US 6,647,689 · Granted 2003-11-18
The Double-Lock Floor Patent That Lets Planks Snap Together Like Lego
Imagine floor planks that lock together in two directions at once — vertically AND horizontally — without any glue, screws, or nails. This patent describes a clever groove-and-tongue system that keeps your flooring from buckling, warping, or popping apart as the house settles and temperature shifts. The design is so smart it reduces damage while you're actually installing the boards.
The plain-English version
What it protects
The claim covers a flooring panel with two separate locking mechanisms built into opposite edges. What's protected here is the specific geometry: one side has a groove paired with a locking lip, the other has a tongue paired with a locking tongue. When panels interlock, the groove-and-tongue joint creates vertical stability, while the locking lip and locking tongue create horizontal stability. The patent also protects the deliberate spacing between the first side edge and the second edge's locking tongue — this gap is what prevents damage during assembly.
Why it matters
Engineered wood flooring and laminate are multi-billion-dollar markets, and installation stability is everything. Before dual-lock systems like this, floors could develop gaps, cupping, or separation problems from seasonal humidity changes or house movement. By locking both vertically and horizontally without fasteners, this design reduces callbacks and warranty claims. The separate mechanism approach also makes the planks less likely to crack or chip during the install process itself — a huge practical advantage for contractors and DIY installers.
Real-world use
Walk across any modern engineered hardwood or laminate floor installed in the past twenty years and you're likely stepping on planks locked together using a variation of this dual-lock principle. Listen for the solid 'click' when installers snap boards together.
Original USPTO abstract
A panel, particularly a floor-covering panel, is provided that has separate horizontal and vertical locking structures. The panel has a first side edge and a second side edge. The first side edge has a groove and a locking lip, and the second side edge has a tongue and a locking tongue. The first side edge of one panel interlocks with the second side edge of another panel without adhesives or fasteners such that the tongue and groove form a joint that provides a vertical interconnection lock and the locking lip and locking tongue form a joint that provides a horizontal interconnection lock. Advantageously, one or more first side edge surfaces opposite surfaces of the second edge locking tongue have a space between them. The separate horizontal and vertical locking structures reduces, if not prevents, damage to the locking structures during joining of panels.
Patent details
- Publication number
- US 6,647,689
- Filing date
- 2002-07-26
- Grant date
- 2003-11-18
- Assignee
- E.F.P. Floor Products Gmbh
- Inventor(s)
- PLETZER STEFAN, WEBER JUERGEN, HEITZINGER JOHANN
- CPC class
- E04F15/04
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