Fastening device for fastening two elements, in particular furniture parts or components of furniture parts, to each other

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Solution Overview

Problem

Existing fastening devices for furniture parts struggle to accommodate a high tolerance spectrum and compensate for large play during assembly, requiring complex tools and procedures.

Innovation Solution

A fastening device featuring a dowel with radially extending, inherently rigid and flexible lamellae that bend upon insertion into a fastening hole, securely anchoring by digging into the hole's wall, allowing for easy manual installation without tools and accommodating varying tolerances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional expansion dowels are used with connecting elements, then furniture components can be fastened together, but the device cannot accommodate large tolerance ranges and requires complex installation tools and procedures

Engineering Contradiction:
Improvetolerance range accommodationVSAvoidinstallation complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The dowel is segmented into multiple independent lamellae that can deflect individually. Each lamella acts as an independent element that bends during insertion and then springs back to grip the hole wall, allowing the dowel as a whole to adapt to varying hole dimensions and tolerances without requiring precise pre-drilling or complex installation tools.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The lamellae are made from a self-stiff, bendable material that changes its effective dimensions through elastic deformation. During insertion, the lamellae compress radially to pass through the fastening hole, then expand back to their original diameter to grip the hole wall, automatically adapting to tolerance variations in the hole size.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If expansion dowels with connecting elements are used, then furniture parts can be connected detachably, but the installation process requires tools and is time-consuming

Engineering Contradiction:
Improveinstallation easeVSAvoidinstallation time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The lamellae are designed to perform the anchoring function automatically through their own elastic properties. When the dowel is inserted into the fastening hole, the lamellae naturally deflect inward to pass through, then spring back outward to grip the hole wall, creating a self-anchoring mechanism that eliminates the need for external expansion mechanisms, tools, or additional installation steps.

Inventive Principle:
Principle #25Self-service

3Strength

If the lamellae cross-section is larger than the fastening hole cross-section to enable gripping, then secure anchoring is achieved, but insertion becomes difficult without tools

Engineering Contradiction:
Improveanchoring strengthVSAvoidinsertion ease
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The lamellae transition from a rigid state during normal operation to a flexible state during insertion. The inherently rigid yet flexible material allows the lamellae to be stiff enough to grip the hole wall securely after insertion, but flexible enough to bend and compress during the insertion process, enabling tool-free installation while maintaining strong anchoring.

Inventive Principle:
Principle #15Dynamics

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

Enables quick, tool-free assembly of furniture components with high flexibility to handle large tolerance ranges, ensuring secure anchoring and simplified installation processes.

Implementation Method 1

the lamellae consist of a self-stiff, bendable material, such that the lamellae bend in the insertion direction when inserted into the associated fastening hole

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the lamellae interlock with the wall of the designated fixing hole, preventing deflection in the other direction, i.e., against the insertion direction

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3258121B1Fastening device for fastening two elements, in particular furniture parts or components of furniture parts, to each other
Publication Date: 2019.10.30 GRASS GMBH
  • EP3258121B1 patent drawingFigure 1
  • EP3258121B1 patent drawingFigure 2~3
  • EP3258121B1 patent drawingFigure 4

AI summary

A fastening device for fastening two components, in particular furniture parts (12) or furniture part components, to one another, has at least one dowel (16) which can be fixed in a fastening hole (15) in the associated component and has a, in particular, cylindrical base body (18 ) and has a plurality of lamellae (19) which are arranged in a row on the base body (18) one behind the other at a distance from one another axially with respect to the longitudinal axis (17), the lamellae (19) each extending radially with respect to the longitudinal axis (17) via a lateral surface (20) of the base body (18), and wherein the lamellae (19) consist of an inherently rigid, flexible material such that the lamellae (19) bend in the insertion direction (21) when they are inserted into the associated fastening hole (15), so that they dig into the wall (22) of the associated fastening hole (15) during a movement counter to the direction of insertion (21).