Flexible Tongue Mitre Joint Locking for Stronger Furniture Panels

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Solution Overview

Problem

Existing mechanical locking devices for furniture panels lack sufficient strength and stability, particularly at mitre joints, which can lead to instability and potential disassembly issues in assembled products like bookshelves, cupboards, and kitchen fixtures.

Innovation Solution

A mechanical locking system featuring a flexible tongue and groove mechanism with angled surfaces and recesses, where the edge tongue extends perpendicular from the junction plane and the edge groove has parallel surfaces, providing increased locking surfaces and stability, and the flexible tongue is displaceable within an insertion groove, enhancing the rigidity and strength of the joint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a mechanical locking device is used to join panels at mitre joints, then the panels can be assembled and locked together, but the strength and stability of the joint is insufficient

Engineering Contradiction:
Improvejoint strengthVSAvoidjoint stability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The locking device is divided into separate functional components: an edge tongue with a tongue groove for one panel, and an edge groove with a flexible tongue for the other panel. This segmentation allows each component to be optimized independently for its specific locking function, improving overall joint strength and stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking mechanism engages in two perpendicular directions: the tongue groove and edge groove lock in a first direction parallel to the junction plane, while the flexible tongue and tongue groove lock in a second direction perpendicular to the junction plane. This two-dimensional locking provides superior strength and stability compared to single-direction locking.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Strength

If the edge tongue and edge groove are designed with locking surfaces, then the panels can be locked together, but the locking surfaces are too small to provide sufficient strength

Engineering Contradiction:
Improvelocking surface areaVSAvoidlocking device structure
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The flexible tongue is nested within the edge groove, and the tongue groove is nested within the edge tongue structure. This nesting arrangement maximizes the locking surface area within a compact geometry, providing large contact surfaces without significantly increasing device complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The flexible tongue can deform elastically during assembly and under load, allowing it to conform to the tongue groove and maximize contact surface area. This dynamic flexibility ensures optimal locking surface engagement while maintaining a relatively simple device structure.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the panels are joined at mitre joints, then the furniture can be assembled, but the joints are prone to disassembly and instability

Engineering Contradiction:
Improvejoint stabilityVSAvoidfurniture stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The edge tongue and edge groove are pre-configured with complementary shapes and locking surfaces that guide the panels into correct alignment during assembly. The auxiliary means including positioning protrusions and recesses ensure proper orientation before the locking mechanism engages, preventing misalignment and instability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The flexible tongue acts as an intermediary element between the two panels, absorbing minor dimensional variations and assembly tolerances. This flexibility compensates for manufacturing variations and prevents stress concentration that could lead to joint failure or disassembly.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution significantly enhances the strength and stability of assembled furniture products by providing larger locking surfaces and improved contact areas, reducing the risk of disassembly and increasing the durability of the joints, even when subjected to various angles and thicknesses of panels.

Implementation Method 1

The edge groove comprises a flexible tongue arranged in an insertion groove, said flexible tongue is configured to cooperate with the tongue groove for locking together the first and the second edges

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3594514B1Panels comprising a mechanical locking device
Publication Date: 2023.01.25 VÄLINGE INNOVATION AB
  • EP3594514B1 patent drawingFigure 1
  • EP3594514B1 patent drawingFigure 2A~2F
  • EP3594514B1 patent drawingFigure 3A~3C

AI summary

A set of panels includes a first panel 2 having a first main plane and a second panel 4 having a second main plane. The panels are provided with a mechanical locking device for locking a first edge of the first panel 2 to a second edge of the second panel 4. The mechanical locking device includes an edge groove 21 at the first edge, wherein an edge tongue 22 of the second edge is insertable into the edge groove. A flexible tongue 30 is arranged in an insertion groove 20 provided in the edge section groove 22, and cooperates with a tongue groove 10 provided at the edge section 22 of the second panel. The first and the second panels are locked at a junction plane J which is extending between the first main plane and the second main plane. The first edge comprises an edge tongue 22 that extends from the junction plane J.