent has been cited by 24 later patents that build on its ideas.
What problem does this patent solve?
This patent marks the origin of Lincoln Logs, one of the most iconic toys in American history. It established a modular construction play pattern that influenced generations of educational toys focused on spatial reasoning and architecture.
What does this patent NOT cover?
Does not cover building systems that use plastic bricks or studs like LEGO.
Same assignee
More from Individual
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