Expansion Dowel With Opposite Punctures For Uniform Load

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Solution Overview

Problem

Existing expansion anchors face challenges in achieving high load values with low production costs and high reliability, while being easy to install, due to limitations in their geometric design and manufacturing processes.

Innovation Solution

A plastic expansion anchor with an expansion channel formed by two punctures from opposite areas of the shaft circumference, which overlap to form a cross-sectional expansion channel, allowing for uniform and flexible expansion, reducing friction during insertion, and enabling efficient anchoring with a simple injection molding process without a core needle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the expansion channel is formed by a single puncture, then the manufacturing process is simpler, but the expansion uniformity and load values are reduced

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidload values
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The expansion channel is segmented into multiple punctures (at least two) instead of a single puncture. These punctures are arranged to overlap in cross-section, creating separate expansion elements that expand uniformly in different directions, thereby improving load values while maintaining manufacturing simplicity through the same injection molding process

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If the expansion channel is formed by overlapping punctures from opposite areas, then the expansion uniformity improves, but the device complexity increases

Engineering Contradiction:
Improveexpansion uniformityVSAvoidgeometric design complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The punctures are positioned asymmetrically from opposite areas of the shaft circumference, creating an expansion channel configuration that is not radially symmetric. This asymmetric arrangement of multiple punctures enables uniform expansion by distributing stress differently compared to a single central puncture, while the complexity remains manageable through standard injection molding techniques

Inventive Principle:
Principle #4Asymmetry

3Reliability

If the expansion area is designed for high load values, then the anchoring reliability improves, but the production cost increases

Engineering Contradiction:
Improveanchoring reliabilityVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The design changes the geometric parameters of the expansion channel by using multiple punctures with specific overlapping arrangements. This parameter change achieves high load values and improved anchoring reliability through better expansion characteristics, while the manufacturing process remains cost-effective by using the same injection molding method without requiring additional core needles or complex tooling

Inventive Principle:
Principle #35Parameter changes

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

The design achieves improved load values through uniform and flexible expansion, reduces friction during installation, and simplifies the production process, resulting in a cost-effective and reliable anchoring solution.

Implementation Method 1

the shank in the expansion area can be expanded radially by inserting an expansion element into the expansion channel for anchoring the expansion anchor in a borehole

Methodology Applied
Scientific EffectRadial expansion: Elasticity

Data Source

PatentEP3077683B1Expansion dowel with expansion area with recesses
Publication Date: 2019.09.18 HILTI AG
  • EP3077683B1 patent drawingFigure 1~5

AI summary

The invention relates to an expansion anchor, comprising a shaft (1), which shaft has a neck region (11) and an expansion region (10), wherein the expansion region (10) is arranged at an axial offset to the neck region (11), and comprising an expansion channel (5), which passes through the neck region (11) and the expansion region (10) of the shaft (1), wherein the shaft (1) can be radially expanded in the expansion region (10) by inserting an expansion element into the expansion channel (5) in order to anchor the expansion anchor in a borehole, and wherein the expansion channel (5) is formed in the expansion region (10) by punctures (21, 31, 22, 32), which start from the shaft periphery and lead into the shaft interior. According to the invention, the expansion channel (5) is formed in at least one cross-sectional plane of the expansion region (10) by two punctures (21, 31), which start from regions of the shaft periphery that lie opposite to each other in the cross-sectional plane.