Stretchable-Matrix Dowel for Multi-Screw Secure Anchoring

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Solution Overview

Problem

Conventional dowels face challenges in securely fastening screws of different thicknesses without causing damage or insufficient expansion, particularly when used in various substrates like brick, concrete, or plasterboard, where a reliable and error-proof method for setting dowels with different fastening elements is needed.

Innovation Solution

A dowel design featuring a first component with circumferentially arranged expansion webs and a connected second component with a stretchable coherent matrix that surrounds the expansion webs, allowing for defined and reproducible expansion when a fastening element is inserted, ensuring secure anchoring in substrates with different properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional dowels are used with screws of different thicknesses, then the dowel can be used for various applications, but the expansion elements may not expand sufficiently or the dowel may be damaged

Engineering Contradiction:
Improvecompatibility with different screw thicknessesVSAvoidsecure anchoring performance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The dowel is divided into two separate components: a first component containing expansion webs and a second component with a continuous matrix. This segmentation allows each component to perform its specific function optimally - the expansion webs provide expansion force while the matrix provides protective containment, enabling reliable performance across different screw thicknesses

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The dowel combines two different plastic materials with distinct properties - the first component is designed for expansion functionality while the second component provides elastic containment. This composite structure enables the dowel to adapt to different screw thicknesses while maintaining secure anchoring through the complementary properties of the two materials

Inventive Principle:
Principle #40Composite materials

2Force

If the expansion webs are allowed to expand freely, then they can provide strong anchoring force, but they may not remain properly positioned relative to each other

Engineering Contradiction:
Improveholding forceVSAvoidposition stability of expansion webs
Core Design Contradiction:
ForceVSStability of the object's composition

Solution Approach 1:

The continuous matrix acts as a flexible elastic shell that surrounds and contains the expansion webs. This flexible containment allows the expansion webs to expand radially outward to generate anchoring force while the elastic matrix maintains their positional relationship and prevents distortion during the expansion process

Inventive Principle:
Principle #30Flexible shells and thin films

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

This design enables high holding forces and secure anchoring in both solid and hollow substrates, allowing for the use of dowels with screws of different diameters without compromising performance or integrity, providing universal compatibility with various surfaces.

Implementation Method 1

a (in particular elastically) stretchable continuous matrix which circumferentially surrounds the first expansion webs at least section by section

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3587840B1Dowel with stretchable beams surrounded by expandable matrix
Publication Date: 2021.05.05 ADOLF WURTH GMBH & CO KG
  • EP3587840B1 patent drawingFigure 1~2
  • EP3587840B1 patent drawingFigure 3~4
  • EP3587840B1 patent drawingFigure 5~6

AI summary

Dowel (100) comprising a first component (170) with a plurality of circumferentially arranged first expansion webs (112), and a second component (180) connected to the first component (170) with a stretchable continuous matrix (116), which matrix (116) circumferentially surrounds the first expansion webs (112) at least sectionally, in particular on the dowel head side.