US 3,950,915 · Granted 1976-04-20
The Plastic Connector That Lets Flat-Pack Furniture Snap Together Without Nails
Imagine building a bookshelf without screws, nails, or glue. This patent describes a clever plastic extrusion — basically a shaped plastic strip — that slides into grooves cut into the edges of wooden panels and locks them together at perfect right angles. Once hammered into place, it holds everything rock-solid.
The plain-English version
What it protects
What's protected here is a plastic extrusion system for joining two flat panels (like plywood or particle board) at right angles without fasteners. The claim covers a design where one panel has a grooved edge and the other has an undercut slot, and a plastic extrusion with an anchoring key slides into the groove and its flanged portion engages inside the undercut slot, preventing lateral movement in both directions and holding the panels firmly together.
Why it matters
This patent solved a real manufacturing headache in the 1970s furniture industry. Before this, joining lightweight materials like particle board required messy glue, visible fasteners, or complex joinery that made assembly, disassembly, and shipping expensive and time-consuming. A plastic connector that could be hammered in and lock two panels solid meant cheaper, easier-to-assemble furniture and smaller shipping boxes — exactly what the emerging flat-pack furniture market needed.
Real-world use
Every time you assemble an IKEA bookshelf or budget cabinet without visible screws on the corners, you're using technology descended from this design concept — a simple plastic or metal connector hidden inside the joint doing all the load-bearing work.
Original USPTO abstract
When attaching cabinet parts together such as the sides of the cabinet to the top or bottom panels or partitions between top and bottom panels or between side panels, it is difficult to produce a firm joint particularly if particle board or plywood is used in the construction, without the use of screws, nails, glue and the like. This prevents easy assembly or disassembly and makes shipping and storage space consuming and expensive. By providing an undercut slot or recess in one part and a substantially parallel sided groove in the edge of the other part, a plastic extrusion can be used to secure the two panels together substantially at right angles to one another. The extrusion is provided with an anchoring key portion which is hammered or forced into frictional engagement within the parallel sided groove. An outwardly flanging attaching portion is formed on the underside of the anchoring portion which slidably engages axially within the undercut slot of the other panel so that lateral movement of the two panels is prevented in either direction and these two panels are held firmly together.
Patent details
- Publication number
- US 3,950,915
- Filing date
- 1974-09-04
- Grant date
- 1976-04-20
- Assignee
- Empire Sheet Metal Mfg. Co. Ltd.
- Inventor(s)
- COLE; WAYNE C. T.
- CPC class
- F16B5/0614
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