Dowel with Separate Expanding Bars for High Anchoring Force

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Solution Overview

Problem

Traditional anchors often lack sufficient anchoring force, especially in applications where a strong hold is required in various substrates such as concrete, wood, or plasterboard.

Innovation Solution

The anchor design features a foot with an opening for a fastener, a head, and an expansion area with multiple spreader bars that are flush and separate, allowing for full-circumferential expansion or knotting around the fastening element, ensuring a secure grip without gaps, thereby enhancing pull-out force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If traditional anchors are used, then they provide anchoring force for various applications, but the anchoring force is insufficient in cases requiring strong hold

Engineering Contradiction:
Improveanchoring forceVSAvoidsecuring capability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The anchor is divided into multiple separate spreader bars (at least two) that are arranged side-by-side in the expansion area. These separate bars can expand independently when the fastener is inserted, creating multiple expansion points that collectively provide superior anchoring force compared to traditional single-piece anchors.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The spreader bars are designed to be flexible and capable of dynamic expansion. When the fastener is inserted, the spreader bars expand radially outward to press against the surrounding material, and this expansion is facilitated by the flexible connection at the foot, allowing the anchor to adapt to the substrate and maximize anchoring force.

Inventive Principle:
Principle #15Dynamics

2Area of stationary object

If separate spreader bars are used, then full-circumferential expansion is achieved, but the structural complexity increases

Engineering Contradiction:
Improveexpansion coverageVSAvoidanchor structure
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

Multiple separate spreader bars are combined at the foot of the anchor through a flexible connection, allowing them to function as an integrated unit during expansion while maintaining their individual separate structures. This merging at the base simplifies the overall design compared to having completely independent components, while still achieving full-circumferential expansion coverage.

Inventive Principle:
Principle #5Merging (Combining)

3Force

If the anchor expands radially outward, then anchoring force increases, but the anchor may rotate during fastener insertion

Engineering Contradiction:
Improvepull-out forceVSAvoidanti-rotation stability
Core Design Contradiction:
ForceVSStability of the object's composition

Solution Approach 1:

The spreader bars are arranged asymmetrically around the circumference of the anchor, with at least two bars positioned at different angular locations. This asymmetric arrangement creates uneven expansion forces that naturally resist rotational movement during fastener insertion, while still achieving full-circumferential expansion coverage for maximum pull-out force.

Inventive Principle:
Principle #4Asymmetry

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 provides a high anchoring force and secure fastening in both solid and hollow substrates, ensuring a universal applicability with strong pull-out values across different materials.

Implementation Method 1

The screw is secured against being pulled out by the frictional connection between the dowel and the surrounding material

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a plurality of spreader bars that are flush with one another in the circumferential direction but are separate

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP3587837B1Dowel with peripherally abutting separate expanding bars
Publication Date: 2020.12.09 ADOLF WURTH GMBH & CO KG
  • EP3587837B1 patent drawingFigure 1~2
  • EP3587837B1 patent drawingFigure 3~4
  • EP3587837B1 patent drawingFigure 5~6

AI summary

Dowel (100) comprising a foot (102) with an opening (104) for inserting a fastening element (106), a head (108) and an expansion area (110) between the foot (102) and the head (108) with a plurality of expansion webs (112, 114) that are flush with each other in the circumferential direction but separate.