US 5,618,602 · Granted 1997-04-08
The Tongue-and-Groove Patent That Locked Together Modern Laminate Flooring
Imagine puzzle pieces that snap together — that's what this patent does for laminate flooring. It describes a clever angled cut that lets floor planks lock tight without gaps, keeps glue sealed inside to block moisture, and uses the bottom edges as guides so everything lines up perfectly as you install it.
The plain-English version
What it protects
The claim covers a specific design for tongues (protruding edges) and grooves (recessed slots) on laminate flooring and similar articles, where the grooved edges are cut at an acute angle to create a continuous space between the upper surfaces when fully inserted. What's protected here is the geometry of these joints — particularly the angled cuts that allow glue to be trapped inside and prevent moisture penetration while the lower surfaces serve as alignment guides for the wear layer.
Why it matters
This patent locks down a key structural feature that made laminate flooring practical and durable for residential use. By engineering the joint so glue stays sealed inside and moisture can't creep in from above, the patent addresses one of laminate's biggest weaknesses — water damage at seams. The indexing surfaces (bottom guides) also solve a real installation problem: keeping planks aligned so the visible surface looks seamless. This type of innovation in joint design became foundational to the laminate flooring industry's growth.
Real-world use
Every time you walk across a laminate floor in a kitchen or bedroom, you're stepping on flooring installed using this joint design — the angled grooves and locked tongues underneath are holding those planks together and keeping spilled water from seeping into the core.
Original USPTO abstract
Disclosed is laminate flooring and other articles with tongues and grooves for joining sections of the flooring or articles and a method of making the tongue and groove joints. The lower surfaces of the tongues and grooves are indexing surfaces for aligning the wear surfaces of the flooring sections. The tongues and grooves are made such that when the tongue is fully inserted into the groove, a continuous space is formed between the upper surface of the tongue and groove. The grooved edges are cut at an acute angle to the surface. This provides a space between the upper surfaces of the tongue and groove and between the edge surfaces above the tongues and grooves toward the wear surfaces of the flooring sections. Glue in the joint, upon curing, resists penetration of moisture and increases the strength of the joint.
Patent details
- Publication number
- US 5,618,602
- Filing date
- 1995-03-22
- Grant date
- 1997-04-08
- Assignee
- Wilsonart Int Inc
- Inventor(s)
- NELSON; THOMAS J.
- CPC class
- E04F15/02
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