Anchor Rail Crack Initiation for Shear Strength

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Solution Overview

Problem

Existing cast-in anchor rails fail to effectively manage shear forces, leading to oblique cracks and fractures when positioned near the edge of a component, resulting in reduced load-bearing capacity under transverse forces.

Innovation Solution

Incorporating crack-initiating agents on the side walls of the anchor rail, which control the formation of two independent cracks, shifting the pressure resultant away from the surface and increasing the fracture surface area, allowing the anchor rail to be positioned closer to the edge or withstand higher transverse forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the anchor rail is positioned close to the edge of the component, then the installation flexibility is improved, but the load-bearing capacity under transverse forces deteriorates due to oblique crack formation

Engineering Contradiction:

Improveinstallation flexibilityVSAvoidload-bearing capacity under transverse forces

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The patent applies preliminary action by providing crack-initiating means (such as notches, grooves, or predefined weak zones) on the side walls of the anchor rail before installation. These pre-defined features guide the crack formation process to occur in predetermined patterns rather than random oblique paths, thereby maintaining load-bearing capacity even when positioned close to component edges.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent converts the harmful effect of crack formation under shear forces into a beneficial controlled process. By introducing crack-initiating means that create predetermined crack paths, the harmful uncontrolled oblique cracking is transformed into a controlled fracture pattern that maintains structural integrity and load-bearing capacity.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Device complexity

If traditional anchor rails are used without crack-initiating means, then the device complexity is reduced, but the load-bearing capacity under shear forces deteriorates due to uncontrolled crack formation

Engineering Contradiction:

Improvestructure simplicityVSAvoidload-bearing capacity under shear forces

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

The patent applies local quality by providing crack-initiating means only at specific locations on the side walls of the anchor rail, rather than throughout the entire structure. These localized features (notches, grooves, or weak zones at specific positions) control crack initiation without requiring complex modifications to the overall rail structure, thus maintaining relative simplicity while improving shear force resistance.

Inventive Principle:

Principle #3Local quality

3Strength

If crack-initiating means are added to the anchor rail, then the load-bearing capacity under transverse forces is improved, but the manufacturing complexity increases

Engineering Contradiction:

Improveload-bearing capacity under transverse forcesVSAvoidmanufacturing complexity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The crack-initiating means are incorporated into the anchor rail during the manufacturing process itself, such as forming notches or grooves as integral features of the rail body or attaching crack-initiating elements before the rail is installed in the component. This preliminary incorporation avoids the need for post-manufacturing modifications and simplifies the overall manufacturing process.

Inventive Principle:

Principle #10Preliminary 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

The controlled crack formation enhances the load-bearing capacity of the anchor rail by distributing the load more effectively, preventing intersecting cracks and increasing the fracture surface area, thereby improving its performance under shear force loading.

Implementation Method 1

a crack initiator is provided on at least one of the side walls... the crack-initiating means arranged on the at least one side wall ensures controlled formation of the first crack... the position of the relevant pressure resultant is shifted away from the surface by a distance defined by the crack initiating agent into the component

Methodology Applied

Scientific EffectStress concentration:

Data Source

PatentEP2478163B1Embeddable anchor rail

Publication Date: 2014.01.01 HILTI AG

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AI summary

The invention relates to a moldable anchor rail (11) having a rail body (12) and anchor elements (21) that can be fixed onto the rail body (12). The rail body (12) has a receiving chamber (13) extending in the longitudinal extension of the rail body (12) for a fastening element (6) which is accessible via an assembly opening (15) bordered by edges (14) and is bordered laterally by opposite lateral walls (16) facing one another. Each of the lateral walls (16) has a crack initiator means (26).