Nested Expansion Anchor Sleeves for Solid and Hollow Walls

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Solution Overview

Problem

Existing expansion dowels are ineffective in providing reliable anchoring with high holding power in both solid and hollow building materials, such as concrete and plasterboard or perforated bricks.

Innovation Solution

The expansion dowel consists of two dowel sleeves made from different plastics, with a first sleeve enclosing a second sleeve, featuring expandable connectors and free spaces that allow for radial expansion, enabling better adaptation to borehole geometry and improved load-bearing capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single anchor sleeve is used, then the structure is simple, but the anchoring reliability in both solid and hollow building materials is insufficient

Engineering Contradiction:
Improveanchoring reliabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a nested structure where the second anchor sleeve is positioned inside the first anchor sleeve, creating a dual-layer anchoring system. The first sleeve provides anchoring in solid building materials while the second sleeve provides anchoring in hollow building materials, allowing the device to adapt to different material types without requiring separate anchoring solutions.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The anchor sleeve is divided into multiple functional segments including expansion legs, connectors, and distinct sleeve sections. The first and second anchor sleeves are segmented along the longitudinal axis, with each segment serving specific anchoring functions for different building material types, enabling versatile performance through modular design.

Inventive Principle:
Principle #1Segmentation

2Force

If expandable connectors are added to enable expansion, then the expansion pressure increases, but the mobility of the connector is hindered by the anchor sleeve material

Engineering Contradiction:
Improveexpansion pressureVSAvoidconnector mobility
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The patent creates free spaces at specific locations adjacent to the connectors where no anchor sleeve material is present. These localized voids allow the connectors to move freely during expansion without being constrained by the surrounding plastic material, while the rest of the anchor sleeve maintains its structural integrity and anchoring function.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If two different plastics are used for the anchor sleeves, then the adaptability to different building materials is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvematerial adaptabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent combines the first and second anchor sleeves into a single integrated component manufactured in one piece using a two-component injection molding process. This manufacturing method allows different plastic materials to be molded together in a single operation, achieving the versatility of multiple materials while maintaining manufacturing efficiency and reducing assembly steps.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4008917B1Expansion anchor
Publication Date: 2024.10.09 FISCHERWERKE ARTUR FISCHER GMBH & CO KG
  • EP4008917B1 patent drawingFigure 1
  • EP4008917B1 patent drawingFigure 2
  • EP4008917B1 patent drawingFigure 3

AI summary

The invention relates to an expansion anchor (1) with a first anchor sleeve (2) and a second anchor sleeve (3) which together extend longitudinally (L) around an expansion channel (4). The first anchor sleeve (2) has at least two expansion legs (5) which are connected to each other by at least one expandable connector (24) such that the expansion legs (5) can be moved away from each other when an expansion element is inserted. According to the invention, a clearance (25) adjacent to the connector (24) is formed on the connector (24).