Detachable Timber Tenon Joint for Low-Effort Panel Assembly

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Solution Overview

Problem

Existing methods for connecting wooden components in timber construction, such as dovetail joints and metal connectors, require high manufacturing effort, are complex, and difficult to assemble, especially for large-area components.

Innovation Solution

A detachable connection system using a tenon with an outer contour and a pocket or groove with an inwardly widening inner contour, allowing easy assembly and alignment of wooden components without complex manufacturing steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If dovetail joints with specially shaped tenons and grooves are used to connect wooden components, then the connection can transmit shear forces and tensile forces, but the manufacturing effort and material removal required are high

Engineering Contradiction:
Improveconnection strengthVSAvoidmanufacturing effort
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The connection system is divided into separate components: a tenon element and a corresponding groove element. These can be manufactured independently using standard machining operations rather than requiring complex simultaneous machining of interlocking surfaces, thereby reducing manufacturing effort while maintaining connection strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A detachable connection element serves as an intermediary between the tenon and groove, facilitating assembly and reducing the complexity of direct tenon-groove engagement. This intermediary component allows for simpler individual part geometries while achieving the same mechanical interlocking function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If metal connectors are used to connect wooden components, then the connection can be strong and reliable, but the connectors are complex to manufacture and require precise pre-assembly

Engineering Contradiction:
Improveconnection reliabilityVSAvoidconnector complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The connection elements are made from the same wooden material as the components being joined, eliminating the need for metal connectors. This homogeneous material approach simplifies manufacturing since all parts can be processed using the same woodworking techniques, while maintaining reliability through proper joint design.

Inventive Principle:
Principle #33Homogeneity

Solution Approach 2:

The tenon and groove elements are pre-formed as separate components with standardized geometries before assembly. This preliminary preparation allows for precise fitting to be achieved through controlled machining operations on individual parts rather than requiring complex pre-assembly of multi-component metal connectors.

Inventive Principle:
Principle #10Preliminary action

3Strength

If traditional tenons and grooves are used for connecting large-area components, then the connection can be made, but a relatively large amount of material would have to be removed

Engineering Contradiction:
Improveconnection strengthVSAvoidmaterial removal
Core Design Contradiction:
StrengthVSLoss of substance

Solution Approach 1:

The tenon element fits nested within the groove element, creating an interlocking joint that requires minimal material removal. The nested geometry allows the connection to be formed by removing only the necessary material for the groove cavity, rather than requiring extensive material removal for traditional dovetail shapes.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The geometry of the tenon and groove is optimized by changing the traditional dovetail parameters to a simpler rectangular or tapered profile. This parameter modification reduces the volume of material that must be removed while maintaining the mechanical interlocking function and connection strength for large-area components.

Inventive Principle:
Principle #35Parameter changes

4Strength

If complex metal connectors with precise pre-assembly are used, then the connection can be strong, but inserting such metal connectors is relatively difficult due to the very limited clearance

Engineering Contradiction:
Improveconnection strengthVSAvoidassembly difficulty
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

Instead of inserting a protruding tenon into a recessed groove as in traditional joints, the design inverts the approach by having the groove element receive the tenon element in a manner that accommodates limited clearance. The inverted geometry allows for easier insertion by reversing the traditional insertion direction or orientation, facilitating assembly in confined spaces.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The connection elements are designed with dynamic adjustment capabilities, allowing for slight variations in alignment and positioning during assembly. This dynamic design accommodates the limited clearance by permitting minor movements and adjustments, making insertion easier compared to rigid, precision-matched traditional joints.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4678838A1Wall, ceiling, façade or roof element connection
Publication Date: 2026.01.14 ADOLF WURTH GMBH & CO KG
  • EP4678838A1 patent drawingFigure 1
  • EP4678838A1 patent drawingFigure 2~4
  • EP4678838A1 patent drawingFigure 5~7

AI summary

An arrangement for a wall, ceiling, facade, or roof element connection for joining rod-, beam-, or panel-shaped wooden components (1, 2) has a tenon (3) with at least one insertion hole (30); and a detachable connection (15) that can be detachably inserted through the at least one insertion hole (30) of the tenon (3) and into a first wooden component (1). The tenon (3) is designed to be attached to a connecting surface (10) on the first wooden component (1) by means of the detachable connection (15). The tenon (3) has an outer contour that widens from the connecting surface (10) towards an opposite end face (11) for connection to a second wooden component (2).The tenon (3) is designed for insertion into an insertion area (5) of a pocket or groove (4) arranged on the second wooden component (2), and the tenon (3) is designed for retention in a retention area (6) of the pocket or groove (4) with an inwardly expanding inner contour adapted to the outer contour of the tenon (3).