Expansion Anchor Bulged Zone for Lateral Load Transfer

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Solution Overview

Problem

Existing expansion anchors face challenges in providing reliable performance, especially under lateral loads, while being easy to manufacture and cost-effective, and offering additional functionality.

Innovation Solution

Incorporating a bulged zone of increased diameter on the anchor bolt, positioned rearward of the abutment zone, which enhances lateral load transfer to the surrounding hole wall without interfering with the anchoring mechanism, and improves manufacturing symmetry through cross wedge rolling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a bulged zone is added to the anchor bolt to improve lateral load transfer, then anchor performance under lateral loads is improved, but device complexity increases

Engineering Contradiction:

Improveanchor performance under lateral loadsVSAvoidstructure of anchor bolt

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The anchor bolt is divided into multiple functional zones (wedge zone, abutment zone, intermediate zone, bulged zone, rear zone) with distinct purposes. The bulged zone is specifically positioned in the rear portion of the anchor bolt to provide lateral load transfer capability without interfering with the expansion mechanism in the front portions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bulged zone provides locally increased diameter and wall bearing surface area specifically in the rear portion of the anchor bolt where lateral load transfer is needed. This localized structural modification allows the anchor bolt to handle lateral loads effectively while maintaining a simple cylindrical shape in other zones where complexity is unnecessary.

Inventive Principle:

Principle #3Local quality

2Reliability

If the bulged zone is positioned close to the abutment zone to maximize lateral load transfer, then lateral load capacity improves, but the anchoring mechanism is interfered with

Engineering Contradiction:

Improvelateral load capacityVSAvoidanchoring mechanism function

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bulged zone is positioned in the axial dimension at the rear of the anchor bolt, creating spatial separation from the abutment zone. This dimensional positioning allows the bulged zone to provide lateral load transfer without interfering with the radial expansion mechanism that occurs at the front of the anchor bolt.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Reliability

If the anchor bolt design is made asymmetric to optimize lateral load transfer, then lateral load performance improves, but manufacturing difficulty increases

Engineering Contradiction:

Improvelateral load transferVSAvoidmanufacturing process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The anchor bolt features an asymmetric design with a bulged zone positioned only in the rear portion, creating an asymmetric load transfer path that optimizes lateral load capacity while maintaining manufacturing feasibility through standard forming processes.

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

The bulged zone enhances the anchor's performance by effectively handling lateral loads and simplifies manufacturing, resulting in a cost-effective and efficient expansion anchor design.

Implementation Method 1

the bulged zone can directly transfer lateral loads into the surrounding hole wall, thereby improving anchor performance

Methodology Applied

Scientific EffectLateral load transfer: Mechanical Force

Implementation Method 2

the anchor bolt comprises a wedge zone for expanding the at least one expansion shell

Methodology Applied

Scientific EffectWedge mechanism: Wedge

Implementation Method 3

an abutment zone forming a rearward stop for the expansion shell

Methodology Applied

Scientific EffectMechanical constraint: Mechanical Force

Data Source

PatentEP3864306B1Expansion anchor with bulged zone

Publication Date: 2022.08.17 HILTI AG

Figure 1~2
Figure 3~6

AI summary

The invention relates to an expansion anchor comprising an anchor bolt, and at least one expansion shell located at the anchor bolt, wherein the anchor bolt comprises, as an integral part of the anchor bolt, a wedge zone for expanding the at least one expansion shell, an abutment zone forming a rearward stop for the expansion shell, the abutment zone being located rearwardly of the wedge zone, and a rear zone for intruding tensile force into the anchor bolt, the rear zone being located rearwardly of the abutment zone, and wherein, located between the abutment zone and the rear zone, and spaced from the abutment zone, the anchor bolt comprises a bulged zone, which radially protrudes on the anchor bolt.