Expansion Anchor Closure Means for Reliable Anchoring

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Solution Overview

Problem

Existing expandable dowels without core needles face difficulties in anchoring due to the formation of expansion channels by punctures from the outside, leading to incomplete anchoring and particle interference, which complicates the setting process and reduces reliability.

Innovation Solution

Incorporating latching elements or a cover to temporarily close some punctures, preventing particle entry into the expansion channel, ensuring reliable anchoring and improved load values, particularly suitable for insulation anchors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the expansion channel is formed by punctures from the outside (without core needle), then production complexity is reduced and manufacturing cost decreases, but particle entry into the expansion channel increases leading to incomplete anchoring and reduced reliability

Engineering Contradiction:
Improveproduction simplicityVSAvoidanchoring reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The punctures are pre-formed in the expansion area before the anchor is inserted into the borehole. This preliminary formation of the expansion channel allows the anchor to be ready for expansion without requiring a core needle during production, while the subsequent closure means will prevent particle entry during the actual anchoring process

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A closure means (such as a closure element or closing mechanism) is introduced as an intermediary component to seal the punctures after the expansion channel is formed but before particles can enter. This closure means acts as a mediator that maintains the benefit of puncture-formed channels while preventing the harmful effect of particle contamination

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the expansion channel remains open for particle-free expansion, then anchoring reliability improves, but production complexity increases due to additional core needle requirements

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

Solution Approach 1:

The core needle, which is a complex production tool required in conventional anchors to form the expansion channel, is completely removed from the manufacturing process. Instead, the expansion channel is formed by simpler punctures that can be created during normal injection molding without requiring the extraction and insertion of a core needle

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If punctures are used to form the expansion channel, then manufacturing cost decreases, but particle interference increases leading to incomplete expansion and reduced load values

Engineering Contradiction:
Improvemanufacturing costVSAvoidparticle interference
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The closure means is designed to seal the punctures in advance before particles can enter the expansion channel during the anchoring process. This preliminary protective action prevents the harmful effect of particle interference while maintaining the manufacturing simplicity of using punctures instead of core needles

Inventive Principle:
Principle #9Preliminary anti-action

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

Enhances the reliability and load-bearing capacity of expandable dowels by preventing particle interference during the anchoring process, ensuring effective expansion and secure fixation in boreholes.

Implementation Method 1

latching elements are provided as closure means, which can hold the expansion area in a compressed state

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Force

Implementation Method 2

the expansion area can be radially expanded 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

PatentEP3173633B1Expansion anchor
Publication Date: 2019.04.17 HILTI AG
  • EP3173633B1 patent drawingFigure 1~3
  • EP3173633B1 patent drawingFigure 4~8

AI summary

The invention relates to an expansion anchor with a shaft (1) having a neck region (11) and an expansion region (10), wherein the expansion region (10) is arranged axially offset to the neck region (11), and an expansion channel (5) which passes through the neck region (11) and the expansion region (10) of the shaft, wherein the shaft in the expansion region (10) can be radially expanded by inserting an expansion element into the expansion channel (5) for anchoring the expansion anchor in a borehole, and wherein the expansion channel (5) in the expansion region (10) is formed by indentations (21, 31, 22, 32; 33, 34) which extend from the circumference of the shaft and lead into the interior of the shaft. According to the invention, the expansion dowel has at least one closing means for at least partially closing at least part of the indentations (21, 31, 22, 32; 33, 34).